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Asian box turtles are in serious danger of extinction in their habitat because they are part of the food base of many Asian countries such as China, where they are captured for local food markets despite captive breeding farms. North American box turtles, on the other hand, are endangered by habitat destruction. The forests converted to farmland greatly reduced the number of turtles in many states. The remaining land is often fragmented with highways and urban projects, destroying the animals' habitat. In an attempt to cross man-made additions, turtles are often killed by cars, animals, and other hazards. They are also facing population decline from a necrotizing bacterial infection first found in this species April 2011.
Another serious treatment of these animals in North America is the capture and sale of hatchling box turtles from the wild. A 3-year study conducted in Texas indicated that more than 7000 box turtles were taken from the wild for commercial trade. A similar study in Louisiana found that over a 41-month period, about 30,000 box turtles were taken from the wild for resale. Once captured, the turtles are often kept in poor conditions, in which more than half die. Those that live long enough to be sold usually suffer from conditions such as malnutrition, dehydration, and infection.
Indiana and many other states created strict laws against the collection of hatchling turtles from the wild. In many states it is illegal to keep them without a special permit. Collecting wild-hatched box turtles can cause irreversible damage to populations, because these turtles have a low reproductive rate, as they take a long time to find a mate.
Most turtle and sea-turtle societies do not recommend the use of turtles as pets for young children despite their popularity as such. Box turtles are easily stressed if touched excessively and require more care than is generally thought. Box turtles can be easily injured by dogs and cats so special care must be taken to protect them from household pets and neighborhood animals. Box turtles require an enclosed outdoor location, consistent sun exposure and a varied diet. Without this, a turtle's growth can be stunted and its immune system weakened. | Box turtle | Wikipedia | 430 | 72092111 | https://en.wikipedia.org/wiki/Box%20turtle | Biology and health sciences | Reptiles | null |
Finding box turtles in the wild and taking them as pets, even for a short period, can have detrimental effects. Box turtles want to stay within the area where they were hatched. If one is moved more than half a mile from its territory, it may not find its way back, but may spend years searching for it. This exposes the animal to danger and also disrupts the breeding cycle of which it would otherwise have been a part.
While box turtles are very popular as pets, it is important that they are preserved in the right matter. Keeping them in a more northern area where they can survive the best in ecological and physiological factor to not damage their way of living.
Taxonomy
North American box turtles
Family Emydidae
Genus Terrapene
Terrapene carolina
Eastern box turtle, Terrapene carolina carolina (Linnaeus, 1758)
Florida box turtle, Terrapene carolina bauri (Taylor, 1894)
Gulf Coast box turtle, Terrapene carolina major (Agassiz, 1857)
Three-toed box turtle, Terrapene carolina triunguis (Agassiz, 1857)
Mexican box turtle, Terrapene carolina mexicana (Gray, 1849)
Yucatán box turtle, Terrapene carolina yucatana (Boulenger, 1895)
Coahuilan box turtle, Terrapene coahuila (Schmidt & Owens, 1944)
Spotted box turtle, Terrapene nelsoni (Stejneger, 1925)
Terrapene ornata
Ornate box turtle, Terrapene ornata ornata (Agassiz, 1857)
Desert box turtle, Terrapene ornata luteola (Smith & Ramsey, 1952)
Asian box turtles
Family Geoemydidae
Genus Cuora
Amboina box turtle, Cuora amboinensis (Suckow, 1798)
Yellow-headed box turtle, Cuora aurocapitata (Luo & Zong, 1988)
Chinese box turtle, Cuora flavomarginata (Gray, 1863)
Indochinese box turtle, Cuora galbinifrons (Bourret, 1939)
McCord's box turtle, Cuora mccordi (Ernst, 1988)
Pan's box turtle, Cuora pani (Song, 1987)
Golden coin turtle, Cuora trifasciata (Bell, 1825)
Yunnan box turtle, Cuora yunnanensis (Boulenger, 1906)
Zhou's box turtle, Cuora zhoui (Zhao, 1990)
Genus Pyxidea | Box turtle | Wikipedia | 503 | 72092111 | https://en.wikipedia.org/wiki/Box%20turtle | Biology and health sciences | Reptiles | null |
Keeled box turtle, Pyxidea mouhotii (Gray, 1862)
Pyxidea mouhotii mouhotii
Pyxidea mouhotii obsti | Box turtle | Wikipedia | 40 | 72092111 | https://en.wikipedia.org/wiki/Box%20turtle | Biology and health sciences | Reptiles | null |
Climate change vulnerability is a concept that describes how strongly people or ecosystems are likely to be affected by climate change. Its formal definition is the "propensity or predisposition to be adversely affected" by climate change. It can apply to humans and also to natural systems (or ecosystems). Issues around the capacity to cope and adapt are also part of this concept. Vulnerability is a component of climate risk. It differs within communities and also across societies, regions, and countries. It can increase or decrease over time. Vulnerability is generally a bigger problem for people in low-income countries than for those in high-income countries.
Higher levels of vulnerability are found in areas with poverty, poor governance and conflict. Also, some livelihoods are more sensitive to the effects of climate change than others. Smallholder farmers, pastoralists, and fishing communities are livelihoods that may be especially vulnerable. Further drivers for vulnerability are unsustainable land and ocean use, inequity, marginalization, and historical and ongoing patterns of inequity and poor governance.
There are many different notions of what it means to be vulnerable. An important distinction is between biophysical and social vulnerability. Biophysical vulnerability is about the effects of climate hazards such as heat waves or tropical cyclones. Social vulnerability, on the other hand, is about the underlying political, institutional, economic and social factors within societies. These factors matter for how and why people are affected, and they put some people and places more at risk than others. People who are more vulnerable include for example people with low incomes, indigenous peoples, women, children, the elderly.
Tools for vulnerability assessment vary depending on the sector, the scale and the entity or system which is thought to vulnerable. For example, the Vulnerability Sourcebook is a guide for practical and scientific knowledge on vulnerability assessment. Climate vulnerability mapping helps to understand which areas are the most vulnerable. Mapping can also help to communicate climate vulnerability to stakeholders. It is useful to carry out vulnerability assessments in advance of preparing local climate adaptation plans or risk management plans. Global vulnerability assessments use spatial mapping with aggregated data for the regional or national level.
Definition
Climate change vulnerability is defined as the "propensity or predisposition to be adversely affected" by climate change. It can apply to humans but also to natural systems (ecosystems), and both are interdependent. Vulnerability is a component of climate risk. Vulnerability will be higher if the capacity to cope and adapt is low. | Climate change vulnerability | Wikipedia | 501 | 66204363 | https://en.wikipedia.org/wiki/Climate%20change%20vulnerability | Physical sciences | Climate change | Earth science |
Climate vulnerability can include a wide variety of different meanings, situations, and contexts in climate change research. It has been a central concept in academic research and IPCC assessments since 2001.
The concept was defined in the Third IPCC report (2001) as "the degree to which a system is susceptible to, and unable to cope with, adverse effects of climate change, including climate variability and extremes".
Early studies focused on biophysical vulnerability to climate change. In other words, the effects of physical climate hazards such as a heat wave or heavy rain events. This direction of research was shaped by earlier natural hazards research and it emphasised physical changes and energy flows in the landscape. It aims to quantify and measure the impacts of an event on the environment and on people. Since (biophysical) vulnerability is interpreted here as the negative outcome of climate change on people or places, it is also sometimes referred to as 'outcome vulnerability'.
An alternative framing focuses on social dimensions of vulnerability that set the context in which climate change happens. These dimensions include the political, institutional, economic and social structures that interact with the physical climate changes. For example, water privatization might affect the ability of people to respond to drought. This direction of research was shaped by human security research and they focus on the current context or 'starting point' for the social and biophysical processes. They are sometimes also referred to as 'contextual vulnerability' approaches. Research in this area focuses on analysing the factors that "put people and places at risk and reduce capacity to respond". See the section on 'Causes' below.
In the Fifth IPCC report, the social context was emphasized. It noted factors such as wealth and employment, access to technology and information, societal values and the role of institutions to resolve conflicts or develop relations among states as important. Vulnerability was defined as a characteristic of people or places independently of physical events. The report included two additional definitions, one of contextual vulnerability and one of outcome vulnerability.
Vulnerability and exposure
In the climate change context, exposure is defined as "the presence of people; livelihoods; species or ecosystems; environmental functions, services, and resources; infrastructure; or economic, social, or cultural assets in places and settings that could be adversely affected.". | Climate change vulnerability | Wikipedia | 457 | 66204363 | https://en.wikipedia.org/wiki/Climate%20change%20vulnerability | Physical sciences | Climate change | Earth science |
In earlier definitions of vulnerability to climate change (in the Third IPCC report and Fourth IPCC report) vulnerability was defined as a function of exposure, sensitivity and adaptive capacity. This changed during the Fifth IPCC cycle. In this report, exposure was defined as one of the three interacting elements of climate risk, rather than as one of the external drivers of vulnerability. This change had two main implications. First, it means that vulnerability is understood as independent of exposure (and hazard) but is contextual. Second, it means that vulnerability assessment could focus on indicators for sensitivity and adaptive capacity to understand the current system weaknesses. For example, weaknesses such as the high ground slope of a farmland or marginalization of households in a community would make people or places sensitive to climate impacts. This makes it important to select the most hazard-relevant indicators for any vulnerability assessment. For example, to assess the vulnerability of traditional coastal fishing communities to sea surge, ‘distance of dwellings from sea’ and ‘elevation of dwellings from sea level’ would be hazard-relevant indicators.
Types
Climate change vulnerability has a wide variety of different meanings and uses of the term have varied and evolved over time. The main distinction is between biophysical and social (or socioeconomic) vulnerability:
Biophysical vulnerability is about the effects of physical climate hazards such as a heat wave or heavy rain events
Social vulnerability considers the many political, institutional, economic and social structures that form the context for climate change
Biophysical or (physical) vulnerability
Early studies focused on biophysical vulnerability to climate change. In other words, the effects of physical climate hazards such as a heat wave or heavy rain events. This direction of research was shaped by earlier natural hazards research and it emphasised physical changes and energy flows in the landscape. It aims to quantify and measure the impacts of an event on the environment and on people. It plays down the role of people themselves in managing these impacts. Since (biophysical) vulnerability is interpreted here as the negative outcome of climate change on people or places, it is also sometimes referred to as 'outcome vulnerability'.
Physical vulnerability tends to focus on outcomes of monetary loss and disruptions. It is also sometimes defined as the "degree of loss" on a scale of 0 (no loss) to 1 (total loss). In this framework, for example, physical vulnerability to surface water hazards in mountain areas has been widely studied. | Climate change vulnerability | Wikipedia | 480 | 66204363 | https://en.wikipedia.org/wiki/Climate%20change%20vulnerability | Physical sciences | Climate change | Earth science |
Social (socioeconomic) vulnerability
Social vulnerability is a more people-centred, holistic perspective on how and why people are affected by climate change. Vulnerability of ecosystems and people to climate change is driven by certain unsustainable development patterns such as "unsustainable ocean and land use, inequity, marginalization, historical and ongoing patterns of inequity such as colonialism, and governance". Therefore, vulnerability is higher in some locations than in others. Certain aspects within a region increase vulnerability, for example poverty, governance challenges and violent conflict. Some types of livelihoods are regarded as particularly climate-sensitive, resulting in a higher level of climate change vulnerability. These include for example smallholder farmers, pastoralists and fishing communities.
At its basic level, a community that is economically vulnerable is one that is ill-prepared for the effects of climate change because it lacks the needed financial resources. Preparing a climate resilient society will require huge investments in infrastructure, city planning, engineering sustainable energy sources, and preparedness systems. From a global perspective, it is more likely that people living at or below poverty will be affected the most by climate change and are thus the most vulnerable, because they will have the least amount of resource dollars to invest in resiliency infrastructure. They will also have the least amount of resource dollars for cleanup efforts after more frequently occurring natural climate change related disasters.
Vulnerability for people of a certain gender or age can be caused by "systemic reproduction of historical legacies of inequality", for example as part of "(post)colonial, (post)apartheid, and poverty discrimination". Social vulnerability of people can be related to aspects that make people different from one another (gender, class, race, age, etc.), and also the situational variables (where they live, their health, who lives with them in the household, how much they earn).
Other categories
Geographic, or place-based vulnerability to climate change is an important dimension. The most geographically vulnerable locations to climate change are those that will be impacted by side effects of natural hazards, such as rising sea levels and by dramatic changes in ecosystem services, including access to food. Island nations are usually noted as more vulnerable but communities that rely heavily on a sustenance based lifestyle are also at greater risk. | Climate change vulnerability | Wikipedia | 467 | 66204363 | https://en.wikipedia.org/wiki/Climate%20change%20vulnerability | Physical sciences | Climate change | Earth science |
Around the world, climate change affects rural communities that heavily depend on their agriculture and natural resources for their livelihood. Increased frequency and severity of climate events disproportionately affects women, rural, dryland, and island communities. This leads to more drastic changes in their lifestyles and forces them to adapt to this change. It is becoming more important for local and government agencies to create strategies to react to change and adapt infrastructure to meet the needs of those impacted. Various organizations work to create adaptation, mitigation, and resilience plans that will help rural and at risk communities around the world that depend on the earth's resources to survive.
Scale
It has been estimated in 2021 that "approximately 3.3 to 3.6 billion people live in contexts that are highly vulnerable to climate change".
The vulnerability of ecosystems and people to climate change is not the same everywhere: there are marked differences among and within regions (see regions that are particularly vulnerable below). Vulnerability can also increase or decrease over time.
People who are more vulnerable
People who are more vulnerable to the effects of climate change than others include for example people with low incomes, indigenous peoples, women, children, the elderly. For example, when looking at the effects of climate change on human health, a report published in The Lancet found that the greatest impact tends to fall on the most vulnerable people such as the poor, women, children, the elderly, people with pre-existing health concerns, other minorities and outdoor workers.
There can be "structural deficits related to social, economic, cultural, political, and institutional conditions" which would explain why some parts of the population are more impacted than others. This applies for example to climate-related risks to household water security for women in remote rural regions in Burkina Faso or the urban poor in sub-Saharan Africa.
The Impact of Climate Change on Health Outcomes
Varying Racial and Ethnic Groups
The extent to which climate change can negatively impact the health outcomes of populations may vary amongst different racial and ethnic groups across the globe. It is also important in this case to note that social positions can be denoted by race or ethnicity. Therefore, there can exist a variance in health outcomes as a result of differences in exposure and accessibility to healthcare to mitigate the health damages caused by climate change. | Climate change vulnerability | Wikipedia | 461 | 66204363 | https://en.wikipedia.org/wiki/Climate%20change%20vulnerability | Physical sciences | Climate change | Earth science |
It is understood that increased exposure to high temperatures as a result of global warming can lead to acute heat-related illnesses such as heat stroke or can aggravate pre-existing conditions. In a study done in Los Angeles, California during a heat wave, it was found that African American populations were at greater risk of mortality. In fact, the mortality rate of African Americans during this 2006 heat wave was double that of the average population. Heat-related emergency department visits were also significantly increased for ethnic populations as there was a spike in emergency department visits found amongst Asian/Pacific Islander populations and African American populations.
Although some may attribute the discrepancy in mortality and hospitalization rates among ethnic groups to physiological differences between populations, not enough evidence has been provided to support this statement. Rather, studies show that these differences in health outcomes amongst different racial and ethnic groups are more likely to be the result of socioeconomic variance. Racial minorities are more likely to be socioeconomically disadvantaged and are therefore more likely to take on underpaid high-risk occupations, live in hazardous areas, and have difficulty finding the financial resources to maintain a healthy level of thermal comfort.
A study done in Phoenix, Arizona highlighted that more heat distress calls were made in neighborhoods consisting of primarily African American and low-income Hispanic populations. It is found that financially disadvantaged communities, often which are composed of ethnic minorities, have a propensity to be warmer neighborhoods despite the lack of access to means of thermal regulation.
The urban heat island effect emphasizes the fact that urban areas tend to be most impacted. During a heat wave in Oklahoma City, a study examined the urban island heat effect in varying communities. It was found that the hotter inner city region, one densely populated by minority residents, was severely inadequately equipped with air-conditioning. This inadequate access to resources that allow for thermal regulation in homes, coupled with overcrowded living spaces in low-income, minority communities can be a significant health hazard. | Climate change vulnerability | Wikipedia | 395 | 66204363 | https://en.wikipedia.org/wiki/Climate%20change%20vulnerability | Physical sciences | Climate change | Earth science |
It is also important to discuss occupational hazards when elaborating upon the impact of climate change on the health outcomes of varying racial and ethnic groups. Extreme heat can be detrimental to outdoor workers. Several studies have revealed that the agricultural workforce has been negatively affected by the growing effects of climate change. The majority of agricultural workers are from Latin America, with also a significant population who are also composed of Asian and Caribbean migrants, and people of Native American and African American descent. In the same analysis done on the 2006 heat wave in California, it was found that there was a significantly increased rate of hospitalization for cardiac-related illnesses amongst crop workers of Hispanic backgrounds as a result of occupational hazards. To mitigate this concern, more relevant occupational health and safety training programs should be set in place and working conditions should be more carefully monitored.
Language barriers may also play a role in the difference of health outcomes amongst varying ethnic groups as a result of climate change. Reduced access to English media and important public health statements as a result of linguistic barriers. This may also lead to a reduction of adaptive behavior and can put some individuals in danger of experiencing heat-related illnesses or exacerbating existing conditions.
Older Adults (65+ years)
Introduction
As global temperatures rise, extreme weather events become more frequent, and air quality worsens due to climate change, older adults (aged 65 and above) face increased risks of heat-related illnesses, chronic disease, and infectious diseases. Both physiological vulnerabilities and sociological factors compound the risk of negative health outcomes that older adults face from climate change.
Reducing vulnerability
Vulnerability can be reduced through climate change adaptation measures. For this reason, vulnerability is often framed in dialogue with climate change adaptation. Furthermore, measures that reduce poverty, gender inequality, bad governance and violent conflict would also reduce vulnerability. And finally, vulnerability would be reduced for everyone if decisive action on climate change was taken (climate change mitigation) so that the effects of climate change are less severe.
Climate change adaptation
Climate resilience
Climate justice | Climate change vulnerability | Wikipedia | 407 | 66204363 | https://en.wikipedia.org/wiki/Climate%20change%20vulnerability | Physical sciences | Climate change | Earth science |
Equity is another essential component of vulnerability and is closely tied to issues of environmental justice and climate justice. As the most vulnerable communities are likely to be the most heavily impacted, a climate justice movement is coalescing in response. There are many aspects of climate justice that relate to vulnerability and resiliency. The frameworks are similar to other types of justice movements and include contractarianism which attempts to allocate the most benefits for the poor, utilitarianism which seeks to find the most benefits for the most people, egalitarianism which attempts to reduce inequality, and libertarianism which emphasizes a fair share of burden but also individual freedoms.
Examples of climate justices approach can be seen by the work done by the United States government on both federal and local levels. On a federal level, The Environmental Protection Agency works toward the goals of Executive Order 12898, Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations. E.O 12898 states the goals of implementing federal environmental justice initiatives that work toward aiding minority and low-income communities that suffer from disproportionate environmental or human health impacts. To alleviate environmental and health challenges within many American communities the U.S Environmental Protection Agency has implemented projects region by region to ensure the development of environmental justice. These developments include but are not limited to population vulnerability, green space development locally as well as federally, and the reevaluation of environmentally disproportionate health burdens.
Climate Vulnerable Forum
Measurement tools
Vulnerability assessment is important because it provides information that can be used to develop management actions in response to climate change. Climate change vulnerability assessments and tools are available at all scales. Macro-scale vulnerability assessment often uses indices. Modelling and participatory approaches are also in use. Global vulnerability assessments are based on spatial mapping using aggregated data for the regional or national level. | Climate change vulnerability | Wikipedia | 378 | 66204363 | https://en.wikipedia.org/wiki/Climate%20change%20vulnerability | Physical sciences | Climate change | Earth science |
Assessments are also done at sub-national and sectoral level, and also increasingly for cities on an urban district or neighbourhood scale. Vulnerability assessment is also done for local communities to evaluate where and how communities and livelihoods are vulnerable to climate change. Studies can vary widely in scope and scale— for example the World Bank and Ministry of Economy of Fiji commissioned a report for the whole country in 2017-18 while the Rochester, New York commissioned a much more local report for the city in 2018. Or, for example, NOAA Fisheries commissioned Climate Vulnerability assessments for marine fishers in the United States. In some cases vulnerability assessment is done in advance of preparing local climate adaptation plans or risk management plans.
Indicators and indices
Global indices for climate change vulnerability include the ND-GAIN Country Index, which measures national climate vulnerability globally, INFORM Risk Index and the WorldRiskIndex, which include social vulnerability indices. Indicator approaches are also used at national and sub-national levels. They use a composite index of many individual quantifiable indicators. To generate the index value or 'score', most often a simple average is calculated across a set of standardized values. However, sometimes weighting is done according what are thought to be the most important determinants of vulnerability.
Climate vulnerability tracking starts identifying the relevant information, preferably open access, produced by state or international bodies at the scale of interest. Then a further effort to make the vulnerability information freely accessible to all development actors is required. Vulnerability tracking has many applications. It constitutes an indicator for the monitoring and evaluation of programs and projects for resilience and adaptation to climate change. Vulnerability tracking is also a decision making tool in regional and national adaptation policies.
