Diatom research from the Drake Passage Core Sediment (GC05-DP02), Antarctica

Abstract

Diatom samples have been extracted from core sediment GC05-DP02 in Drake Passage, Antarctica. High number of diatom valves per gram of dry sediment was observed in core, ranging from 0.2 to 2.8 ×106/g. The open ocean diatoms from the core are dominated by Fragilariopsis kerguelensis and Thalassiosira lentiginosa which are about 69.8% of the total. We believe that there is little effect by the sea-ice even in the glacial periods, because high abundance of these Southern Ocean endemic taxa indicates sea-ice free waters. Diatom valve abundance and open ocean species are scarce in Unit B, D, F and H, identified as glacial periods (magnetic susceptibility: high). On the contrary, The Unit A, C, E, G and I shows high valve concentration and increasing open ocean species, identified as interglacial periods (magnetic susceptibility: low). The distribution pattern of Hemidiscus karstenii (FAO: 0.42 Ma (MIS 11), LAO: 0.19 Ma (MIS 7)) indicates interglacial periods during Marine Isotope Stages 7 and 9 in the Unit E and G, GC05-DP02.