[Coral-List] So you think you understand coral bleaching?

[sealab at earthlink.net]

Hi Scott,

Your ideas certainly raise some interesting points. I agree that the reef science community here can sometimes get bogged down discussing how to minimize our carbon footprints, but I was struck most by your assertion that instead, finding a CURE for bleaching should consume “99.9% of the best thinking time” of coral reef scientists. As I view it, coral scientists are in no way resigned to the belief that reducing global carbon emissions is the “sole solution”. If anything, there are already great efforts being made to divert attention away from the need to address climate change and towards an efficacy favoring restoration involving some form of enhanced resistance. These projects may not be based on the FRONT END of the bleaching response as you described, but they are focused on similar goals. In addition, if the favorable symbiotic conditions you seek are dependent on “ensuring a severe limitation of the seawater supply of nutrients” - haven’t we been striving for this all along? It sounds to me like the venerable call for improvements in water quality that many have been advocating for years. Let’s just imagine that the supply of nutrients was miraculously brought under control and water quality was restored. With that elusive goal achieved, wouldn’t it be better to work to reduce carbon emissions and then let nature take its course? Why would we want to turn our backs on trying to solve the existential problem that is climate change with all of its implications for both marine and terrestrial ecosystems in search of a highly improbable “cure” or coral bleaching? What could be better than envisioning a scenario whereby we effectively address climate change AND restore water quality thereby reducing widespread bleaching and outbreaks of coral diseases all in one fell swoop? That’s what I would call going for the gold! If our current crisis with COVID-19 teaches us anything, it should serve as testimony to the connectivity and fragility of life on this planet. A lesson that we would all do well to apply to climate change and the many challenges it presents to us all.

Regards,

Steve

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On 3/24/20, 6:17 AM, Scott Wooldridge via Coral-List <coral-list at coral.aoml.noaa.gov> wrote:

Dear Coral Listers,

I think it is fine that the reef science community discusses strategies

that can help formulate new ways of doing (and reporting) our science that

can help minimize our carbon footprint. But can I suggest that we owe the

global public and the coral ecosystems themselves so much more than this.

Like those scientists tasked with finding a vaccine for COVID-19, we need

to keep challenging ourselves to find the CURE for coral bleaching. This

must consume 99.9% of the best thinking time of coral reef scientists. And

before we resign ourselves to believing that reducing global carbon

emissions (and by inference future sea temperatures) is the sole solution

we can offer the global public, I believe we need to double down on our

efforts to understanding the suite of cellular processes that initiate

coral bleaching, especially those at the FRONT END of the bleaching

response.

By FRONT END I mean those processes that happen in the days-weeks before we

see any visual sign of bleaching (i.e. symbiosis breakdown). They are

subtle, not well studied, and not well understood. But when you start to

investigate them more deeply, you quickly realize that the conceptual coral

bleaching model adopted by most-all coral reef scientists is WRONG; which

at its crudest, explains coral bleaching in terms of corals BOILING TO

DEATH in hot water.

The issue I specifically draw your attention to in this post, is the

little-known FACT that the endosymbiont population increases its size and

growth rate (as measured by cellular division rate) in the days and weeks

of warming leading up to the visual coral bleaching response. THEREFORE,

immediately before the break down of the symbiosis, the endosymbionts are

by our best measures very happy, and by adding some anthropomorphism -

think that the symbiotic lifestyle cannot be much better.

Don’t believe this? Don’t take my word for it. It has been very well

reported by others, most recently;

https://www.researchgate.net/publication/331593854_Effects_of_increased_heat_on_fluorescence_and_dinoflagellate_density_in_the_captive_coral_Anthelia_sp

And obviously, given my intent to get people thinking about the science of

the response, I have already had my say on this issue.

https://www.researchgate.net/publication/307695433_Breakdown_of_the_coral-algae_symbiosis_Towards_formalizing_a_linkage_between_warm-water_bleaching_thresholds_and_the_growth_rate_of_the_intracellular_zooxanthellae?_sg=-2o85tlB6whC-hSPB0t8oWFed2eECtwPxvsoVRgGKUmzu6k0TIDq5aSV6BwcOhlLqeiGGYr3KAwOMLqI2UkuYtNLnddwaWcl1ReDnhNh.pvBbZTSCSahzvcVu-JkqhLKf-zq1EbYJ6GquHXoR2Nfs2G8--J5_4bxKPwNXk0lfNXJmGnuvk3srT7GzoZSkmQ

https://www.researchgate.net/publication/44644540_Is_the_coral-algae_symbiosis_really_'mutually_beneficial'_for_the_partners?_sg=j-rvYFlYazoFU-eah3oORE-zhln-XE-Rt9sIsBFdHrjKHFWO3E1jvDuSBJmwoJ97CP1_RYFtuY-gXbicnyXyRuLK-0gAgwvn2XMNqukP.Mdg_vAKy_Zgedumry2ZUKz9kDoEj6KH_K84VDQ57AebVQnp8oLXLx95adt-cwLzuRjJ2I-j5St_pcMDr-2jtEA

All these articles ULTIMATELY explain coral bleaching in terms of a loss of

host control of the demographic parameters of its endosymbiont population.

This is very far from the CORALS BOILING IN HOT WATER conceptual model. And

that is good news!! Since it provides hope, that if we can limit the

thermo-kinetic growth potential of the endosymbionts, whilst simultaneously

retaining their capacity to release fixed carbon, we may be well on the way

to understanding what constitutes a BLEACHING RESISTANT coral. Much more

testing needs to be done on this issue. For example, can this favorable

symbiotic condition be achieved by ensuring a severe limitation of the

seawater supply of nutrients, such that the symbiont doesn’t have access to

the prerequisite nitrogenous material needed for cellular division, even

during thermo-kinetic events that promote increased division? Or, do we

need to look/find/evolve a new type/species of endosymbiont, most likely

one with a bigger cellular diameter, that will have a slower thermo-kinetic

division rate?

There are so many questions. Still unknown. Still unconsidered. Still

untested.

My challenge, especially to all the fresh thinking young scientists out

there, is to keep an open mind. Keep striving for the CURE. Never let

yourself be convinced that we already know all the necessary science to

answer this. WE DON’T and we are so very very far from it….

And finally, for a bit of comic relief as well as encouragement I am

forever drawn to the excited words of an old Australian swim coach, who

famously stated STUFF THE SILVER, WE CAME FOR THE GOLD. For those old

enough to remember, he orchestrated a brilliant tactical race for his

swimmer to beat the best simmers in the world at the 1988 Olympics. The

SILVER in coral bleaching research is to be content to quibble about the

relative merits of ways to reduce our global carbon footprint. We need to

refocus, go back to the beginning and keep searching for a CURE. Or in the

words of the excited swim coach STUFF THE SILVER, GO FOR GOLD.

https://www.youtube.com/watch?v=zgGr-quFf2k

For your consideration,

Scott Wooldridge

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