Ian Wren

High nutrient concentrations can cause increased phytoplankton biomass, low dissolved oxygen, and increased harmful algal blooms and toxins, with detrimental effects on species and ecosystems. San Francisco Bay receives high nutrient loads mainly from discharged wastewater, but high turbidity, strong tidal mixing, and abundant filter-feeding clams have kept algal blooms in check. Following the historic algal bloom of 2022, regulators and managers recognize the Bay’s resilience to high nutrient loading is waning and nitrogen concentrations must be managed more proactively.