[Coral-List] Question Thermal vs pH shift

Douglas Fenner dfenner at blueskynet.as
Sun Jan 13 16:54:25 EST 2008


Keep in mind that many soft corals and gorgonia are zooxanthellate and 
bleach and die in high temperatures just like zooxanthellate hard corals. 
Zooxanthellate soft corals tend to be the dull colored ones out in the 
light, and azooxanthellate soft corals tend to be the ones with bright 
colors found in shaded locations.  The book on Soft Corals of the 
Indo-Pacific by Fabricius and Alderslade has pictures of bleached soft 
corals - they seem to melt away as they die.  After a mass bleaching event 
you can often find rounded pillow-shaped formations which are the spiculite 
bases of soft corals that were killed.  Some of the larger soft corals may 
be a hundred years old or more, so the large colonies are unlikely to be 
quickly replaced after bleaching.  So if high temperatures kill things 
before CO2, many soft corals will die out along with the hard corals, and 
they will no longer contribute to building the reef.  In some places there 
contribution may be significant.
    -Doug

----- Original Message ----- 
From: "John McManus" <jmcmanus at rsmas.miami.edu>
To: "'Ken Caldeira'" <kcaldeira at stanford.edu>
Cc: <coral-list at coral.aoml.noaa.gov>; <arietta.Venizelos at noaa.gov>; "'konrad 
Hughen'" <khughen at whoi.edu>; <tyler.volk at nyu.edu>; "'Michael Robert 
Rampino'" <mrr1 at nyu.edu>
Sent: Saturday, January 12, 2008 12:13 PM
Subject: Re: [Coral-List] Question Thermal vs pH shift


>I tend to agree. After some number of decades there may be a predominance 
>of
> communities on slowly eroding reef substrates heavily dominated with soft
> corals. Soft coral communities exist in many reef areas today, but seem
> likely to become increasingly common. Even these may change, as spicule
> formation in many soft coral species may suffer. The reduction in 3D
> heterogeneity will undoubtedly alter the fish communities and thus the
> levels of herbivory, but it is currently difficult to forecast what the 
> net
> result will be in terms of algal cover in areas where nutrient loading is
> kept below overwhelming levels.  We need to start figuring out what will
> result from those changes in terms  of reef composition and resources, and
> simulation models are going to have to play a role there. I suspect that 
> the
> remaining soft coral communities will be well worth protecting from
> eutrophication.
>
>
>
> In the meantime, I would like to see more experiments with the growth of
> heavily aragonite and calcite dependent organisms under increased pH 
> levels.
>
>
>
>
> Cheers!
>
>
>
>
>
> 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
>
>
>
>
>
>
>
>
>
> From: kcaldeira at gmail.com [mailto:kcaldeira at gmail.com] On Behalf Of Ken
> Caldeira
> Sent: Saturday, January 12, 2008 1:16 AM
> To: John McManus
> Cc: James Cervino PhD.; coral-list at coral.aoml.noaa.gov;
> arietta.Venizelos at noaa.gov; konrad Hughen; tyler.volk at nyu.edu; Michael
> Robert Rampino
> Subject: Re: [Coral-List] Question Thermal vs pH shift
>
>
>
> 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
> ************************************
>
>
>
>
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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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