San Francisco Bay is a large tidal estuary in the U.S. state of California, and gives its name to the San Francisco Bay Area. It is dominated by the cities of San Francisco, San Jose, and Oakland.
San Francisco Bay
Aerial panorama of the northern Bay, the Bay Bridge, Golden Gate, and Marin Headlands on a clear morning. November 2014 photo by Doc Searls.
Panorama of San Francisco Bay, and the city skyline seen from Marin County in the Golden Gate National Recreation Area
Population density and low elevation coastal zones in San Francisco Bay (2010). The San Francisco Bay is especially vulnerable to sea level rise.
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environments and are an example of an ecotone. Estuaries are subject both to marine influences such as tides, waves, and the influx of saline water, and to fluvial influences such as flows of freshwater and sediment. The mixing of seawater and freshwater provides high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world.
Río de la Plata estuary
New York–New Jersey Harbor Estuary
River Exe estuary
Estuary mouth located in Darwin, Northern Territory, Australia
