PP51A-2274
Temperature Calibration of a Northern Gulf of Mexico Siderastrea siderea Coral
Friday, 18 December 2015
Poster Hall (Moscone South)
Amy J Wagner1, Kristine L DeLong2, Kathryn Jelinek1, Kelly H Kilbourne3, Julie N Richey4, Emma Hickerson5 and Niall C. Slowey6, (1)California State University, Sacramento, Sacramento, CA, United States, (2)Louisiana State University, Geography and Anthropology, Baton Rouge, LA, United States, (3)University of Maryland Center for Environmental Science Appalachian Laboratory, Frostburg, MD, United States, (4)USGS Coastal and Marine Science Center St. Petersburg, St Petersburg, FL, United States, (5)NOAA National Marine Fisheries, Flower Garden Banks National Marine Sanctuary, Galveston, TX, United States, (6)Texas A & M University, College Station, TX, United States
Abstract:
The Gulf of Mexico (GOM) is sensitive to oceanic and atmospheric variability in both the Atlantic and Pacific Oceans (i.e., Atlantic Multidecadal Oscillation (AMO), El Niño Southern Oscillation (ENSO), Pacific North American Pattern (PNA), and Pacific Decadal Oscillation (PDO)). The major GOM current, the Loop Current, feeds the Gulf Stream as it transports oceanic heat to the northern Atlantic Ocean. The northern GOM is the northernmost summer extent of the western hemisphere warm pool (WHWP) that drives oceanic moisture flux and precipitation into the Americas. Decadally-resolved foraminifera reconstructions from the northern GOM indicates SST was 2 to 4ºC colder on average than today during the Little Ice Age (LIA, ~1850), whereas a subannually-resolved coral reconstruction from the southeastern GOM find 1.5 to 2ºC colder intervals and reduced areal extent of the WHWP on interannual time scales during some intervals of the LIA. However, records capable of resolving annual and subannual SST variability from the northern GOM, necessary for investigating WHWP northern extent, are still lacking. Here we present a new temperature reconstruction for the northern GOM derived from strontium-to-calcium (Sr/Ca) ratios of approximately monthly samples milled from a Siderastrea siderea coral core collected from the Flower Garden Banks National Marine Sanctuary (FGBNMS; 27° 52.5’N, 93° 49’W) growing at a water depth of 20 m. Coral Sr/Ca is calibrated to reef temperature data from FGBNMS Hobotemp data loggers near the reef cap in ~22 m water depth (1986–2004) and to NOAA OISST (1981–2004), which co-varies with the reef temperature (r=0.95, p<0.05, n=146) and consistently captures winter values in reef temperature with slightly warmer summers (0.9ºC on average). The Sr/Ca-SST calibration slope (–0.043, r=–0.89, n=136, p<0.01 for reef temperature; –0.039, r=–0.94, n=275, p<0.01 for OISST) agrees well with published coral Sr/Ca-SST calibrations for S. siderea in the southeastern GOM from shallower water depths.
