[Coral-List] Question Thermal vs pH shift

Thomas Goreau goreau at bestweb.net
Sun Jan 13 09:50:10 EST 2008


I agree with you, James, this hope of poleward shift of functional  
coral reefs in nonsense that just a few people supporting global  
warming range expansion have long pushed. There is clear evidence of  
corals expanding into warmer water at the limits of their ranges, but  
this results in coral communities, not coral reefs, which take  
centuries to thousands of years to develop. Even if the corals could  
adapt to warmer temperatures, and there seems to be no really good  
evidence that they can on the time scale that would be needed, the  
existing reefs would die quickly, and it could take thousands of  
years for new reefs to be established. But the nutrients in these  
newly warmer poleward coastal zones are way too high for corals, so  
you'd get algae instead. Ken Caldeira is right that there are times  
in the past when the ocean was too acidic for big reefs, and corals  
survived only in marginal habitats. But the way to best prevent the  
ocean becoming so acid that dead reefs dissolve is to stop global  
warming now so we can save the existing corals, and not count on the  
trial and error of evolution over millenia to millions of years to  
cough up something that can make it.

Thomas J. Goreau, PhD
President
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
617-864-4226
goreau at bestweb.net
http://www.globalcoral.org

On Jan 13, 2008, at 12:22 AM, James Cervino PhD. wrote:

