RECENT & ONGOING RESEARCH

Coral reefs in the Caribbean are degrading at an alarming rate. It is essential that the current state of the reefs be documented, so that we can quantify and understand this degradation. To this end, a benthic assessment of the isolated Cayman Islands was completed at 42 sites in 1999 and 2000. Coral cover and species richness were measured at all sites using the AGGRA (Atlantic and Gulf Rapid Reef Assesment) method. Major changes in the reef community structure were documented by comparison with earlier studies. This study will be continued in the future so that we can ascertain the rate of degradation of the reefs around the Cayman Islands.

Dr. Chris Langdon, Lamont Doherty Earth Observatory, Effect of Elevated CO2 on Coral Reefs (supported by a Packard Foundation Grant)

Levels of carbon dioxide, a greenhouse gas found in Earth's atmosphere, have increased since pre-industrialized times, primarily due to the combustion of fossil fuels. Based on realistic scenarios of future emissions, this trend will continue, resulting in a projected doubling of atmospheric carbon dioxide levels relative to pre-industrial levels by the year 2065 (Houghton et al. 1996). This projected atmospheric change brings with it other potential and uncertain changes to Earth's atmosphere, biosphere and hydrosphere. As an example, the rise in atmospheric carbon dioxide will cause a significant decrease in the pH of the surface ocean. The pH of the surface ocean has already dropped by approximately 0.1 pH unit in the last twenty years. In the next 50 to 100 years, it could drop by another 0.2 to 0.3 units unless CO2 emissions are curtailed. This drop in pH may sound small, but it will cause major changes in the availability of certain ions, which are essential to marine organisms that secrete calcium carbonate body parts. A 0.3 unit drop in pH is sufficient to cause a 35% drop in the concentration of carbonate ion [CO3=]. This compound is essential to the organisms responsible for building and sustaining coral reefs, i.e. corals, coralline algae, and many invertebrate grazers. We are coming to Little Cayman to investigate its use as a natural laboratory. This would involve installation of instrumentation that would monitor the CO2 chemistry of the water and its effects on the health of a variety of reef organisms.

Dr. Vania Coelho, Lamont Doherty Earth Observatory, Biosphere 2, Diversity of Epifaunal Communities Associate with Algae in Coral Reefs

This project will focus on how coral species richness changes according to location, community complexity and algal coverage. Areas with greatest coral coverage are not always the same as the ones with highest coral diversity. The sites chosen for this study will be located both, inside and outside of the marine parks, as well as on the windward and leeward sides of the island. Marine parks are believed to protect many marine species from the dangers of overfishing, and other human impacts. In this project, we will examine if there is a significant difference in coral cover and species richness inside and outside of the marine parks. We will also analyze how coral cover and species richness changes according to community complexity and wind exposure.

Dr. John Pandolfi, Smithsonian Institution, Department of Paleobiology, National Museum of Natural History, Dr. Nancy Budd, University of Iowa "The origin of the modern Caribbean reef coral fauna: ecology, evolution and extinction within the Montastraea annularis species complex"

One of my major research programs is to examine speciation, extinction, and morphologic stability within one dominant reef coral clade (the Montastraea annularis species complex) during and shortly after a major episode of Plio-Pleistocene turnover, which transformed the community structure and established the modern taxonomic composition of Caribbean reefs. Dr. Ann F. Budd and I are focusing on ecological and geographic factors associated with speciation and extinction events in order to better understand their cause. In the present proposal, we will conduct paleoecological field surveys and collect specimens for morphometric analysis within raised reef terraces at the Cayman Islands, to complement previous work in Florida and The Bahamas in the northern Caribbean. BSI supported fieldwork in Barbados last year complemented our previous collections from San Andr￩s and Curaao in the southern Caribbean. The research program uses the Montastraea annularis species complex as a model system, integrating molecular, morphologic, ecologic and fossil data in an ecologically important but manageable size clade. In addition to paleontology, the results will contribute in important ways to coral reef biology, ecology, systematics, and molecular evolution (we have complementary data for living M. annularis). Interpretation of modern distributions will be aided by evaluation of the past ecological roles of these species, and how these roles changed after habitat reduction (due to Pleistocene glaciation) and subsequent extinction. The results from this work will aid in our ultimate goal of understanding both the origins of coral reef biodiversity and the environmental influence over ecological change.