Ocean heatwaves bring dramatic shifts to wildlife

Skinny California sea lion pups stranded in record numbers on Southern California beaches as a marine heatwave known as "The Blob" warmed the Pacific Ocean and shifted their prey north.
Credit: Jim Milbury/NOAA Fisheries

Climate change is altering the preferred temperatures of a wide range of wildlife, marine heatwaves can do the same in a fraction of the time, NOAA scientists found. In a recent paper in Nature, the researchers introduce the metric of “thermal displacement” to measure these changes.

“It may give us an idea how the ecosystem may change in the future,” said Michael Alexander, research meteorologist at NOAA’s Physical Sciences Laboratory and a co-author of the new research.

Marine heatwaves are shifting ocean temperatures at scales similar to climate change predictions but in a much shorter time. Average long-term temperature shifts associated with ocean warming have been estimated at about 13 miles per decade. Marine heatwaves have displaced temperatures about 120 miles in a matter of months.

A 2014-2015 Pacific marine heatwave known as “the Blob” shifted surface temperatures more than 400 miles, along the West Coast of the United States and in the Gulf of Alaska. That moved California sea lion prey farther from their rookeries in the Channel Islands off Southern California, stranding hundreds of starving sea lion pups on beaches.

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