A J Waite RCF Abstract 2007 Citizen’s Board Research and Creativity Forum In an effort to better understand the interaction between salinity, water masses, and temperature in the Atlantic and Caribbean, a number of coral cores (Montastraea faveolata and Siderastrea sidereal) were acquired from the Lesser Antilles. The cores, which span the region from Barbuda to Union Island, were collected under the objectives of the CAribbean Salinity Experiment (CASE) in 2002. Here, stable isotopes and the trace element composition of the coral skeletons are utilized as a multi-proxy approach to the reconstruction of regional climate, water mass flow, and riverine (Amazon and Orinoco) inputs. Since instrumental records from all of the collection locations demonstrate similar variations in water temperature, changes between the oxygen isotopic signatures of the corals at the individual localities should principally reflect differing salinity conditions. Early findings from Bequia, Union Island, Guadaloupe, and St. Croix specimens exhibit differences in oxygen isotope composition, with the specimens originating from more southerly islands possessing values more negative than their northern counterparts. This implies the presence of less saline waters around the southern portion of the Lesser Antilles. On a local scale, some corals demonstrate less pronounced cyclicity in oxygen isotopes, while maintaining a clear annual carbon cycle; this seems to suggest that runoff from land may be both amplifying the carbon isotopic signature and masking that of the oxygen. Ultimately, the observed isotopic differences will allow for the quantification of salinity changes experienced in the Caribbean over more than 150 years, providing a clearer picture of the regional oceanographic conditions through time.