Vulnerability curves
Climate vulnerability curves are a method of assessing physical vulnerability on various sectors such as agriculture, infrastructure, health, and ecosystems. They show a relationship between different levels of climate-related hazards (like extreme temperatures, sea-level rise, or intense precipitation) and the effects, or damages. | Climate change vulnerability | Wikipedia | 400 | 66204363 | https://en.wikipedia.org/wiki/Climate%20change%20vulnerability | Physical sciences | Climate change | Earth science |
Tools for vulnerability assessment
Similarly as for climate risk assessment, tools for vulnerability assessment vary depending on the sector, the scale at which the study is being carried out, and the entity or system which is thought to vulnerable. Modelling and other participatory tools include WEAP for understanding water resource vulnerabilities and assessing adaptation options. The Vulnerability Sourcebook is a guide for practical and scientific knowledge on vulnerability assessment. Climate vulnerability mapping is also used to understand which areas are the most geographically vulnerable. A systematic review published in 2019 found 84 studies focused on the use of mapping to communicate and do analysis of climate vulnerability.
By region and country
All regions of the world are vulnerable to climate change but to a different degree. With high confidence, researchers concluded in 2001 that developing countries would tend to be more vulnerable to climate change than developed countries. Based on development trends in 2001, scientists have found that few developing countries would have the capacity to efficiently adapt to climate change. This was partly due to their low adaptive capacity and the high costs of adaptation in proportion to their GDP.
The Arctic is extremely vulnerable to climate change. It was predicted in 2007 that there would be major ecological, sociological, and economic impacts in the region. Among those being disproportionately impacted by issues regarding climate change have been the Indigenous peoples of the Arctic, such as the Inuit, Yupik, and Saami, who are particularly vulnerable. Traditional livelihoods, including hunting, fishing, and reindeer herding, are threatened by changes in ice conditions, wildlife migration patterns, and habitat availability. Additionally, thawing permafrost can damage infrastructure and contaminate water sources, posing health and safety risks to communities.
Small island Developing States are particularly vulnerable to climate change. Partly this was attributed to their low adaptive capacity and the high costs of adaptation in proportion to their GDP. Climate change leads to more frequent and intense extreme weather events such as hurricanes, typhoons, and cyclones. Small islands are especially susceptible to these events, which can cause widespread destruction, loss of life, and economic setbacks.
In comparison, the climate vulnerability of Europe is lower than in developing countries. This was attributed to Europe's high GNP, stable growth, stable population, and well-developed political, institutional, and technological support systems. | Climate change vulnerability | Wikipedia | 463 | 66204363 | https://en.wikipedia.org/wiki/Climate%20change%20vulnerability | Physical sciences | Climate change | Earth science |
Injury is physiological damage to the living tissue of any organism, whether in humans, in other animals, or in plants.
Injuries can be caused in many ways, including mechanically with penetration by sharp objects such as teeth or with blunt objects, by heat or cold, or by venoms and biotoxins. Injury prompts an inflammatory response in many taxa of animals; this prompts wound healing. In both plants and animals, substances are often released to help to occlude the wound, limiting loss of fluids and the entry of pathogens such as bacteria. Many organisms secrete antimicrobial chemicals which limit wound infection; in addition, animals have a variety of immune responses for the same purpose. Both plants and animals have regrowth mechanisms which may result in complete or partial healing over the injury. Cells too can repair damage to a certain degree.
Taxonomic range
Animals
Injury in animals is sometimes defined as mechanical damage to anatomical structure, but it has a wider connotation of physical damage with any cause, including drowning, burns, and poisoning. Such damage may result from attempted predation, territorial fights, falls, and abiotic factors.
Injury prompts an inflammatory response in animals of many different phyla; this prompts coagulation of the blood or body fluid, followed by wound healing, which may be rapid, as in the cnidaria. Arthropods are able to repair injuries to the cuticle that forms their exoskeleton to some extent.
Animals in several phyla, including annelids, arthropods, cnidaria, molluscs, nematodes, and vertebrates are able to produce antimicrobial peptides to fight off infection following an injury.
Humans
Injury in humans has been studied extensively for its importance in medicine. Much of medical practice, including emergency medicine and pain management, is dedicated to the treatment of injuries. The World Health Organization has developed a classification of injuries in humans by categories including mechanism, objects/substances producing injury, place of occurrence, activity when injured and the role of human intent. In addition to physical harm, injuries can cause psychological harm, including post-traumatic stress disorder.
Plants | Injury | Wikipedia | 443 | 74872973 | https://en.wikipedia.org/wiki/Injury | Biology and health sciences | Illness and injury | null |
In plants, injuries result from the eating of plant parts by herbivorous animals including insects and mammals, from damage to tissues by plant pathogens such as bacteria and fungi, which may gain entry after herbivore damage or in other ways, and from abiotic factors such as heat, freezing, flooding, lightning, and pollutants such as ozone. Plants respond to injury by signalling that damage has occurred, by secreting materials to seal off the damaged area, by producing antimicrobial chemicals, and in woody plants by regrowing over wounds.
Cell injury
Cell injury is a variety of changes of stress that a cell suffers due to external as well as internal environmental changes. Amongst other causes, this can be due to physical, chemical, infectious, biological, nutritional or immunological factors. Cell damage can be reversible or irreversible. Depending on the extent of injury, the cellular response may be adaptive and where possible, homeostasis is restored. Cell death occurs when the severity of the injury exceeds the cell's ability to repair itself. Cell death is relative to both the length of exposure to a harmful stimulus and the severity of the damage caused. | Injury | Wikipedia | 240 | 74872973 | https://en.wikipedia.org/wiki/Injury | Biology and health sciences | Illness and injury | null |
Synthetic biopolymers are human-made copies of biopolymers obtained by abiotic chemical routes. Synthetic biopolymer of different chemical nature have been obtained, including polysaccharides, glycoproteins, peptides and proteins, polyhydroxoalkanoates, polyisoprenes.
Synthesis of biopolymer
The high molecular weight of biopolymers make their synthesis inherently laborious. Further challenges can arise from specific spatial arrangement adopted by the natural biopolymer, which may be vital for its properties/activity but not easily reproducible in the synthetic copy. Despite this, chemical approaches to obtain biopolymer are highly desirable to overcome issues arising from low abundance of the target biopolymer in Nature, the need for cumbersome isolation processes or high batch-to-batch variability or inhomogeneity of the naturally-sourced species.
Examples of synthetic biopolymers obtained by chemical routes
cis-1,4-polyisoprene (synthetic analogue of rubber) and trans-1,4-polyisoprene (synthetic analogue of gutta percha) are obtained by coordination polymerisation using suitable Ziegler-Natta catalysts.
Polyhydroxoalkanoates such as poly(3-hydroxobutyrate), poly(hydroxovaleric acid) etc. obtained by polycondensation and polyaddition. Low-molecular weight polylactide and other polyglycolides can also be obtained by chemical synthesis.
Oligonucleotides and polynucleotides (DNA or RNA) can be obtain by chemical synthesis through a variety of established approaches.
A variety of proteins have been obtained by chemical synthesis. A successful approach relies on native chemical ligation, which achieves the synthesis of proteins by linking shorter unprotected peptides. This strategy allowed to obtain, amongst many others, proteins such as insulin-like growth factor 1, the precursor of Aequorea green fluorescent protein and the influenza A virus M2 membrane protein.
Examples of biopolymers obtained by chemoenzymatic routes | Synthetic biopolymer | Wikipedia | 439 | 61243379 | https://en.wikipedia.org/wiki/Synthetic%20biopolymer | Technology | Biotechnology | null |
Polyhydroxoalkanoates and polyesters obtained by enzyme-assisted esterification using lipases.
Heparin, heparan sulfate and other glycosaminoglycans and plant glycans.
Polysaccharides such as cellulose, amylose, chitin and derivatives
Natural and non-natural polynucleotides can be successfully obtained by enzyme-assisted synthesis using ligase- or polymerase-based approaches and template-assisted polymerisation.
Human-made biopolymers obtained through approaches that involve genetic engineering or recombinant DNA technology are different from synthetic biopolymers and should be referred to as artificial biopolymer (e.g., artificial protein, artificial polynucleotide, etc.).
Applications of synthetic biopolymers
As their natural analogues, synthetic biopolymers find applications in numerous fields, including materials for commodities, drug delivery, tissue engineering, therapeutic and diagnostic applications. | Synthetic biopolymer | Wikipedia | 202 | 61243379 | https://en.wikipedia.org/wiki/Synthetic%20biopolymer | Technology | Biotechnology | null |
The electric eels are a genus, Electrophorus, of neotropical freshwater fish from South America in the family Gymnotidae. They are known for their ability to stun their prey by generating electricity, delivering shocks at up to 860 volts. Their electrical capabilities were first studied in 1775, contributing to the invention of the electric battery in 1800.
Despite their name, electric eels are not closely related to the true eels (Anguilliformes) but are members of the electroreceptive knifefish order Gymnotiformes. This order is more closely related to catfish. In 2019, electric eels were split into three species: for more than two centuries before that, the genus was believed to be monotypic, containing only Electrophorus electricus.
They are nocturnal, obligate air-breathing animals, with poor vision complemented by electrolocation; they mainly eat fish. Electric eels grow for as long as they live, adding more vertebrae to their spinal column. Males are larger than females. Some captive specimens have lived for over 20 years.
Evolution
Taxonomy
When the species now defined as Electrophorus electricus was described by Carl Linnaeus in 1766, based on early field research by Europeans in South America and specimens sent back to Europe for study, he used the name Gymnotus electricus, placing it in the same genus as Gymnotus carapo (the banded knifefish). He noted that the fish is from the rivers of Surinam, that it causes painful shocks, and that it had small pits around the head.
In 1864, Theodore Gill moved the electric eel to its own genus, Electrophorus.
The name is from the Greek ( 'amber, a substance able to hold static electricity'), and ( 'I carry'), giving the meaning 'electricity bearer'. In 1872, Gill decided that the electric eel was sufficiently distinct to have its own family, Electrophoridae. In 1998, Albert and Campos-da-Paz lumped the Electrophorus genus with the family Gymnotidae, alongside Gymnotus, as did Ferraris and colleagues in 2017.
In 2019, C. David de Santana and colleagues divided E. electricus into three species based on DNA divergence, ecology and habitat, anatomy and physiology, and electrical ability. The three species are E. electricus (now in a narrower sense than before), and the two new species E. voltai and E. varii.
Phylogeny | Electric eel | Wikipedia | 501 | 61262925 | https://en.wikipedia.org/wiki/Electric%20eel | Biology and health sciences | Fishes | null |
Electric eels form a clade of strongly electric fishes within the order Gymnotiformes, the South American knifefishes. Electric eels are thus not closely related to the true eels (Anguilliformes). The lineage of the Electrophorus genus is estimated to have split from its sister taxon Gymnotus sometime in the Cretaceous. Most knifefishes are weakly electric, capable of active electrolocation but not of delivering shocks. Their relationships, as shown in the cladogram, were analysed by sequencing their mitochondrial DNA in 2019. Actively electrolocating fish are marked with a small yellow lightning flash . Fish able to deliver electric shocks are marked with a red lightning flash .
Species
There are three described species in the genus, not differing significantly in body shape or coloration:
Electrophorus electricus This, the type species, has a U-shaped head, with a flattened skull and cleithrum.
Electrophorus voltai This species is the strongest bioelectricity generator in nature, capable of generating 860 V. Like E. electricus, this species has a flattened skull and cleithrum but the head is more egg-shaped.
Electrophorus varii Compared to the other two species, this one has a thicker skull and cleithrum but the head shape is more variable.
E. varii appears to have diverged from the other species around 7.1 mya during the late Miocene, while E. electricus and E. voltai may have split around 3.6 mya during the Pliocene.
Ecology
The three species have largely non-overlapping distributions in the northern part of South America. E. electricus is northern, confined to the Guiana Shield, while E. voltai is southern, ranging from the Brazilian shield northwards; both species live in upland waters. E. varii is central, largely in the lowlands. The lowland region of E. varii is a variable environment, with habitats ranging from streams through grassland and ravines to ponds, and large changes in water level between the wet and dry seasons. All live on muddy river bottoms and sometimes swamps, favouring areas in deep shade. They can tolerate water low in oxygen as they swim to the surface to breathe air. | Electric eel | Wikipedia | 455 | 61262925 | https://en.wikipedia.org/wiki/Electric%20eel | Biology and health sciences | Fishes | null |
Electric eels are mostly nocturnal. E. voltai mainly eats fish, in particular the armoured catfish Megalechis thoracata. A specimen of E. voltai had a caecilian (a legless amphibian), Typhlonectes compressicauda, in its stomach; it is possible that this means that the species is resistant to the caecilian's toxic skin secretions. E. voltai sometimes hunts in packs; and have been observed targeting a shoal of tetras, then herding them and launching joint strikes on the closely packed fish. The other species, E. varii, is also a fish predator; it preys especially on Callichthyidae (armoured catfishes) and Cichlidae (cichlids).
Biology
General biology
Electric eels have long, stout bodies, being somewhat cylindrical at the front but more flattened towards the tail end. E. electricus can reach in length, and in weight. The mouth is at the front of the snout, and opens upwards. They have smooth, thick, brown-to-black skin with a yellow or red underbelly and no scales. The pectoral fins each possess eight tiny radial bones at the tip.
They have over 100 precaudal vertebrae (excluding the tail), whereas other gymnotids have up to 51 of these; there can be as many as 300 vertebrae in total.
There is no clear boundary between the tail fin and the anal fin, which extends much of the length of the body on the underside and has over 400 bony rays. Electric eels rely on the wave-like movements of their elongated anal fin to propel themselves through the water. | Electric eel | Wikipedia | 347 | 61262925 | https://en.wikipedia.org/wiki/Electric%20eel | Biology and health sciences | Fishes | null |
Electric eels get most of their oxygen by breathing air using buccal pumping. This enables them to live in habitats with widely varying oxygen levels including streams, swamps, and pools. Uniquely among the gymnotids, the buccal cavity is lined with a frilled mucosa which has a rich blood supply, enabling gas exchange between the air and the blood. About every two minutes, the fish takes in air through the mouth, holds it in the buccal cavity, and expels it through the opercular openings at the sides of the head. Unlike in other air-breathing fish, the tiny gills of electric eels do not ventilate when taking in air. The majority of carbon dioxide produced is expelled through the skin. These fish can survive on land for some hours if their skin is wet enough.
Electric eels have small eyes and poor vision. They are capable of hearing via a Weberian apparatus, which consists of tiny bones connecting the inner ear to the swim bladder. All of the vital organs are packed in near the front of the animal, taking up only 20% of space and sequestered from the electric organs.
Electrophysiology
Electric eels can locate their prey using electroreceptors derived from the lateral line organ in the head. The lateral line itself is mechanosensory, enabling them to sense water movements created by animals nearby. The lateral line canals are beneath the skin, but their position is visible as lines of pits on the head. Electric eels use their high frequency-sensitive tuberous receptors, distributed in patches over the body, for hunting other knifefish.
Electric eels have three pairs of electric organs, arranged longitudinally: the main organ, Hunter's organ, and Sachs' organ. These organs give electric eels the ability to generate two types of electric organ discharges: low voltage and high voltage. The organs are made of electrocytes, modified from muscle cells. Like muscle cells, the electric eel's electrocytes contain the proteins actin and desmin, but where muscle cell proteins form a dense structure of parallel fibrils, in electrocytes they form a loose network. Five different forms of desmin occur in electrocytes, compared to two or three in muscle, but its function in electrocytes remained unknown as of 2017. | Electric eel | Wikipedia | 466 | 61262925 | https://en.wikipedia.org/wiki/Electric%20eel | Biology and health sciences | Fishes | null |
Potassium channel proteins involved in electric organ discharge, including KCNA1, KCNH6, and KCNJ12, are distributed differently among the three electric organs: most such proteins are most abundant in the main organ and least abundant in Sachs's organ, but KCNH6 is most abundant in Sachs's organ. The main organ and Hunter's organ are rich in the protein calmodulin, involved in controlling calcium ion levels. Calmodulin and calcium help to regulate the voltage-gated sodium channels that create the electrical discharge. These organs are also rich in sodium potassium ATPase, an ion pump used to create a potential difference across cell membranes.
The maximum discharge from the main organ is at least 600 volts, making electric eels the most powerful of all electric fishes. Freshwater fishes like the electric eel require a high voltage to give a strong shock because freshwater has high resistance; powerful marine electric fishes like the torpedo ray give a shock at much lower voltage but a far higher current. The electric eel produces its strong discharge extremely rapidly, at a rate of as much as 500 Hertz, meaning that each shock lasts only about two milliseconds. To generate a high voltage, an electric eel stacks some 6,000 electrocytes in series (longitudinally) in its main organ; the organ contains some 35 such stacks in parallel, on each side of the body. The ability to produce high-voltage, high-frequency pulses in addition enables the electric eel to electrolocate rapidly moving prey. The total electric current delivered during each pulse can reach about 1 ampere.
It remains unclear why electric eels have three electric organs but basically produce two types of discharge, to electrolocate or to stun. In 2021, Jun Xu and colleagues stated that Hunter's organ produces a third type of discharge at a middle voltage of 38.5 to 56.5 volts. Their measurements indicate that this is produced just once, for less than 2 milliseconds, after the low-voltage discharge of Sachs's organ and before the high-voltage discharge of the main organ. They believed that this is insufficient to stimulate a response from the prey, so they suggested it may have the function of co-ordination within the electric eel's body, perhaps by balancing the electrical charge, but state that more research is needed. | Electric eel | Wikipedia | 472 | 61262925 | https://en.wikipedia.org/wiki/Electric%20eel | Biology and health sciences | Fishes | null |
When an electric eel identifies prey, its brain sends a nerve signal to the electric organ; the nerve cells involved release the neurotransmitter chemical acetylcholine to trigger an electric organ discharge. This opens ion channels, allowing sodium to flow into the electrocytes, reversing the polarity momentarily. The discharge is terminated by an outflow of potassium ions through a separate set of ion channels. By causing a sudden difference in electric potential, it generates an electric current in a manner similar to a battery, in which cells are stacked to produce a desired total voltage output. It has been suggested that Sachs' organ is used for electrolocation; its discharge is of nearly 10 volts at a frequency of around 25 Hz. The main organ, supported by Hunter's organ in some way, is used to stun prey or to deter predators; it can emit signals at rates of several hundred hertz. Electric eels can concentrate the discharge to stun prey more effectively by curling up and making contact with the prey at two points along the body. It has also been suggested that electric eels can control their prey's nervous systems and muscles via electrical pulses, keeping prey from escaping, or forcing it to move so they can locate it, but this has been disputed. In self-defence, electric eels have been observed to leap from the water to deliver electric shocks to animals that might pose a threat. The shocks from leaping electric eels are powerful enough to drive away animals as large as horses.
Life cycle
Electric eels reproduce during the dry season, from September to December. During this time, male-female pairs are seen in small pools left behind after water levels drop. The male makes a nest using his saliva and the female deposits around 1,200 eggs for fertilisation. Spawn hatch seven days later and mothers keep depositing eggs periodically throughout the breeding season, making them fractional spawners. When they reach , the hatched larvae consume any leftover eggs, and after they reach they begin to eat other foods. Electric eels are sexually dimorphic, males becoming reproductively active at in length and growing larger than females; females start to reproduce at a body length of around . The adults provide prolonged parental care lasting four months. E. electricus and E. voltai, the two upland species which live in fast-flowing rivers, appear to make less use of parental care. The male provides protection for both the young and the nest. Captive specimens have sometimes lived for over 20 years. | Electric eel | Wikipedia | 508 | 61262925 | https://en.wikipedia.org/wiki/Electric%20eel | Biology and health sciences | Fishes | null |
As the fish grow, they continually add more vertebrae to their spinal column. The main organ is the first electric organ to develop, followed by Sachs' organ and then Hunter's organ. All the electric organs are differentiated by the time the body reaches a length of . Electric eels are able to produce electrical discharges when they are as small as .
Interactions with humans
Early research
The first written mention of the electric eel or ('the one that numbs' in Tupi) is in records by the Jesuit priest Fernão Cardim in 1583.
The naturalists Bertrand Bajon, a French military surgeon in French Guiana, and the Jesuit in the River Plate basin, conducted early experiments on the numbing discharges of electric eels in the 1760s. In 1775, the "torpedo" (the electric ray) was studied by John Walsh; both fish were dissected by the surgeon and anatomist John Hunter. Hunter informed the Royal Society that "Gymnotus Electricus[...] appears very much like an eel[...] but it has none of the specific properties of that fish." He observed that there were "two pair of these [electric] organs, a larger [the main organ] and a smaller [Hunter's organ]; one being placed on each side", and that they occupied "perhaps[...] more than one-third of the whole animal [by volume]". He described the structure of the organs (stacks of electrocytes) as "extremely simple and regular, consisting of two parts; viz. flat partitions or septa, and cross divisions between them." He measured the electrocytes as thick in the main organ, and thick in Hunter's organ. | Electric eel | Wikipedia | 354 | 61262925 | https://en.wikipedia.org/wiki/Electric%20eel | Biology and health sciences | Fishes | null |
Also in 1775, the American physician and politician Hugh Williamson, who had studied with Hunter, presented a paper "Experiments and observations on the Gymnotus Electricus, or electric eel" at the Royal Society. He reported a series of experiments, such as "7. In order to discover whether the eel killed those fish by an emission of the same [electrical] fluid with which he affected my hand when I had touched him, I put my hand into the water, at some distance from the eel; another cat-fish was thrown into the water; the eel swam up to it ... [and] gave it a shock, by which it instantly turned up its belly, and continued motionless; at that very instant I felt such a sensation in the joints of my fingers as in experiment 4." and "12. Instead of putting my hand into the water, at a distance from the eel, as in the last experiment, I touched its tail, so as not to offend it, while my assistant touched its head more roughly; we both received a severe shock."
