Community Dynamics along a Salinity Gradient in Florida Bay

This project evaluates seagrass associated fish and invertebrate (caridean and penaeid shrimp) community structure in relation to seagrass and salinity across Florida Bay. Project objectives include documenting fish and shrimp community structure: at the end of the dry season (annual high salinity) and wet season (annual low salinity); along local depth gradients (bank, basin and near key); in relation to seagrass micro-habitat (seagrass blade density, blade length, biomass, etc.); and in years when the bay functioned as a positive estuary and as a negative estuary. Florida Bay is a marine lagoon located downstream of the Florida Everglades. Salinity patterns influence biological activities greatly. Direct freshwater flow into Florida Bay occurs through Taylor Slough or the C-111 Canal into northeastern Florida Bay. Shark River Slough, the principal freshwater flow way of Everglades National Park, empties into Whitewater Bay and the mangrove estuaries of the Park’s southwest coast. Freshwater from Shark River Slough enters Florida Bay from the west after mixing with near shore waters of the Gulf of Mexico. Salinity conditions in Florida Bay vary with rainfall in south Florida both seasonally and inter-annually. During extremely wet periods in south Florida estuarine conditions may extend over most of Florida Bay. Thus, among years, Florida Bay ranges between a positive and negative estuary, during very wet and very dry years, respectively. Storing and diverting water for water supply and flood control have modified the quantity, timing and distribution of fresh water flows entering Florida Bay. This thought to have contributed to a general marinification of the bay over the last century and to have increased the frequency and intensity of hypersaline events. Upstream channelization has increased the speed with which floodwaters enter the bay and the rapidity with which subsequent salinity changes occur, especially in northeastern Florida Bay.