[Coral-List] Decline of Red Sea coral reefs

[Austin Bowden-Kerby]

Dear Joseph,

Based on what I see here in the South Pacific, I agree 100% with your
conclusions; that even the coral reefs we expected to be doing the very
best in the face of climate change, are now collapsing due to warming
seas.  There is indeed very little runoff and low fishing pressure on these
Red Sea Reefs, especially as compared to most Caribbean and IndoPacific
reefs.  Certainly oil spills and pollution related to shipping have been
chronic and not something new, and mostly minor and not a forcing factor,
so they can not be blamed on the sudden and recent demise of these reefs.

The Chagos, Phoenix and Line Islands are also in this category of extreme
impacts from bleaching and virtually none from pollution or overfishing.
While many of these degraded reefs of pristine waters continue to be
dominated by dead coral rock, a few reports have come out on these reefs
loudly celebrating "recovery" of these systems, however these reports have
glossed over the fact that although coral cover has indeed recovered, coral
biodiversity has not, as the reefs have become dominated by one or very few
species, with multiple local extinctions or near extinctions of Acropora
and other species.

With the global thermal anomaly of +0.7C or which occurred in 2023
continuing, we have now gone over the edge.
https://climatereanalyzer.org/clim/sst_daily/   Very quickly now we will
see that bleaching and mass coral death due to marine heat waves will begin
to outstrip all other factors in coral reef decline.  With mass coral
die-offs, all progress with MPAs and pollution control are swept away.  But
as long as there are some coral larvae, the consolation is that these
better managed reefs might recover more quickly?

We have entered a new reality that most of us will have a hard time
embracing.  Most coral reefs of the Caribbean experienced 20 Degree Heating
Weeks and some even went to 25 DHW. last summer.  And we are now entering a
springtime with record heat levels in the region, with Tobago predicted to
be at bleaching warning stage in 9-12 weeks!
https://coralreefwatch.noaa.gov/product/vs/gauges/leeward_caribbean.php
 So unless a series of early hurricanes forms and continues to form in the
tropical Atlantic, it looks like this coming summer has the potential to be
as bad or worse than last summer.  So are you ready?

I strongly believe that it is time that we embrace our new reality, realize
that the situation will worsen very quickly now, and that if we do not
begin active coral-focused measures to keep coral species alive and in
genetically diverse condition, that we are going to lose them, reef by
reef, nation by nation.  I know it is difficult to imagine our reefs
experiencing 25-27 DHW, but that is now an actual danger!  It is time to
face this new reality and to develop plans and actions to keep
corals alive, species by species, and in the ocean.  I have some ideas on
how to do this:  In 2016, I began working with the coral reefs of
Kiritimati Atoll (Christmas Atoll), on the equator, just south of Hawaii.
Kiritimati is the clear leader globally for being the most severely
impacted of all coral reefs by bleaching, with 27 DHW experienced in
2015-16.   After seeing the severe impacts and local extinctions of so many
coral species, my question was this: what could we have done to prevent the
coral extinctions that occurred?   I came up with some answers, and I
launched these ideas and strategies as "Reefs of Hope", with pilot sites in
six Pacific Island nations.  The good news is that Reefs of Hope has just
this month been endorsed by UNESCO as an Ocean Decade Action:
https://oceandecade.org/actions/reefs-of-hope/   I think this makes Reefs
of Hope the first UN-endorsed corla-focused climate change adaptation
strategy for coral reefs!

An underlying assumption of the Reefs of Hope model is that even during the
most severe of marine heat waves the open ocean generally does not get
above 31-32C, 33C in the extreme.  We also assume that ocean facing reefs
are generally cooler than nearshore reefs.  Nearshore coral populations
located on hot reef flats and in closed lagoons can easily take 31-33C and
above without bleaching, however during severe marine heat waves these hot
areas can really cook, reaching temperatures similar to the 38.4C recorded
in Florida last summer.  So with mass bleaching we are also losing our
greatest genetic treasures: the coral hosts, the symbionts, and the
microbiomes present.  However, these same corals will do just fine if we
can get them into cooler more oceanic waters beforehand.  So one of our
Reefs of Hope strategies is hot to cooler translocation of corals at local
scale in order to prevent their death during increasingly severe marine
heat waves.   If we are too late, another method we use is to collect the
few unbleached corals after mass bleaching events (when the waters begin to
cool), to protect them from predators, using these corals to build the gene
bank nurseries, later trimmed to create "nucleation patches" on the reef to
reboot natural adaptation and recovery processes, as well as to restore
effective sexual reproduction to declining coral species.

I am not saying that we have all the answers, and we are still learning,
but the answers we urgently need will only come with concerted actions and
the sharing of knowledge.  It is time to work together and to develop
regional and global strategies and programs.  Every man for himself is not
a good way to win a war.

Regards,

Austin

Austin Bowden-Kerby, PhD
Corals for Conservation
P.O. Box 4649 Samabula, Fiji Islands
https://www.corals4conservation.org
Publication on C4C's coral-focused climate change adaptation strategies:
https://www.mdpi.com/2673-1924/4/1/2/pdf
Film on our "Reefs of Hope" coral restoration for climate change adaptation
strategies:  https://www.youtube.com/watch?v=BG0lqKciXAA
https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/
<https://www.globalgiving.org/projects/emergency-response-to-massive-coral-bleaching/>



On Sat, Feb 24, 2024 at 2:50 AM Pawlik, Joseph via Coral-List <
coral-list at coral.aoml.noaa.gov> wrote:

> Greetings, list,
>
> More sad news about which you may not be aware: Red Sea coral reefs are
> rapidly losing coral cover from south to north because of summer high
> temperature events and unprecedented storms. Some of us had hoped that
> these reefs were resistant to climate change impacts, but evidently not.
>
> Here is a video that shows the dramatic change in coral cover between 2019
> and 2023 (effects of 5 summers) on reefs south of Marsa Alam, Egypt.
>
> https://youtu.be/_-v7s4eBok0
>
> Note the recently dead and toppled Porites lutea - many of these heads are
> hundreds, if not thousands of years old.
> The video also shows dead reefs south of Al Lith on the Saudi Arabian side
> of the Red Sea - this is further south of the Egyptian reefs in the first
> part of the video, and these reefs died before 2017.
>
> Important relative to recent discussions on this list is that these tragic
> losses are due entirely to high temperature events - these reefs are not
> impacted by human settlements or sources of pollution, nor is there
> evidence of disease events.
>
> Regards,
>
> Joe
>
> **************************************************************
>
> Joseph R. Pawlik
>
> Frank Hawkins Kenan Distinguished Professor of Marine Biology
>
> Dept. of Biology and Marine Biology
>
> UNCW Center for Marine Science
>
> 5600 Marvin K Moss Lane
>
> Wilmington, NC  28409
>
> Office:(910)962-2377; Cell:(910)232-3579
>
> Website: http://people.uncw.edu/pawlikj/index.html
>
> PDFs: http://people.uncw.edu/pawlikj/pubs2.html
>
> Video Channel: https://www.youtube.com/user/skndiver011
>
> **************************************************************
>
>
>
>
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