HR: 0800h
AN: PP51D-0632    [Abstracts]
TI: Sea surface temperature variability in the Southern Gulf of California: A 400 planktonic foraminifera high-resolution record.
AU: * Staines-Urias, F
EM: staines@usc.edu
AF: University of Southern California, 3658 Trousdale Pwy, SCI 117, Los Angeles, CA 90089-0740 United States
AU: Douglas, R
EM: rdouglas@usc.edu
AF: University of Southern California, 3658 Trousdale Pwy, SCI 117, Los Angeles, CA 90089-0740 United States
AB: A 400yrs high-resolution sea surface temperature record (SST) from the Gulf of California was reconstructed using planktonic foraminifera ( Globigerina bulloides and Pulleniatina obliquiloculata).
Foraminifera specimens were obtained from two multicores containing laminated sediments from the Oxygen Minimum Zone in the southern Gulf of California. These sediments represent a high-resolution record of the high-frequency variations in SST caused by changes in the upwelling intensity in the area.
The multicore chronostratigraphy is based on excess ²¹⁰Pb profiles. Computed sedimentation rates indicate that each sample (2mm) represent an accumulation of about 2-5 years.
Oxygen and Carbon isotopic analysis were conducted on specimens picked from the >63μm size fraction.
From the comparison between the instrumental SST record and the δ¹⁸O_G.bulloides reconstructed SST series, we observed that the mean of the isotopically reconstructed SST agrees fairly well with the instrumental ones, and that major SST anomalies observed in the southern Gulf also occur in the reconstructed series.
The reconstructed δ¹⁸O_G.bulloides series shows a warming in the winter SST following the end of Little Ice Age, ca. 1850. The calculated SST increment was 2.38±0.67C° for the east side of the Gulf and 2.47±0.83C° for west side. Calculated δ¹⁸O_{P.obliquiloculata} temperatures show a similar trend of lower magnitude. In the 20th Century isotopically derived SST seem to be parallel to instrumental observations. The variability in the composition of the foraminiferal assemblages agrees with the calculated increased in the winter temperatures.
The results of a spectral analysis performed to the SST series verify the existence of decadal and interdecadal frequency climate oscillations and that they play an important role in the variability of the SST in the Gulf.
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4944 Micropaleontology (0459, 3030)
DE: 4954 Sea surface temperature
DE: 4964 Upwelling (4279)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005