[Coral-List] Bleaching Refuges and Bleaching Responses

Austin Bowden-Kerby abowdenkerby at gmail.com
Fri Apr 15 19:32:21 EDT 2016

Dear Deborah,

My understanding is that in bleaching the hot water only indirectly causes
bleaching. The hot temperature causes a breakdown in the photosynthetic
reaction.  The "light reaction" continues to work but the enzymes essential
to the "dark reaction" don't function, and so that reaction stops and
does not use the toxic radicals (OH) generated by the light reaction, which
then burn the zooxanthellae. This is why preventing photosynthesis by
shading can help save the corals- not so much that it will cool the

Bleaching will be back, so unless you plan to plant your nursery-reared
corals where the water stays cooler during future bleaching events, you may
be fooling yourself that you are restoring the reef.  In a decade or less
the water will warm again and the corals will only bleach and die.  What
makes a lot more sense would be to allow nature to take its course in your
nursery, and to use this mass bleaching event as an opportunity to identify
corals that are bleaching resistant. You can then re-do your nursery using
these resistant corals.  Whatever restoration you do with those corals will
be more permanent and will help build resistance to climate change. Pockets
of healthy, bleaching resistant corals, that have enough genetic diversity
within each species to ensure successful spawning, would generate coral
larvae that would then spread resilience throughout the wider reef system.
Isolated corals would on the other hand be unlikely of spawning

A second strategy to protect the few corals that don't bleach- from
predators and from algal overgrowth could make a big difference to
post-bleaching coral survival and ultimately to reef recovery, while
helping build resilience in the system.  What a shame if the resistant
corals so vital to the future of reefs end up as COTS food!  A COTS removal
program might be in order on many reefs right now.

Very few on Coral List have such easy access to the coral reef at such a
critical time as we do, so it is important that we use this opportunity


Good Luck and Thanks for a that you do,


Austin Bowden-Kerby, PhD
Corals for Conservation
P.O. Box 4649 Samabula, Fiji Islands

Sustainable Environmental Livelihoods Farm
Km 20 Sigatoka Valley Road, Fiji Islands
(679) 938-6437





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