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mia9

Dataset card Data Studio Files
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canopy height (cm)
sediment depth (cm) and texture
water depth (cm)
turbidity (NTU)
water temperature (
oC)
salinity (‰)
SFWMD
DERM
BB22
SERC-FIU
BISC 130
1979-1996, 1998-
2003, 2009-present
1996-2008
Center of POM basin
(see Figure 4)
Lat. 25.4522553
Long. -80.1027368
Lat. 25.454799
Long. -80.101801
water temperature (
oC)
salinity (‰)
turbidity (NTU)
dissolved oxygen (DO) (mg/L)
pH (field units)
Chlorophyll-a (CHL-A) (mg/M3
)
organic-carbon (OC) (mg/L)
nitrate plus nitrite (NOx) (mg/L)
total phosphate (P) (mg/L)
NOAA 2005-2011 Virginia Key, Miami
(see Figure 4)
rainfall (in)
air temperature (
oC)
30
period (2005-2011). General linear models were used to detect annual and seasonal
variations in vegetation (seagrass and algae) occurrence in FIAN data.
For purposes of this study, the replicate quadrats from Braun-Blanquet surveys
were averaged to give an overview of vegetation groups present at each of the 30 sample
sites within the basin. Seagrass canopy height measurements were averaged from the
quadrat replicates for each site as well. Cover-density for vegetation groups at each
FIAN sample site were calculated from the ranked abundance codes using the following
formulas based on Braun-Blanquet (1965) methodology (Robblee 2005):
Cover-Density = sum of B-B scale values/ total # of quadrats
Nonparametric tests were used to analyze the calculated Braun-Blanquet
vegetation data due to the ordinal nature of the ranked vegetation abundance codes.
Kruskal-Wallis tests were used to compare the calculated FIAN vegetation cover-density
data and the seagrass canopy heights across years and between the 30 sample sites; to test
for seasonal effects a Mann-Whitney U test was used.
For the FIAN physical and environmental measurements, mean sediment depth,
water depth, turbidity, and surface and bottom temperature and salinity measurements
were calculated for each sample site for annual and seasonal comparison. For surface
and bottom temperature and salinity measurements, independent samples t-tests were
used to determine any significant difference in the water column. General Linear Models
were also constructed to determine potential temporal (annual/seasonal) effects of all
physical and environmental factors within the sample basin. A post hoc analysis was
used to identify specific years for which differences have been observed. Spatial
variation between the thirty FIAN sample sites within the POM basin was determined by
a One-way ANOVA. Visual inspection of site location and data measurements were
compared.
Environmental data collected for the SFWMD from other agencies were averaged
for the sample period and graphed for comparison with data from this study. One-way
ANOVAs were used to determine any significant temporal variation between the
available sample years for each variable. Related variables were also compared with
NOAA weather data for the region during the sample period.
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Spearman’s rank correlation coefficient (Spearman’s rho) was used to evaluate a
potential relationship between vegetation and environmental and physical measurements
(sediment, temperature, salinity, turbidity, and water and sediment depth). Multiple
linear regression models were used to evaluate temporal effects (sampling years and
seasons), physical and environmental factors (depth, sediment, temperature, salinity, and
turbidity), and algae on the benthic community of seagrass (cover-density, occurrence,
and canopy height) during the collection period. Four main models were constructed for
the (vegetation) seagrass cover-densities: 1. Effects of year and season on benthic
community, 2. Effects of physical and environmental factors (depth, sediment,
temperature, salinity, and turbidity) on benthic community, 3. Effects of physical and
environmental factors, year and season on benthic community, and 4. Effects of algae,
physical and environmental factors, year and season on benthic community.
3.0 Results
3.1 FIAN Seagrass Community Measurements
Four genera of seagrass, Syringodium, Thalassia, Halodule and Halophila, were
observed in the POM basin. Twenty-eight genera of algae were observed consisting of:
6 genera of green algae, including Avrainvillea, Anadyomene, Batophora and Caulerpa;
11 genera of Rhodophyta, red algae, including Laurencia and Gracilaria; two genera of
Phaeophyta, brown algae, including Sargassum and Dictyota; and five genera of
Chlorophyta, green algae, including Rhipocephalus, Acetabularia, Halimeda, Udotea and
Penicillus. In FIAN some algae were not identified to species but rather lumped by
genera in an “Other” group (e.g. Red Other, Green Other, Brown Other, Calcareousgreen Other).
Seagrasses were present at 91.7% of the 420 sites and 77% of the 2159 quadrats
sampled over the collection period. Syringodium filiforme was the most abundant
seagrass species within the sample location, present at 66.4% of monitoring sites.
Thalassia testudinum and H. wrightii were the second most abundant seagrasses, present
at 52.4% and 50% of the sites, respectively. The Halophila genera, with three species (H.
engelmanni, H.decipiens, H. johnsonii), was rarely present and found to only be in 7.6%