HR: 1330h
AN: PP12A-0225    [PDF]
TI: Improving the Value of Deep-Marine Ostracodes for Paleoclimatic and Paleoenvironmental Studies
AU: * Didi\'{e}, C
EM: cdidie@awi-bremerhaven.de
AF: Alfred Wegener Institute, Waddensea Research Station, Hafenstrasse 43, List/Sylt, 25992 Germany
AU: Mackensen, A
EM: amackensen@awi-bremerhaven.de
AF: Alfred Wegener Institute, Columbusstrasse, Bremerhaven, 27568 Germany
AB: The stable carbon and oxygen isotopic composition of benthic foraminiferal tests is an important tool for paleoclimatic reconstructions. In contrast to the marine environment the valves of ostracodes provide this important information in freshwater environments. Following these two approaches, an earlier study on sediment cores from the North Atlantic revealed that particularly the oxygen isotopes of two common deep marine ostracode genera are utilizable in the same way as those from benthic foraminifers. To further test the potential influence of different molt stages on the isotope values, numerous juvenile and adult specimens of {\it Krithe} and {\it Henryhowella} from various samples from the North and South Atlantic were analyzed. The oxygen isotope values of both taxa showed no systematic offset between juvenile or adult valves, whereas the carbon isotope values especially from juvenile specimens of {\it Krithe} displayed lighter values than the adult valves. The latter is in contrast to studies on freshwater ostracodes. Additionally to the isotope analyses, several surface sediment samples from the SW Atlantic, already analyzed for the benthic foraminiferal fauna by Harloff and Mackensen (1997), were studied for their ostracode fauna. The aim was to gain new information on the still not well known ecology of the ostracodes using a comparison to the benthic foraminiferal fauna together with available environmental information. First results revealed a highly diverse ostracode fauna with several new taxa. Using factor analysis the samples were subdivided into 4 groups, each characterized by different dominating taxa. However, so far the connection between spatial distribution of this sample groups and certain environmental conditions remains unclear. Especially in this area the complex bathymetry, several interfering water masses, frontal systems, and the combination of surface primary production and winnowing through strong currents have to be considered in more detail.
DE: 1635 Oceans (4203)
DE: 3030 Micropaleontology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting