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Effects of Bleaching and Cyclones on Coral Reefs of French Polynesia
Adjeroud, M., Chancerelle, Y., Schrimm, M., Perez, T., Lecchini, D., Galzin, R. and Salvat, B.  2005.  Detecting the effects of natural disturbances on coral assemblages in French Polynesia: A decade survey at multiple scales.  Aquatic Living Resources 18: 111-123.

What was done
In 1992 the authors "initiated a monitoring program that includes 13 islands (eight atolls and five high volcanic islands) in four of the five archipelagoes in French Polynesia, with the goal of documenting the effects of natural perturbations on coral assemblages."  All surveys were conducted on the outer reef slopes of these sites, because, as Adjeroud et al. describe it, "anthropogenic disturbances, such as dredging, construction activities, sewage discharges and runoffs, which may have important impacts on fringing reef communities, have a negligible one on the reef slopes of high islands and atolls."  For the period covered by this report (1992-2002, which constitutes the first decade of the monitoring program), these reefs were subjected to three major coral bleaching events (1994, 1998, 2002) and three cyclones (1997), while prior to this period, the sites had experienced an additional seven bleaching events and fifteen cyclones, as well as several Acanthaster planci outbreaks.

What was learned
Adjeroud et al. discovered that "the impacts of a natural disturbance such as bleaching events or cyclones may be largely variable among different sites around an island, and among islands within a region," and that "this local and regional variability of the impacts of disturbances complements the variability reported on other reefs around the world."  In their initial ten-year survey, for example, they observed three different temporal trends: "(1) ten sites where coral cover decreased in relation to the occurrence of major disturbances; (2) nine sites where coral cover increased, despite the occurrence of disturbances affecting seven of them; and (3) a site where no significant variation in coral cover was found."  In addition, they report that "an interannual survey of reef communities at Tiahura, Moorea, showed that the mortality of coral colonies following a bleaching event was decreasing with successive events, even if the latter have the same intensity (Adjeroud et al., 2002)."

What it means
Commenting on their and other researchers' observations, the seven French scientists say the "spatial and temporal variability of the impacts observed at several scales during the present and previous surveys may reflect an acclimation and/or adaptation of local populations," such that "coral colonies and/or their endosymbiotic zooxanthellae may be phenotypically (acclimation) and possibly genotypically (adaptation) resistant to bleaching events," citing the work of Rowan et al. (1997), Hoegh-Guldberg (1999), Kinzie et al. (2001) and Coles and Brown (2003) in support of this conclusion.  Hence, it would appear that earth's corals may be considerably better equipped to deal with whatever climate or weather phenomena nature may bring their way than many people have thought ... and that most climate alarmists have claimed.

Adjeroud, M., Augustin, D., Galzin, R. and Salvat, B.  2002.  Natural disturbances and interannual variability of coral reef communities on the outer slope of Tiahura (Moorea, French Polynesia): 1991 to 1997.  Marine Ecology Progress Series 237: 121-131.

Coles, S.L. and Brown, B.E.  2003.  Coral bleaching - Capacity for acclimatization and adaptation.  Advances in Marine Biology 46: 183-223.

Hoegh-Guldberg, O.  1999.  Climate change, coral bleaching and the future of the world's coral reefs.  Marine and Freshwater Research 50: 839-866.

Kinzie III, R.A., Takayama, M., Santos, S.C. and Coffroth, M.A.  2001.  The adaptive bleaching hypothesis: Experimental tests of critical assumptions.  Biological Bulletin 200: 51-58.

Rowan, R., Knowlton, N., Baker, A. and Jara, A.  1997.  Landscape ecology of algal symbionts creates variation in episodes of coral bleaching.  Nature 388: 265-269.

Reviewed 21 December 2005