ABSTRACT
The Everglades ecosystem apparently evolved under conditions of relatively low phosphorus inputs, mostly from direct rainfall, which contributed approxi mately 196 tonnes annually to the 500,000-ha freshwater marsh within the Water Conservation Areas and Everglades National Park. Phosphorus inputs to the Water Conservation Areas have increased nearly threefold (from 129 tonnes under predrainage conditions to 376 tonnes currently) due to inflows of agricultural runoff water. Everglades National Park appears to have experienced smaller increases in annual phosphorus input, from 88 tonnes predrainage to 89 tonnes currently. The spatial distribution of surface water phosphorus within Everglades marshes takes the form of gradients from high concentrations at or near inflow points to nearly nondetectable concentrations within interior marsh areas.
