Environment

Warm Ocean 'Blob' Triggers Worst-Ever Toxic Algae Blooms

Blooms of algae along the West Coast of the U.S. in 2015 were bigger and more toxic than ever before, contaminating food webs and closing fisheries from southern California to as far north as British Columbia, in Canada. Now, a new study links them to elevated ocean temperatures, with algae growth spurred by a mysterious patch of warmer-than-average ocean that scientists first noted years earlier and had dubbed "the warm blob."

The warm blob, which first appeared in 2013 and hung around into 2014, helped one species of toxic algae — Pseudo-nitzschia australis — increase in unprecedented numbers and expand farther north than was previously possible, with devastating effects on a wide range of marine life. [Yuck! Photos of 'Rock Snot' Algae Infestations]

Toxic algae events that are serious enough to merit fishery closures occur off the coasts of Washington and Oregon every three to five years, but the 2015 bloom was the largest by far, according to Ryan McCabe, the study's lead author and a researcher at the University of Washington's Joint Institute for the Study of the Atmosphere and Ocean in Seattle.