HR: 1330h
AN: PP32B-0291    [PDF]
TI: Tropical Storm Allison (2001) Recorded in Oxygen Isotopic Composition of Shells of Living Ostracoda
AU: * Lawrence, J R
EM: JLawrence@uh.edu
AF: Department of Geosciences, University of Houston, Houston, TX 77204-5007 United States
AU: Hyeong, K
EM: kshyeong@kordi.re.kr
AF: Deep-Sea Resources Research Center, Korea Ocean R&D Institute Ansan P.O.Box 29, Seoul, 425-600 Korea, Republic of
AB: The oxygen isotopic composition of rain from tropical cyclones is distinctly lower than that of normal rain in the tropics or subtropics (GRL, Lawrence and Gedzelman, 1996). Therefore when heavy rains fall in lowland coastal areas the surface waters show a sharp decrease in oxygen isotope values that persists for a few weeks (Chem. Geol., Lawrence 1998). In early June of 2001 Tropical Storm Allison dropped on the order of 600 mm of rain in the area around Houston, Texas. The oxygen isotopic composition of surface waters in east Houston dropped to -11.4 per mil and slowly returned to a more normal summertime value of -2 per mil over a three week period. Water samples were collected on June 6, 10, 13, 17 and 26. Attempts were made to collect samples of living Ostracoda on these dates. On June 17 and 26 samples of living Cypridopsis and Potamocypris were found and collected. The carbonate shells of these specimens were analyzed for their oxygen isotope values. The distinct difference observed in the oxygen isotopic composition of the surface waters on the two dates was mirrored in the analyzed shells of the Ostracoda. These results suggest that in fresh water shallow lake environments sediment cores containing shells of Ostracoda may provide a record of tropical cyclone activity over the last several thousands of years.
DE: 1040 Isotopic composition/chemistry
DE: 3344 Paleoclimatology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting