Phytoplankton blooms followed by hypoxia and fish kills have been associated with nutrient enrichment in Rodeo Lagoon, Golden Gate National Recreation Area (GOGA), California. Fish kills in the Lagoon occurred as recently as 2018, and without proper management actions poor water quality will continue to negatively impact the ecosystem and threaten protected species.

While previous investigations have indicated that lagoon sediments may be a significant source of nutrients to the lagoon, sediment nutrient storage and fluxes have never been systematically measured in Rodeo Lagoon. This study will quantify sediment nutrient storage, transformation, and release in Rodeo Lagoon to determine the extent to which internal nutrient cycling fuels phytoplankton blooms and associated hypoxic events.