| Summary: | Maintenance and Update Frequency: notPlanned Statement: Samples for foraminifera picking were dried in the oven at 60oC before being re-soaked in distilled water. Samples were then wet sieved through a series of four mesh sizes before the size fractions were transferred to drying trays. After drying foraminifera were picked from under microscope for the large size fractions of >300 µm and >400µm. 10-15 individuals of each species were hand picked for isotope analysis. The samples were washed in methanol and ultrasonicated for 30 secs to remove any surface and internal particles. The samples were analysed at the Research School of Earth Science, Australian National University, using an automated individual carbonate reaction (Kiel) device coupled with a Finnigan MAT-251 mass spectrometer. Statement: 13-C values are normalised to TIC (total inorganic carbon) for 3 of the 5 foraminifera species analysed. The 13-C of the Cibicidoides genus is considered to reflect the 13-C of bottom water with relatively little fractionation relative to equilibrium calcite, while no correction is available for Gr. truncatulinoides. The noramlisation accounts for interspecies variability in fractionating carbon isotopes. The record of G. ruber, G. sacculifer and Gr. menardii is provided consistently every 5-10 cm of the core, down to a depth of 510cm. The results for Gr. menardii and Gr. truncatulinoides are more sporadic due to the absence of these species within some intervals of the core, generally in the top 150cm. From 150cm (~16340 yrs BP) down, results are provided for every 5-10cm. Credit Funded by The Australian Research Council (ARC) Credit Funded by The Australian National University (ANU) Faculties Research Grant Scheme Purpose The analysis of stable isotopes in multiple species of planktonic foraminifera provides an insight into changes in the gradients of physical and biological properties in the water column. Carbon isotopes ratios are used to track changes in biological productivity and have been the ...
|
|---|