Southern Ocean surface sediment diatom abundances

Published: 24-12-2020| Version 1 | DOI: 10.17632/2tnxcww6c8.1
Contributor:
Matthew Chadwick

Description

Diatom percentage abundances in the surface sediments for five Southern Ocean marine sediment cores (TC290, TC288, TC287, U1361A and BC508). Abundances are presented for 45 species and groups and reflect a time-averaged environmental signature for the last 500 yrs at each core site. For each sample a minimum of 300 diatoms were counted with a light microscope (BH-2 Olympus, x1000 magnification).

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For each surface sediment sample, microscope slides were produced using a method adapted from Scherer (1994). Samples of 7-20 mg were exposed to 10% Hydrochloric acid to remove any carbonate, 30% Hydrogen peroxide to break down organic material and a 4% Sodium Hexametaphosphate solution to promote disaggregation and placed in warm water bath for minimum 12 hours. The material was homogenised into a ~10cm water column and allowed to settle randomly onto coverslips over a minimum of 4 hours. The water was drained away and coverslips were mounted on microscope slides with Norland Optical Adhesive (NOA 61). Slides were investigated with a light microscope (Olympus BH-2 at x1000 magnification) and a minimum of 300 diatom valves were counted for each sample. Scherer R.P. 1994. A new method for the determination of absolute abundance of diatoms and other silt-sized sedimentary particles. Journal of Paleolimnology, 12 (2): 171-179.