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Biogeochemical Characteristics of the Everglades Sloughs
Author(s) -
Vaithiyanathan Panchabi,
Richardson Curtis J.
Publication year - 1998
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq1998.00472425002700060021x
Subject(s) - periphyton , macrophyte , water column , biogeochemical cycle , aquatic ecosystem , environmental chemistry , chemistry , wetland , aquatic plant , hydrology (agriculture) , environmental science , ecology , nutrient , biology , geology , geotechnical engineering , organic chemistry
Everglades sloughs are alkaline hardwater systems. Mean water column dissolved phosphate (5 µg/L) and TP (9 µg/L) concentrations in the sloughs are typical of oligotrophic waters. Molar ratios of dissolved inorganic N and P (DIN:DIP = 28:1) in the surface waters suggest that P may be limiting the aquatic primary productivity in the Everglades sloughs. Variations in water column TP and TN in the sloughs were inversely related to the water depth fluctuations ( P <0.0001) suggesting a strong link with hydrology. Periphyton and macrophytes in the sloughs exhibited N/P ratios indicative of depletion in P relative to N. The N/P ratios in the Everglades slough communities were in the upper range of values reported for aquatic plants from other ecosystems. The N/P ratios in periphyton were higher than macrophytes suggesting that P depletion was even greater for periphyton. As a result any introduced inorganic phosphate was taken up rapidly by the periphyton reducing the water column PO 4 ‐P to near background levels. Our results suggest that C/N/P ratios of the periphyton provide a reliable measure of the P‐status of the Everglades sloughs whereas the water column P concentration may not truly reflect the P‐status of the system. Periphyton mat also plays an important role in oxygenating the water column of the sloughs. Experimental results show that a decline in periphyton mat cover will result in a decrease in the water column dissolved oxygen concentration and may also lead to other ecosystem changes by enhancing the PAR availability to the slough bottom.