The staghorn coral, Acropora cervicornis, was a dominant space occupant and an important framework constructor of Caribbean coral reefs during the Pleistocene and Holocene. Populations of Acropora were killed throughout the region in the 1980s and 1990s by outbreaks of white-band disease, a bacterial infection. On lagoonal reefs in Belize, the demise of Acropora led to dominance by the lettuce coral Agaricia tenuifolia. This Acropora-to-Agaricia transition produced a clear signature in the subsurface sediments in Belize, and analysis of cores extracted from these reefs showed this sequence of events to have been unique in at least the last 3,000–4,000 years. Similar Agaricia-dominated communities are common today in Bahía Almirante, a coastal lagoon on the Caribbean side of Panamá more than 1,000 km from the Belizean reefs. We have conducted an intensive program of coring to determine whether the Panamanian reefs have a similar history to those in Belize. In Panamá we have discovered that the transition was from branching Porites to Agaricia, rather than from Acropora to Agaricia. As in Belize, the shift was unprecedented in the past several thousand years, but the cause was different. In Panamá, biogeochemical studies suggest that changing patterns of land use, related primarily to agricultural development, were responsible for the transition to Agaricia.
This research has been funded by the National Science Foundation, the Smithsonian Institution, and the National Geographic Society