[Coral-List] starvation?

Billy Causey billy.causey at noaa.gov
Thu Jun 1 11:53:01 EDT 2006


Excellent points Mark!  Billy

Mark Eakin wrote:

> Follow-up to the mass bleaching in the Caribbean has revealed that
> coral death from large scale thermal stress results from a wide range
> of causes.  Some of the corals died very quickly (ca. 1 week).  This
> is probably thermal stress.  Some died within a few weeks.  Lack of
> nutrition from zooxanthellae and loss of reserves probably
> contributed here (starvation).  Some died later, often from disease.
>
> I think when dealing with the press and public, the message that
> thermal stress and bleaching may result in mortality is the important
> message.  The rest is for us to debate.
>
> Cheers,
> Mark
>
> On May 31, 2006, at 1:06 PM, jmcmanus wrote:
>
> > Most likely we are dealing with two phenomena in severe bleaching
> > events:
> >
> > 1. Stresses related to the loss of Symbiodinium
> > 2. Thermal stress per se.
> >
> > All organisms have upper thermal tolerance limits, set by various
> > physiological mechanisms (oxygen uptake, other aspects of metabolism,
> > protein and enzyme production, etc.). Many organisms live nearer
> > the upper
> > than the lower tolerance limits, which is why it is usually safer to
> > transport marine organisms in colder water than they are used to
> > than in
> > warmer water. During periods of very warm water, other species on a
> > reef may
> > die suddenly, such as mollusks and fish. It may be that coral death
> > that is
> > too quick to be explained in terms of starvation may not
> > necessarily be
> > related to the loss of the Symbiodinium.
> >
> > Cheers!
> >
> > John
> >
> > John W. McManus, PhD
> > Professor, Marine Biology and Fisheries
> > Coral Reef Ecology and Management Laboratory (CREM Lab)
> > Director, National Center for Coral Reef Research (NCORE)
> > Rosenstiel School of Marine and Atmospheric Science
> > University of Miami, 33149
> > Office: 305-421-4814/4820, Fax: 305-421-4910, Website:
> > www.ncoremiami.org
> >
> > If I cannot build it, I do not understand it. -- Richard Feynman,
> > Nobel
> > Laureate
> >
> >
> > -----Original Message-----
> > From: coral-list-bounces at coral.aoml.noaa.gov
> > [mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Julian
> > Sprung
> > Sent: Wednesday, May 31, 2006 10:15 AM
> > To: coral-list at coral.aoml.noaa.gov
> > Subject: [Coral-List] starvation?
> >
> > As a follow up to the post I just sent, I have not yet seen this
> > recent
> > paper in Nature and look forward to reading it- My comments about
> > starvation
> > are not in any way intended to dismiss the conclusions of the paper.
> >
> > I am only commenting on what I believe to be true with regard to
> > temperature
> > induced bleaching and mass die off of corals-- that the majority of
> > the die
> > off usually occurs in a matter of days, far too quickly to be
> > caused by
> > starvation.
> >
> > It is an interesting point to compare what can be achieved in an
> > aquarium
> > with respect to food inputs as opposed to food supply on reefs. In
> > general
> > the live and particulate food supply on reefs is greater than what
> > is the
> > norm for most aquariums, but I agree aquariums could achieve higher
> > inputs
> > to meet the demands of a particular coral, given the effort of an
> > aquarist
> > to make it happen. The idea that some corals might not be able to
> > get enough
> > food in the wild if they lack zooxanthellae is new to me- if true,
> > it would
> > mean I have to revise my opinion about starvation as being too broad!
> >
> > Julian
> >
> >
> >
> >> ----------
> >> From:        coral-list-bounces at coral.aoml.noaa.gov on behalf of Andréa
> > Grottoli
> >> Sent:        Tuesday, May 30, 2006 3:37 PM
> >> To:  coral-list at coral.aoml.noaa.gov; goreau at bestweb.net
> >> Subject:     [Coral-List] coral bleaching: response to Goreau
> >>
> >> Dear Tom,
> >>
> >> I read your contribution on the coral list about
> >> coral bleaching with interest.  As the lead
> >> author of the recent Nature paper on
> >> heterotrophic plasticity in bleached corals, I
> >> would like to comment.  You stated:
> >>
> >> "The recent paper that claims to have discovered "for the first time"
> >> that corals eat zooplankton and can survive bleaching better if
> >> fed is
> >> not new either. The fact that corals don't get their carbon from
> >> zooxanthellae is also very old knowledge, but for decades people have
> >> ignored the old literature and have mistaken the net oxygen
> >> balance to
