[Coral-List] Excess algal symbionts increase coral susceptibility to bleaching

[Jim Hendee]

Billy,

  Ever since you first told me (in the mid 90s) of the doldrums preceding
bleaching in the FKNMS, we utilized wind in our CREWS software production
rules for bleach forecasting, as well as light (less wind means less wave
action means greater transmittance of light through the water column, as
well as less atmospheric oxygen reaching the seas). To us, it's not always
about high sea temperature in bleaching, but sometimes high light pushing
the final button on bleaching for corals stressed through high sea
temperature.  (The physiological mechanisms are of course  complex.) Those
constructs are still in place for all of our sites (
http://ecoforecast.coral.noaa.gov).  Your practical knowledge was captured
back then and has proved to be a part many of the models.  You are
immortalized in programming code!  :D

Now, for the new extension of the CREWS Network in the Caribbean, my
colleagues and I are talking of trying to add oxygen sensors!

Thanks!

  Cheers, Jim

On Thu, Nov 15, 2012 at 2:34 PM, Billy Causey <billy.causey at noaa.gov> wrote:

> Andrew,
> Once again, you and your students are doing some cutting edge
> research.  Congratulations to you and Ross!
>
> At great risk of generating a debate of some sort, I wanted to share
> some thoughts pertaining to your findings in this current paper.
>
> Just prior to and during the massive bleaching in the Florida Keys
> (1983, 87, 90, and 97-98) we had slick-calm, doldrum weather for weeks
> at a time.  Prior to the onset of bleaching, the reef fish would
> appear stressed (pumping opercula), as if there was low O2 in the
> water.  The seas were slick, the water was hot, day and night .... and
> everything was demanding O2 at night. Even the symbionts living in the
> coral tissue.  Now, you have discovered that corals with more
> symbionts are more susceptible to bleaching.  To me, that translates
> to possibly meaning there are more symbionts demanding or using O2 at
> night in the coral tissue.  I have always felt that the role of
> dissolved O2, especially at night, was another factor that contributes
> to triggering coral bleaching.
>
> Imagine, you are the tissue of a coral, stuffed with symbionts, and
> the water is hot, DO is low, even during the day, nightfall comes,
> photosynthesis stops at night, everything is demanding O in the coral
> tissue, even the crowed symbionts.  This cycle goes on day and night
> for the extent of the doldrum weather.  The coral tissue and symbionts
> compete for O2, especially at night .... and soon something has to
> give.  The symbionts are either expelled or consumed .... and
> bleaching occurs.
>
> I realize this is rather simplistic, but it is something that I have
> thought about for years.
>
> Your's and Ross' research triggered my thinking again about the role
> of symbionts and levels of DO in the reef community.
>
> Again, congratulations for a great paper!   Billy
>
> Billy D. Causey, Ph.D.
> Southeast Regional Director
> NOAA's Office of National Marine Sanctuaries
>
> 33 East Quay Road
> Key West, Florida 33040
>
> Phone:
> 305 809 4670 office
> 305 395 0150 mobile
> 305 293 5011 fax
>
> Email:
> billy.causey at noaa.gov
>
>
> On Nov 12, 2012, at 8:55 PM, Andrew Baker <abaker at rsmas.miami.edu> wrote:
>
> > Dear all
> >
> >
> >
> > A paper published recently in Nature Climate Change might be of interest
> to
> > list subscribers. It shows that corals with too many algal symbionts are
> > more susceptible to bleaching, contrary to conventional wisdom that
> corals
> > with more symbionts are protected from bleaching because they have "more
> > symbionts to lose". It suggests that corals have to balance maximizing
> the
> > photosynthetic benefits provided by their algal symbionts against the
> risk
> > of having too many symbionts if exposed to high temperatures.
> >
> >
> >
> > This has some real world implications, providing a mechanistic
> explanation
> > for why corals exposed to nutrient pollution are more sensitive to
> bleaching
> > (see also Wiedenmann et al. 2012 for another, not necessarily mutually
> > exclusive, mechanism). It may also influence the bleaching
> susceptibility of
> > corals exposed to increasing pCO2.
> >
> >
> >
> > Link to paper:
> >
> http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1711.html
> >
> > Press release:
> >
> http://www.rsmas.miami.edu/news-events/press-releases/2012/too-much-of-a-goo
> > d-thing-can-be-bad-for-corals/
> >
> > Reference: Cunning R, Baker AC (2012) Excess symbionts increase the
> > susceptibility of reef corals to bleaching. Nature Climate Change.
> > doi:10.1038/nclimate1711
> >
> >
> >
> > Pdf available on request from lead author Ross Cunning
> > (rcunning at rsmas.miami.edu)
> >
> >
> >
> > Sincerely
> >
> > Andrew Baker
> >
> > ___________________
> >
> > Andrew C. Baker, Ph.D.
> >
> > Associate Professor, University of Miami
> >
> > Pew Fellow in Marine Conservation
> >
> >
> >
> > Lab webpage link here
> > <http://www.rsmas.miami.edu/people/faculty-index/?p=andrew-c-baker>
> >
> > Google Scholar profile link here
> > <http://scholar.google.com/citations?user=aQuKSs4AAAAJ&hl=en>
> >
> > Visit the lab on Facebook by clicking
> > <
> http://www.facebook.com/pages/University-of-Miami-Coral-Reef-Conservation-R
> > esearch-Lab-CR2/149751198419595> here
> >
> >
> >
> > Division of Marine Biology and Fisheries
> >
> > Rosenstiel School of Marine and Atmospheric Science
> >
> > University of Miami
> >
> > 4600 Rickenbacker Cswy.
> >
> > Miami, FL 33149, USA
> >
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> >
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> >
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> >
> > Email:  <mailto:abaker at rsmas.miami.edu> abaker at rsmas.miami.edu
> >
> >
> >
> > Associate Conservation Scientist
> >
> > Wildlife Conservation Society
> >
> > <http://www.wcs.org/marine> www.wcs.org/marine
> >
> >
> >
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