Dry rivers, dead bays

San Francisco Chronicle - Evidence of what scientists are calling the planet’s Sixth Mass Extinction is appearing in San Francisco Bay and its estuary, the largest on the Pacific Coast of North and South America, according to a major new study.

So little water is flowing from the rivers that feed the estuary, which includes the Sacramento-San Joaquin River Delta, Suisun Marsh and the bay, that its ecosystem is collapsing, scientists who conducted the study say.

Human extraction of water from the rivers is not only pushing the delta smelt toward extinction, they say, but also threatening dozens more fish species and many birds and marine mammals, including orca whales, that depend on the estuary’s complex food web.