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mia9

Dataset card Data Studio Files
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Jan-81
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Jan-01
Rain (mm).
Joe Bay Station. Rain
0.0
1.0
2.0
3.0
4.0
5.0
Jan-90
Jan-92
Jan-94
Jan-96
Jan-98
Jan-00
Jan-02
Jan-04
Jan-06
Jan-08
Jan-10
Rainfall (in) .
0
2
4
6
8
10
12
14
FCE LTER Rain (mm)
1 2 3 4 5 6 7 8 9 10 11 12
0
2
4
6
8
10
12 Miami Station. Rain
1 2 3 4 5 6 7 8 9 10 11 12
0
2
4
6
8
10
12
14 Tamiami Station. Rain mm
1 2 3 4 5 6 7 8 9 10 11 12 0
.2
.4
.6
.8
1
1.2
1.4
1.6
Joe Bay. Rain (mm)
1 2 3 4 5 6 7 8 9 10 11 12
22
Figure 2.5: Zcusum charts for precipitation on Lower Everglades watershed. Significant
inflections from higher to lower precipitation rates (green arrows) and viceversa (black
arrows) occurred in 1971 and 1991 respectively
Rainwater chemistry data is scarce for South Florida and the only National
Atmospheric Deposition Program (NADP) monitoring station with available data is the
one located in Everglades National Park (site FL11; Lat: 25.39, Lon:-80.68; Table 2.1).
Concentrations and fluxes of NO3 and NH4 increased in atmospheric deposition until
2007 (Fig 2.6). On the other hand, Ca, Mg, K, Na and Cl have declined and the pH
experienced a sharp decline from 5.42 to 5.07 pH units during 1994. Sodium and
chloride display similar pattern and their molar relationships are very close to that of sea
water indicating their origin as cyclic salts. The decline in these salts is important
because it suggests changes from ocean to land source of rainwater.
As shown in Table 2.1, average concentration of inorganic nitrogen species in
rain water (NH4=0.159 mg/l and NO3=0.811 mg/l), are significantly higher than those
found in South Florida estuarine and coastal waters (mean NO3=0.016 mg/l; mean
NH4=0.028 mg/l) . That chemistry has the potential to cause impact especially in
waterbodies like BB where rainfall contributes 40% of the freshwater budget with
concentrations one order of magnitude above those of Bay waters. Additionally, the pH
drop of about half a pH unit in 1994 has important environmental implications especially
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for potential impacts on soil biogeochemistry and nutrient release/fixation processes
(Burns et al. 1998, 2006; Hejzlar et al. 2003; De Wit 2007; Briceño and Boyer 2009).
Figure 2.6: Zcusum charts picture detailed and complex patterns, where NH4 and NO3 have
similar increasing trends (cup-shaped cusums), while Ca, Mg, K, Na and Cl declined (skewed
dome-shaped cusum), and the pH shifted from above to below average tendency in 1995.
Table 2.1. Descriptive statistics of rainwater chemical composition at station NADP FL11,
Everglades National Park for the period Jun/1980 to Jan/2011 (units are mg/l except for pH)
-25
-20
-15
-10
-5
0
5
10
15
20
Jan-79
Jan-81