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

[Dennis Hubbard]

Thanks Scott. This is a VERY interesting finding. I have often wondered
whether the pathway involved the corals expelling the endosymbionts of the
latter "bailing out" as a defense (or other) mechanism. Might you have any
ideas on what the specific pathways and linkages look like and how we might
"short-circuit" them - if I understand your point?

Best,

Dennis

On Tue, Mar 24, 2020 at 6:31 PM 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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-- 
Dennis Hubbard
Chair, Dept of Geology-Oberlin College Oberlin OH 44074
(440) 775-8346

* "When you get on the wrong train.... every stop is the wrong stop"*
 Benjamin Stein: "*Ludes, A Ballad of the Drug and the Dream*"