| Summary: | Maintenance and Update Frequency: notPlanned Statement: Material collected using a Kullenberg core aboard the research vessel Marion Dufresne. The method used to produce the diatom slides is detailed in the 'methodology' document uploaded with this record. Statement: The sediment was sampled every 10cm from the sediment surface down to a depth of 1030cm. Parameters: Core depth (cm) diatom species, diatom subtotal and silica subtotal. Credit Centre des Faibles Radioactivities mixte CNRS CEA (France) Credit Institute of Antarctic and Southern Ocean Studies (IASOS) Credit Institut Français pour la Recherche et Technologie Polaires (IFRTP) Credit Terres Australes et Antarctiques Françaises (TAAF) Credit Australian Postgraduate Research Awards (APRA) Purpose To reconstruct the first sea-surface temperature and sea-ice record history of the Southern Ocean south of Australia. Core MD88-787 was recovered during the French ASPARA IV cruise in 1988, aboard the Marion Dufresne. The core was located on the Tasman Fracture Zone of the Mid-Ocean Ridge, within the Polar Front Zone. A total of 69 diatom species and taxa were recorded in core MD88-787. Over time, the core indicates a reduction in the number of diatom valves in the sediments for the last glacial. This trend is not observed during the previous 'glacial' period in isotope-stage 4, but is again noted in isotope-stage 6. Interglacial isotope-stages 3 and 5 indicate higher- or equivalent-diatom content comparable to isotope-stage 1. The reduced diatom signal during the glacials appears odd since the expectation was for an enhanced diatom signal produced by the northward shifting fronts. The decrease in signal could be interpreted as being affected by sea-ice cover and the resulting change towards more lightly silicified diatom species.
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