The studies by Williamson, Walsh, and Hunter appear to have influenced the thinking of Luigi Galvani and Alessandro Volta. Galvani founded electrophysiology, with research into how electricity makes a frog's leg twitch; Volta began electrochemistry, with his invention of the electric battery.
In 1800, the explorer Alexander von Humboldt joined a group of indigenous people who went fishing with horses, some thirty of which they chased into the water. The pounding of the horses' hooves, he noted, drove the fish, up to long out of the mud and prompted them to attack, rising out of the water and using their electricity to shock the horses. He saw two horses stunned by the shocks and then drowned. The electric eels, having given many shocks, "now require long rest and plenty of nourishment to replace the loss of galvanic power they have suffered", "swam timidly to the bank of the pond", and were easily caught using small harpoons on ropes. Humboldt recorded that the people did not eat the electric organs, and that they feared the fish so much that they would not fish for them in the usual way. | Electric eel | Wikipedia | 451 | 61262925 | https://en.wikipedia.org/wiki/Electric%20eel | Biology and health sciences | Fishes | null |
In 1839, the chemist Michael Faraday extensively tested the electrical properties of an electric eel imported from Surinam. For a span of four months, he measured the electrical impulses produced by the animal by pressing shaped copper paddles and saddles against the specimen. Through this method, he determined and quantified the direction and magnitude of electric current, and proved that the animal's impulses were electrical by observing sparks and deflections on a galvanometer. He observed the electric eel increasing the shock by coiling about its prey, the prey fish "representing a diameter" across the coil. He likened the quantity of electric charge released by the fish to "the electricity of a Leyden battery of fifteen jars, containing of glass coated on both sides, charged to its highest degree".
The German zoologist Carl Sachs was sent to Latin America by the physiologist Emil du Bois-Reymond, to study the electric eel; he took with him a galvanometer and electrodes to measure the fish's electric organ discharge, and used rubber gloves to enable him to catch the fish without being shocked, to the surprise of the local people. He published his research on the fish, including his discovery of what is now called Sachs' organ, in 1877.
Artificial electrocytes
The large quantity of electrocytes available in the electric eel enabled biologists to study the voltage-gated sodium channel in molecular detail. The channel is an important mechanism, as it serves to trigger muscle contraction in many species, but it is hard to study in muscle as it is found in extremely small amounts. In 2008, Jian Xu and David Lavan designed artificial cells that would be able to replicate the electrical behaviour of electric eel electrocytes. The artificial electrocytes would use a calculated selection of conductors at nanoscopic scale. Such cells would use ion transport as electrocytes do, with a greater output power density, and converting energy more efficiently. They suggest that such artificial electrocytes could be developed as a power source for medical implants such as retinal prostheses and other microscopic devices. They comment that the work "has mapped out changes in the system level design of the electrocyte" that could increase both energy density and energy conversion efficiency. In 2009, they made synthetic protocells which can provide about a twentieth of the energy density of a lead–acid battery, and an energy conversion efficiency of 10%. | Electric eel | Wikipedia | 489 | 61262925 | https://en.wikipedia.org/wiki/Electric%20eel | Biology and health sciences | Fishes | null |
In 2016, Hao Sun and colleagues described a family of electric eel-mimicking devices that serve as high output voltage electrochemical capacitors. These are fabricated as flexible fibres that can be woven into textiles. Sun and colleagues suggest that the storage devices could serve as power sources for products such as electric watches or light-emitting diodes. | Electric eel | Wikipedia | 71 | 61262925 | https://en.wikipedia.org/wiki/Electric%20eel | Biology and health sciences | Fishes | null |
Bird wings are a paired forelimb in birds. The wings give the birds the ability to fly, creating lift.
Terrestrial flightless birds have reduced wings or none at all (for example, moa). In aquatic flightless birds (penguins), wings can serve as flippers.
Anatomy
Like most other tetrapods, the forelimb of birds consists of the shoulder (with the humerus), the forearm (with the ulna and the radius), and the hand.
The hand of birds is substantially transformed: some of its bones have been reduced, and some others have merged with each other. Three bones of the metacarpus and part of the carpal bones merge into a carpometacarpus. The bones of three fingers are attached to it. The frontmost one bears an alula—a group of feathers that act like the slats of an airplane. Usually, this finger has one phalanx bone, the next has two, and the back has one (but some birds have one more phalanx on the first two fingers—the claw).
Finger identity problem
The bones of three fingers are preserved in the bird wing. The question of which fingers they are has been discussed for about 150 years, and an extensive literature is devoted to it. The anatomical, paleontological, and molecular data suggests that these are fingers 1–3, but embryological data suggests that these are actually fingers 2–4. Several hypotheses have been proposed to explain this discrepancy. Most likely, in birds, finger buds 2–4 began to follow the genetic program for the development of fingers 1–3.
Wing shape
The shape of the wing is important in determining the flight capabilities of a bird. Different shapes correspond to different trade-offs between advantages such as speed, low energy use, and maneuverability.
Two important parameters are the aspect ratio and wing loading. Aspect ratio is the ratio of wingspan to the mean of its chord (or the square of the wingspan divided by wing area). Wing loading is the ratio of weight to wing area.
Most kinds of bird wings can be grouped into four types, with some falling between two of these types. These types of wings are elliptical wings, high-speed wings, high aspect ratio wings and soaring wings with slots. | Bird wing | Wikipedia | 468 | 64767216 | https://en.wikipedia.org/wiki/Bird%20wing | Biology and health sciences | External anatomy and regions of the body | Biology |
Elliptical wings
Elliptical wings are rounded and short. This type of wing allows for tight maneuvering in confined spaces such as dense vegetation. Elliptical wings are common in forest raptors (such as Accipiter hawks), and many passerines, particularly non-migratory ones (migratory species have longer wings). They are also common in species that use a rapid takeoff to evade predators, such as pheasants and partridges.
High speed wings
High-speed wings are short, pointed wings that when combined with a heavy wing loading and rapid wingbeats provide an energetically expensive, but high-speed flight. This type of wing is present in fast-flying birds such as ducks. Birds that use their wings to "fly" underwater such as the auks also have small and elongated wings.
The peregrine falcon has the highest recorded dive speed of 242 mph (389 km/h). Peregrine falcons have relatively large wings but they partially close their wings during dives. The fastest straight, powered flight is the spine-tailed swift at 105 mph (170 km/h).
High aspect ratio wings
High aspect ratio (elongated) wings confer high flight efficiency for flights of long duration. When combined with a low wing loading, they are used for slow flight. This may take the form of almost hovering (as used by kestrels, terns and nightjars) or in soaring and gliding flight, particularly the dynamic soaring used by seabirds, which takes advantage of wind speed variation at different altitudes (wind shear) above ocean waves to provide lift. Low-speed flight is also important for birds that plunge-dive for fish.
Soaring wings with deep slots
These wings are favored by larger species of inland birds, such as eagles, vultures, pelicans, and storks. The slots at the end of the wings, between the primaries, reduce the induced drag and wingtip vortices by "capturing" the energy in air flowing from the lower to upper wing surface at the tips, whilst the shorter size of the wings aids in takeoff (high aspect ratio wings require a long taxi to get airborne). | Bird wing | Wikipedia | 435 | 64767216 | https://en.wikipedia.org/wiki/Bird%20wing | Biology and health sciences | External anatomy and regions of the body | Biology |
Asteriornis ("Asteria's bird") is an extinct genus of bird from the Late Cretaceous of Belgium which is known from a single species, Asteriornis maastrichtensis. It was closely related to birds of the extant superorder Galloanserae such as chickens and ducks. Members of the genus were small, long-legged birds (~) that lived near the coastline and co-existed with more "primitive" types of birds such as Ichthyornis. Asteriornis is one of the oldest-known birds irrefutably belonging to the group Neornithes, which encompasses all modern birds. It possesses characteristics of both galliformes (chicken-like birds) and anseriformes (duck-like birds), indicating its position as a close relative of the last common ancestor for both groups.
Asteriornis may shed light on why Neornithes were the only dinosaurs to survive the Cretaceous–Paleogene extinction event. Its coexistence with non-neornithean birds such as Ichthyornis implies that competition was not a primary factor for the extinction of non-neornitheans, which resembled modern birds in most respects but died out with other non-avian dinosaurs. Small size, a terrestrial lifestyle, and a generalist diet have all been inferred as ecological advantages possessed by early neornithes, allowing them to survive and diversify in the wake of the extinction. Asteriornis fulfills these qualities, suggesting that such suspicions were justified. Asteriornis is also evidence against a different hypothesis stating that modern birds originated from southern continents. This was supported by biogeographic ancestral reconstructions using phylogenies and the discovery of Vegavis (a possible neornithean from Antarctica), but Asteriornis's presence in Europe suggests that modern birds may have been widespread in northern continents in their early evolution. | Asteriornis | Wikipedia | 400 | 63413093 | https://en.wikipedia.org/wiki/Asteriornis | Biology and health sciences | Prehistoric birds | Animals |
Discovery and naming
Asteriornis is based on specimen NHMM 2013 008, held in the Maastricht Natural History Museum (Dutch: Natuurhistorisch Museum Maastricht), which consists of an almost complete skull and fragments of leg bones and a radius. It was retrieved from four blocks of sediment found at the CBR-Romontbos quarry near Eben-Emael in the Maastricht Formation of Belgium, and was first unearthed in 2000, by amateur paleontologist Maarten van Dinther, who donated it to the museum. This geological formation is the namesake of the Maastrichtian stage, which was the last stage of the Cretaceous period and the Mesozoic era. It is dated to around 66.8 to 66.7 million years old, less than a million years before the arrival of the asteroid that caused the Cretaceous–Paleogene extinction event, killed off all non-avian dinosaurs (and many other animals), and began the Cenozoic era.
The genus name, Asteriornis, was constructed from ornis, the Greek word for bird, and from Asteria, a Greek goddess who was associated with falling stars, and about whom there is a famous myth in which she transforms herself into a quail. The Asteri part of genus name thus alludes to the Chicxulub impactor (a "falling star"), and also alludes to quails which are members of the galloanserans. The species name A. maastrichtensis is named after the Maastricht Formation. The researchers who discovered and described the fossil gave Asteriornis the nickname "Wonderchicken", which was picked up by various news outlets.
Description | Asteriornis | Wikipedia | 364 | 63413093 | https://en.wikipedia.org/wiki/Asteriornis | Biology and health sciences | Prehistoric birds | Animals |
The beak was slightly downcurved and lightweight. Unlike galloanserans, the beak did not have any specialized connections to the rest of the skull, nor a hooked tip. Instead its front tip was slightly rounded. The skull was narrowest over the orbits (eye sockets), where the frontal bones were incised by a V-shaped part of the nasal bones. The bones forming the jaw joint were very galloanseran-like. The quadrate bone (the cranium's contribution to the jaw joint) connected to the skull roof via two pronounced knobs, which were adjacent to a third smaller knob, the tuberculum subcapitulare. The mandible (lower jaw) connected to the quadrate with a pair of sockets, and the rear end of the lower jaw had a large hooked rearward-facing retroarticular process as well as a smaller inward-facing medial process. All of these characteristics are considered unique to (or at least most common in) galloanserans.
In some respects the skull seems more similar to galliform birds such as chickens and pheasants. These include unfused snout bones and nasal bones which fork in front of the eyes. In other respects it resembles anseriform birds such as ducks and geese. Such features include the hooked retroarticular process of the jaw and a postorbital process (the portion of bone forming the rear edge of the eye socket) which curves forward at its lower extent. These demonstrate a principle of evolution that animals close to the common ancestor of two groups share some similarities with each group.
The radius fragment flattens and widens towards the wrist, where it possesses a large hooked bump. Leg bones are elongated and slender, similar in proportions and structure to modern ground-living birds. The femur has well-developed muscle ridges and a large, angular medial condyle. The tibiotarsus is widest towards the knee, while the tarsometatarsus is thinner and covered with ridges. | Asteriornis | Wikipedia | 410 | 63413093 | https://en.wikipedia.org/wiki/Asteriornis | Biology and health sciences | Prehistoric birds | Animals |
Classification
A phylogenetic analysis placed Asteriornis near the base of Galloanserae, an expansive superorder containing birds such as chickens, ducks, pheasants, and other types of fowl and gamebirds. The precise placement varied based on whether the analysis used parsimony or Bayesian protocol. Parsimony placed it as the sister taxon to Galloanserae, meaning that it was a distant relative of the last common ancestor of chickens and ducks. Bayesian protocol instead placed it within Galloanserae, specifically as the sister taxon to Galliformes. This means that it was more closely related to chickens than to ducks, but also that was not a direct ancestor of modern chicken-like birds.
Classifying Asteriornis as a relative of chickens and ducks means that it is unequivocally a neornithean. This is important because Neornithes originated at the last common ancestor of all living birds, and corresponds to the term "bird" as it refers to modern-day animals. Pre-neornithean birds such as Ichthyornis, enantiornitheans, or Archaeopteryx generally resemble modern birds but retain primitive features such as teeth or wing claws. Neornithean fossils are extremely rare from the Mesozoic age, and are generally fragmentary or poorly described. The oldest known neognath, specifically a stem-anseriform, is the presbyornithid Teviornis from the Nemegt Formation of Mongolia around . Vegavis from the Late Cretaceous (~66.5 Ma) of Antarctica was originally described as a relative of ducks and geese, but the classification of vegaviids is controversial and some paleontologists do not consider it a proper neornithean, or at least not an anseriform or a galloanserine. Asteriornis is based on diagnostic and well-preserved skull material and its status is less unstable, so it can be considered among the oldest known undisputed fossil of a modern-style neornithean bird. | Asteriornis | Wikipedia | 425 | 63413093 | https://en.wikipedia.org/wiki/Asteriornis | Biology and health sciences | Prehistoric birds | Animals |
At least one study in 2021 has recovered Asteriornis as a paleognath, albeit "with limited support". Subsequent studies still support Asterornis as a neornithean closely related to or within Galloanserae based on morphometric and phylogenetic analyses. A 2024 cladistic analysis placed Asteriornis within the crown-group Galloanserae, specifically as a stem-galliform, though reexaminations of its mandible suggested that it lacked a key galloanserine feature. | Asteriornis | Wikipedia | 107 | 63413093 | https://en.wikipedia.org/wiki/Asteriornis | Biology and health sciences | Prehistoric birds | Animals |
Shringasaurus (meaning "horned lizard", from Sanskrit शृङ्ग (śṛṅga), "horn", and Ancient Greek (sauros), "lizard") is an extinct genus of archosauromorph reptile from the Middle Triassic (Anisian) of India. It is known from the type and only known species, S. indicus. Shringasaurus is known from the Denwa Formation in the state of Madhya Pradesh. Shringasaurus was an allokotosaur, a group of unusual herbivorous reptiles from the Triassic, and is most closely related to the smaller and better known Azendohsaurus in the family Azendohsauridae. Like some ceratopsid dinosaurs, Shringasaurus had two large horns over its eyes that faced up and forwards from its skull. Shringasaurus also bears convergent physical similarities to sauropodomorph dinosaurs, such as its long neck, its shoulders and forelimbs, and the shape of its teeth. Shringasaurus possibly occupied a similar ecological niche as a large browsing herbivore before such dinosaurs had evolved.
Description
Shringasaurus was a large-bodied quadruped, with an estimated body length of . It closely resembles the related Azendohsaurus, with its small, boxy head on a long neck and a large, barrel-shaped body with deep shoulders and ribs, sprawled to semi-sprawled limbs and a short tail. Aside from being notably larger than Azendohsaurus, Shringasaurus is most recognisable for its long curving brow horns, as well as for having a proportionately shorter and thicker neck than other azendohsaurids and much taller neural spines in the neck and over the shoulders.
Skull
The skull of Shringasaurus is not completely known, but what's preserved indicates that the skull was small and boxy, with a short, deep snout with rounded jaw tips and bony nostrils fused into a single, confluent opening at the front of the snout. This is broadly similar to the completely known skull of Azendohsaurus, but the lower jaw of Shringasaurus has a more conspicuous taper towards the tip compared to the deep, down-turned dentary of the Azendohsaurus. | Shringasaurus | Wikipedia | 460 | 54977531 | https://en.wikipedia.org/wiki/Shringasaurus | Biology and health sciences | Other prehistoric reptiles | Animals |
The horns of Shringasaurus closely resemble those seen in ceratopsid dinosaurs, despite azendohsaurids and ceratopsids being totally unrelated to each other. The horns are attached to the frontal bones on the roof of the skull over the eyes, and sit across almost the entire breadth of the skull. They are pointed up and curve forwards from the skull, with slight variation in size and orientation existing among large individuals. Smaller and younger individuals had smaller, more gracile horns, indicating that the horns did not fully develop until the animals were mature. Intriguingly, at least one small specimen lacks horns entirely, whereas another similarly small specimen has small but well developed horns. It is suggested then that Shringasaurus was sexually dimorphic, and that possibly the females lacked horns.
The horns themselves have a rough, grooved texture that implies they were covered with a keratinous sheath of horn in life, also like ceratopsid horns, and so would have likely been longer than the bony cores indicate. The bones of the skull beneath the horns are unusually thick, and in the larger individuals the bones of roof of the skull (the nasal, prefrontal, frontal and postfrontal) are fused together on each side.
The teeth of Shringasaurus are low and leaf-shaped (lanceolate) with large denticles on either side, similar in shape to those of Azendohsaurus but lacking the prominent expansion above the root, like the teeth of Pamelaria. Because the skull and jaws are incompletely known, the total tooth count of Shringasaurus is unknown, but like Azendohsaurus it had four teeth in each premaxilla. Shringasaurus also had numerous palatal teeth (though known only from the vomer thus far), and like Azendohsaurus they are uniquely as well developed as the marginal teeth along the edge of the jaw. Like them, they were leaf-shaped and serrated, but in Shringasaurus the palatal teeth are even more lanceolate than the marginal rows. Such palatal teeth are unusual, as most other herbivorous reptiles with them have much simpler, domed palatal teeth, and palatal teeth identical to those of the jaw margins are otherwise only found in the related allokotosaurs Azendohsaurus and Teraterpeton.
Skeleton | Shringasaurus | Wikipedia | 475 | 54977531 | https://en.wikipedia.org/wiki/Shringasaurus | Biology and health sciences | Other prehistoric reptiles | Animals |
The vertebral column is well known in Shringasaurus, including the whole cervical series, various dorsal vertebrae, both sacral vertebrae and some caudal vertebrae. Like other azendohsaurids, the first-through-middle cervical vertebrae are characteristically elongated, giving Shringasaurus a long, raised neck, although it is proportionately shorter than in Azendohsaurus and Pamelaria. The neck is also much taller than in other azendohsaurids, with tall, prominent neural spines. This trend continues into the dorsals of the back, which although are not as long as the cervicals have neural spines twice the height of their centra. The 2nd–5th cervicals of Shringasaurus sport prominent epipophyses, structures for supporting neck musculature. The first twelve dorsals are also marked by various well-defined laminae that bound deep fossae (depressions in the bone), similar to those found on the vertebrae of sauropods. Like Azendohsaurus, Shringasaurus has two sacral vertebrae with well-developed ribs that articulate with the ilia.
The shoulder and forelimb are broadly similar to those of Azendohsaurus, with a tall scapula that is concave along the front with an expanded tip, and an interclavicle with a long paddle-like process on the back and a short forward-pointing process (an unusual feature for archosauromorphs but also found in Azendohsaurus). The coracoid articulates with the scapula to form a glenoid (shoulder socket) that faces out to the sides and back. The humerus is likewise similar, with broad ends and a narrow midshaft, and a very well-developed deltopectoral crest half as long as the whole bone, indicating powerful forelimbs. The ulna, however, can be distinguished by a lower olecranon process below the elbow than in Azendohsaurus. | Shringasaurus | Wikipedia | 411 | 54977531 | https://en.wikipedia.org/wiki/Shringasaurus | Biology and health sciences | Other prehistoric reptiles | Animals |
The hips and hind limbs are very similar to those of Azendohsaurus. The ilium has a prominent, semi-circular process at the front while the rear process is longer and thinner, and the acetabulum (hip socket) is also solid, unlike the perforated hip socket of dinosaurs. The femur is robust and slightly s-shaped, held out to the sides in a sprawl, with a robust tibia and a fibula only half as wide in the lower leg. The foot is typical for early archosauromorphs, including Azendohsaurus.
