Nutrient fluxes of a restored salt pond in San Francisco Bay

By Krista Garrett
Whitman College, Walla Walla, Washington

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 1800’s.  In 2003, the California Department of Fish and Game and the U.S. Fish and Wildlife Service bought 15,100 acres of salt ponds for wildlife restoration.  Concentrations of phosphorus and nitrogen in 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 phosphorus and nitrogen through Pond A3W of the Alviso Salt Pond Complex were measured.  It was determined that the fluxes of these nutrients through the pond are tidally controlled.  The results of this study will augment ongoing research by the U.S. Geological Survey to assist in restoring the historic wetlands of San Francisco Bay.