A new marine heat wave that’s nearly as big and as warm as the infamous "Blob" that lingered off the Pacific Coast five years ago formed off the coast of Washington this summer, and it has scientists more than a little concerned.
“Right now, it’s still fairly young and the area is already very close to rivaling the size of The Blob itself,” Andrew Leising, research oceanographer at NOAA’s Southwest Fisheries Science Center, said at a Sept. 5 news conference.
The Northeast Pacific Marine Heatwave of 2019 is already the North Pacific’s second largest heat wave since 1981, when quality satellite images became available to evaluate. “This current event, it really does resemble in many ways that past event—The Blob—but this is a new event,” Leising said. He said it’s similar in size and shape to The Blob, and has already reached the costs of Washington and northern Oregon. “Really, only time will tell if it’s going to persist.”
If it does persist, scientists say, it could be every bit as bad as—or worse than—the Blob.
Then again, they say, it could dissipate quickly. It would still be the second worst heat wave known to the North Pacific, but if it dissipates, it probably wouldn’t lead to the same level of environmental disruption as the Blob.
From 2014 to 2016, the Pacific Ocean’s largest-known heatwave wreaked havoc up and down the West Coast (CU No. 1841 ). It caused the largest and most harmful algal bloom ever recorded, shutting down crabbing and clamming for months. Vital parts of the food web crashed. Multiple fishery disasters were declared. Fish, mammals and other sea creatures ventured to places where they’d never been seen before.
It’s an event that oceanographers are still studying, and one that marine ecosystems are still recovering from. Now, the prospect of another is at hand.
NOAA scientists at the news conference said this new heat wave resembles the early stages of the Blob, although it’s a persistent low Blob system that’s been in place since June rather than the “ridiculously resilient” high Blob ridge that marked the start of the Blob. Still, the impact from the low Blob system has been to dampen winds that usually mix and cool the ocean’s surface. Already, sea surface temperatures are as high as 5 degrees Fahrenheit above average.
This heat wave is also almost as large as the Blob. Both encompassed an area in the North Pacific stretching from southern California to Alaska to Hawaii. The Blob was roughly 3 million square miles while the current heat wave is about 2.5 million square miles.
But, NOAA research scientist Nate Mantua said, ocean temperatures during the Blob were very warm to depths of about 650 feet, and warmer than usual all the way to 1,600 feet, whereas the current heat wave is largely affecting the upper 150 to 300 feet. And while there’s still a lot of heat left over from the Blob in the upper 100 meters of the ocean, this new heat wave hasn’t been around long enough to warm the cooler, deeper levels of the ocean.
Mantua said the underlying cause of the low Blob is unknown, and scientists don’t know whether it’s related to climate change. However, the climate crisis has already contributed to nearly 2 degrees of warming across much of the North Pacific Ocean, he noted.
Mantua said the latest heat wave is already changing the food web in ways that are harmful to salmon populations that rely on cooler water and more productive coastal areas. “It probably hasn’t had such a big impact on many salmon stocks yet, but if it goes onshore and is there next spring and summer, it will likely make things very tough on juveniles that are outmigrating.”
Conditions this summer were also unusual. Coastal areas from Washington to Northern California saw weak upwelling, and fish surveys have been poor. “If it persists, it will very likely have negative impacts on salmon growth and survival rates,” he added.
NOAA Fisheries has been watching the situation since October (CU No. 1874 [9.2]), Leising said. “It did dissipate a little,” he said, “but came back with a vengeance in the spring.”
The agency is now focusing on monitoring the new heat wave, and will provide fish managers with information on how the unusually warm conditions could affect fish stocks, and the marine ecosystem.
“We learned with ‘The Blob’ and similar events worldwide that what used to be unexpected is becoming more common,” Cisco Werner, NOAA Fisheries director of scientific programs and chief science advisor said in a news release. “We will continue to inform the public about how the heat wave is evolving, and what we might anticipate based on experience.”