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https://theconversation.com/safe-no-more-off-the-charts-marine-heat-has-severely-damaged-ningaloo-and-other-pristine-coral-reefs-263028>
"Until now, many of Western Australia’s most pristine coral reefs have avoided
the worst bleaching brought by marine heatwaves. But their luck has now run
out. The state’s longest lasting, largest and most intense underwater heatwave
has hammered them.
The unusual heat began late last year off the northwest coast, before spreading
south, eventually affecting seas along more than 1,500km of coastline. Surface
temperatures hit up to 4°C above average in places.
For coral, sustained heat stress is measured using degree heating weeks (DHW).
At 4 DHW, coral bleaching is likely. At 8 DHW, many corals are at risk of
bleaching and dying.
The data so far suggests heat stress on most reefs was more than double that.
Central Ningaloo hit 20 DHW. Off some parts of the Pilbara coast, heat stress
hit an almost unthinkable 30 DHW.
My colleagues and I have recorded the result: intense bleaching at iconic
Ningaloo reef, as well as across the spots we hoped would be more resilient,
such as the Rowley Shoals well offshore, and the vast but little-known reefs of
the northern Kimberley.
It’s undoubtedly the most widespread coral bleaching event yet recorded in WA.
For the worst-hit reefs, it’s hard to see how recovery to their previous glory
is possible, given temperatures will continue to rise in the coming years."
Cheers,
*** Xanni ***
--
mailto:xanni@xanadu.net Andrew Pam
http://xanadu.com.au/ Chief Scientist, Xanadu
https://glasswings.com.au/ Partner, Glass Wings
https://sericyb.com.au/ Manager, Serious Cybernetics
