[Coral-List] Coral bleaching and ocean acidification

Thomas Goreau goreau at bestweb.net
Thu Feb 12 12:07:32 EST 2009

Dear Lee,

Thanks! No question that the equilibration across the surface boundary  
layer is fast and is wind driven. But my point is that the temperature  
solubility gradient will result in coral reefs always being the LAST  
surface water habitat to be affected by acidification, and we have  
ALREADY seen the temperature impacts, so now it is only a question of  
when the next extreme hot year will be.

Ray Hayes and I have shown from analysis of SST records for all major  
reef areas of the world from 1982-2003 that these extreme events are  
increasing significantly in amplitude and frequency so it is only a  
matter of time. We can predict mean trends, but we can't predict the  
extreme events except in real time, and they are the real killer.

Best wishes,

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

On Feb 12, 2009, at 9:13 AM, Lee Kump wrote:

> Dear Tom,
> Although I agree with much of what you say about warming and
> bleaching, you are wrong in assuming that acidification will take
> thousands of years to develop. In fact, just the opposite: surface
> water acidification is immediate, because the surface ocean is
> in intimate contact with the atmosphere, and atmospheric pCO2
> is increasing. This can be easily shown both theoretically and
> through observation: see for example the review article
> by Orr et al. (2005; Nature 437: 681-686) or a nice wikipedia
> site: http://en.wikipedia.org/wiki/Ocean_acidification.
> Rapid acidification such as what is occurring now affects surface
> waters first, then deep waters, where carbonate dissolution occurs.
> Slower additions of CO2, such as those that led to the high  
> atmospheric
> CO2 levels of the Cretaceous (100 million years ago) occurred at
> such a slow rate that geological processes (e.g., weathering of the
> continents) were able to keep the ocean surface waters supersaturated
> despite high CO2. Rates matter, as you say, but not in the way you
> suggest.
> Cheers,
> Lee

More information about the Coral-List mailing list