cc: sandy.tudhope@ed.ac.uk, k.briffa@uea.ac.uk, mhughes@ltrr.arizona.edu date: Tue, 15 May 2001 10:41:54 -0700 from: Julia Cole subject: Re: comments? to: Keith Alverson , "Raymond S. Bradley" Hi Keith and all, I was away late last week and did not have a chance to look at the newsletter article until today. A few comments on the coral section, if it isn't too late - - The comment on Urvina Bay implies that the reef from which the published long record came was destroyed in 1982 - in fact that reef was uplifted tectonically (above sea level) in 1954 or so.... additional living corals from the Bay itself may have been killed by that event however. Maybe better to say that the 1982-3 ENSO event caused coral mortality throughout the Galapagos. We saw this clearly in a 1989 visit. - Recent studies are confirming that corals and other calcifying marine organisms are under geochemical threat from rising CO2. As atmospheric CO2 increases, oceanic CO2 rises and carbonate drops, making the oceans more acidic and removing the CO3 needed for skeletal formation. Carbonate supersaturation is maintained, but even a drop in the supersaturation level appears to influence the ability of corals and other organisms to form calcium carbonate skeletons (Marubini and Atkinson 1999; Kleypas et al. 1999; Langdon et al. 2000). This effect is strictly a geochemical phenomenon - it is not a consequence of how much the oceans warm or whether circulation changes. It is likely to augment additional stresses currently affecting coral reefs, particularly where CO3 is already naturally low. - Corals are also under threat from more localized stresses. Dynamite and cyanide fishing, nutrient overloading, the disruption of grazing fish populations (which allow algal overgrowth), coastal pollution, and unregulated development all contribute to coral mortality, particularly in populated regions of the tropics. The combination of these localized stresses with background warming and increasing CO2 means that corals are experiencing multiple stresses on many fronts - physical, ecological, geochemical - and are increasingly vulnerable to mass mortality. - on the Moore et al. citation - I read this paper; thanks for sending it Keith. The message of your paper is clear - teleconnections with this site can change through time, even reverse. So how do you go from that conclusion to saying that it provides a record of ENSO? It sounds like you are trying to have it both ways.... you can't reconstruct ENSO unless you know what direction the teleconnections are working in the past. A better ref for this statement might be Henderson et al. 1999 (below), although this one hasn't been tested against long records either.... - I'd use speleothems rather than either stalagmites or stalactites... Hope this isn't too late to be of use, cheers, Julie GenevaHenderson, K. A., L. G. Thompson and P.-N. Lin (1999). "Recording of El Niņo in ice core d18O records from Nevado Huascaran, Peru." Journal of Geophysical Research 104: 31,053-31,065. Kleypas, J. A., R. W. Buddemeier, D. Archer, J. P. Gattuso, B. N. Opdyke, C. Langdon and M. Frankignoulle (1999). "Geochemical consequences of increased atmospheric CO2 on corals and coral reefs." Science 284: 118-120. Langdon, C., T. Takahashi, C. Sweeney, D. Chipman, J. Goddard, F. Marubini, H. Aceves, H. Barnett and M. Atkinson (2000). "Effect of calcium carbonate saturation state on the calcification rate of an experimental coral reef." Global Biogeochemical Cycles 14: 639-954. Marubini, F. and M. Atkinson (1999). "Effect of lowered pH and elevated nitrate on coral calcification." Marine Ecology Progress Series 188: 117-121. __________________________________ Dr. Julia Cole Dept. of Geosciences Gould-Simpson Bldg. 1040 E. 4th St. University of Arizona Tucson AZ 85721 phone 520-626-2341 fax 520-621-2672 __________________________________