[Coral-List] CO2 and corals

Thomas Goreau goreau at bestweb.net
Thu Feb 12 12:48:37 EST 2009

> Tom Williams raises some interesting points that I only alluded to  
> in passing. Changes in ocean circulation will indeed have profound  
> effects on CO2 equilibration, transport, and surface acidification,  
> especially if surface waters become too warm to sink and the warm  
> layer thickens and increases ocean vertical stratification, which  
> would have a positive feedback effect on both atmospheric CO2  
> buildup AND ocean acidification. In fact such changes are already  
> underway globally, as Ray Hayes and I published some 4 years ago. We  
> found that by analyzing the global pattern of rise of SST from  
> satellite data spanning 1983-2003 that all the warm currents and all  
> the cold currents and all the marginal semi enclosed seas and all  
> the upwelling zones were warming faster than the ocean average, and  
> that areas warming more slowly than the average included all the  
> remote (from land) gyres and around Antarctica where wind speed was  
> increasing. More alarming we found that several upwelling zones had  
> gotten so warm that upwelling to the surface had shut off, so that a  
> major part of the fisheries crisis in these areas is not (only)  
> overfishing but collapse of the pelagic food chain from the bottom  
> up. It is much later than we think, and aggressive control of CO2 is  
> the only solution, in fact CO2 needs to be decreased by about a  
> third from the present level.

Tim Wijgerde's point is correct, there are many lab studies showing  
decreasing calcification with acidification, and good studies showing  
seasonal variations in reef calcification related to upwelling events  
of CO2 rich water. However it is a mistake to equate the external  
solution with the internal milieu, because corals are able to calcify  
in acidic waters since they can concentrate calcium through active  
pumping and generate alkalinity through zooxanthellae photosynthesis  
removing internal CO2 and generating strong internal pH gradients that  
change diurnally. But the key point I was really making is that the  
Australians nicely showed data of decreasing coral growth and blamed  
it on ocean acidification without ever mentioning that these corals  
have undergone repeated bleaching events due to high temperature, and  
that bleached corals completely stop growing! How this stuff gets  
published indicates failure of the review process.

Thomas J. Goreau, PhD
President, Global Coral Reef Alliance
Coordinator, United Nations Commission on Sustainable Development  
Partnership in New Technologies for Small Island Developing States
37 Pleasant Street, Cambridge MA 02139
goreau at bestweb.net

> Date: Wed, 11 Feb 2009 19:04:21 -0800 (PST)
> From: Tom Williams <ctwiliams at yahoo.com>
> Subject: Re: [Coral-List] CO2 and tropical waters.
> To: "coral-list at coral.aoml.noaa.gov" <coral-list at coral.aoml.noaa.gov>,
> 	John Ware <jware at erols.com>
> Message-ID: <923842.39298.qm at web50411.mail.re2.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
> Listers
> John's email presumes that the CO2 concentrations are constant  
> worldwide...although AtmCO2 losses to OceCO2 in the Aluetian and  
> North Atlantic and circumAntarctica may be higher than those in the  
> tropics.
> Interestingly the colder polar waters are getting warmer and  
> especially in the Arctic the transfers may be reducing and thereby  
> maintaining a higher AtmCO2 than may be expected from model. If the  
> oceanic circulation between the Antarctic circumpolar currents  
> decrease due to reducing Olar/Tropic differentials, polar transfers  
> of Atm>OceCO2 may further change the balances as the OCeCO2 may  
> reach saturation more quickly as the water is not descending and  
> drawing in other less saturated waters.
> Pre-"Global Warming" Atm/OceCO2 concentration were or have been  
> influenced by the surface ocean, descending (downwelling), and  
> upwelling currents and few models that I have heard of reflect the  
> "sluggish" ocean circulation in horizontal and vertical regimes.
> Losses of Arctic pack ice and Antarctic shelf ice will contribute to  
> an even greater variation in current and winds, and temperatures  
> related to albedos which appear to further confuse and confound US.
> During Plocene (3-9MY) climates appeared to be more randomized, and  
> present day strongly seasonal climates and stronger ocean currents  
> appear to be retrograding to the Pliocene conditions. They can't get  
> back to those conditions due to existing mountain ranges but  
> climates and current may become more randomized and more weakly  
> defined than in the recent past.
> Tom Williams
> Date: Thu, 12 Feb 2009 15:02:17 +0100 (CET)
> From: "Tim Wijgerde" <t.wijgerde at coralscience.org>
> Subject: Re: [Coral-List] figures aquarium trade
> To: coral-list at coral.aoml.noaa.gov
> Message-ID:
> 	<51487. at webmail.coralscience.org>
> Content-Type: text/plain; charset="iso-8859-1"
> p.s. related to the
> Goreau topic; Thomas, I would agree that coral decalcification is
> secondary to bleaching, but don't you think that the simple decrease  
> in
> aragonite saturation state will decrease coral growth long before its
> starts dissolving? This would be another stressor for reefs,  
> although not
> killing them yet. This is already noticable in temperate seas, where  
> arag
> and calcite sats have already declined significantly and this is  
> reflected
> by a decreased growth of calcifying organisms.

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