Dr. Katie L. Cramer


Project Title: Changes in Caribbean coral reef environments and fish communities over the last millennium

Advisors:  Torben Rick, Aaron O’Dea

Caribbean reef corals have declined precipitously since the 1980s from coral bleaching and disease outbreaks related to climate change, and algal overgrowth related to overfishing. Paleoecological data collected in Bocas del Toro, Panama for my dissertation work revealed that declines in coral and molluscan communities occurred at least decades before coral bleaching and disease, implicating pre-historical/historical land clearing and fishing. However, the extent of earlier degradation from these local anthropogenic stressors is unresolved due to a lack of a quantitative ecological baseline of reef environments and fish communities.

To resolve this issue, I will implement a retrospective monitoring program for Caribbean coral reefs, utilizing the fossil record to document ecological change over large temporal and geographic scales. A millennial-scale quantitative record of reef environments and fish communities in Bocas del Toro and southern Belize will be obtained from sediment cores collected from up to 5m below modern lagoonal reefs. This work will launch a new interdisciplinary collaboration among collaborators Dr. Torben Rick at NMNH, Aaron O’Dea at STRI, and Dr. Richard Norris at Scripps Institution of Oceanography. 

Trends in land-based sediments and pollution will be assessed from sediment elemental composition, grain size distribution, and percent carbonate/organic material, whereas trends in reef fish abundance, taxonomic composition, and trophic structure will be assessed from fish teeth. Results will be compared with historical trends in coral communities previously documented in my dissertation work and a coring study in Belize to assess the role of past land clearing and fishing in more recent reef decline. This study will provide a more complete understanding of the full extent of long-term anthropogenic and natural change in the structure and function of coral reefs and will directly address several fundamental questions posed by MarineGEO.