What killed California’s Sea Stars and Urchins?

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In August 2011, scientists walked into their labs and were met with a disturbing sight: thousands of purple sea urchins and other marine invertebrates were dead in their tanks—which are fed directly by seawater.

Outside, the tea-colored ocean washed up carcasses of red abalone, large sea stars, and football-sized, snail-like chitons.

Less conspicuous—but even more heavily impacted as a population—were millions of purple sea urchins and tiny sea stars that died along a 62-mile stretch of coast in Northern California, according to a new study published in PLOS ONE.

“We might not have known urchins and six-armed sea stars were affected if lab-held animals hadn’t died right in front of us,” says Laura Jurgens, a graduate student at the Bodega Marine Laboratory at the University of California, Davis.

Instead, the mass mortality was likely caused by a harmful algal bloom. Such blooms are expected to occur more often due to the combination of global warming, ocean acidification, and land-use changes, scientists warn.

That is all the more reason why documenting such mass mortality events is important to better understand—and prepare for—trends happening to ocean ecosystems, Jurgens says.

The complete story can be found HERE.