Oyster aquaculture is well established on the U.S. Pacific coast. Oysters are widely regarded as ecosystem engineers due to their high capacity for filter feeding, which impacts water quality, but the consequences of oyster introduction and removal are poorly understood. This project will observe biogeochemical and ecological impacts of removal of over 5 million cultured oysters from Drakes Estero, CA, a low-inflow estuary within the Point Reyes National Seashore. The project will measure changes in water quality, nutrients, primary producers and general ecosystem health, including the presence of harmful or nuisance algae. Results will be shared through publications and through outreach activities at the annual SFSU open house and workshops for high school teachers.