Discovery and naming
Shringasaurus is known from a single bone bed of fossils in the upper Denwa Formation, India. The formation is part of the Satpura Gondwana Basin, located in the Hoshangabad district in the state of Madhya Pradesh. The precise age of the Denwa Formation is not known, but vertebrate biostratigraphy has been used to narrow it down to a range in the early Middle Triassic with conflicting opinions on an early or late Anisian age. The upper Denwa Formation is characteristically dominated by red mudstones with ribbon-shaped sandstone sheets encased within them. The bonebed itself was preserved in a crevasse splay deposit composed of cross-bedded, dipped sandstone with irregular boundaries that breached along the south edge of an ancient filled river channel. This flooding event was unlikely to be an isolated event, as the size of the crevasse splay suggests multiple phases of flooding that cumulatively buried the remains of the herd.
The Shringasaurus bone bed consists of mostly disarticulated bones (although one partial skeleton was found in articulation) scattered within a 5 m X 5 m () area of red mudstone with fine, sandy laminations. The bonebed is monodominant, only containing fossils of Shringasaurus, and preserves eight individuals based on the minimum number of unique right femora, left humeri, skull roofs and horns discovered. The specimens also represent a variety of different ontogenetic stages of growth with a wide range of body sizes, from juveniles to adults. Of these individuals, only one or two lacked horns, and it's suggested that the bone bed was taphonomically biased towards the heavier, solidly built skulls of horned individuals while being transported and preserved. | Shringasaurus | Wikipedia | 481 | 54977531 | https://en.wikipedia.org/wiki/Shringasaurus | Biology and health sciences | Other prehistoric reptiles | Animals |
However, the retention of bones rapidly lost in transport (such as ribs and limb bones), as well as minimal abrasion to many of the bones, indicates they were not transported a great distance after death. Although the bones were later disarticulated after transportation (apart from a single series of six dorsal vertebrae and ribs), they remained in closely associated clusters. They also show little weathering, indicating that most of the bones only remained exposed on the surface for perhaps only 1–3 years, with only a few exposed for longer (3–15 years). The articulated vertebrae, found lowest in the bonebed, was likely buried immediately, while the remaining bones higher in the bonebed were buried by subsequent floods. Similarly, the bones show now signs of trampling or marks from scavenging and plant growth, indicative of their short exposure before burial.
The fossils were excavated and prepared by Professor Saswati Bandyopadhyay, Dhurjati Sengupta and Shiladri Das of the Indian Statistical Institute, Kolkata, where the fossils are also stored. It was then described and named in August 2017 by Sarandee Sengupta and Bandyopadhyay, as well as by Martín D. Ezcurra of the Bernardino Rivadavia Natural Sciences Argentine Museum in Argentina. The holotype specimen, ISIR 780, consists of a partial skull roof including the prefrontal, frontal, postfrontal and parietal bones, along with a pair of large supra-orbital horns. The various other specimens from the bone bed have been designated as paratypes and consist of multiple cranial and postcranial bones from much of the skeleton. The genus was named using the ancient Sanskrit word for "horn", 'Śṛṅga' (शृङ्ग), for the unique horns on its skull, combined with the Ancient Greek σαῦρος (sauros) for "lizard". The specific name indicus is Latin for "Indian", to refer to its country of discovery. | Shringasaurus | Wikipedia | 415 | 54977531 | https://en.wikipedia.org/wiki/Shringasaurus | Biology and health sciences | Other prehistoric reptiles | Animals |
Classification
Shringasaurus is recognised as a member of the family Azendohsauridae, and as the closest relative of Azendohsaurus itself. The family is typically grouped within the recently recognised clade Allokotosauria, along with the trilophosaurids, as was recovered by Sengupta and colleagues when they described Shringasaurus and analysed its phylogenetic relationships in 2017. Another analysis of archosauromorph relationships in 2019 that used a different dataset from Sengupta et al. (2017)—that of Pritchard et al. (2018)—was updated to include Shringasaurus, and similarly recovered it and Azendohsaurus as each other's closest relatives within Allokotosauria, further supporting an azendohsaurid affinity for Shringasaurus.
The results found by Sengupta and colleagues in 2017 is shown below as an excerpt of the full cladogram, simplified and focused on the relationships of Shringasaurus to other allokotosaurs:
Shringasaurus and other azendohsaurids share several features, including confluent nares, leaf-shaped teeth and a long neck, as well as a few other minor details of the skeleton. It is particularly similar to Azendohsaurus in features of the parietals, the lower jaw, shoulder, hip, femur and vertebrae, but can be distinguished by teeth that are not expanded above the roots, the lack of a groove on the inside surface of the maxilla, tall neural spines, and of course the horns.
Palaeobiology
The Shringasaurus bonebed suggests that it was a gregarious animal that lived in herds. The herd appears to have died in a mass mortality event and was buried in a short span of time, possibly drowned by a breached levee. The bonebed includes juveniles, sub-adults and adults, further suggesting that Shringasaurus lived in mixed-age herds. The herd was also mixed-sex, based on the presence of both purported males and females, although it is unclear if they lived mixed-sex year round or if they only did so during part of the year, namely the breeding season (as observed in domestic sheep and related herbivores where males similarly spar with their horns). The herd was likely congregating around a nearby river channel during a period of environmental stress such as a drought, as occurs in living herbivores and has also been inferred for some dinosaurs. | Shringasaurus | Wikipedia | 510 | 54977531 | https://en.wikipedia.org/wiki/Shringasaurus | Biology and health sciences | Other prehistoric reptiles | Animals |
Function of the horns
The horns of Shringasaurus are its most prominent feature, and so some focus was placed on their role and function in its initial description. Its describers considered its horns to be likely products of sexual selection, not primarily for defence or species recognition (as has been proposed for the head ornaments of dinosaurs). The horns grow notably larger and more robust in large adults, while smaller individuals have shorter and more graceful horns. The possibility that Shringasaurus was sexually dimorphic, with probable females lacking horns, further supports this interpretation. This would be similar to modern horned bovids, but unlike ceratopsid dinosaurs, and indeed other archosauromorphs, which do not appear to have been dimorphic.
Palaeopathology
One specimen of Shringasaurus is known to have had a pair of malformed vertebrae in its neck. The two cervicals are partially fused together, interpreted as either the result of a birth defect, spondyloarthropathy (a type of arthritis), or possibly a bacterial or fungal disc infection. The vertebrae belonged to a large adult animal, so it is unlikely that the quality of life for the individual was severely affected by the disorder, and it was probably not fatal to the animal. One of the vertebrae also preserves a healed fracture, although the cause for this injury is unknown.
Palaeoecology | Shringasaurus | Wikipedia | 280 | 54977531 | https://en.wikipedia.org/wiki/Shringasaurus | Biology and health sciences | Other prehistoric reptiles | Animals |
In the upper Denwa Formation, Shringasaurus coexisted with the lungfish Ceratodus sp. and a variety of temnospondyl amphibians, including the capitosaurid Paracyclotosaurus crookshanki, the mastodonsaurid Cherninia denwai, a lonchorhynchine trematosaurid, and a brachyopid. Other terrestrial vertebrates include a large undescribed rhynchosaur and two species of dicynodonts, a mid-sized species similar to Kannemeyeria and a larger species interpreted as similar to Stahleckeria. The environment is interpreted as representing a dry, semi-arid floodplain with slow moving, anabranching rivers that periodically burst their banks. Rainfall was seasonal, and the environment experienced droughts that dried up ephemeral rivers and ponds. The large body size of Shringasaurus and its convergent similarity to sauropodomorphs—including its jaws and teeth as well as a superficially similar body shape—suggests that it possibly occupied the role of a large, relatively high-browsing herbivore in its environment. | Shringasaurus | Wikipedia | 244 | 54977531 | https://en.wikipedia.org/wiki/Shringasaurus | Biology and health sciences | Other prehistoric reptiles | Animals |
Acanthosoma is a genus of shield bugs in the family Acanthosomatidae, found in Europe, Asia, and Oceania. There are over 30 described species in the genus Acanthosoma.
Species
The following species are recognised in the genus Acanthosoma:
Acanthosoma alaticorne
Acanthosoma asahinai
Acanthosoma atayal
Acanthosoma axicia
Acanthosoma chinanum
Acanthosoma cornutum
Acanthosoma crassicaudum
Acanthosoma debile
Acanthosoma denticaudum
Acanthosoma emeiense
Acanthosoma expansum
Acanthosoma fallax
Acanthosoma firmatum
Acanthosoma forcipatum
Acanthosoma forfex
Acanthosoma forficula
Acanthosoma haemorrhoidale - Hawthorn Shieldbug
Acanthosoma hampsoni
Acanthosoma ishiharai
Acanthosoma joursacensis
Acanthosoma labiduroides
Acanthosoma laevicorne
Acanthosoma livida
Acanthosoma maculata
Acanthosoma montanum
Acanthosoma morloti
Acanthosoma murreeanum
Acanthosoma nigricorne
Acanthosoma nigrodorsum
Acanthosoma pteridis
Acanthosoma pugnax
Acanthosoma rufescens
Acanthosoma rufispinum
Acanthosoma shensiense
Acanthosoma sichuanense
Acanthosoma sinense
Acanthosoma sp.
Acanthosoma sp.
Acanthosoma spinicolle
Acanthosoma tauriforme
Acanthosoma taurina
BOLD:AAJ3749 (Acanthosoma sp.) | Acanthosoma | Wikipedia | 366 | 63429503 | https://en.wikipedia.org/wiki/Acanthosoma | Biology and health sciences | Hemiptera (true bugs) | Animals |
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. The term excludes seawater and brackish water, but it does include non-salty mineral-rich waters, such as chalybeate springs. Fresh water may encompass frozen and meltwater in ice sheets, ice caps, glaciers, snowfields and icebergs, natural precipitations such as rainfall, snowfall, hail/sleet and graupel, and surface runoffs that form inland bodies of water such as wetlands, ponds, lakes, rivers, streams, as well as groundwater contained in aquifers, subterranean rivers and lakes.
Water is critical to the survival of all living organisms. Many organisms can thrive on salt water, but the great majority of vascular plants and most insects, amphibians, reptiles, mammals and birds need fresh water to survive.
Fresh water is the water resource that is of the most and immediate use to humans. Fresh water is not always potable water, that is, water safe to drink by humans. Much of the earth's fresh water (on the surface and groundwater) is to a substantial degree unsuitable for human consumption without treatment. Fresh water can easily become polluted by human activities or due to naturally occurring processes, such as erosion.
Fresh water makes up less than 3% of the world's water resources, and just 1% of that is readily available. About 70% of the world's freshwater reserves are frozen in Antarctica. Just 3% of it is extracted for human consumption. Agriculture uses roughly two thirds of all fresh water extracted from the environment.
Fresh water is a renewable and variable, but finite natural resource. Fresh water is replenished through the process of the natural water cycle, in which water from seas, lakes, forests, land, rivers and reservoirs evaporates, forms clouds, and returns inland as precipitation. Locally, however, if more fresh water is consumed through human activities than is naturally restored, this may result in reduced fresh water availability (or water scarcity) from surface and underground sources and can cause serious damage to surrounding and associated environments. Water pollution also reduces the availability of fresh water. Where available water resources are scarce, humans have developed technologies like desalination and wastewater recycling to stretch the available supply further. However, given the high cost (both capital and running costs) and - especially for desalination - energy requirements, those remain mostly niche applications. | Fresh water | Wikipedia | 499 | 62557527 | https://en.wikipedia.org/wiki/Fresh%20water | Physical sciences | Water: General | Earth science |
A non-sustainable alternative is using so-called "fossil water" from underground aquifers. As some of those aquifers formed hundreds of thousands or even millions of years ago when local climates were wetter (e.g. from one of the Green Sahara periods) and are not appreciably replenished under current climatic conditions - at least compared to drawdown, these aquifers form essentially non-renewable resources comparable to peat or lignite, which are also continuously formed in the current era but orders of magnitude slower than they are mined.
Definitions
Numerical definition
Fresh water can be defined as water with less than 500 parts per million (ppm) of dissolved salts.
Other sources give higher upper salinity limits for fresh water, e.g. 1,000 ppm or 3,000 ppm.
Systems
Fresh water habitats are classified as either lentic systems, which are the stillwaters including ponds, lakes, swamps and mires; lotic which are running-water systems; or groundwaters which flow in rocks and aquifers. There is, in addition, a zone which bridges between groundwater and lotic systems, which is the hyporheic zone, which underlies many larger rivers and can contain substantially more water than is seen in the open channel. It may also be in direct contact with the underlying underground water.
Sources
The original source of almost all fresh water is precipitation from the atmosphere, in the form of mist, rain and snow. Fresh water falling as mist, rain or snow contains materials dissolved from the atmosphere and material from the sea and land over which the rain bearing clouds have traveled. The precipitation leads eventually to the formation of water bodies that humans can use as sources of freshwater: ponds, lakes, rainfall, rivers, streams, and groundwater contained in underground aquifers.
In coastal areas fresh water may contain significant concentrations of salts derived from the sea if windy conditions have lifted drops of seawater into the rain-bearing clouds. This can give rise to elevated concentrations of sodium, chloride, magnesium and sulfate as well as many other compounds in smaller concentrations. | Fresh water | Wikipedia | 428 | 62557527 | https://en.wikipedia.org/wiki/Fresh%20water | Physical sciences | Water: General | Earth science |
In desert areas, or areas with impoverished or dusty soils, rain-bearing winds can pick up sand and dust and this can be deposited elsewhere in precipitation and causing the freshwater flow to be measurably contaminated both by insoluble solids but also by the soluble components of those soils. Significant quantities of iron may be transported in this way including the well-documented transfer of iron-rich rainfall falling in Brazil derived from sand-storms in the Sahara in north Africa.
In Africa, it was revealed that groundwater controls are complex and do not correspond directly to a single factor. Groundwater showed greater resilience to climate change than expected, and areas with an increasing threshold between 0.34 and 0.39 aridity index exhibited significant sensitivity to climate change. Land-use could affect infiltration and runoff processes. The years of most recharge coincided with the most precipitation anomalies, such as during El Niño and La Niña events. Three precipitation-recharge sensitivities were distinguished: in super arid areas with more than 0.67 aridity index, there was constant recharge with little variation with precipitation; in most sites (arid, semi-arid, humid), annual recharge increased as annual precipitation remained above a certain threshold; and in complex areas down to 0.1 aridity index (focused recharge), there was very inconsistent recharge (low precipitation but high recharge). Understanding these relationships can lead to the development of sustainable strategies for water collection. This understanding is particularly crucial in Africa, where water resources are often scarce and climate change poses significant challenges.
Water distribution
Saline water in oceans, seas and saline groundwater make up about 97% of all the water on Earth. Only 2.5–2.75% is fresh water, including 1.75–2% frozen in glaciers, ice and snow, 0.5–0.75% as fresh groundwater. The water table is the level below which all spaces are filled with water, while the area above this level, where spaces in the rock and soil contain both air and water, is known as the unsaturated zone. The water in this unsaturated zone is referred to as soil moisture. | Fresh water | Wikipedia | 451 | 62557527 | https://en.wikipedia.org/wiki/Fresh%20water | Physical sciences | Water: General | Earth science |
Below the water table, the entire region is known as the saturated zone, and the water in this zone is called groundwater. Groundwater plays a crucial role as the primary source of water for various purposes including drinking, washing, farming, and manufacturing, and even when not directly used as a drinking water supply it remains vital to protect due to its ability to carry contaminants and pollutants from the land into lakes and rivers, which constitute a significant percentage of other people's freshwater supply. It is almost ubiquitous underground, residing in the spaces between particles of rock and soil or within crevices and cracks in rock, typically within of the surface, and soil moisture, and less than 0.01% of it as surface water in lakes, swamps and rivers.
Freshwater lakes contain about 87% of this fresh surface water, including 29% in the African Great Lakes, 22% in Lake Baikal in Russia, 21% in the North American Great Lakes, and 14% in other lakes. Swamps have most of the balance with only a small amount in rivers, most notably the Amazon River. The atmosphere contains 0.04% water. In areas with no fresh water on the ground surface, fresh water derived from precipitation may, because of its lower density, overlie saline ground water in lenses or layers. Most of the world's fresh water is frozen in ice sheets. Many areas have very little fresh water, such as deserts.
Freshwater ecosystems
Water is a critical issue for the survival of all living organisms. Some can use salt water but many organisms including the great majority of higher plants and most mammals must have access to fresh water to live. Some terrestrial mammals, especially desert rodents, appear to survive without drinking, but they do generate water through the metabolism of cereal seeds, and they also have mechanisms to conserve water to the maximum degree.
Challenges
The increase in the world population and the increase in per capita water use puts increasing strains on the finite resources availability of clean fresh water. The response by freshwater ecosystems to a changing climate can be described in terms of three interrelated components: water quality, water quantity or volume, and water timing. A change in one often leads to shifts in the others as well.
Limited resource
Minimum streamflow
An important concern for hydrological ecosystems is securing minimum streamflow, especially preserving and restoring instream water allocations. Fresh water is an important natural resource necessary for the survival of all ecosystems.
Water pollution
Society and culture
Human uses
Uses of water include agricultural, industrial, household, recreational and environmental activities. | Fresh water | Wikipedia | 511 | 62557527 | https://en.wikipedia.org/wiki/Fresh%20water | Physical sciences | Water: General | Earth science |
Global goals for conservation
The Sustainable Development Goals are a collection of 17 interlinked global goals designed to be a "blueprint to achieve a better and more sustainable future for all". Targets on fresh water conservation are included in SDG 6 (Clean water and sanitation) and SDG 15 (Life on land). For example, Target 6.4 is formulated as "By 2030, substantially increase water-use efficiency across all sectors and ensure sustainable withdrawals and supply of freshwater to address water scarcity and substantially reduce the number of people suffering from water scarcity." Another target, Target 15.1, is: "By 2020, ensure the conservation, restoration and sustainable use of terrestrial and inland freshwater ecosystems and their services, in particular forests, wetlands, mountains and drylands, in line with obligations under international agreements." | Fresh water | Wikipedia | 168 | 62557527 | https://en.wikipedia.org/wiki/Fresh%20water | Physical sciences | Water: General | Earth science |
GW170817 was a gravitational wave (GW) signal observed by the LIGO and Virgo detectors on 17 August 2017, originating from the shell elliptical galaxy NGC 4993, about 140 million light years away. The signal was produced by the last moments of the inspiral process of a binary pair of neutron stars, ending with their merger. , it is the only GW detection to be definitively correlated with any electromagnetic observation. Unlike the five prior GW detections—which were of merging black holes and thus not expected to have detectable electromagnetic signals—the aftermath of this merger was seen across the electromagnetic spectrum by 70 observatories on 7 continents and in space, marking a significant breakthrough for multi-messenger astronomy. The discovery and subsequent observations of GW170817 were given the Breakthrough of the Year award for 2017 by the journal Science.
The gravitational wave signal, designated GW170817, had an audible duration of approximately 100 seconds, and showed the characteristic intensity and frequency expected of the inspiral of two neutron stars. Analysis of the slight variation in arrival time of the GW at the three detector locations (two LIGO and one Virgo) yielded an approximate angular direction to the source. Independently, a short gamma-ray burst (sGRB) of around 2 seconds, designated GRB 170817A, was detected by the Fermi and INTEGRAL spacecraft beginning 1.7 seconds after the GW merger signal. These detectors have very limited directional sensitivity, but indicated a large area of the sky which overlapped the gravitational wave position. The co-occurrence confirmed a long-standing hypothesis that neutron star mergers describe an important class of sGRB progenitor event.
An intense observing campaign was prioritized, to scan the region indicated by the gravitational wave detection for the expected emission at optical wavelengths. During this search, 11 hours after the signal, an astronomical transient SSS17a, later designated kilonova AT 2017gfo, was observed in the galaxy . It was captured by numerous telescopes, from radio to X-ray wavelengths, over the following days and weeks, and was found to be a fast-moving, rapidly-cooling cloud of neutron-rich material, as expected of debris ejected from a neutron-star merger. | GW170817 | Wikipedia | 464 | 55053716 | https://en.wikipedia.org/wiki/GW170817 | Physical sciences | Notable transient events | Astronomy |
In October 2018, astronomers reported that, in retrospect, an sGRB event detected in 2015 () may represent an earlier case of the same astrophysics reported for GW170817. The similarities between the two events in terms of gamma ray, optical, and x-ray emissions, as well as to the nature of the associated host galaxies, were considered "striking", suggesting that the earlier event may also be the result of a neutron star merger, and that together these may signify a hitherto-unknown class of kilonova transients, making kilonovae more diverse and common in the universe than previously understood. Later research further construed —another sGRB predating GW170817—also to be a kilonova, again based its resemblance to the signature.
Announcement
The observations were officially announced on 16 October 2017 at press conferences at the National Press Club in Washington, D.C., and at the ESO headquarters in Garching bei München in Germany.
Some information was leaked before the official announcement, beginning on 18 August 2017 when astronomer J. Craig Wheeler of the University of Texas at Austin tweeted "New LIGO. Source with optical counterpart. Blow your sox off!" He later deleted the tweet and apologized for scooping the official announcement embargo. Other people followed up on the rumor, and reported that the public logs of several major telescopes listed priority interruptions in order to observe , a galaxy away in the Hydra constellation. The collaboration had earlier declined to comment on the rumors, not adding to a previous announcement that there were several triggers under analysis.
