PARENT SESSION
Oral Session #57: Aquatic Ecology: Wetlands, Estuaries, Marine. Presiding: T. Klinger.
Wednesday, August 8, 2001. 1:00 PM to 5:15 PM. Hall of Ideas J.
Short-term changes in an oligotrophic Everglades wetland ecosystem receiving experimental phosphorus enrichment.
Noe, Gregory1, Childers, Daniel1, Scinto, Leonard1, Edwards, Adrienne2, Gaiser, Evelyn1, Lee, David1, Trexler, Joel1, Jones, Ronald1, 1 2
ABSTRACT- Natural, unenriched Everglades wetlands are known to be limited by phosphorus (P) and responsive to P enrichment. We tested the response of Everglades wet prairie wetlands to continuous, low-level additions of P (0, 5, 15, and 30 ug L-1 above ambient) in replicate, 100 m flow-through flumes located in unenriched Everglades National Park. After the first six months of dosing, the concentration and standing stock of P increased in the surface water, periphyton, and flocculent detrital layer (floc), but not in the soil or macrophytes. Of the ecosystem components measured, the floc responded most strongly to P enrichment (30 ug L-1: mean = 4,268 ug P g-1, control: mean = 337 ug P g-1). Significant short-term responses of P concentration and standing stock were observed primarily in the high dose (30 ug L-1 above ambient) treatment. In addition, the biomass and estimated P standing stock of aquatic consumers increased in the 30 and 5 ug L-1 treatments. Alterations in P concentration and standing stock occurred only at the upstream ends of the flumes nearest to the point source of added P. Finally, the ecosystem in the flumes retained only a small proportion of the P added over the first six months. These results indicate that oligotrophic Everglades wetlands respond rapidly to short-term, low-level P enrichment, and the initial response is largest in the floc.
KEY WORDS: phosphorus, wetland, everglades, biogeochemistry