ABOVE: Southerly species like these giant owl limpets started appearing on northern California shores following the 2013–2015 marine heatwave.
FLICKR, JERRY KIRKHART
Land-based heatwaves have a less obvious though equally important sibling: marine heatwaves. In 2013, the largest marine heatwave on record began when an unusually warm mass of water formed in the Gulf of Alaska. By the next summer, the warm water spread south, raising average water temperatures along the United States west coast by 3.6 to 7.2 degrees Fahrenheit (2 to 4 Celsius). In 2015, a strong El Niño event strengthened the marine heatwave further.
And so “the Blob,” as oceanographers have dubbed this huge body of warm water, was born.
Interestingly, a number of species moved northward to places along the west coast of the U.S. where the water had previously been too cold for them.
We are a marine evolutionary biologist and a marine ecologist, and are ...