Gravitational wave detection
The gravitational wave signal lasted for approximately 100 seconds starting from a frequency of 24 hertz. It covered approximately 3,000 cycles, increasing in amplitude and frequency to a few hundred hertz in the typical inspiral chirp pattern, ending with the collision received at 12:41:04.4 UTC. It arrived first at the Virgo detector in Italy, then 22 milliseconds later at the LIGO-Livingston detector in Louisiana, United States, and another 3 milliseconds later at the LIGO-Hanford detector in the state of Washington, in the United States. The signal was detected and analyzed by a comparison with a prediction from general relativity defined from the post-Newtonian expansion. | GW170817 | Wikipedia | 480 | 55053716 | https://en.wikipedia.org/wiki/GW170817 | Physical sciences | Notable transient events | Astronomy |
An automatic computer search of the LIGO-Hanford datastream triggered an alert to the LIGO team about 6 minutes after the event. The gamma-ray alert had already been issued at this point (16 seconds post-event), so the timing near-coincidence was automatically flagged. The LIGO/Virgo team issued a preliminary alert (with only the crude gamma-ray position) to astronomers in the follow-up teams at 40 minutes post-event.
Sky localisation of the event required combining data from the three interferometers, but this was delayed by two problems. The Virgo data were delayed by a data transmission problem, and the LIGO Livingston data were contaminated by a brief burst of instrumental noise a few seconds prior to the event peak, which persisted parallel to the rising transient signal in the lowest frequencies. These required manual analysis and interpolation before the sky location could be announced about 4.5 hours after the event. The three detections localized the source to an area of 31 square degrees in the southern sky at 90% probability. More detailed calculations later refined the localization to within 28 square degrees. In particular, the absence of a clear detection by the Virgo interferometer implied that the source was localized within one of its blind spots, a constraint which reduced the search area considerably.
Gamma ray detection
The first electromagnetic signal detected was GRB 170817A, a short gamma-ray burst, detected after the merger time and lasting for about 2 seconds.
GRB 170817A was first recorded by the Fermi Gamma-ray Space Telescope, which issued an automatic alert just 14 seconds after the detection. After the LIGO/Virgo circular 40 minutes later, manual processing of data from the INTEGRAL gamma-ray telescope retrieved independent data for the event. The difference in arrival time between Fermi and INTEGRAL helped to improve the sky localization.
This GRB was relatively faint given the proximity of the host galaxy , possibly due to its jets not being pointed directly toward Earth, but rather at an angle of about 30 degrees off axis.
Electromagnetic follow-up | GW170817 | Wikipedia | 422 | 55053716 | https://en.wikipedia.org/wiki/GW170817 | Physical sciences | Notable transient events | Astronomy |
A series of alerts to other astronomers were issued, beginning with a report of the gamma-ray detection and single-detector LIGO trigger at 13:21 UTC, and a three-detector sky location at 17:54 UTC. These prompted a massive search by many survey and robotic telescopes. In addition to the expected large size of the search area (about 150 times the area of a full moon), this search was challenging because the search area was near the Sun in the sky and thus visible for at most a few hours after dusk for any given telescope.
In total six teams (One-Meter, Two Hemispheres (1M2H), DLT40, VISTA, Master, DECam, and Las Cumbres Observatory (Chile)) imaged the same new source independently in a 90-minute interval. The first to detect optical light associated with the collision was the 1M2H team running the Swope Supernova Survey, which found it in an image of taken 10 hours and 52 minutes after the GW event by the Swope Telescope operating in the near infrared at Las Campanas Observatory, Chile. They were also the first to announce it, naming their detection SSS17a in a circular issued 1226 post-event. The new source was later given an official International Astronomical Union (IAU) designation AT 2017gfo.
The 1M2H team surveyed all galaxies in the region of space predicted by the gravitational wave observations, and identified a single new transient. By identifying the host galaxy of the merger, it is possible to provide an accurate distance consistent with that based on gravitational waves alone.
The detection of the optical and near-infrared source provided a huge improvement in localisation, reducing the uncertainty from several degrees to 0.0001 degree; this enabled many large ground and space telescopes to follow up the source over the following days and weeks.
Within hours after localization, many additional observations were made across the infrared and visible spectrum. Over the following days, the color of the optical source changed from blue to red as the source expanded and cooled. | GW170817 | Wikipedia | 422 | 55053716 | https://en.wikipedia.org/wiki/GW170817 | Physical sciences | Notable transient events | Astronomy |
Numerous optical and infrared spectra were observed; early spectra were nearly featureless, but after a few days, broad features emerged indicative of material ejected at roughly 10 percent of light speed. There are multiple strong lines of evidence that AT 2017gfo is indeed the aftermath of GW170817. The color evolution and spectra are dramatically different from any known supernova. The distance of NGC 4993 is consistent with that independently estimated from the GW signal. No other transient has been found in the GW sky localisation region. Finally, various archive images show nothing at the location of AT 2017gfo, ruling out a foreground variable star in the Milky Way.
The source was detected in the ultraviolet (but not in X-rays) 15.3 hours after the event by the Swift Gamma-Ray Burst Mission. After initial lack of X-ray and radio detections, the source was detected in X-rays 9 days later using the Chandra X-ray Observatory, and 16 days later in the radio using the Karl G. Jansky Very Large Array (VLA) in New Mexico. More than 70 observatories covering the electromagnetic spectrum observed the source.
The radio and X-ray light increased to a peak 150 days after the merger, diminishing afterwards. Astronomers have monitored the optical afterglow of GW170817 using the Hubble Space Telescope. In March 2020, continued X-ray emission at 5-sigma was observed by the Chandra Observatory 940 days after the merger.
Other detectors
No neutrinos consistent with the source were found in follow-up searches by the IceCube and ANTARES neutrino observatories and the Pierre Auger Observatory. A possible explanation for the non-detection of neutrinos is because the event was observed at a large off-axis angle and thus the outflow jet was not directed towards Earth.
Astrophysical origin and products
The origin and properties (masses and spins) of a double neutron star system like GW170817 are the result of a long sequence of complex binary star interactions. The gravitational wave signal indicated that it was produced by the collision of two neutron stars with a total mass of solar masses (). If low spins are assumed, consistent with those observed in binary neutron stars that will merge within a Hubble time, the total mass is . The total energy output of the gravitational wave was ≃63 Foe. | GW170817 | Wikipedia | 492 | 55053716 | https://en.wikipedia.org/wiki/GW170817 | Physical sciences | Notable transient events | Astronomy |
The masses of the progenitor stars have greater uncertainty. The chirp mass, a directly observable parameter which may be roughly equated to the geometric mean of the prior masses, was measured at . The larger progenitor () has a 90% chance of being between , and the smaller () has a 90% chance of being between . Under the low spin assumption, the ranges are for and for , inside a 12 km radius.
The neutron star merger event resulted in a spherically expanding kilonova, characterized by a short gamma-ray burst followed by a longer optical afterglow powered by the radioactive decay of heavy r-process nuclei. GW170817 therefore confirmed neutron star mergers to be viable sites for the r-process, where the neucleosynthesis of around half the isotopes in elements heavier than iron can occur. A total of 16,000 times the mass of the Earth in heavy elements is believed to have formed, including approximately 10 Earth masses just of the two elements gold and platinum.
A hypermassive neutron star was believed to have formed initially, as evidenced by the large amount of ejecta (much of which would have been swallowed by an immediately forming black hole). At first, the lack of evidence for emissions being powered by neutron star spindown, which would occur for longer-surviving neutron stars, suggested it collapsed into a black hole within milliseconds. However, a more detailed analysis of the GW170817 signal tail later found evidence of further features consistent with the seconds-long spindown of an intermediate or remnant hypermassive magnetar, the energy of which was below the estimated sensitivity of the LIGO search algorithms at the time. This was confirmed in 2023 by a statistically independent method of analysis revealing the central engine of GRB170817A. , the precise nature of the ultimately stable remnant remains uncertain.
Scientific importance
Scientific interest in the event was enormous, with dozens of preliminary papers (and almost 100 preprints) published the day of the announcement, including 8 letters in Science, 6 in Nature, and 32 in a special issue of The Astrophysical Journal Letters devoted to the subject. The interest and effort was global: The paper describing the multi-messenger observations is coauthored by almost 4,000 astronomers (about one-third of the worldwide astronomical community) from more than 900 institutions, using more than 70 observatories on all 7 continents and in space. | GW170817 | Wikipedia | 506 | 55053716 | https://en.wikipedia.org/wiki/GW170817 | Physical sciences | Notable transient events | Astronomy |
The event also provided a limit on the difference between the speed of light and that of gravity. Assuming the first photons were emitted between zero and ten seconds after peak gravitational wave emission, the difference between the speeds of gravitational and electromagnetic waves, vGW − vEM, is constrained to between −3×10−15 and +7×10−16 times the speed of light, which improves on the previous estimate by about 14 orders of magnitude.
In addition, GW170817 allowed investigation of the equivalence principle (through Shapiro delay measurement) and Lorentz invariance. The limits of possible violations of Lorentz invariance (values of 'gravity sector coefficients') are reduced by the new observations by up to ten orders of magnitude.
The event also excluded some alternatives to general relativity, including variants of scalar–tensor theory, Hořava–Lifshitz gravity, Dark Matter Emulators, and bimetric gravity, Furthermore, an analysis published in July 2018 used GW170817 to show that gravitational waves propagate fully through the 3+1 curved spacetime described by general relativity, ruling out hypotheses involving "leakage" into higher, non-compact spatial dimensions.
Gravitational wave signals such as GW170817 may be used as a standard siren to provide an independent measurement of the Hubble constant. An initial estimate of the constant derived from the observation is (km/s)/Mpc, broadly consistent with current best estimates. Further studies improved the measurement to (km/s)/Mpc. Together with the observation of future events of this kind, the uncertainty is expected to reach two percent within five years and one percent within ten years.
Electromagnetic observations help support the theory that neutron star mergers contribute to rapid neutron capture (r-process) nucleosynthesis—previously assumed to be associated with supernova explosions—and are therefore the primary source of r-process elements heavier than iron, including gold and platinum. The first identification of r-process elements in a neutron star merger was obtained during a re-analysis of GW170817 spectra. The spectra provided direct proof of strontium production during a neutron star merger. This also provided the most direct proof that neutron stars are made of neutron-rich matter. Since then, several r-process elements have been identified in the ejecta including yttrium, lanthanum and cerium. | GW170817 | Wikipedia | 497 | 55053716 | https://en.wikipedia.org/wiki/GW170817 | Physical sciences | Notable transient events | Astronomy |
In October 2017, Stephen Hawking, in his last broadcast interview, discussed the overall scientific importance of GW170817. In September 2018, astronomers reported related studies about possible mergers of neutron stars (NS) and white dwarfs (WD): including NS-NS, NS-WD, and WD-WD mergers. | GW170817 | Wikipedia | 70 | 55053716 | https://en.wikipedia.org/wiki/GW170817 | Physical sciences | Notable transient events | Astronomy |
Extensive investigation into vaccines and autism spectrum disorder has shown that there is no relationship between the two, causal or otherwise, and that vaccine ingredients do not cause autism. The American scientist Peter Hotez researched the growth of the false claim and concluded that its spread originated with Andrew Wakefield's fraudulent 1998 paper, and that no prior paper supports a link.
Despite the scientific consensus for the absence of a relationship and the retracted paper, the anti-vaccination movement at large continues to promote theories linking the two. A developing tactic appears to be the "promotion of irrelevant research [as] an active aggregation of several questionable or peripherally related research studies in an attempt to justify the science underlying a questionable claim."
Claimed mechanisms
The claimed mechanisms have changed over time, in response to evidence refuting each in turn. The CDC published updated statistics on autism in children for the year 2020. It states that in the year 2000, there were 1 in 150 children who were born in 1992 diagnosed with autism. In 2020, they found 1 in 36 children born in 2012 were diagnosed with autism. Anti-vaccination groups believe this to be the increased number of vaccines in children. Although there has been an increase in vaccines, there has been an increase in autism screenings. It is clear from the literature and the CDC the increased number of children diagnosed with autism is due to the increase in ways to diagnose it. The anti-vaccine groups credit ingredients in the vaccines to be the connection to autism. Some of the most mentioned ones are thiomersal, aluminum adjuvants, and formaldehyde. The MMR vaccine will be explained as well. Celebrity and social media involvement seem to play a role in the anti-vaccine movement.
Autism screening history | Vaccines and autism | Wikipedia | 351 | 59882582 | https://en.wikipedia.org/wiki/Vaccines%20and%20autism | Biology and health sciences | Vaccines | Health |
In the early 2000s, evidence-based tools were being used for children as early as 36 months to help with the diagnosis of autism, and parents of children were able to identify signs of autism by the time the child turned 2.
In 2001, the Modified Autism Checklist for Toddlers (M-CHAT) was used and could diagnose children with signs of autism at 24 months.
In 2006, the American Academy of Pediatricians mandated screening, specifically for autism, at a child's 18-month checkup and later mandated for the 24-month visit as well.
As of May 2024, the CDC mentioned that healthcare workers, community members, and even schools can screen for autism. The diagnosis of autism in a child by the age of two conducted by a professional is evaluated as very reliable.
Vaccine-derived measles virus
The idea of a link between the MMR vaccine and autism came to prominence after the publication of a paper by Andrew Wakefield and others in The Lancet in 1998. This paper, which was retracted in 2010 and whose publication led to Wakefield being struck off the United Kingdom medical register, has been described as "the most damaging medical hoax of the last 100 years".
Wakefield's primary claim was that he had isolated evidence of vaccine-strain measles virus RNA in the intestines of autistic children, leading to a condition he termed autistic enterocolitis (a condition never recognised or adopted by the scientific community). This finding was later shown to be due to errors made by the laboratory where the polymerase chain reaction (PCR) tests were performed.
In 2009, The Sunday Times reported that Wakefield had manipulated patient data and misreported results in his 1998 paper, thus falsifying a link with autism. A 2011 article in the British Medical Journal describes the way in which Wakefield manipulated the data in his study in order to arrive at his predetermined conclusion. An accompanying editorial in the same journal described Wakefield's work as an "elaborate fraud" which led to lower vaccination rates, putting hundreds of thousands of children at risk and diverting funding and other resources from research into the true cause of autism.
On 12 February 2009, a special court convened in the United States to review claims under its National Vaccine Injury Compensation Program ruled that parents of autistic children are not entitled to compensation in their contention that certain vaccines caused their children to develop autism. | Vaccines and autism | Wikipedia | 492 | 59882582 | https://en.wikipedia.org/wiki/Vaccines%20and%20autism | Biology and health sciences | Vaccines | Health |
The Centers for Disease Control and Prevention (CDC), the IOM of the United States National Academy of Sciences, and the National Health Service have all concluded that there is no link between the MMR vaccine and autism. A systematic review by the Cochrane Library concluded that there is no credible link between the MMR vaccine and autism, that the MMR vaccine has prevented diseases that still carry a heavy burden of death and complications, that the lack of confidence in the MMR vaccine has damaged public health, and that the design and reporting of safety outcomes in MMR vaccine studies are largely inadequate. Further, an epidemiology study concluded that even children labeled high risk for autism, due to an older autistic sibling, that received the MMR vaccine resulted in no causal connection between the vaccine and autism or the increased risk of being diagnosed with autism. The assumption that MMR vaccines cause autism is not isolated to the United States. A seven-year study was done in Denmark from 1991 to 1998 following children who received the MMR vaccine. The results of the study found that when comparing the vaccinated children to the unvaccinated children, the risk of autism in the vaccinated group was 0.92. Also, the risk of another autism disorder was 0.83. The study concluded there was no association between the MMR vaccine and autism. The result held even when exploring the age of the child when the vaccine was given, the vaccination date, or the amount of time after the vaccine.
Thiomersal | Vaccines and autism | Wikipedia | 310 | 59882582 | https://en.wikipedia.org/wiki/Vaccines%20and%20autism | Biology and health sciences | Vaccines | Health |
Thiomersal is an antifungal preservative used in small amounts in some multi-dose vaccines (where the same vial is opened and used for multiple patients) to prevent contamination of the vaccine. Thiomersal contains ethylmercury, a mercury compound which is related to, but significantly less toxic than, the neurotoxic pollutant methylmercury. Despite decades of safe use, public campaigns prompted the CDC and the American Academy of Pediatrics (AAP) to request vaccine makers to remove thiomersal from vaccines as quickly as possible on the precautionary principle. Thiomersal is now absent from all common United States and European Union vaccines, except for some preparations of influenza vaccine. (Trace amounts remain in some vaccines due to production processes, at an approximate maximum of 1 microgramme, around 15% of the average daily mercury intake in the US for adults and 2.5% of the daily level considered tolerable by the World Health Organization [WHO].) The action engendered concern thiomersal could have been responsible for autism.
The idea that thiomersal was a cause or trigger for autism is now considered disproven, as incidence rates for autism increased steadily even after thiomersal was removed from childhood vaccines. The cause of autism and mercury poisoning being associated is improbable because the symptoms of mercury poisoning are not present and are inherently inconsistent with the behaviors or symptoms of autism. There is no accepted scientific evidence that exposure to thiomersal is a factor in causing autism. A study by the CDC exploring mercury poisoning in vaccines concluded no signs of poisoning were present.
Under the U.S. Food and Drug Administration (FDA) Modernization Act (FDAMA) of 1997, the FDA conducted a comprehensive review of the use of thiomersal in childhood vaccines. Conducted in 1999, this review found no evidence of harm from the use of thiomersal as a vaccine preservative, other than local hypersensitivity reactions. Despite this, starting in 2000, parents in the United States pursued legal compensation from a federal fund arguing that thiomersal caused autism in their children. A 2004 Institute of Medicine (IOM) committee favored rejecting any causal relationship between autism and vaccines containing thiomersal and rulings from the vaccine court in three test claims in 2010 established the precedent that thiomersal is not considered a cause of autism.
Vaccine overload | Vaccines and autism | Wikipedia | 507 | 59882582 | https://en.wikipedia.org/wiki/Vaccines%20and%20autism | Biology and health sciences | Vaccines | Health |
Following the belief that individual vaccines caused autism was the idea of vaccine overload, which claims that too many vaccines at once may overwhelm or weaken a child's immune system and lead to adverse effects. The Children's Hospital of Philadelphia Vaccine Education Center compiled a list of vaccines recommended to children throughout history. They found that from 1985-1994, the recommended number of vaccines totaled to eight. The schedule for 2011 to 2020 revealed the recommended number of vaccines totaled to fourteen. Vaccine overload became popular after the Vaccine Injury Compensation Program in the United States accepted the case of nine-year-old Hannah Poling. Poling had encephalopathy, putting her on the autism spectrum disorder, which was believed to have worsened after getting multiple vaccines at nineteen months old. There have been multiple cases reported similar to this one, which led to the belief that vaccine overload caused autism. However, scientific studies show that vaccines do not overwhelm the immune system. In fact, conservative estimates predict that the immune system can respond to thousands of viruses simultaneously. It is known that vaccines constitute only a tiny fraction of the pathogens already naturally encountered by a child in a typical year. Common fevers and middle ear infections pose a much greater challenge to the immune system than vaccines do. Other scientific findings support the idea that vaccinations, and even multiple concurrent vaccinations, do not weaken the immune system or compromise overall immunity and evidence that autism has any immune-mediated pathophysiology has still not been found.
Vaccines recommended from 1985-1994:
Diphtheria
Tetanus
Pertussis
Measles
Mumps
Rubella
Polio
Hib
Hepatitis B (1991)
Vaccines recommended from 2011-2020:
Diphtheria
Tetanus
Pertussis
Measles
Mumps
Rubella
Polio
Hib
Hepatitis B
Varicella
Hepatitis A
Pneumococcal
Influenza
Rotavirus
Diphtheria, Tetanus, and Pertussis were given together as the DTap. Measles, Mumps, and Rubella were given together as MMR. | Vaccines and autism | Wikipedia | 425 | 59882582 | https://en.wikipedia.org/wiki/Vaccines%20and%20autism | Biology and health sciences | Vaccines | Health |
Aluminium adjuvants
As mercury compounds in vaccines have been definitively ruled out as a cause of autism, some anti-vaccine activists propose aluminium adjuvants as the cause of autism. Aluminium adjuvants, simulates immune receptors and causes a strengthened response to the antigen in a way that is natural to the body. Aluminium adjuvants can be used in the form of soluble salts, alumina, and hydroxl. There is no substantial scientific evidence that aluminium adjuvants are linked to autism. When confirming that aluminium adjuvants are not dangerous in vaccines, it was concluded that there was no traces of aluminium in the children's hair or blood over the minimum level of risks according to the Agency for Toxic Substances and Disease Registry. Anti-vaccination activists commonly cite a number of papers which claim that there is in fact a link. These are mainly published in predatory open access journals, where peer-review is virtually non-existent. Work conducted by Christopher Shaw, Christopher Exley and Lucija Tomljenovic has been funded by the anti-vaccination Dwoskin Family Foundation. The work published by Shaw et al. has been discredited by the World Health Organization.
Formaldehyde
Formaldehyde is another assumed link between vaccines and autism. Even though the assumption still circles around, formaldehyde has been used safely in the diphtheria vaccines to detoxify the bacteria used to make the vaccine. Another way it can be used is to inactivate the disease to be used in the vaccine. Formaldehyde can be found naturally in the body and environment. The human body uses formaldehyde to build amino acids and to generate the energy we need. Formaldehyde is all around us in daily life activities. It can be found in preservatives, materials used to build, and many products in homes. There is no safety concern for formaldehyde in vaccines. The most concerning repercussion is cancer after exposure to high levels of formaldehyde in the air. The amount of formaldehyde in some vaccines is less than what the body naturally produces.