> >> assume that corals are also autotrophic in carbon. This recent
> >> error has
> >> become dogma, despite being wrong, because nowadays people don't read
> >> the literature or ask those who know it. The first radiocarbon tracer
> >> experiments, done by Thomas F. Goreau and Nora I. Goreau more than 50
> >> years ago showed that very little zooxanthella carbon translocation
> >> contributed to coral carbon, and that corals relied on zooplankton
> >> for
> >> the vast bulk of their carbon needs. They kept corals completely
> >> bleached in the dark for years, feeding them on zooplankton. So
> >> survival
> >> of bleached fed corals has been known for over half a century and
> >> is not
> >> a "new discovery" at all. Like so much else in the current
> >> literature."
> >>
> >> I would like to point out that our paper showed
> >> that only one species, Montipora capitata,
> >> consumed enough zooplankton to meet all of its
> >> metabolic demand heterotrophically when
> >> bleached.   When healthy, M. capitata met less
> >> than 15% of its metabolic demand
> >> heterotrophically.  The other two species we
> >> studied, Porites compressa and Porites lobata,
> >> only met 21-35% of their daily metabolic demand
> >> heterotrophically when they were either healthy
> >> or bleached.   In all cases, our corals were
> >> exposed to naturally occurring zooplankton on the
> >> reef.  Thus under natural reef conditions, not
> >> all bleached corals can meet all of their
> >> metabolic needs heterotrophically.  Under
> >> artificially fed conditions (i.e., coral exposed
> >> to higher than ambient concentrations of
> >> zooplankton or brine shrimp in tanks), things can
> >> be quite different.   As you pointed out, the
> >> fact that corals do get some fixed carbon from
> >> zooplankton has been know for a very long
> >> time.  However, the fact that when bleached at
> >> least one species can  increase heterotrophic
> >> feeding to meet all of its metabolic needs while
> >> two others could not, is novel.  Our results
> >> suggest that not all species of corals would be >
> >> able to meet their metabolic demand when
> >> maintained in the dark under natural
> >> concentrations and abundance of zooplankton (i.e,
> >> P compress and P lobata probably could not get
> >> all of their energy needs met heterotrophically
> >> when bleached under darkness... but this would
> >> need to be specifically tested).   In addition,
> >> bleaching induced by keeping corals in the dark
> >> is not necessarily the same as
> >> temperature-induced bleaching.  The chain of
> >> physiological stress responses that occur under
> >> high temperature include free radical and stress
> >> protein production, making any heterotrophic
> >> responses under tempreature-induced bleaching
> >> possibly quite different than hetertrophic
> >> responses under sustained darkness.
> >>
> >> Sincerely,
> >>
> >> Andrea Grottoli
> >>
> >> *******************************************************
> >> Andréa G. Grottoli, Assistant Professor
> >> Ohio State University
> >> Department of Geological Sciences
> >> 125 South Oval Mall
> >> Columbus, OH 43210-1398
> >> office:  614-292-5782
> >> lab: 614-292-7415
> >> fax: 614-292-7688
> >> email: grottoli.1 at osu.edu
> >> web: www.geology.ohio-state.edu/~grottoli
> >> Office location: 329 Mendenhall Labs
> >>
> >> *******************************************************
> >>
> >> _______________________________________________
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> >>
> >>
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> ------------------------------------------------------------------------
> ------------------------
> C. Mark Eakin, Ph.D.
> Coordinator, NOAA Coral Reef Watch
> National Oceanic and Atmospheric Administration
> Center for Satellite Applications and Research
> Satellite Oceanography & Climate Division
> e-mail: mark.eakin at noaa.gov
> url: coralreefwatch.noaa.gov
>
> E/RA31, SSMC1, Room 5308
> 1335 East West Hwy
> Silver Spring, MD 20910-3226
> 301-713-2857 x109                   Fax: 301-713-3136
>
> The contents of this message are mine personally and do not
> necessarily reflect any position of the Government or the National
> Oceanic and Atmospheric Administration.
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--



----
Billy D. Causey
Superintendent
Florida Keys National Marine Sanctuary
P.O. Box 500368
Marathon, FL  33050

phone: (305) 743-2437 x26
fax: (305) 743-2357

http://floridakeys.noaa.gov





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