Potential for Phosphorus Transport and Ecosystem Restoration Success in the Greater Everglades Ecosystem Watershed

Phosphorus (P) mobility in watersheds relies on complex interrelated physical, chemical, and biological processes that can alternate P between organic and inorganic forms comprising varying degrees of mobility. To assess the potential for P movement through a watershed, both short-term storage of P (assimilation into vegetation, translocation within above and below-ground plant biomass, microorganisms, algae, and detritus) and long-term storage (retention by inorganic and organic soil particles and net accretion of organic matter) need to be considered. Here, we discuss the influence of biotic and abiotic regulation on P reactivity and mobility using the South Florida, Greater Everglades system as a canvas and relate restoration activities to potential transport of P within the system.. Total P storage in the detrital layer and surface soils (0-10 cm) is estimated to be 400,000 metric tons (mt) across the entire Greater Everglades Ecosystem, of which 40% is present in the Lake Okeechobee Basin (LOB), 11% in sediments of Upper Chain of Lakes, Lake Istokpoga, and Lake Okeechobee, 30% in the Everglades Agricultural Area (EAA), and 19% in the Stormwater Treatment Areas (STAs) and the Everglades system. In a low P environment, burial of P may be hindered by macrophytes which continually access buried soil P and maintain P at the soil surface. Approximately, 35% of the P stored in the watershed is in chemically nonreactive (not extractable after sequential extraction with acid or alkali) pool and is assumed to be stable. A range of P pool mobility scenarios suggest that P has a high tendency for transport through the watershed which can ultimately affect success of the Everglades restoration effort.