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Diatom recovery from core MD88-779: Raw counts

Created 25/06/2017

Updated 11/08/2023

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Core MD88-779 was taken during the 1988 French ASPARA IV cruise in the South East Indian Ocean aboard the Marion Dufresne. The core is situated on the South Tasman Rise (47º50.690S, 146º32.750E) at a depth of 2260m. Although the core recovered was 6.7m long, only the top 2.6m were studied as preliminary investigations had indicated that this section covered the last two glacial cycles.

A total of 37 diatom species and taxa were observed in the core samples, comprising predominantly warm-water fauna. The majority of samples were poorly preserved and showed high levels of dissolution making identification to species level often difficult. Species with greatest abundances were those more heavily silicified (e.g. Fragilariopsis kerguelansis), and to a lesser extent the warm-water forms (e.g. Fragilariopsis doliolu).

The complete loss of a diatom record at 170cm and 210/220cm in the core is extremely unusual. The diatom signal is interpreted as having been removed by increased water mass velocity, extreme post-depositional silica dissolution or decreased productivity. There is no sedimentological evidence from the core which provides further interpretation.

The diatom recovery from this core is considerably low when compared to samples from the Southern Ocean.

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Title Diatom recovery from core MD88-779: Raw counts
Language English
Licence Creative Commons Attribution 2.5 Australia
Landing Page https://data.gov.au/data/dataset/8ef0c08f-722f-4166-aefa-42a2a031b662
Contact Point
Department of Biological Sciences, Macquarie University
leanne.armand@mq.edu.au
Reference Period 25/06/2017
Geospatial Coverage
Map data © OpenStreetMap contributors
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Data Portal Data.gov.au