Celebrity involvement and social media
Some celebrities have spoken out on their views that autism is related to vaccination, including: Jenny McCarthy, Kristin Cavallari, Robert De Niro, Jim Carrey, Bill Maher, and Pete Evans. | Vaccines and autism | Wikipedia | 487 | 59882582 | https://en.wikipedia.org/wiki/Vaccines%20and%20autism | Biology and health sciences | Vaccines | Health |
McCarthy, one of the most outspoken celebrities on the topic, has said her son Evan's autism diagnosis was a result of the MMR vaccine. She authored Louder than Words: A Mother's Journey in Healing Autism and co-authored Healing and Preventing Autism. She also founded Generation Rescue, an organisation which provides resources for families affected by autism.
In a September 2015 U.S. presidential debate, Republican Party candidate and future United States President Donald Trump stated he knew of a 2-year-old child who had recently received a combined vaccine, developed a fever, and subsequently autism.
Robert F. Kennedy, Jr. is one of the most notable proponents of the anti-vaccine movement. Kennedy published the book Thimerosal: Let the Science Speak: The Evidence Supporting the Immediate Removal of Mercury--A Known Neurotoxin--From Vaccines. He is also chairman of the board of Children's Health Defense, a group and website widely known for its anti-vaccination stance.
A study conducted through Facebook explored the results of anti-vaccine ads and pro-vaccine ads. The study found that even with a similar number of anti-vaccine ads and pro-vaccine ads, the middle point in the data set of ads per buyer was higher in anti-vaccine ads. Another difference the study revealed was that the anti-vaccine ads were primarily targeted toward women and young adults who possibly had children. The pro-vaccination ads were presented evenly to different ages.
Public opinion
In December 2020, a poll of 1,115 U.S. adults found 12% of respondents believed there is evidence vaccinations cause autism; 51% believed there is no evidence; and 37% did not know.
An updated survey, conducted in March 2023, concluded that adults think the MMR health benefits are high/very high, at 72%, and the risk of side effects is low/very low, at 64%. There has also been a drop from 2019 in United States adults who believe students in schools should be fully vaccinated. The 2023 survey showed that a decrease to 70% of U.S. adults agree that children should be vaccinated for school but an increase to 28% believe that it is the parent's right to choose if the child is vaccinated for school. | Vaccines and autism | Wikipedia | 471 | 59882582 | https://en.wikipedia.org/wiki/Vaccines%20and%20autism | Biology and health sciences | Vaccines | Health |
Goby is a common name for many species of small to medium sized ray-finned fish, normally with large heads and tapered bodies, which are found in marine, brackish and freshwater environments.
Traditionally most of the species called gobies have been classified in the order Perciformes as the suborder Gobioidei but in the 5th Edition of Fishes of the World this suborder is elevated to an order Gobiiformes within the clade Percomorpha. Not all the species in the Gobiiformes are referred to as gobies and the "true gobies" are placed in the family Gobiidae, while other species referred to as gobies have been placed in the Oxudercidae. Goby is also used to describe some species which are not classified within the order Gobiiformes, such as the engineer goby or convict blenny Pholidichthys leucotaenia. The word goby derives from the Latin gobius meaning "gudgeon", and some species of goby, especially the sleeper gobies in the family Eleotridae and some of the dartfishes are called "gudgeons", especially in Australia. | Goby | Wikipedia | 248 | 58261265 | https://en.wikipedia.org/wiki/Goby | Biology and health sciences | Acanthomorpha | null |
The jacanas (sometimes referred to as Jesus birds or lily trotters) are a group of tropical waders in the family Jacanidae. They are found in the tropical regions around the world. They are noted for their elongated toes and toenails that allow them to spread out their weight while foraging on floating or semi-emergent aquatic vegetation. They are also among the somewhat rare groups of birds in which females are larger, and several species maintain harems of males in the breeding season with males solely responsible for incubating eggs and taking care of the chicks.
Taxonomy
The family Jacanidae was introduced in 1854 by the French naturalists Jean-Charles Chenu and Marc des Murs. They used the spelling "Jacaneinae". The modern spelling "Jacanidae" was used by Leonhard Stejneger in 1885.
The pronunciation of the word jacana is debated. Jacana is Linnæus' scientific Latin spelling of the Portuguese jaçanã which in turn is derived from a Tupi name of the bird, ñaha'nã. The Portuguese word is pronounced approximately . As in façade, Provençal, and araçari, the Ç is meant to be pronounced as an S. US dictionaries give various pronunciations: , , as well as the anglicised , which is the only pronunciation in an Australian dictionary. A British dictionary gives for the spelling "jacana" and for "jaçana".
Diversity
Eight species of extant jacana are known from six genera and four fossil species have been described from the Oligocene of Egypt and from the Pliocene of Florida. A fossil from Miocene strata in the Czech Republic was assigned to this family, but more recent analysis disputes the placement and moves the species to the Coraciidae. | Jacanidae | Wikipedia | 362 | 58290264 | https://en.wikipedia.org/wiki/Jacanidae | Biology and health sciences | Charadriiformes | Animals |
Jacanas are identifiable by their elongated toes and claws which enable them to walk on floating vegetation in the shallow lakes that are their preferred habitat. They have sharp bills and rounded wings, some with carpal spurs, and many species also have wattles and frontal lappets on their foreheads. Jacanas were once placed in the family Parridae based on the genus Parra but the family name is now Jacanidae based on the type genus Jacana. The family is placed within the order Charadriiformes under the suborder Scolopaci and is a sister of the Rostratulidae. They have 10 tail feathers unlike most others wader groups which have twelve. They have a rudimentary caecum. Most jacanas have five neck vertebrae with the exception of Hydrophasianus chirurgus which has six.
In terms of sexual size dimorphism, female jacanas are larger than the males but are alike in plumage. The latter, as in some other wader families like the phalaropes, take responsibility for incubation and care of chicks, and most species (with the exception of the monogamous lesser jacana) are polyandrous. They construct relatively flimsy nests on floating vegetation, and lay eggs with dark irregular lines on their shells, providing camouflage amongst water weeds. The eggs are slightly smaller than in comparable species and it has been considered that this may be due to an evolutionary tradeoff given the larger number of clutches that are laid. Male jacanas brood eggs between the wings and the body. This wing-brooding may be assisted by a special adaptation in the wing bones with either a broadening of the radius or a widening of the gap between the radius and ulna. Young chicks may also be held under the wing and transported to safety by the parent bird in some species. Young chicks dive underwater and stay submerged with only their bill out of water. Some adult jacanas also use the same technique. African jacanas go through a simultaneous moult of their flight feathers leading to a period of flightlessness. Their moult is related to their ability to breed opportunistically based on the availability of rains. | Jacanidae | Wikipedia | 452 | 58290264 | https://en.wikipedia.org/wiki/Jacanidae | Biology and health sciences | Charadriiformes | Animals |
Their diet consists mainly of insects and other invertebrates picked from floating vegetation or the water's surface but plant seeds may also be eaten. Wattled jacanas are known to pick ticks off capybaras. The stomach contents of jacanas have been found to include algae, as well as plant roots and stems, but it is thought that this may be incidentally ingested along with their invertebrate prey.
Most species have rounded wings and short tails. The flight tends to be slow and weak. Most species are sedentary, but the pheasant-tailed jacana migrates from the north of its range into peninsular India and southeast Asia.
Species | Jacanidae | Wikipedia | 137 | 58290264 | https://en.wikipedia.org/wiki/Jacanidae | Biology and health sciences | Charadriiformes | Animals |
Climate change in Brazil is mainly the climate of Brazil getting hotter and drier. The greenhouse effect of excess carbon dioxide and methane emissions makes the Amazon rainforest hotter and drier, resulting in more wildfires in Brazil. Parts of the rainforest risk becoming savanna.
Brazil's greenhouse gas emissions per person are higher than the global average, and Brazil is among the countries which emit a large amount of greenhouse gases. Greenhouse gas emissions by Brazil are almost 3% of the annual world total, firstly due to cutting down trees in the Amazon rainforest, which emitted more carbon dioxide in the 2010s than it absorbed, and secondly from large cattle farms, where cows belch methane. In the Paris Agreement, Brazil promised to reduce its emissions, but the Bolsonaro government between 2019 and 2022 has been criticized for doing too little to limit climate change or adapt to climate change.
Greenhouse gas emissions
In 2020, official figures were reported for 2016: agriculture 33.2%, energy sector 28.9%, land use, land-use change, and forestry (LULUCF) 27.1%. Industrial Processes and Product Use (IPPU) and waste contributed 6.4% and 4.5%, respectively.
According to the Brazilian Climate Observatory, the country emitted 2.17 billion gross tons of carbon dioxide equivalent (te) in 2019. Deforestation accounted for 968 million te, which was 44% of the total, agriculture emitted 598.7 million te (28%) and the energy sector 413.6 million te (19%), industry 99 million te (5%) and waste 96 million te (4%).
Emissions for 2019 are estimated at 2.8% of the world total. , Brazil is the 4th heaviest cumulative emitter at 110 Gt. In 2019, on average, Brazilians emitted 10 gross tons of equivalent each, compared to the global average of 7 tons per person.
Although the government has pledged net zero emissions by 2050, critics complain that immediate action is not being taken. Researcher Emilio La Rovere, one of the coordinators of a report from 2013, said: "if nothing is done to restrict post-2020 emissions, Brazil may emit 2.5 billion tons of carbon dioxide as early as 2030. To give you an idea, the number exceeds the total for 2005, when emissions totaled around 2 billion tons."
Agriculture
Cattle | Climate change in Brazil | Wikipedia | 482 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
In 2012, Brazil had the second largest number of cattle in the world, with 205 million head. Cows are ruminants that emit greenhouse gases such as methane and nitrous oxide.
Deforestation
Trees are cut down to create fields for cattle and soya. Deforestation peaked in 2004, then decreased until the early 2010s. Since then, deforestation has tended to increase through 2020.
Fossil fuels
The largest single emitter in the energy sector is oil products used as fuel for transport in Brazil, but some natural gas and coal is burnt by the electricity sector in Brazil. In 2016/17, coal-fired power stations in Brazil received over 1 billion reals in subsidies. In the Convention on Biological Diversity, Brazil committed to phasing out environmentally harmful subsidies by 2020, but the government said in 2022 that coal power would be subsidized until 2040.
Impacts on the natural environment
Temperature and weather changes
According to José Marengo, of the National Institute for Space Research, recent studies show that, with the exception of stretches of the coast of Chile, where there has been a slight cooling in recent decades, in all other areas of South America, forecasts indicate an increase in temperature. | Climate change in Brazil | Wikipedia | 243 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
The Amazon has a prominent role in regulating the climate throughout Brazil and other regions in South America. Its forest is a major carbon sink and is essential for the formation of the rains that irrigate much of the country. According to Marengo et al., 30% to 50% of the rainfall in the Amazon Basin originates in the forest itself through evaporation. "In addition, the humidity originated in the Amazon Basin is carried by the winds to other parts of the continent and is considered important in the formation of precipitation in regions distant from the Amazon itself." Naturally, if the forest disappears, the rains will disappear. A vicious circle is created in which if deforestation exceeds a certain critical level, estimated at losses of 40%, the forest will be unable to generate enough rain to maintain itself: the less forest, the less precipitation, and the less precipitation, the less forest. About 19% of the Amazon forest has already been lost, and recent studies indicate that it is close to passing the critical point, beyond which its degradation will become irreversible. In addition to the problems in the Amazon, all other national biomes – the Cerrado, the Semi-Arid, the Pantanal, the Atlantic Forest and the Pampa – also suffer important effects, most of them with an increasing tendency, contributing to amplify the cascading effects.
Another important part of the Brazilian rains comes from the circulation of ocean moisture. Global warming also has an impact on ocean currents that influence the Brazilian climate, and the winds that carry the humidity that reaches Brazil are having their patterns modified, with the effect of reducing the level of atmospheric humidity and disturbing the formation of clouds, reducing precipitation. Reducing rainfall, in turn, can dry underground aquifers. These combined factors mean, in total, a generalized reduction in the availability of water and drier environments in most of the nation. In some regions, however, due to different mechanisms, rainfall is expected to increase, also bringing adverse effects. According to the PBMC, "the change with the greatest impact will be a change in rainfall patterns. Research shows that in the south and southeast, regions that suffer from floods and landslides, rains will become stronger and more frequent. In the northeast, the trend is the opposite.
Projections of the First National Assessment Report on Climate Change (2012) | Climate change in Brazil | Wikipedia | 475 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
In the executive summary of the 1st PBMC Report, the limitations of the study are highlighted. Because some projections were made based on incomplete data, there is some uncertainty about the conclusions. Despite this,
"In general, the results of the models managed to capture the behavior of the present climate very well and, thus, despite the uncertainties, the projections of future climate changes throughout the 21st century are plausible. Therefore, such projections constitute innovative and valuable information both for the purpose of mitigation, as well as the planning of adaptation and minimization of impacts and vulnerability actions with the set of inhabiting society in different Brazilian biomes. Taking into account the different projections that imply potential impacts on natural and human systems (socioeconomic and environmental), it is already possible to analyze the expected impacts of climate change in the various sectors of Brazil, and the planning and decision making to define adaptation strategies and mitigation policies."
For the Semi-Arid-Caatinga, an increase of up to 4.5 °C in air temperature and a reduction of up to 50% in rainfall are predicted. The environment, naturally very dry and with sparse vegetation, can partially become desert. For the Cerrado the disturbances would be similar, with an increase in temperature of up to 5.5 °C and a decrease of up to 45% in rainfall. The Cerrado today concentrates most of the agricultural activities in Brazil. The Pantanal would also be very affected, with up to a 4.5 °C increase and up to 45% less rain. In the Atlantic Forest, the climate would stay up to 3 °C warmer and up to 30% rainier. For Pampa, there would be up to 3 °C increase in temperature averages, and rains up to 40% above normal.
Not only will precipitation totals change, it may start to occur in more erratic and violent patterns, with more intense and prolonged droughts and more severe and frequent flooding episodes, varying in different regions. According to the report, "the scenarios point to a decrease in rainfall in the winter months across the country, as well as in the summer in eastern Amazonia and the Northeast. [...] In contrast, the country could experience an increase in the frequency and intensity of intense rain in the subtropical region (South region and part of the Southeast) and in the extreme west of the Amazon." Changes in the levels and availability of groundwater are also foreseen. | Climate change in Brazil | Wikipedia | 494 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
Sea level rise
Measurements on the coast of São Paulo indicate that sea level has risen 30 cm in the last century, surpassing the world average, and there are already many signs of coastal erosion, groundwater is gradually salted, the hangovers become higher, causing damage to the infrastructure of coastal cities. Twenty beaches are in danger of disappearing. In Recife, the famous Boa Viagem beach lost some sections swallowed by the sea, and Olinda lost 59% of its strip of sand between 1995 and 2010.
Ecosystems
Brazil's ecosystems will be impacted by temperature changes and rainfall changes. In the projections of the 1st Report, by the end of the 21st century, the Amazon may experience a reduction of up to 45% in rainfall, and an increase in the average temperature of up to 6 °C. This comes close to the worst scenarios foreseen by the Intergovernmental Panel on Climate Change (IPCC), which predicted important changes in most of the biome. However, the impact of deforestation was not considered in the assessment, which will certainly increase the levels of variation to some extent. The evolution of the future scenario will depend on the country's success in managing the serious threats to the biome. After a decade-long trend of reduced deforestation rates, recent years have documented a rapid increase in destruction of trees. A report estimated that if 40% of the forest disappears, droughts will increase and turn much of the forest into savanna. This will result in a drastic reduction in biodiversity and will also have a negative effect on the amount of rain Brazil can expect.
Impacts on people
Economic impacts
There are multiple impacts of climate change on basic Brazilian production systems, such as increasing existing shortages and increasing production costs. It is also expected that more and more serious natural disasters will occur. This will likely result in major problems for food supply, public health, industrial production, trade, installed infrastructure, the general quality of life of the population and national security as a whole, with the poor suffering the most serious consequences. The areas most vulnerable to major impacts are the Northeast and Southeast regions, exactly where most of the Brazilian people are concentrated, and large cities, which in general are poorly prepared to face the challenge.
Agriculture | Climate change in Brazil | Wikipedia | 449 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
In the agricultural sector, the impacts of climate change in Brazil would be multiple and significant. About 11 million hectares of arable land could be lost by 2030 due to warming. As global warming also produces several chemical and physical changes in the ocean, interfering with aquatic life, problems are foreseen for national fishing, both by reducing stocks and by geographic redistribution of economically valuable species.
A 2008 study, directly inspired by the work of the IPCC, especially in the Fourth Report, was produced by Embrapa focusing on agribusiness and food security. Its main conclusions are:
Global warming can jeopardize Brazilian food production, leading to losses that can reach 7.4 billion reals in 2020 and up to 14 billion in 2070;
Soy, whose explosive growth in the last 30 years has triggered an unprecedented change in the country's economic structure, is likely to be the crop most affected. In the worst-case scenario, losses could reach 40% in 2070, leading to a loss of up to 7.6 billion reals;
Coffee is expected to lose up to 33% of the low-risk area in the main producing states, São Paulo and Minas Gerais, although it may have gains in the south of the country;
Corn, rice, beans, cotton and sunflower will suffer a strong reduction of low risk area in the Northeast, with significant loss of production.
Cassava will have a general gain in low risk area, but will likely suffer severe losses in the Northeast;
Sugarcane, one of the few favored crops, could double its area in the coming decades.
"From one of the villains of global warming (See note:), agriculture can become a victim. Throughout the world, warming will only benefit agriculture practiced in high-latitude regions. ... The configuration of Brazilian agricultural production, as it is known today, can change significantly due to global warming. ... Regions that are currently the largest grain producers may not be able to plant well before the end of the century. ... Despite the losses, agriculture can be part of the solution to the problem. A more appropriate use of the soil, with the adoption, for example, of agropastoral, agro-forestry and no-tillage systems, besides reducing the use of fertilizers, can prevent new deforestation, increase the capture of carbon dioxide from the atmosphere and recover the soil. Some new techniques for growing rice and raising livestock are also being tested to decrease methane emissions". | Climate change in Brazil | Wikipedia | 508 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
In 2022, a study found that 28% of the agricultural land in Brazil is no longer climatically optimal for agriculture due to climate change and to change in local climate as a result of deforestation. The number will go up to 51% by 2030 and 74% by 2060 if the change in climate will continue in the same way.
Cattle Industry
The 2012 drought in the Northeast affected more than ten million people and generated a loss of more than R$16 billion. In 2013, the phenomenon was repeated with even greater intensity, being considered by the UN the worst of the last 50 years, leaving 1,200 municipalities in a state of emergency. In Paraíba alone, 360,000 heads of cattle died.
Energy sector
Climate change in Brazil may also result in an energy crisis, since the largest percentage of national electricity is generated by hydroelectric plants. It is expected that there will be an important drop in the flow of most of the great national hydrographic basins. According to the Climate Observatory, | Climate change in Brazil | Wikipedia | 201 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
"The result is dramatic for those who think that the Southeast of Brazil has suffered enough from lack of water and the threat of energy rationing in the last three years: in the best scenario, several rivers in Minas Gerais, São Paulo, Goiás, Tocantins, Bahia and Pará will have flow reductions of 10% to 30%. Transposed to hydroelectric plants, the flow data presents a challenge for the energy sector in Brazil: the most important plants in the country – Furnas, Itaipu, Sobradinho and Tucuruí – would have flow reductions of 38% to 57% in the worst case scenario. In the Amazon, a region elected by the government as the new frontier for hydroelectricity in the country, the falls would also be significant, as the Climate Observatory said in April: the flow of Belo Monte would fall from 25% to 55%, that of Santo Antônio, from 40% to 65%, and that of the planned plant in São Luís do Tapajós, from 20% to 30%. With the exception of São Luís, most of the new plants in the Amazon are run-of-river, that is, they do not have a large reservoir. This means that its capacity factor, that is, the amount of constant energy generated throughout the year, is reduced, since the flow of Amazonian rivers varies enormously between the dry and the rainy seasons. Belo Monte, for example, has a capacity factor of around 40%, which, reduced by half, would give the R$30 billion hydroelectric power plant a smaller capacity factor than that of wind farms – at which Brazilian energy planners and President Dilma Rousseff turn up their noses, as these plants are not capable of generating 'firm power' in periods without wind. In total, hydroelectric generation falls from 8% to 20% in the country. ... | Climate change in Brazil | Wikipedia | 383 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
"The researchers' analysis shows that, in all the scenarios analyzed, there is a drop in the flow of the main Brazilian hydrographic basins, which pushes the electrical system into a situation of structural imbalance: the system is unable to meet demand, causing load shedding – that is blackouts. Without measures to cut emissions, in the worst case scenario, the flow of reservoirs drops by 30% and the risk of deficit in some years approaches 100% – the margin considered 'safe' by the government to prevent blackouts is 5%. In the best scenario, the drop in flow from hydroelectric plants reaches 10%, and the risk of deficit, 60% in some years. The cost of operating the system, which takes into account even the activation of thermal plants, rises eight times in the best scenario and 16.7 times in the worst ".
This would have negative consequences in other ways, as it would encourage the use of coal and natural gas-fired power plants, which are major emitters of greenhouse gases.
