Ostracode fauna of sediment core GIK23414-9 in the northeast Atlantic

Sediment core M23414 from the Rockall Plateau (North Atlantic) covering the last two climatic cycles, marine isotope stages (MIS) 7 to 1, was investigated for glacial-interglacial variations in the deep-sea benthic ostracode fauna. A highly diversified ostracode fauna including 98 species was found. Two climate-related assemblages were identified, associated with interglacial and peak glacial periods, respectively. The 'interglacial' group occurs during the end of MIS 7, 5 and 1 and is composed of the genera Henryhowella, Pelecocythere, Echinocythereis, Cytherella, Bradleya, Aversovalva and Eucytherura. The 'glacial' group consists of the genera Acetabulastoma (which is known as 'sea ice indicator' in the modern Arctic Ocean), Polycope, Bythoceratina, ?Rhombobythere, and some species possibly belonging to the genus Pseudocythere and is found during MIS 6, 4 and 2. These longer-term variations within the ostracode fauna seem related to the particular glacial and interglacial climate conditions that affected both deep-water production as well as primary production in the surface waters. However, a detailed comparison of ostracode abundances with the occurrence of events marked by increased ice-rafted debris reveals also much shorter-term climate related changes in the ostracode fauna. Thus, the temporal fluctuations within ostracode assemblages reflect long- and short-term alterations of the deep-sea environment that are clearly linked to climate changes.

Stable oxygen isotope composition of the sea water in the Mediterranean Sea

During the cruises No 17 and 22 of the German research vessel "Meteor", 45 water samples were taken at 4 stations in the central part of the Mediterranean Sea. Mass spectrometrical analyses showed that systematic, but time variable changes of the oxygen isotope ratios occur. Deep water samples (T> 500 m) have a ± constant isotopic composition of d18O = +1.79? (SMOW) and a Chlorinity of 21.399?. These data are discussed with respect to paleotemperature determinations.