> Hi Ken long time since NYU,
>
> You make some very valid points in your post. However, what  
> concerns me is the
> terminology pertaining to corals establishing themselves poleward  
> in a more
> tolerable environment.  The key question is, what types of corals  
> will even be
> able to take this journey? For the purposes of addressing the  
> students,
> policymakers, and journalists reading this healthy discussion, I  
> would like to
> point out a very important factor. Let’s use the 100+ different  
> species of
> Acroporids (the most sensitive to thermal stress). The success of  
> these
> organisms’ reproductive productivity can be determined by factors  
> specific to
> global and coastal adaptive pressures, i.e., thermal stress,  
> sedimentation,
> nutrient enrichment & pathogens. Because these factors are  
> occurring at such a
> rapid rate, these thermally sensitive species will not move/adapt  
> within the
> time you are hypothesizing.
>
> Sensitive species (all species, really) need time to adapt! As  
> Steven J. Gould
> so eloquently stated in the “Return of the Hopeful Monster”: The  
> essence of
> Darwinism lies in a single phrase: natural selection is the major  
> creative
> force of evolutionary change and no one denies that natural  
> selection will play
> a negative role in eliminating the unfit. However, selection occurs  
> by building
> “gradual adaptations” in a series of steps (again “time”),   
> preserving at each
> stage, the advantageous part in a random spectrum of genetic  
> variability.
>
> For those who are thinking optimistically, what is the time frame  
> in which
> you’re thinking that corals will adapt and move northward?   Did  
> the surviving
> corals of the 1998 Indian Ocean Hot-Spot bleaching pass some of these
> heat-tolerant genes north and establish themselves there, thereby  
> escaping the
> heat? Is there evidence of this genetic drift? Let’s look at the  
> real-time
> observations since the 1982-83 major thermal bleaching event. This  
> will be
> important to investigate the reality of what’s occurring. The  
> thermal hot-spot
> events have been growing more severe year after year since 1982-83  
> and I have
> not seen documentation of these keystone species’ (as we know  
> them)  mass
> northward migration to escape from the heat.  Does anyone have  
> evidence of this
> adaptation and drift?
>
>> From our recent clade sub-type experiments I can identify a more  
>> heat tolerant
> Symbiodinium spp. as shown by (Sotka and Thacker, 2005) and one  
> that resists
> Vibrio pathogens during short-term exposure due to unknown defense  
> mechanisms.
>  However, as shown by Baker et al. &  LaJeunesse  et al., major  
> reef-building
> corals can be found  hosting multiple symbiont species at the clade  
> level.
> However, radiation or drift of these symbioants northward escaping  
> the heat
> thereby taking up residence on the top of some algal lawn has to  
> take time, and
> not at the time scale some optimists want to think. The projected  
> increases in
> the frequency and severity of thermal bleaching events and coral  
> resilience
> depends, on whether phenotypic and genotypic changes in host–symbiont
> associations can match the time factors at which their cellular  
> biochemical
> processes can adapt. In conclusion, given what we are seeing in  
> real-time, this
> genetic adaptation and migration northward to preserve these 100+  
> Acroporid spp.
> as we know them, is highly un-probable and will die long before the  
> oceans
> become acidic.
>
> Sincerely- James
>
> *************************************
> Dr. James M. Cervino
> Pace University & Visiting Scientist
> Woods Hole Oceanographic Inst.
> Department of Marine Chemistry
> Woods Hole MA.
> Cell: 917-620*5287
> ************************************
>
>
> Quoting Ken Caldeira <kcaldeira at stanford.edu>:
>
> * John,
> *
> * In the absence of dramatic reductions in CO2 emissions, the range of
> * aragonite saturation in  the entire surface ocean will not  
> intersect the
> * range of aragonite saturation in which coral reefs grew in the
> * pre-industrial ocean.
> *
> * In contrast, areas of ocean will still be found with temperatures  
> in the
> * range in which coral grew pre-industrially (they will just be  
> closer to the
> * poles). If temperature were the only issue, we could imagine reefs
> * establishing themselves poleward of their current range.
> *
> * So, while temperature is a threat (perhaps a lethal threat), if  
> temperature
> * were the only threat their would be some hope for adaptation and  
> migration.
> *
> * While corals survive and recover in a fish tank at low pH, their  
> growth
> * rates are slowed and it is likely that they will be less fit to  
> compete
> * ecologically, so we may not see acute lethality but rather a  
> weakening that
> * leads to a loss of ecological competitiveness -- for example,  
> less success
> * at repopulating an area after disturbance.
> *
> * My sense is that temperature is more of a threat to reefs today  
> but if CO2
> * emissions continue eventually aragonite saturation will become more
> * important than temperature.
> *
> * Ken
> *
> * On Jan 11, 2008 1:29 PM, John McManus <jmcmanus at rsmas.miami.edu>  
> wrote:
> *
> * > The recovery from pH changes is in line with the paper of Fine and
> * > Tchernov
> * > "Scleractinian Coral Species Survive
> * > and Recover from Decalcification" SCIENCE VOL 315 30 MARCH  
> 2007, in which
> * > species of Oculina and Madracis corals lost skeletons at high  
> pH and
> * > regained them upon returning to low pH. They did not test major  
> reef
> * > builders, but the results are astounding anyway.
> * >
> * > As for thermal stress, some glimmer of hope lies in the fact that
> * > temperatures that kill a species in one locality may be  
> tolerated by the
> * > same species elsewhere, whether via coral physiological  
> adaptation or
> * > genetics, or via differences in Symbiodinium. There is also  
> species
> * > substitution (susceptible for tolerant) and natural temperature  
> refugia
> * > for
> * > some species (mesophotic reefs, upwelling areas, etc.). Not to  
> minimize
> * > the
> * > immense problems ahead, but the patient does still have a pulse...
> * >
> * > Cheers! (at least for the optimists)
> * >
> * >
> * > John
> * >
> * > John W. McManus, PhD
> * > Director, National Center for Coral Reef Research (NCORE)
> * > Professor, Marine Biology and Fisheries
> * > Coral Reef Ecology and Management Lab (CREM Lab)
> * > Rosenstiel School of Marine and Atmospheric Science (RSMAS)
> * > University of Miami, 4700 Rickenbacker Causeway, Miami, 33149
> * > jmcmanus at rsmas.miami.edu      http://ncore.rsmas.miami.edu
> * >  Phone: 305-421-4814   Fax: 305-421-4910
> * >
> * >  "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  
> James Cervino
> * > PhD.
> * > Sent: Friday, January 11, 2008 9:06 AM
> * > To: coral-list at coral.aoml.noaa.gov
> * > Cc: arietta.Venizelos at noaa.gov; konrad Hughen;  
> tyler.volk at nyu.edu; Michael
> * > Robert Rampino; kcaldeira at stanford.edu
> * > Subject: [Coral-List] Question Thermal vs pH shift
> * >
> * > Dear Coral Scientists-
> * >
> * >
> * > A while ago at the MBL when we compared pH shifts vs thermal  
> stress to
> * > investigate what will induce expulsion (bleaching) first I  
> noticed the
> * > following: During every trial exposing corals to thermal  
> stress, heat
> * > killed
> * > the corals far faster than pH changes in vitro. I am not saying  
> that acid
> * > like
> * > conditions are not seriously inducing cell impairments in  
> corals or
> * > carbonate
> * > substrates as both arriving at the same conclusion, death for  
> corals.
> * >
> * > With that said, all the data (real time, not models) points to  
> the corals
> * > dying
> * > of heat stroke far before acid like conditions take effect. Are  
> we not
> * > witnessing the death of reefs in real-time due to thermal stress?
> * >
> * > Just a question Cheers, James
> * >
> * >
> * > *************************************
> * > Dr. James M. Cervino
> * > Pace University & Visiting Scientist
> * > Woods Hole Oceanographic Inst.
> * > Department of Marine Chemistry
> * > Woods Hole MA.
> * > Cell: 917-620*5287
> * > ************************************
> * >
> * >
> * >
> * >
> * > ----------------------------------------------------------------
> * > This message was sent using IMP, the Internet Messaging Program.
> * >
> * > _______________________________________________
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> * > Coral-List at coral.aoml.noaa.gov
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> * >
> * >
> * >
> *
> *
> * --
> * ===============================
> * Ken Caldeira
> * Department of Global Ecology
> * Carnegie Institution
> * 260 Panama Street
> * Stanford, CA 94305 USA
> * +1 650 704 7212; fax: +1 650 462 5968
> *
> * kcaldeira at stanford.edu
> *
> * http://globalecology.stanford.edu/DGE/CIWDGE/home/main%20page/ 
> caldeira.php
> *
>






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