Belize Coral: End of a Millennium

Apparently the coral devastation at MoHo Reef and other locations along the Belizean barrier reef has gotten scientists’ as well as divers’ attention. The story is starting to sound familiar: during the summer of 1998, sea temperatures ranged between 30 and 31.5° C (86 - 88.7° F) for a period of several months. As was the case in Palau, the Maldives, and other areas, these sustained high temperatures drove out the endosymbiotic algae the coral is dependent upon, and the coral bleached and finally died. According to American researchers reporting in Nature last month, almost all the Agaricia tenuilfolia, the most abundant coral on Belize’s reef, died, and other corals were damaged. As has been the case with coral bleachings from Australia’s Great Barrier Reef to Christmas Island, Thailand, and the Philippines, the increased water temperatures and increasing frequency of El Niño weather patterns was linked to global warming.

Of course, it’s a difficult link to prove. How do we know, the argument goes, that such periodic die-offs aren’t a natural phenomenon, something that’s been going on forever that we just didn’t know about until people started diving? The study by Alabama’s Dauphin Island Sea Lab set out to address that question by drilling 12 core samples from the reef, then using radiocarbon dating on the samples to determine whether the earlier loss of coral species to disease and the recent death of Agaricia corals were unique or episodic events. The results showed no similar die-offs in the reef’s 3,000 year existence, and researchers determined that these “were novel events on a time scale of millennia.”

Based on an article in Nature by Richard B. Aronson; William F. Precht; Ian G. Macintyre; and Thaddeus J. T. Murdoch