HR: 1340h
AN: PP43A-0661    [Abstracts]
TI: Holocene Deep-Sea Ecosystem Variability of the Aegean Sea
AU: * Kuhnt, T
EM: tkuhnt@rz.uni-leipzig.de
AF: Gerhard H. Schmiedl, Institute of Geophysics and Geology, University of Leipzig, Talstrasse 35 , Leipzig, 04103 Germany
AB: We accomplished high-resolution analyses on late glacial and Holocene benthic foraminiferal faunas and stable isotopes of two sediment cores from the deep northern and southern Aegean Sea to reconstruct the variability of paleoceanography and paleoclimate of this region. During the last glacial maximum and the transition to the Holocene diverse faunas and elevated benthic foraminiferal numbers indicate enhanced organic matter availability and well-ventilated deep-water masses. Highest organic matter availability is observed in the southern Aegean Sea. The organic matter is likely derived from a combination of elevated marine productivity as response to wind-induced mixing and the transfer of degraded organic matter from continental sources and with bottom currents. During the formation of sapropel S1, drops in benthic foraminiferal numbers and diversity are more significant at the shallower site in the southern Aegean Sea when compared to the deeper site in the northern Aegean Sea. This suggests the persistence of local deep-water formation in the northern Aegean Sea during sapropel formation. In addition, faunal fluctuations at both sites suggest the repeated influence of short-term climate changes on re-ventilation and re-colonization of deep-sea ecosystems in the whole Aegean Sea. During the middle and late Holocene the faunas indicate a clear spatial differentiation of Aegean deep-sea environments. While the southern Aegean Sea is characterized by oligotrophic and well-ventilated conditions, the faunas at the northern site reflect repeated drops in oxygenation of deep-waters. These fluctuations are likely caused by perturbations of local deep-water sources during periods of enhanced fresh-water runoff of local rivers. Particularly humid intervals are centered around 4 and 2 kyr as indicated by the presence of deep infaunal species that are adapted to low oxygen contents. Comparison with records from different climate archives suggests that these events are part of periodic millennial-scale changes in humidity of the borderlands.
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4936 Interglacial
DE: 4944 Micropaleontology (0459, 3030)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005