HR: 1340h
AN: PP43B-1257    [Abstracts]
TI: Alkenone Production and UK'37 Temperature Estimates: A Time-Series Study in the Santa Barbara Basin, California
AU: * Hardee, M L
EM: michelle.hardee@msci.sc.edu
AF: Marine Science Program, University of South Carolina, 712 Main St., EWS 603, Columbia, SC 29208, United States
AU: Thunell, R C
EM: thunell@geol.sc.edu
AF: Marine Science Program, University of South Carolina, 712 Main St., EWS 603, Columbia, SC 29208, United States
AU: Thunell, R C
EM: thunell@geol.sc.edu
AF: Department of Geological Sciences, University of South Carolina, 701 Sumter St., EWS 617, Columbia, SC 29208, United States
AB: Accurate interpretations of past changes in oceanographic and climatic conditions preserved in deep sea sediments directly hinges on our understanding of the present-day factors influencing climate proxies used to estimate these conditions. In this study, the alkenone unsaturation index (U^K'₃₇) was measured in both an 11-year time series of sediment trap samples (1993-2004) and a gravity core from the Santa Barbara Basin (SBB). The U^K'₃₇ values for the sediment trap samples were correlated to concurrently measured temperature data in order to determine where in the water column this temperature signal is acquired. Our results indicate that changes in alkenone unsaturation are best correlated with temperatures at the chlorophyll maximum. Temperatures calculated from our chlorophyll maximum equation correspond closely with those calculated using the Prahl et al. (1988) equation. The majority of the sediment core U^K'₃₇ temperatures fall within ±1 SD of the weekly averaged SST record for this 13-year period, correlating best with late winter - spring SSTs. While the U^K'₃₇ ratio in the sediment trap samples clearly records seasonal and interannual temperature variability, the U^K'₃₇ record preserved in Santa Barbara Basin sediments is weighted towards spring temperatures due to highest alkenone production during this season. Comparison of the downcore U^K'₃₇ record to the Southern Oscillation Index shows a good degree of correspondence between the temperature signal preserved in the SBB and the ENSO climate signal. This study provides an important verification of the reliability of the alkenone paleotemperature proxy for determining past ocean temperature variability on a variety of time scales.
DE: 4215 Climate and interannual variability (1616, 1635, 3305, 3309, 4513)
DE: 4277 Time series experiments (1872, 3270, 4475)
DE: 4850 Marine organic chemistry (0470, 1050)
DE: 4922 El Nino (4522)
DE: 4954 Sea surface temperature
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting