https://www.theguardian.com/us-news/2026/apr/04/high-ocean-temperatures-california-marine-heatwave
Researchers warn the high-pressure conditions could disrupt marine life and ecosystems if it continues
…
The waters of southern California historically warm every few years as tropical currents make their way north, a phenomenon known as El Niño. But the marine heatwave that started last fall wasn’t caused by tropical currents. Instead, a high-pressure atmospheric system – think of calm, sunny days – has perched above southern California, warming both air and sea above historic levels. The same phenomenon has helped fuel a ferocious California heatwave on land.
The extended ocean warming has drawn comparisons to “the Blob”, a three-year marine heatwave caused by similar prolonged high-pressure conditions a decade ago that devastated marine life. The next few weeks are likely to determine whether this marine heatwave fizzles out or evolves into something more Blob-like, scientists say.
“The biggest concern is how the year plays out,” Andrew Leising, an oceanographer with the National Oceanic and Atmospheric Administration, said. “We could be looking at much larger impacts next fall and winter, if it stays warm and then it’s followed by a strong El Niño.”
…
Prolonged ocean heat has a devastating impact on phytoplankton and can cause harmful algal blooms. Those changes can wreak havoc on many forms of marine life, from sea lions and dolphins, to shore birds and halibut. The Blob years led to one of the worst Dungeness crab seasons in recent history, said Melissa Carter, a researcher at the UC-San Diego Scripps Institution of Oceanography.
Such heatwaves are becoming more common and lasting longer, partly because of the slow warming of the oceans driven by the climate crisis, and partly because of atmospheric changes that scientists are still struggling to understand.
https://www.theguardian.com/us-news/2026/apr/04/high-ocean-temperatures-california-marine-heatwave
