'Marine heatwaves may last longer and be more intense in deeper water,
potentially threatening sensitive species as climate change makes the extreme
events more frequent, researchers said on Monday.
Oceans have absorbed 90 percent of the excess heat produced by the carbon
pollution from human activity since the dawn of the industrial age.
Marine heatwaves – episodes of abnormally high water temperatures – have become
more frequent and intense.
These can have a particularly severe impact on species that cannot migrate to
escape intolerably warm waters, like corals in the Great Barrier Reef and kelp
forests off southern Australia and the northeastern Pacific.
In a new study published in the journal Nature Climate Change
looked at impacts of temperature spikes in deeper waters, which lead author
Eliza Fragkopoulou said was "the first attempt to look into marine heatwaves
below the surface".
"Marine heatwaves and their effects have been studied mostly at the ocean
surface and we did not know much about their characteristics in the deep
ocean," she told AFP
Using on-site observations and modelling, researchers examined global marine
heatwaves from 1993 to 2019, including data up to 2,000 metres (6,562 feet)
below the surface.
They found the intensity was highest at 50 to 200 metres below the surface,
occasionally up to 19 percent stronger than the surface heatwave.
The duration also increased with depth, with warming persisting up to two
years after temperatures returned to normal on the surface, the study said.'
Via Rixty Dixet.
*** Xanni ***
Chief Scientist, Xanadu
Partner, Glass Wings
Manager, Serious Cybernetics