Unprecedented toxic algal bloom caused by unusual warm blob

Sunday, October 9, 2016, 7:02 PM - A massive algal bloom in 2015 set records for being the largest and most toxic bloom in recorded history. A new study has now linked warm ocean conditions to this potentially deadly and unprecedented phenomenon.

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Research led by scientists at the University of Washington in partnership with National Oceanic and Atmospheric Administration found that "the blob" -- an abnormally warm patch of water in the Pacific -- provided a thriving atmosphere to Pseudo-nitzschia australis, which is the single species of diatom that dominated 2015's toxic algal bloom.

These unusually warm ocean conditions occurred during the Spring and Winter of 2014.

“This paper is significant because it identifies a link between ocean conditions and the magnitude of the toxic bloom in 2015 that resulted in the highest levels of domoic acid contamination in the food web ever recorded for many species,” said Kathi Lefebvre, marine biologist at NOAA’s Northwest Fisheries Science Center, in a statement. Lefebvre is a co-author of the new study.

“This is an eye-opener for what the future may hold as ocean conditions continue to warm globally.”

The study examined the Pseudo-nitzschia australis from 2015's bloom. It found that when the cells are exposed to warmer temperatures, they get more nutrients, doubling or tripling their cell division rates and enabling them to bloom into a large population quite quickly.

The "warm blob" neared shore and spread along the West Coast by early 2015, prompting fishery closures stretching from northern British Columbia down to southern California.

"When springtime shifts in wind direction brought deeper, nutrient-rich water upward near the coast, a small population of P. australis became a big population, which was then washed ashore along the West Coast by late spring storms,” notes Barbara Hickey, professor of oceanography at the University of Washington and the study's co-author.

This cycle proved especially damaging in a year dominated by P. australis.

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“This species is almost always highly toxic,” said Raphael Kudela, marine ecologist at the University of California and co-author of the study.

The species blooms every spring off the coast of California, bringing significant health threats to humans and marine mammals. Among the potential dangers are gastrointestinal distress, seizures, memory loss and even death.

The study was published in Geophysical Research Letters, a journal of the American Geophysical Union.

Related Video: Algae bloom in B.C. captured by NASA satellites

SOURCE: American Geophysical Union