[Coral-List] pH or acidity?
goreau at bestweb.net
Sat Jan 12 12:57:54 EST 2008
The posting below by John McManus got the pH effects backwards
because pH seems to have been unfortunately confused with acidity.
James Cervino is right, high temperature has already killed most of
the corals, and acidity will dissolve their dead skeletons only
decades after they have died of heatstroke. Acidification is a
serious global ocean issue, but it is a red herring as an imminent
threat to corals, and allows those who don't want to deal with the
fact that coral reefs can't take any more warming with a further
excuse to delay action.
Despite the recent hoopla about CO2 caused ocean acidification, this
has long been known. In the 1970s Dick Holland and I would make
Harvard undergraduate geochemistry students calculate the equilibrium
decrease in ocean pH from doubling of CO2 as a homework exercise
problem. What seems to be missing in the recent discussion is that
since both CO2 and limestone are far less soluble in warm water than
cold water, CO2 is degassed from the tropical ocean and dissolves
near the poles. It is the cold polar and deep waters that will be the
first to be affected, and the tropical surface waters and reefs will
be the last place to be impacted.
Thomas J. Goreau, PhD
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
goreau at bestweb.net
> Date: Fri, 11 Jan 2008 16:29:35 -0500
> From: "John McManus" <jmcmanus at rsmas.miami.edu>
> Subject: Re: [Coral-List] Question Thermal vs pH shift
> To: "'James Cervino PhD.'" <jcervino at whoi.edu>,
> <coral-list at coral.aoml.noaa.gov>
> Cc: arietta.Venizelos at noaa.gov, 'konrad Hughen' <khughen at whoi.edu>,
> tyler.volk at nyu.edu, 'Michael Robert Rampino' <mrr1 at nyu.edu>,
> kcaldeira at stanford.edu
> Message-ID: <email@example.com>
> Content-Type: text/plain; charset="us-ascii"
> The recovery from pH changes is in line with the paper of Fine and
> "Scleractinian Coral Species Survive
> and Recover from Decalcification" SCIENCE VOL 315 30 MARCH 2007, in
> 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 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
> 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;
> 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
> conditions are not seriously inducing cell impairments in corals or
> substrates as both arriving at the same conclusion, death for corals.
> With that said, all the data (real time, not models) points to the
> 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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