Daria Siciliano and collaborator Konrad Hughen from Woods Hole Oceanographic Institution holding a coral core.
Paleoclimate reconstructions in Cuba inferred from coral core aragonite
Geochemical records from reef-building coral such as stable isotopic compositions (d18O, d13C) and elemental ratios (Sr/Ca) can provide high-resolution records of past climatic conditions and variability. Such paleoclimatic records can elucidate our understanding of climate variability over timescales ranging from intra- and inter-annual, to inter-decadal to centennial , documenting variability associated with seasonality as well as regional phenomena such as the North Atlantic Oscillation (NAO). Coral paleoceanographic reconstructions are of particular value in the Atlantic basin because of the paucity of data currently available. In Cuba, the largest island in the Caribbean, there is limited instrumental data and our knowledge of multi-decadal climate sensitivity is very incomplete. Cuba is also an interesting and ideal site to study seasonal variations in corals because the annual SST range is high (19 to 31 deg C) and its shallow platform displays high salinity and density gradients. We are collecting cores throughout the island, and are currently focusing our efforts on a 227 year coral core collected in February 2015 from a Siderastrea siderea colony in Cayo Algodon, in the Golfo the Ana Maria, off the South-central Cuban coast. This core represents the first long core ever collected in Cuban waters. We are working on high temporal-resolution measurements of Sr/Ca and d18O which provide information about the seasonal balance between precipitation and evaporation, and a record of SST for this region. The goal is to reconstruct climate over the two centuries spanned by this core. Additional cores to be collected throughout the Cuban coast will provide important information about variability and localized effects. This research fills a void in paleoclimate reconstructions in this region and provide great potential to integrate these records into a Caribbean-wide framework for greater understanding of past and, ultimately, future climate variability in the Caribbean basin.
Geochemical records from reef-building coral such as stable isotopic compositions (d18O, d13C) and elemental ratios (Sr/Ca) can provide high-resolution records of past climatic conditions and variability. Such paleoclimatic records can elucidate our understanding of climate variability over timescales ranging from intra- and inter-annual, to inter-decadal to centennial , documenting variability associated with seasonality as well as regional phenomena such as the North Atlantic Oscillation (NAO). Coral paleoceanographic reconstructions are of particular value in the Atlantic basin because of the paucity of data currently available. In Cuba, the largest island in the Caribbean, there is limited instrumental data and our knowledge of multi-decadal climate sensitivity is very incomplete. Cuba is also an interesting and ideal site to study seasonal variations in corals because the annual SST range is high (19 to 31 deg C) and its shallow platform displays high salinity and density gradients. We are collecting cores throughout the island, and are currently focusing our efforts on a 227 year coral core collected in February 2015 from a Siderastrea siderea colony in Cayo Algodon, in the Golfo the Ana Maria, off the South-central Cuban coast. This core represents the first long core ever collected in Cuban waters. We are working on high temporal-resolution measurements of Sr/Ca and d18O which provide information about the seasonal balance between precipitation and evaporation, and a record of SST for this region. The goal is to reconstruct climate over the two centuries spanned by this core. Additional cores to be collected throughout the Cuban coast will provide important information about variability and localized effects. This research fills a void in paleoclimate reconstructions in this region and provide great potential to integrate these records into a Caribbean-wide framework for greater understanding of past and, ultimately, future climate variability in the Caribbean basin.
Daria Siciliano and her student Karen Lykkebo.
|
A Siderastrea siderea colony with a concrete plug on the site of the extracted core.
|
