Friday, November 19, 2010

Summary of Caribbean Bleaching in PLoS-One by Eakin et al.

The new paper by Eakin et al. in PLoS-One (open access) summarizes the extent of the 2005 coral bleaching event in the Caribbean, an event discussed at length on Maribo. The paper includes data from dozens of coral reef sites across the Caribbean that were affected by the prolonged period of water water in the late summer and fall of 2005, the same unusual warmth which helped promote the strong Atlantic hurricane season. 

The figures at right give an idea of the scale of the event, and the scale of the data collected by Eakin et al. The top panel shows the heat stress ("degree heating weeks") experienced by reefs across the Caribbean; the lower panel summarize the percent of corals in each region that bleached (data is collected in some cases by counting number of bleaching colonies, in others by estimating the percent of total coral cover that bleached). The figure shows that bleaching tended to be the most extensive in the areas that experienced the greatest heat stress, particularly the core of the "hot spot" in the Lesser Antilles.

We've seen a near repeat of this event in the past few months; the effect of the follow-up event on living coral cover won't be known for some time. From a climate standpoint. The fact that it has happened again five years later is, in itself, remarkable. Eakin et al. report that the sea surface temperatures in the fall of 2005 were the warmest since records began in the mid-1800s. The new record appears to have only lasted five years.

1 comment:

Steve L said...

You probably have a link to something that describes other relevant variables affecting bleaching rates. Temperature explains a lot of variation, obviously; how about pH, algae, coral species, etc? Many things are changing at the same time, so even the 'simple' evolutionary response relationship to temperature won't necessarily predict what happens to the reefs in coming years. Help appreciated. Thanks,