Health impacts
Heat waves
A special alert was given in a 2015 report for the increased risk of extreme heat waves, mainly affecting the elderly and the North and Northeast regions, further aggravating pre-existing diseases, such as respiratory problems. José Feres, from the Institute of Applied Economic Research, said that Brazil's ageing population is particularly at risk. The report also pointed to the tendency towards an increase in endemic infectious diseases such as malaria, dengue and leptospirosis, the tendency towards an increase in the problems of conservation of the road network, and showed concern about Brazil's little preparation in the management of climatic disasters and the scarce information available on the future impacts of rising sea levels.
Floods and landslides
In the city of São Paulo alone, where rain is forecast to increase, flooding causes a loss of 762 million reals per year. In the floods and landslides in Rio de Janeiro in 2011, the greatest natural tragedy ever experienced in the country, 906 people died, 400 were reported missing, 30,000 had to leave their homes, 770 hillsides had their stability compromised, and will need to be reconsolidated at an estimated cost of 3.3 billion reals. The loss for companies reached R$470 million. In 2011, according to the UN calculation, floods throughout Brazil totaled 10 billion reals in material losses and claimed more than a thousand lives, in addition to leaving homeless crowds and producing disorders of various orders that will take years to be balanced. | Climate change in Brazil | Wikipedia | 511 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
A report from 2013 found that the coastal region, where the vast majority of the country's population lives, should receive special attention, in view of a likely increase in floods, landslides, severe weather, coastal erosion, rising sea levels and other natural disasters caused by warming: "It is no longer possible, as a Brazilian, to accept more disasters that kill more than a thousand Brazilians at once. Protective and preventive measures have to be taken urgently. Extreme events are happening more often. The population that is not prepared, will suffer from it."
Impacts on housing
Researcher Andrea Santos, executive secretary of PBMC, warned in 2013 about the likely impact on megacities such as Rio and São Paulo, stating that the current infrastructure, especially in transport and urban mobility, was not designed to face rising temperatures and more intense rainfall.
"Between 1991 and 2012, more than half of the Brazilian population had their lives affected by extreme weather events. Droughts, floods and landslides affected 127 million people. The number of records has grown 40% in the past decade compared to the previous one, according to the Brazilian Atlas of Natural Disasters. Recent tragedies include that of Santa Catarina, in 2008, and that of serra fluminense, in 2011. This year, a fifth of the country's municipalities entered an emergency or public calamity situation. Global warming, combined with urban expansion and the development problems that Brazil already has, allows us to project a gloomy scenario for this century, in which the number of people affected and the cost of tragedies for the economy only increase. And no one will be spared."
Impacts on indigenous peoples
Indigenous people consist of 40 million of the Latin American-Caribbean populations. They populate most of the rural poor areas in countries such as Ecuador, Brazil, Peru and Paraguay. This makes these populations extremely susceptible to threats of climate change due to socioeconomic, geographic, and political factors.
Mitigation and adaptation
Policies and legislation | Climate change in Brazil | Wikipedia | 402 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
Suzana Bustamante, one of the coordinators of Working Group 3 of the 5th IPCC Report, considers that the greatest threats hanging over Brazil stem from the expected reduction in rainfall in most of the area of food production and capture for hydroelectric and consumption, the country's strategy, both adaptive and mitigating, of investing in reducing deforestation must be a priority for the country, as forests are major producers and conservators of water resources, in addition to all the other essential environmental services they provide and all the biodiversity they harbor. Brazil is the most biodiverse country in the world, an invaluable wealth that is at great risk and is suffering continuous losses.
Jair Bolsonaro has said that foreigners should stop complaining about fires in the Amazon, and the country's environmental policies and in 2020 accused them of a "brutal disinformation campaign." In 2021, Brazil announced that it will not block carbon market agreements in COP26 what has significant importance.
Brazil 2040: scenarios and alternatives for adapting to climate change
Published in 2015 by the Secretariat for Sustainable Development of the Secretariat for Strategic Affairs of the Presidency of the Republic, the Brazil 2040 report was considered by the Climate Observatory to be the largest study carried out to date on climate change in Brazil. It had the main objective of giving guidance to the government for the establishment of a more coherent and solid climate policy, focusing on the areas of health, water resources, energy, agriculture and infrastructure (coastal and transport), and using two theoretical models that were used by the IPCC. The report obtained results that are broadly consistent with other studies, pointing to a country that is mostly drier and warmer in the future. | Climate change in Brazil | Wikipedia | 347 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
Brazil 2040 emphasized the country's lack of preparedness to face the expected climatic disasters that are expected to worsen with the progress of climate change, such as major droughts and floods, storms, rising levels sea and landslides caused by torrential rains. It was also identified that despite the numerous mitigation and adaptation programs already approved by the Union, States and Municipalities, they typically do not leave the paper, or produce timid or marginal results.
Analyzing the case of the emergency support structure in the city of Rio de Janeiro, it was pointed out that the majority of the resources for assisting the population (hospitals, military and police facilities, fire departments, etc.) are located in medium or high areas. Vulnerability to natural disasters, along rivers and canals or in low-lying regions, which can easily flood, or at the seaside, subject to rising levels and coastal storms, and can be compromised even in small climatic events, harming their functionality and increasing impacts on society. The majority of water and sewage treatment plants are located in the same regions, as well as many points on the main highways and streets, including some major road junctions, offering increased risks in the event of a disaster in terms of sanitation, supply and transportation of flagellates. Even worse is the situation of transportation by the subway, which is mostly in regions of high vulnerability. Citing the threat of sea level rise, it was pointed out that there is real estate value in the order of 124 billion reals located in areas of high vulnerability, and 2.7 trillion reals in areas of medium vulnerability. In the case of the city of Santos, most of the urban area is in an area of high vulnerability and many in areas of very high vulnerability, which puts the entire city at high risk, with more than R$100 billion in real estate values in regions of high vulnerability. The report stated that these examples can be extrapolated to many other regions of Brazil with a high demographic density, since most cities are in low coastal regions or next to rivers, lakes and fragile hillsides. Port areas also present increased risks of deterioration or destruction of structures, flooding, silting of channels and estuarine bars and others, and a large part of Brazil's national and international trade depends on them. | Climate change in Brazil | Wikipedia | 462 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
Suzana Kahn Ribeiro, president of the Scientific Committee of the Brazilian Panel on Climate Change, has a very similar opinion: "Brazil needs to find a direction, define what it wants to be when it grows up. ... Brazil is showing mixed signals all the time. We reduce IPI tax on car so that everyone gets bottled up in traffic. We are experiencing a blackout of climate coordination ". André Ferretti, general coordinator of the Climate Observatory, says the same:
"Today we have trillions of resources to be invested in infrastructure, plans to expand energy generation mainly from fossil sources (about 70% of the country's investments), annual harvest plans and industry incentives, without any connection with the logic of development. low carbon. We have a set of disconnected climate policies, without coordination and that do not even have their potential positive impacts monitored; and the Climate Fund is completely threatened and with limited resources. ... The great message of the IPCC's fifth report is that the situation is increasingly critical, and that if nothing or very little is done, we will enter a very dangerous path. The window of opportunity for us to prevent the collapse of the climate system is narrow."
Even some sectors of the government agree that there are problems in this area: Carlos Nobre, secretary of Research and Development Policies and Programs at the Ministry of Science, Technology and Innovation, said that "the Ministry of Science and Technology is playing its part, investing in research development and knowledge generation, but there is still a lack of integration between research and policy making."
Another of Brazil's latest Nationally Determined Contribution to the Paris Agreement aims to reduce greenhouse gas emissions by 48 percent by 2025 and 53 percent by 2030. President Luiz Inácio “Lula” da Silva has prioritized combating climate change, reestablishing the Amazon Fund to prevent deforestation and promote sustainable use of the Amazon. The United States Agency for International Development supports these efforts through initiatives focusing on biodiversity conservation, sustainable management of protected areas, and innovative financial instruments for nature-based solutions.
USAID’s Climate Change Program: Objectives and Results
USAID's climate change program in Brazil focuses on leveraging resources from the private sector for biodiversity conservation and improving local livelihoods. Key results from 2022 include avoiding more than 23 million metric tons of CO2 equivalent GHG emissions, strengthening the management of 117 Protected Areas covering 47.9 million hectares, and reducing deforestation rates in USAID-supported areas.
Society and culture | Climate change in Brazil | Wikipedia | 512 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
Activism
Calculations in 2021 showed that, for giving the world a 50% chance of avoiding a temperature rise of 2 degrees or more, Brazil should increase its climate commitments by 90%. For a 95% chance, it should increase the commitments by 165%. For giving a 50% chance of staying below 1.5 degrees Brazil, should increase its commitments by 170%.
A report from 2013 aimed to dispel some ingrained myths that represent major obstacles to the general acceptance of mitigation projects, such as that progress and nature conservation are opposed, or that the consequence of reducing emissions will be economic recession. | Climate change in Brazil | Wikipedia | 123 | 66412282 | https://en.wikipedia.org/wiki/Climate%20change%20in%20Brazil | Physical sciences | Climate change | Earth science |
The calcium cycle is a transfer of calcium between dissolved and solid phases. There is a continuous supply of calcium ions into waterways from rocks, organisms, and soils. Calcium ions are consumed and removed from aqueous environments as they react to form insoluble structures such as calcium carbonate and calcium silicate, which can deposit to form sediments or the exoskeletons of organisms. Calcium ions can also be utilized biologically, as calcium is essential to biological functions such as the production of bones and teeth or cellular function. The calcium cycle is a common thread between terrestrial, marine, geological, and biological processes. Calcium moves through these different media as it cycles throughout the Earth. The marine calcium cycle is affected by changing atmospheric carbon dioxide due to ocean acidification.
Calcium weathering and inputs to seawater
Calcium is stored in geologic reservoirs, most commonly in the form of calcium carbonate or as calcium silicate. Calcium-containing rocks include calcite, dolomite, phosphate, and gypsum. Rocks slowly dissolve by physical and chemical processes, carrying calcium ions into rivers and oceans. Calcium ions (Ca2+) and magnesium ions (Mg2+) have the same charge (+2) and similar sizes, so they react similarly and are able to substitute for each other in some minerals, such as carbonates. Ca2+-containing minerals are often more easily weathered than Mg2+ minerals, so Ca2+ is often more enriched in waterways than Mg2+. Rivers containing more dissolved Ca2+ are generally considered more alkaline.
Calcium is one of the most common elements found in seawater. Inputs of dissolved calcium (Ca2+) to the ocean include the weathering of calcium sulfate, calcium silicate, and calcium carbonate, basalt-seawater reaction, and dolomitization.
Biogenic calcium carbonate and the biological pump
Biogenic calcium carbonate is formed when marine organisms, such as coccolithophores, corals, pteropods, and other mollusks transform calcium ions and bicarbonate into shells and exoskeletons of calcite or aragonite, both forms of calcium carbonate. This is the dominant sink for dissolved calcium in the ocean. Dead organisms sink to the bottom of the ocean, depositing layers of shell which over time cement to form limestone. This is the origin of both marine and terrestrial limestone.
Calcium precipitates into calcium carbonate according to the following equation: | Calcium cycle | Wikipedia | 496 | 58446217 | https://en.wikipedia.org/wiki/Calcium%20cycle | Physical sciences | Earth science basics: General | Earth science |
Ca2+ + 2HCO3− → CO2+ H2O + CaCO3
The relationship between dissolved calcium and calcium carbonate is affected greatly by the levels of carbon dioxide (CO2) in the atmosphere.
Increased carbon dioxide leads to more bicarbonate in the ocean according to the following equation:
CO2 + CO32− + H2O → 2HCO3−
With ocean acidification, inputs of carbon dioxide promote the dissolution of calcium carbonate and harm marine organisms dependent on their protective calcite or aragonite shells. The solubility of calcium carbonate increases with pressure and carbon dioxide and decreases with temperature. Thus, calcium carbonate is more soluble in deep waters than surface waters due to higher pressure and lower temperature. As a result, precipitation of calcium carbonate is more common in shallower oceans. The depth at which the rate of calcite dissolution equals the rate of calcite precipitation is known as calcite compensation depth.
Changes in global climate and the calcium cycle
Ocean acidity due to carbon dioxide has already increased by 25% since the industrial revolution. As carbon dioxide emissions continually increase and accumulate, this will negatively affect the lives of many marine ecosystems. The calcium carbonate used to form many marine organisms' exoskeletons will begin to break down, leaving these animals vulnerable and unable to live in their habitats. This ultimately has a flow on effect to predators, further affecting the function of many food webs globally.
Changes in calcium concentrations over geologic time
Calcium stable isotopes have been used to study inputs and outputs of dissolved calcium in marine environments. For example, one study found that calcium levels have decreased between 25 and 50 percent over a 40 million year timespan, suggesting that dissolved Ca2+outputs have exceeded its inputs. The isotope Calcium-44 can help to indicate variations in calcium carbonate over long timespans and help explain variants in global temperature. Declines in the isotope Calcium-44 usually correlate with periods of cooling, as dissolution of calcium carbonate typically signifies a decrease in temperature. Thus, Calcium isotopes correlate with Earth's climate over long periods of time. | Calcium cycle | Wikipedia | 424 | 58446217 | https://en.wikipedia.org/wiki/Calcium%20cycle | Physical sciences | Earth science basics: General | Earth science |
Human/animal use of calcium
Being an essential element, calcium is obtained through dietary sources, the majority of which comes from dairy products. The most significant mechanisms controlling calcium use within the body are intestinal absorption, renal filtration, renal reabsorption and bone turnover, which are controlled predominantly by hormones and their corresponding receptors in the gut, kidneys and bones respectively. This allows for calcium use throughout the body, namely in bone growth, cellular signalling, blood clotting, muscle contraction and neuron function.
Calcium is one of the essential components of bone, contributing to its strength and structure in addition to being the main site at which it is stored within the body. Within the muscles, its primary use is to enable contractions. Muscle cells draw calcium from the blood, allowing it to bind with troponin, a component of the muscle fibre that signals for a contraction by moving actin and myosin. After a contraction, calcium dissipates and the filaments move back to a resting state before the release of more calcium for the next contraction. Furthermore, calcium plays a significant role in allowing nerve impulses to be transmitted between neurons. The release of calcium ions from voltage gated ion channels signals for the release of neurotransmitters into the synapse. This allows for the depolarisation of a neuron, thus transmitting the signal to the next neuron where this process is once again repeated. Without the presence of calcium ions, the release of neurotransmitters would not occur, preventing signals from being sent and hindering body processes. | Calcium cycle | Wikipedia | 326 | 58446217 | https://en.wikipedia.org/wiki/Calcium%20cycle | Physical sciences | Earth science basics: General | Earth science |
Negative feedback mechanisms are implemented in order to control calcium levels. When low calcium levels are detected in the body, the parathyroid releases parathyroid hormone (PTH) which travels through the bloodstream to the bones and kidneys. In the bones, the presence of PTH stimulates osteoclasts. These cells break down bone to release calcium into the bloodstream where it can be used by the rest of the body in the above processes. In the kidneys, PTH stimulates re-absorption of calcium so it in not lost from the body through urine and returned to the bloodstream instead. Lastly, PTH acts on the intestines by indirectly promoting enzymes that activate vitamin D, a signal for the intestines to absorb more calcium, further increasing blood calcium levels. This will continue until the body releases too much calcium into the bloodstream. Excess calcium then promotes the release of calcitonin from the thyroid gland, effectively reversing the process of PTH. Osteoclast activity is stopped and osteoblasts take over, utilising the excess calcium in the bloodstream to form new bone. Calcium re-absorption in the kidney is prevented, allowing the excretion of excess calcium through the urine. Through these hormonal mechanisms, calcium homeostasis is maintained within the body.
Calcium in plants and soil | Calcium cycle | Wikipedia | 279 | 58446217 | https://en.wikipedia.org/wiki/Calcium%20cycle | Physical sciences | Earth science basics: General | Earth science |
Calcium is an essential component of soil. When deposited in the form of lime, it cannot be used by plants. To combat this, carbon dioxide produced by plants reacts with water in the environment to produce carbonic acid. Carbonic acid is then able to dissolve limestone, enabling the release of calcium ions. This reaction is more readily available with smaller particles of limestone than it is with large pieces of rock due to the increased surface area. When lime is leached into soil, calcium levels inevitably increase, both stabilising pH and enabling calcium to mix with water to form Ca2+ ions, thus making it soluble and accessible to plants to be absorbed and utilised by the root system. The calcium ions travel up the xylem of the plant alongside water to reach the leaves. The plant can utilise this calcium in the form of calcium pectate to stabilise cell walls and provide rigidity. Calcium is also used by plant enzymes to signal growth and coordinate life-promoting processes. Additionally, the release of calcium ions enables microorganisms to access phosphorus and other micro nutrients with greater ease, improving the soil ecosystem drastically thus indirectly promoting plant growth and nutrition.
Inevitable plant and animal death results in the return of calcium contained within the organism back into the soil to be utilised by other plants. Decomposing organisms break them down, returning the calcium back into the soil and enabling the cycling of calcium to continue. Additionally, these animals and plants are eaten by other animals, similarly continuing the cycle. It is however important to note the modern introduction of calcium into the soil by humans (through fertilisers and other horticultural products) has resulted in a higher concentration of calcium contained within soil.
Industrial uses of calcium and its impact on the calcium cycle
The naturally occurring calcium cycle has been altered by human intervention. Calcium is predominantly extracted from limestone deposits to be utilised by many industrial processes. Purification of iron ore and aluminium, replacing asbestos brake linings and some coatings for electric cables, are some of these major uses of calcium. Furthermore, calcium is used within the household to maintain alkaline pH of swimming pools, counteracting acidic disinfectants and in the food production industry to produce bicarbonate soda, some wines and dough. | Calcium cycle | Wikipedia | 456 | 58446217 | https://en.wikipedia.org/wiki/Calcium%20cycle | Physical sciences | Earth science basics: General | Earth science |
With its widespread uses, a large volume of calcium must be obtained from mines and quarries to supply the high demand. As more limestone and water is removed from mines, underground stores of rock are often weakened making the ground more susceptible to sink holes. Sinkholes and mining both affect the presence of groundwater, potentially leading to a lower water table or altered pathways of flowing water. This may affect local ecosystems or farmland as the water supply is restricted. Additionally, the water that is released from mining areas will have higher concentrations of dissolved calcium. This can either be released into oceans or absorbed by the soil. Whilst not always detrimental, it alters the natural calcium cycle which may have flow-on effects for ecosystems. Furthermore, water being pumped from mines increases the danger of downstream flooding whilst simultaneously decreasing the volume on water in upstream reservoirs such as marshes, ponds of wetlands It is however important to note than limestone mining is comparatively less damaging than other mining process, with potential to restore the environment after the mine is no longer in use
The importance of the calcium cycle and future predictions
The calcium cycle links ionic and non ionic calcium together in both marine and terrestrial environments and is essential for the functioning of all living organisms. In animals, calcium enables neurons to transmit signals by opening voltage gated channels that allow neurotransmitters to reach the next cell, bone formation and development and kidney function, whilst being maintained by hormones that ensure calcium homeostasis is reached. In plants, calcium promotes enzyme activity and ensures cell wall function, providing stability to plants. It also enables crustaceans to form shells and corals to exist, as calcium provides structure, rigidity and strength to structures when complexed (combined) to other atoms. Without its presence in the environment, many life-preserving processes would not exist. In the modern context, calcium also enables many industrial processes to occur, promoting further technological developments.
With its close relation to the carbon cycle and the effects of greenhouse gasses, both calcium and carbon cycles are predicted to change in the coming years. Tracking calcium isotopes enables the prediction of environmental changes, with many sources suggesting increasing temperatures in both the atmosphere and marine environment. As a result, this will drastically alter the breakdown of rock, the pH of oceans and waterways and thus calcium sedimentation, hosting an array of implications on the calcium cycle. | Calcium cycle | Wikipedia | 469 | 58446217 | https://en.wikipedia.org/wiki/Calcium%20cycle | Physical sciences | Earth science basics: General | Earth science |
Due to the complex interactions of calcium with many facets of life, the effects of altered environmental conditions are unlikely to be known until they occur. Predictions can however be tentatively made, based upon evidence-based research. Increasing carbon dioxide levels and decreasing ocean pH will alter calcium solubility, preventing corals and shelled organisms from developing their calcium-based exoskeletons, thus making them vulnerable or unable to survive. | Calcium cycle | Wikipedia | 86 | 58446217 | https://en.wikipedia.org/wiki/Calcium%20cycle | Physical sciences | Earth science basics: General | Earth science |
An ecosystem, short for ecological system, is defined as a collection of interacting organisms within a biophysical environment. Ecosystems are never static, and are continually subject to both stabilizing and destabilizing processes. Stabilizing processes allow ecosystems to adequately respond to destabilizing changes, or perturbations, in ecological conditions, or to recover from degradation induced by them: yet, if destabilizing processes become strong enough or fast enough to cross a critical threshold within that ecosystem, often described as an ecological 'tipping point', then an ecosystem collapse (sometimes also termed ecological collapse). occurs.
Ecosystem collapse does not mean total disappearance of life from the area, but it does result in the loss of the original ecosystem's defining characteristics, typically including the ecosystem services it may have provided. Collapse of an ecosystem is effectively irreversible more often than not, and even if the reversal is possible, it tends to be slow and difficult. Ecosystems with low resilience may collapse even during a comparatively stable time, which then typically leads to their replacement with a more resilient system in the biosphere. However, even resilient ecosystems may disappear during the times of rapid environmental change, and study of the fossil record was able to identify how certain ecosystems went through a collapse, such as with the Carboniferous rainforest collapse or the collapse of Lake Baikal and Lake Hovsgol ecosystems during the Last Glacial Maximum.
