Nutrient fluxes of a restored salt pond in San Francisco Bay

In the southern part of San Francisco Bay, large tracts of wetlands have been enclosed by dikes and used as shallow salt production ponds since the 1800s. In 2003, the California Department of Fish and Game and the U.S. Fish and Wildlife Service purchased 61 km² of salt ponds for wildlife restoration. Concentrations of macronutrients (e.g, phosphorus and nitrogen) in the water column and benthos of these ponds affect primary productivity and the likelihood of cyanobacteria blooms. In order to understand the production, consumption, and tidal transfer of nutrients, the concentrations and fluxes of dissolved (0.2-micron filtered) orthophosphate and ammonia through Pond A3W of the Alviso Salt Pond Complex were determined. Results from this study indicate that the fluxes of these nutrients through the pond are tidally controlled, and will augment ongoing research by the U.S. Geological Survey and collaborating agencies to assist in restoring the historic wetlands and avian-migration habitats of San Francisco Bay.