Calibration of the alkenone paleotemperature index U37K′ based on core-tops from the eastern South Atlantic and the global ocean (60°N-60°S)

摘要: Abstract We have analysed alkenones in 149 surface sediments from the eastern South Atlantic order to establish a sediment-based calibration of U37K′ paleotemperature index. Our study covers major tropical subpolar production systems and sea-surface temperatures (SST’s) between 0° 27°C. In define most suitable for this region, values were correlated seasonal, annual, production-weighted annual mean atlas compared previously published culture core-top calibrations. The best linear correlation SST was obtained using 0 10 m water depth (U37K′ = 0.033 T + 0.069, r2 0.981). Data scattering increased significantly waters deeper than 20 m, suggesting that reflects mixed-layer alkenone at thermocline depths not high enough bias signal. Regressions based on both actual virtually identical, indicating regional variations seasonality primary no discernible effect vs. relationship. Comparison with calibrations other oceanic regions revealed degree accordance. We, therefore, established global data 370 sites 60°S 60°N Atlantic, Indian, Pacific Oceans (0–29°C) depth. resulting relationship 0.044, 958) is identical within error limits widely used E. huxleyi Prahl Wakeham (1987) et al. (1988) attesting their general applicability. observation extending over various biogeographical coccolithophorid zones are strongly better accordance suggests less species-dependent indicated by experiments. results also suggest growth rate algae nutrient availability do affect sedimentary record open ocean environments.