| Biogeochemistry of inorganic forms of carbon, nitrogen, and phosphorus in the aquatic component of three Okefenokee wetland sites representing Nymphaea sp. dominated aquatic bed marsh, Cyrilla - Lyonia shrub swamp and cypress (Taxodium ascendens) with broad - leaved evergreen swamp habitats was described for a one year cycle. During the first three months, surface water was absent and peat exposed. In the first 1-2 months after flooding resumed, high levels of DIN (up to 2.5 mg N(.)L('-1) as NH(,4)+NO(,3)+NO(,2)) were released. Release of high levels of SRP, DP, and DON in the first three months of reflooding was also demonstrated. Normal levels of DIN were < 100 (mu)g N(.)L('-1) and of SRP were < 20 (mu)g P(.)L('-1).; Most carbon, nitrogen, and phosphorus was in dissolved and particulate forms. Concentrations of DP averaged 100 (mu)g P(.)L('-1) and of DON, 3 mg N(.)L('-1). Dissolved organic carbon was also very high, averaging 45.5 mg C(.)L('-1). Particulate matter was low in surface water except that collected near the peat substrate. In bottom samples from the marsh site, POM was greatest due to the abundance of periphyton, and POM was lowest in the shrub site where leaf litter remained undecomposed.; Surface water was supersaturated with CO(,2) by factors of 2 to 30 and with CH(,4) by 3 to 5 orders of magnitude. Both CO(,2) and CH(,4) fluxes from the water surface were measured in situ. Carbon dioxide fluxes were high during the drought when peats were exposed, but remained < 3 mmol(.)m('-2)(.)h('-1) under flooding. Methane fluxes were very low during the drought, but increased to 100-2500 (mu)mol(.)m('-2)(.)h('-1) under flooding.; Mean carbon content of surface peat was found to be 49.5% dry weight, and mean nitrogen and phosphorus were 2.38% and 0.0557% dry weight. Phosphorus and nitrogen appear to be conserved in surface peat.; The carbon data were used to quantify models of the carbon cycle in the aquatic component of each site, conceptualized within a system theory framework. The three models, identical in structure, were compared by employing environ analysis. Environ analysis, by partitioning flows and storages associated with each input and output, traces the fate of inputs and the source of outputs. |
