Toxic Algae May Thrive as Climate and Oceans Warm, Study Says

As oceans soak up the Earth's excess heat, algae blooms that can have fatal implications to humans are becoming far more common, researchers show.

A newly established link between warmer ocean temperatures and toxin-spawning algae provides the latest sign that climate change is causing biological disturbances in the oceans.  Scientists tracked West Coast outbreaks of the planktonic algae back to 1991, finding them strongly correlated with warm phases of Pacific Ocean cycles.

The new research, published last week in the Proceedings of the National Academy of Sciences, focused on a single-cell species of phytoplankton called Pseudo-nitzschia.  It produces domoic acid, which can be fatal to humans if consumed at high levels by eating shellfish.  Domoic acid has also been implicated in mass die-offs of marine mammals, including sea lions, sea otters, dolphins and whales.

A 2015 Pseudo-nitzschia bloom from the central California coast up to Alaska was the most widespread on record, taking a $100 million bite out of the Dungeness crab industry in Washington, Oregon and California, according to NOAA.  Scientists monitor for the toxin and close down fisheries when it reaches dangerous levels.  There were unprecedented outbreaks of similar pathogens around the world that year, which was Earth's warmest on record (until it was surpassed by 2016).

Researchers have documented the changes to plankton cycles in recent years, including bigger and longer-lasting blooms spreading to new territory.  Evidence points to ocean warming as a big part of the problem, with some regional nuances.  In 2014, a European Union science report concluded that toxic algae blooms will increase under climate change.

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