Today, the ongoing Holocene extinction is caused primarily by human impact on the environment, and the greatest biodiversity loss so far had been due to habitat degradation and fragmentation, which eventually destroys entire ecosystems if left unchecked. There have been multiple notable examples of such an ecosystem collapse in the recent past, such as the collapse of the Atlantic northwest cod fishery. More are likely to occur without a change in course, since estimates show that 87% of oceans and 77% of the land surface have been altered by humanity, with 30% of global land area is degraded and a global decline in ecosystem resilience. Deforestation of the Amazon rainforest is the most dramatic example of a massive, continuous ecosystem and a biodiversity hotspot being under the immediate threat from habitat destruction through logging, and the less-visible, yet ever-growing and persistent threat from climate change. | Ecosystem collapse | Wikipedia | 465 | 58458383 | https://en.wikipedia.org/wiki/Ecosystem%20collapse | Biology and health sciences | Ecology | Biology |
Biological conservation can help to preserve threatened species and threatened ecosystems alike. However, time is of the essence. Just as interventions to preserve a species have to occur before it falls below viable population limits, at which point an extinction debt occurs regardless of what comes after, efforts to protect ecosystems must occur in response to early warning signals, before the tipping point to a regime shift is crossed. Further, there is a substantial gap between the extent of scientific knowledge how extinctions occur, and the knowledge about how ecosystems collapse. While there have been efforts to create objective criteria used to determine when an ecosystem is at risk of collapsing, they are comparatively recent, and are not yet as comprehensive. While the IUCN Red List of threatened species has existed for decades, the IUCN Red List of Ecosystems has only been in development since 2008.
Definition
Ecosystem collapse has been defined as a "transformation of identity, loss of defining features, and replacement by a novel ecosystem", and involves the loss of "defining biotic or abiotic features", including the ability to sustain the species which used to be associated with that ecosystem. According to another definition, it is "a change from a baseline state beyond the point where an ecosystem has lost key defining features and functions, and is characterised by declining spatial extent, increased environmental degradation, decreases in, or loss of, key species, disruption of biotic processes, and ultimately loss of ecosystem services and functions". Ecosystem collapse has also been described as "an analogue of species extinction", and in many cases, it is irreversible, with a new ecosystem appearing instead, which may retain some characteristics of the previous ecosystem, yet has agreatly altered structure and function. There are exceptions where an ecosystem can be recovered past the point of a collapse, but by definition, will always be far more difficult to reverse than allowing a disturbed yet functioning ecosystem to recover, requiring active intervention and/or a prolonged period of time even if it can be reversed.
Drivers
While collapse events can occur naturally with disturbances to an ecosystem—through fires, landslides, flooding, severe weather events, disease, or species invasion—there has been a noticeable increase in human-caused disturbances over the past fifty years. The combination of environmental change and the presence of human activity is increasingly detrimental to ecosystems of all types, as our unrestricted actions often increase the risk of abrupt (and potentially irreversible) changes post-disturbance; when a system would otherwise have been able to recover. | Ecosystem collapse | Wikipedia | 499 | 58458383 | https://en.wikipedia.org/wiki/Ecosystem%20collapse | Biology and health sciences | Ecology | Biology |
Some behaviors that induce transformation are: human intervention in the balance of local diversity (through introduction of new species or overexploitation), alterations in the chemical balance of environments through pollution, modifications of local climate or weather with anthropogenic climate change, and habitat destruction or fragmentation in terrestrial/marine systems. For instance, overgrazing was found to cause land degradation, specifically in Southern Europe, which is another driver of ecological collapse and natural landscape loss. Proper management of pastoral landscapes can mitigate risk of desertification.
Despite the strong empirical evidence and highly visible collapse-inducing disturbances, anticipating collapse is a complex problem. The collapse can happen when the ecosystem's distribution decreases below a minimal sustainable size, or when key biotic processes and features disappear due to environmental degradation or disruption of biotic interactions. These different pathways to collapse can be used as criteria for estimating the risk of ecosystem collapse. Although states of ecosystem collapse are often defined quantitatively, few studies adequately describe transitions from pristine or original state towards collapse.
Geological record
In another example, 2004 research demonstrated how during the Last Glacial Maximum (LGM), alternations in the environment and climate led to a collapse of Lake Baikal and Lake Hovsgol ecosystems, which then drove species evolution. The collapse of Hovsgol's ecosystem during the LGM brought forth a new ecosystem, with limited biodiversity in species and low levels of endemism, in Hovsgol during the Holocene. That research also shows how ecosystem collapse during LGM in Lake Hovsgol led to higher levels of diversity and higher levels of endemism as a byproduct of subsequent evolution.
In the Carboniferous period, coal forests, great tropical wetlands, extended over much of Euramerica (Europe and America). This land supported towering lycopsids which fragmented and collapsed abruptly. The collapse of the rainforests during the Carboniferous has been attributed to multiple causes, including climate change and volcanism. Specifically, at this time climate became cooler and drier, conditions that are not favourable to the growth of rainforests and much of the biodiversity within them. The sudden collapse in the terrestrial environment made many large vascular plants, giant arthropods, and diverse amphibians to go extinct, allowing seed-bearing plants and amniotes to take over (but smaller relatives of the affected ones survived also).
Historic examples of collapsed ecosystems | Ecosystem collapse | Wikipedia | 491 | 58458383 | https://en.wikipedia.org/wiki/Ecosystem%20collapse | Biology and health sciences | Ecology | Biology |
The Rapa Nui subtropical broadleaf forests in Easter Island, formerly dominated by an endemic Palm, are considered collapsed due to the combined effects of overexplotaition, climate change and introduced exotic rats.
The Aral Sea was an endorheic lake between Kazakhstan and Uzbekistan. It was once considered one of the largest lakes in the world but has been shrinking since the 1960s after the rivers that fed it were diverted for large scale irrigation. By 1997, it had declined to 10% of its original size, splitting into much smaller hypersaline lakes, while dried areas have transformed into desert steppes.
The regime shift in the northern Benguela upwelling ecosystem is considered an example of ecosystem collapse in open marine environments. Prior to the 1970s sardines were the dominant vertebrate consumers, but overfishing and two adverse climatic events (Benguela Niño in 1974 and 1984) lead to an impoverished ecosystem state with high biomass of jellyfish and pelagic goby.
Another notable example is the collapse of the Grand Banks cod in the early 1990s, when overfishing reduced fish populations to 1% of their historical levels.
Contemporary risk
There are two tools commonly used together to assess risks to ecosystems and biodiversity: generic risk assessment protocols and stochastic simulation models. The most notable of the two tactics is risk assessment protocol, particularly because of the IUCN Red List of Ecosystems (RLE), which is widely applicable to many ecosystems even in data-poor circumstances. However, because using this tool is essentially comparing systems to a list of criteria, it is often limited in its ability to look at ecosystem decline holistically; and is thus often used in conjunction with simulation models that consider more aspects of decline such as ecosystem dynamics, future threats, and social-ecological relationships. | Ecosystem collapse | Wikipedia | 362 | 58458383 | https://en.wikipedia.org/wiki/Ecosystem%20collapse | Biology and health sciences | Ecology | Biology |
The IUCN RLE is a global standard that was developed to assess threats to various ecosystems on local, regional, national, and global scales, as well as to prompt conservation efforts in the face of the unparalleled decline of natural systems in the last decade. And though this effort is still in the earlier stages of implementation, the IUCN has a goal to assess the risk of collapse for all of the world's ecosystems by 2025. The concept of ecosystem collapse is used in the framework to establish categories of risk for ecosystems, with the category Collapsed used as the end-point of risk assessment. Other categories of threat (Vulnerable, Endangered and Critically Endangered) are defined in terms of the probability or risk of collapse. A paper by Bland et al. suggests four aspects for defining ecosystem collapse in risk assessments:
qualitatively defining initial and collapsed states
describing collapse and recovery transitions
identifying and selecting indicators of collapse
setting quantitative collapse thresholds.
Early detection and monitoring
Scientists can predict tipping points for ecosystem collapse. The most frequently used model for predicting food web collapse is called R50, which is a reliable measurement model for food web robustness. However, there are others: i.e. marine ecosystem assessments can use RAM Legacy Stock Assessment Database. In one example, 154 different marine fish species were studied to establish the relationship between pressures on fish populations such as overfishing and climate change, these populations; traits like growth rate, and the risk of ecosystem collapse.
The measurement of "critical slowing down" (CSD) is one approach for developing early warning signals for a potential or likely onset of approaching collapse. It refers to increasingly slow recovery from perturbations.
In 2020, one paper suggested that once a 'point of no return' is reached, breakdowns do not occur gradually but rapidly and that the Amazon rainforest could shift to a savannah-type mixture of trees and grass within 50 years and the Caribbean coral reefs could collapse within 15 years once a state of collapse has been reached. Another indicated that large ecosystem disruptions will occur earlier under more intense climate change: under the high-emissions RCP8.5 scenario, ecosystems in the tropical oceans would be the first to experience abrupt disruption before 2030, with tropical forests and polar environments following by 2050. In total, 15% of ecological assemblages would have over 20% of their species abruptly disrupted if as warming eventually reaches ; in contrast, this would happen to fewer than 2% if the warming were to stay below .
Rainforest collapse | Ecosystem collapse | Wikipedia | 505 | 58458383 | https://en.wikipedia.org/wiki/Ecosystem%20collapse | Biology and health sciences | Ecology | Biology |
Rainforest collapse refers to the actual past and theoretical future ecological collapse of rainforests. It may involve habitat fragmentation to the point where little rainforest biome is left, and rainforest species only survive in isolated refugia. Habitat fragmentation can be caused by roads. When humans start to cut down the trees for logging, secondary roads are created that will go unused after its primary use. Once abandoned, the plants of the rainforest will find it difficult to grow back in that area. Forest fragmentation also opens the path for illegal hunting. Species have a hard time finding a new place to settle in these fragments causing ecological collapse. This leads to extinction of many animals in the rainforest.
A classic pattern of forest fragmentation is occurring in many rainforests including those of the Amazon, specifically a 'fishbone' pattern formed by the development of roads into the forest. This is of great concern, not only because of the loss of a biome with many untapped resources and wholesale death of living organisms, but also because plant and animal species extinction is known to correlate with habitat fragmentation.
In the year 2022, research found that more than three-quarters of the Amazon rainforest has been losing resilience due to deforestation and climate change since the early 2000s as measured by recovery-time from short-term perturbations (the critical slowing down), reinforcing the theory that it is approaching a critical transition. Another study from 2022 found that tropical, arid and temperate forests are substantially losing resilience.
Coral reefs
A major concern for marine biologists is the collapse of coral reef ecosystems.). An effect of global climate change is the rising sea levels which can lead to reef drowning or coral bleaching. Human activity, such as fishing, mining, deforestation, etc., serves as a threat for coral reefs by affecting the niche of the coral reefs. For example, there is a demonstrated correlation between a loss in diversity of coral reefs by 30-60% and human activity such as sewage and/or industrial pollution.
Conservation and reversal | Ecosystem collapse | Wikipedia | 413 | 58458383 | https://en.wikipedia.org/wiki/Ecosystem%20collapse | Biology and health sciences | Ecology | Biology |
As of now there is still not much information on effective conservation or reversal methods for ecosystem collapse. Rather, there has been increased focus on the predictability of ecosystem collapse, whether it is possible, and whether it is productive to explore. This is likely because thorough studies of at-risk ecosystems are a more recent development and trend in ecological fields, so collapse dynamics are either too recent to observe or still emerging. Since studies are not yet long term, conclusions about reversibility or transformation potential are often hard to draw from newer, more focused studies. | Ecosystem collapse | Wikipedia | 110 | 58458383 | https://en.wikipedia.org/wiki/Ecosystem%20collapse | Biology and health sciences | Ecology | Biology |
Windows 11 is the latest major release of Microsoft's Windows NT operating system, released on October 5, 2021. It succeeded Windows 10 (2015), and is available for free for any Windows 10 devices that meet the new Windows 11 system requirements.
Windows 11 features major changes to the Windows shell influenced by the canceled Windows 10X, including a redesigned Start menu, the replacement of its "live tiles" with a separate "Widgets" panel on the taskbar, the ability to create tiled sets of windows that can be minimized and restored from the taskbar as a group, and new gaming technologies inherited from Xbox Series X and Series S such as Auto HDR and DirectStorage on compatible hardware. Internet Explorer (IE) has been replaced by the Chromium-based Microsoft Edge as the default web browser, like its predecessor, Windows 10, and Microsoft Teams is integrated into the Windows shell. Microsoft also announced plans to allow more flexibility in software that can be distributed via the Microsoft Store and to support Android apps on Windows 11 (including a partnership with Amazon to make its app store available for the purpose).
Citing security considerations, the system requirements for Windows 11 were increased over Windows 10; Microsoft only officially supports the operating system on devices using an eighth-generation Intel Core CPU or newer (with some minor exceptions), a second-generation AMD Ryzen CPU or newer, or a Qualcomm Snapdragon 850 ARM system-on-chip or newer, with UEFI and Trusted Platform Module (TPM) 2.0 supported and enabled. There are some exceptions to these requirements, however . While the OS can be installed on devices with unsupported configurations, Microsoft does not guarantee the availability of updates. Furthermore, Windows 11 completely removes support for 32-bit CPUs, including both 32-bit x86 and 32-bit ARM processors, ensuring compatibility only with 64-bit x86-64 and ARM64 processors. | Windows 11 | Wikipedia | 395 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
Windows 11 received a mixed reception at launch. Pre-release coverage of the operating system focused on its stricter hardware requirements, with discussions over whether they were legitimately intended to improve the security of Windows, or as a ploy to upsell customers to newer devices, and over the e-waste associated with the changes. Upon release, it was praised for its improved visual design, window management, and stronger focus on security, but was criticized for various modifications to aspects of its user interface that were seen as worse than its predecessor; some were seen as an attempt to dissuade users from switching to competing applications. Additionally, some users have pointed out disadvantages such as the removal of features like the ability to move the taskbar and increased system requirements that may exclude older devices.
, Windows 11, accounting for 35% of Windows installations worldwide, is the second most popular Windows version in use, with its predecessor Windows 10 still being the most used version in virtually all countries (with Guyana being an exception, where Windows 11 is the most used), having over 2 times the market share globally. Windows 11 has an estimated 23% share of all PCs (the rest being other Windows editions and other operating systems such as macOS and Linux), and an estimated 8.6% share of all devices (including mobile, tablet and console) are running Windows 11.
To comply with the Digital Markets Act, Microsoft is allowing users in the European Economic Area to remove the Microsoft Edge browser, Microsoft Bing search engine, and advertisements to comply with users' interests.
Following the discontinuation of Windows Phone with Windows 10 Mobile in 2020, Windows 11 is the first major version of Windows NT without a companion mobile version.
Development
At the 2015 Ignite conference, Microsoft employee Jerry Nixon stated that Windows 10 would be the "last version of Windows". The operating system was considered to be a service, with new builds and updates to be released over time. PC World argued that the widely reported comment was however taken out of context, noting that the official event transcript marks it only as a segue rather than a core part of the talk. It argues that Nixon was referring to the fact that he could talk freely at the event because 10 was the last version in current development. | Windows 11 | Wikipedia | 456 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
In October 2019, Microsoft announced "Windows 10X", a future edition of Windows 10 designed exclusively for dual-touchscreen devices such as the then-upcoming Surface Neo. It featured a modified user interface designed around context-sensitive "postures" for different screen configurations and usage scenarios, and changes such as a centered taskbar and updated Start menu without Windows 10's "live tiles". Legacy Windows applications would also be required to run in "containers" to ensure performance and power optimization. Microsoft stated that it planned to release Windows 10X devices by the end of 2020.
In May 2020, during the COVID-19 pandemic, Panos Panay, Microsoft's chief product officer for Microsoft Windows and Microsoft Office, stated that "as we continue to put customers' needs at the forefront, we need to focus on meeting customers where they are now", and announced that Windows 10X would only launch on single-screen devices at first, and that Microsoft would "continue to look for the right moment, in conjunction with our OEM partners, to bring dual-screen devices to market".
In October 2020, reports emerged that Microsoft was working on a user interface refresh for Windows 10 codenamed "Sun Valley", scheduled to be included in a late-2021 feature update codenamed "Cobalt". Internal documentation stated that the aim for "Sun Valley" was to "reinvigorat[e]" the Windows user interface and make it more "fluid", with a more consistent application of WinUI, while reports suggested Microsoft planned to adapt UI elements seen in Windows 10X. In January 2021, it was reported that a job listing referring to a "sweeping visual rejuvenation of Windows" had been posted by Microsoft.
By December 2020, Microsoft had begun to implement and announce some of these visual changes and other new features on Windows 10 Insider Preview builds, such as new system icons (which also included the replacement of shell resources dating back as far as Windows 95), improvements to Task View to allow changing the wallpaper on each virtual desktop, x86-64 emulation on ARM, and adding the Auto HDR feature from Xbox Series X.
On May 18, 2021, Head of Windows Servicing and Delivery John Cable stated that Windows 10X had been canceled and that Microsoft would be "accelerating the integration of key foundational 10X technology into other parts of Windows and products at the company". | Windows 11 | Wikipedia | 494 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
Announcement
At the Microsoft Build 2021 developer conference, CEO and chairman Satya Nadella teased about the existence of the next generation of Windows during his keynote speech. According to Nadella, he had been self-hosting it for several months. He also teased that an official announcement would come very soon. Just a week after Nadella's keynote, Microsoft started sending invitations for a dedicated Windows media event at 11:00 a.m. ET on June24, 2021. Microsoft also posted an 11-minute video of Windows start-up sounds to YouTube on June10, 2021, with many people speculating both the time of the Microsoft event and the duration of the Windows start-up sound video to be a reference to the name of the operating system as Windows 11.
On June 24, 2021, Windows 11 was officially announced at a virtual event hosted by Chief Product Officer Panos Panay. According to Nadella, Windows 11 is "a re-imagining of the operating system". Further details for developers such as updates to the Microsoft Store, the new Windows App SDK (code-named "Project Reunion"), new Fluent Design guidelines, and more were discussed during another developer-focused event on the same day.
Release and marketing
The Windows 11 name was accidentally released in an official Microsoft support document in June 2021. Leaked images of a purported beta build of Windows 11's desktop surfaced online later on June 15, 2021, which were followed by a leak of the aforementioned build on the same day. The screenshots and leaked build show an interface resembling that of the canceled Windows 10X, alongside a redesigned out-of-box experience (OOBE) and Windows 11 branding. Microsoft would later confirm the authenticity of the leaked beta, with Panay stating that it was an "early weird build".
At the June 24 media event, Microsoft also announced that Windows 11 would be released in "Holiday 2021". Its release will be accompanied by a free upgrade for compatible Windows 10 devices through Windows Update. On June 28, Microsoft announced the release of the first preview build and SDK of Windows 11 to Windows Insiders. | Windows 11 | Wikipedia | 429 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
On August 31, 2021, Microsoft announced that Windows 11 was to be released on October 5, 2021. The release would be phased, with newer eligible devices to be offered the upgrade first. Since its predecessor Windows 10 was released on July 29, 2015, more than six years earlier, this is the longest time span between successive releases of Microsoft Windows operating systems, beating the time between Windows XP (released on October 25, 2001) and Windows Vista (released on January 30, 2007).
The first television commercial for Windows 11 premiered during the 2021 NFL Kickoff Game on September 9, 2021; it was intended to showcase a "feeling of immersion and fluidity", with imagery of operating system features and Xbox Game Studios' Halo Infinite. Other promotional campaigns on release day included the Burj Khalifa in Dubai being illuminated with imagery of the Windows 11 logo and default "Bloom" wallpaper, and Mikey Likes It ice cream parlors in New York City distributing free cups of "Bloomberry" ice cream.
Though a support document listed October 4, 2021, as the initial release date, Microsoft officially released Windows 11 on October 5, 2021, as an opt-in, in-place upgrade through either the Windows 11 Installation Assistant application (which can perform the upgrade, or generate an ISO image or USB install media), or via Windows Update in a phased rollout; Microsoft anticipated that Windows 11 would be available via Windows Update to all eligible devices by mid-2022. New installations of Windows 10 on eligible hardware may present an option to upgrade during the OOBE. Retail copies of Windows 11 (consisting of a license key and USB flash drive) were released on May 9, 2022, and digital licenses became available via Microsoft Store on July 28, 2022. On September 20, 2023, around two years after the release date of Windows 11, Microsoft announced that users would no longer be able to use Windows 7 or Windows 8/8.1 keys to activate Windows 10/11. However, as of 2024, there are some reports that they still work, under certain conditions.
Features
Windows 11, the first major Windows release since 2015, builds upon its predecessor by revamping the user interface to follow Microsoft's new Fluent Design guidelines. The redesign, which focuses on ease of use and flexibility, comes alongside new productivity and social features and updates to security and accessibility, addressing some of the deficiencies of Windows 10. | Windows 11 | Wikipedia | 489 | 67953981 | https://en.wikipedia.org/wiki/Windows%2011 | Technology | Operating Systems | null |
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