[Coral-List] [Fwd: Re: Temperature and elevated pCO2]

Joan Kleypas kleypas at ucar.edu
Fri Jul 14 16:02:29 EDT 2006


Dear Dr. Jameson:

Apologies for my delay in responding -

Here is a breakdown of the main points regarding the McNeil et al. 
(2005) analysis and the ensuing discussion (both our comment and their 
reply) about its applicability to predicting future calcification on 
coral reefs.

The McNeil et al. paper combined modeled predictions of future 
temperature and aragonite saturation state to derive estimates of the 
"combined" temperature and saturation state effects on coral reef 
calcification. Their combined response was calculated as a sum of the 
reduced calcification due to a decrease in saturation state and the 
increased calcification due to an increase in temperature. The sum of 
these effects led the authors to conclude that the temperature effect 
will outweigh the saturation state effect so that coral reef 
calcification will increase in the future.

The primary criticism of the analysis was that two assumptions about the 
temperature effects on calcification were wrong, namely: (1) the 
assumption that the calcification versus temperature relationship is 
linear, when it is typically a curvilinear one (hyperbolic or Gaussian) 
whereby corals calcify faster with increasing temperature until a point, 
beyond which calcification rate declines; and (2) the failure to include 
the effect of coral bleaching on corals and coral cover (and thus coral 
and coral community calcification rates).

While no one argues that temperature is a major factor in coral 
calcification, it is unlikely to counter the effects of changing 
carbonate chemistry to the extent that the McNeil et al. paper 
suggested. However, their paper did highlight the need for continued 
research on the combined effects of multiple variables on calcification 
rates of coral reef calcifiers.

I hope this clears up the confusion!

Joanie Kleypas
National Center for Atmospheric Research
Boulder CO 80302


Dr. Stephen Jameson wrote:
Dear Jean-Pierre,

Thanks for the ocean acidification note regarding:

 
> The following papers address the interaction between temperature and
> elevated pCO2:
>
> Kleypas J. A., Buddemeier R. W., Eakin C. M., Gattuso J.-P., Guinotte
> J., Hoegh-Guldberg O., Iglesias-Prieto R., Jokiel P. L., Langdon C.,
> Skirving O. W. & Strong A. E., 2005. Comment on ³Coral reef
> calcification and climate change: The effect of ocean warming².
> Geophysical Research Letters L08601. doi:10.1029/2004GL022329.
>
> Reynaud S., Leclercq N., Romaine-Lioud S., Ferrier-Pagès C., Jaubert J.
> & Gattuso J.-P., 2003. Interacting effects of CO2 partial pressure and
> temperature on photosynthesis and calcification in a scleractinian
> coral. Global Change Biology 9(11):1660-1668.
>
> Cheers,
> jp
>     

JP, In your reference list I'm surprised you didn't include McNeil's
counter-response:

McNeil, B. I., R. J. Matear, and D. J. Barnes (2005),
Reply to comment by Kleypas et al. on ŒŒCoral reef calcification
and climate change: The effect of ocean warming,¹¹ Geophys. Res.
Lett., 32, L08602, doi:10.1029/2005GL022604.

to your first reference:

 
> Kleypas J. A., Buddemeier R. W., Eakin C. M., Gattuso J.-P., Guinotte
> J., Hoegh-Guldberg O., Iglesias-Prieto R., Jokiel P. L., Langdon C.,
> Skirving O. W. & Strong A. E., 2005. Comment on ³Coral reef
> calcification and climate change: The effect of ocean warming².
> Geophysical Research Letters L08601. doi:10.1029/2004GL022329.
>     

I've attached McNeil's response below for the benefit of the Coral-List
readers, who like myself have limited time and are trying to make sense out
of ocean acidification research results and recent newspaper/magazine
articles that do not put the ocean acidification problem in perspective 
with
respect to increasing sea surface temperature.

So back to my original request,

 
> Joan     

 
> Your thoughts/guidance would be appreciated, so we can all respond to 
> these
> calcification challenge questions accurately.
>     


Best regards,

Dr. Stephen C. Jameson, President
Coral Seas Inc. - Integrated Coastal Zone Management
4254 Hungry Run Road, The Plains, VA  20198-1715  USA
Office:  703-754-8690, Fax:  703-754-9139
Email:  sjameson at coralseas.com
Web Site:  http://www.coralseas.com

and

Research Collaborator
Smithsonian National Museum of Natural History
Washington, DC 20560




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