<
https://reneweconomy.com.au/heat-stress-leads-to-worst-bleaching-on-record-for-coral-reef-ecosystems/>
"The worst coral bleaching ever recorded has been confirmed by scientists for
tropical reefs off Australia’s western coastline.
While researchers are still assessing the full extent of the damage wrought by
a marine heatwave, the Australian Institute of Marine Science has confirmed the
most widespread bleaching on record for Western Australia.
“The length and intensity of the heat stress, and its footprint across multiple
regions, is something we’ve never seen before on most of the reefs in WA,” the
institute’s senior research scientist James Gilmour said.
“Areas which had given us hope because they’d rarely or not bleached before,
like the Rowley Shoals, north Kimberley and Ningaloo, have been hit hard this
time.”
Sensitive to heat stress, corals expel the algae living in their tissues in
warm water, causing the coral to go pale.
Bleaching is not always fatal but if underwater heat is prolonged and severe,
corals can die.
Sea surface temperatures around Australia last summer were the warmest on
record since 1900, with coral heat stress peaking in January.
Conditions varied across the tropical reefs spanning 1500km – from “extreme”,
or 90 per cent bleached or dead, to “medium”, somewhere between 11 per cent
and 30 per cent.
Mermaid and Clerke reefs in the Rowley Shoals, 300km west of Broome, recorded
“very high” levels of mortality, between 61 per cent and 90 per cent.
The World Heritage-listed Ningaloo Reef, known for its whale sharks,
experienced “high” bleaching and mortality between 31 per cent and 60 per cent.
Dr Gilmour said climate change was driving the increased frequency and severity
of mass coral bleaching events and giving them little time to bounce back in
between.
“They need 10 to 15 years to recover fully,” he said.
“The key to helping coral reefs survive under climate change is to reduce
greenhouse gas emissions.”
Improving water quality and cracking down on overfishing can also support reef
health."
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
