Deadly marine ‘cold spells’ could become more frequent with climate change, scientists warn

In March 2021, a grisly scene materialized on the beaches of South Africa. Giant bat-winged manta rays sprawled belly up on rocks. Hulking bull sharks lay dead in the sand. Puffer fish littered shorelines like deflated footballs. Such fish kills are usually triggered by hot water, low oxygen, or toxic algae blooms. But this time it was a surprising culprit. In the middle of the southern summer, these fish died of cold—a phenomenon that may be linked to climate change, according to a new paper . At a time when global warming is driving ocean temperatures to record-setting highs and marine heat waves are striking around the globe , it might seem paradoxical that climate change could be linked to the underwater equivalent of a cold snap. But researchers now say that in some parts of the world, incidents like the 2021 cold spell appear to be getting more common as currents change, with potentially lethal consequences for marine life. “This kind of a phenomenon is certainly not something that I’ve ever been aware of,” said Oregon State University marine ecologist Bruce Menge, who studies how currents shape coastal ecosystems but was not involved in the fish kill research, published today in Nature Climate Change . The die-off in South Africa caught the attention of Australian shark researcher Nicolas Lubitz, then a Ph.D. student at James Cook University, who worked with a group of ecologists and oceanographers to piece ...
Source: Science of Aging Knowledge Environment - Category: Geriatrics Source Type: research