[Coral-List] Climate change and coral reef sequestration of carbon

John Ware jware at erols.com
Mon Dec 10 12:10:06 EST 2007

Hi Tom and Jim + List,

Those more interested in details about reefs as sources of atmospheric 
carbon as CO2 might want to look at :

Coral reefs: Sources or sinks of atmospheric CO2
Ware, Smith,  and Reaka-Kudla
Coral Reefs 1991.

If there is any interest in this publication I may be able to scan it 
into pdf format, but right now there are just hard copies.


P.S.  By the way, the answer to the question is: SOURCES but not much.


James Cervino PhD. wrote:

>Message From Tom Goreau at the Global Warming Conference:
>I can't post to the server, so please post the following on my behalf. I'm a
>delegate at the UN Climate Change Conference, busy shootng down many false and
>erroneous claims like the one that reefs are a carbon sink. Yhey are

>Not only is the entire claim that coral reefs are a CO2 sink completely
>incorrect, they are in fact a source of CO2 to the atmosphere even while they
>remove carbon from the ocean. This has been understood by carbonate chemists
>for a very long time  but we keep having to deal with this popular error over
>and over again. 

>Fundamentally, because the ocean is a pH buffered system in which electrical
>charge is conserved, for every atom of bicarbonate in seawater that is
>converted to carbonate and deposited as limestone one molecule of bicarbonate
>is converted to carbonic acid and then to CO2 to balance the charge. So in
>effect for each atom of carbon removed from the ocean into limestone, one atom
>is released as CO2 to the atmosphere.
>On a geological time scale limestone deposition and volcanic emissions are the
>two major sources of atmosheric CO2 (since photosynthesis and respiration plus
>decomposition balance),and are balanced by the fact that CO2 dissolves in fresh
>water, where it is the major acid once it ionizes, and is then neutralized by
>chemical weathering of limestone on land and of igneous and metamorphic rocks,
>being converted into bicarbonate which washes into the sea, resuming the cycle.
>Half of all the limestone buried in the sea is buried in coral reefs (since most
 ooceanic production dissolves in the deep sea), but to put it into
>perspective, this natural source of CO2 is 50 TIMES SMALLER THAN FOSSIL FUEL
>INPUTS, showing how seriously we have perturbed the natural carbon cycles.

>The only way that reefs could be a CO2 sink would be if they were autotrophic
>ecosystems that buried most of the algae carbon before it could decompose. But
>in fact reef sediments have very low buried organic carbon content, because the
>organic carbon is almost entirely decomposed. In fact, reefs are not autotrophic
>at all, they are heterotrophic systems that rely on external organic carbon
>input from land and oceanic zooplankton.
>Whenever I have measured oxygen in a reef it has always been below saturation,
>except directly over dense shallow seagrass beds in full sunlight. Overall the
>reef organic carbon cycle is consuming oxygen and producing CO2,  as well as
>the CO2 produced by limestone deposition. 

  Coral reefs are the
>first and worst victims of global warming, but they do not contribute to
>removing CO2 form the atmosphere at all. We must save them for their
>biodiversity, fisheries, shore protection, and tourism services, not because of
>false and misqguided claims that they are carbon sinks.

>Tom Goreau
  President, Global Coral Reef Alliance

>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.
>Coral-List mailing list
>Coral-List at coral.aoml.noaa.gov

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    *                      John R. Ware, PhD                    *
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