A micro-manipulation technique for the purification of diatoms for isotope and geochemical analysis

A method is described for the purification and extraction of diatom samples for isotope and geochemical analysis. The technique involves a micro-manipulator attached to an inverted microscope with a cellular micro-injector system used to remove contaminants or separate assemblages into single-species samples. Whilst time consuming, the advances associated with this technique, eliminating issues related to contamination and the impact of species-dependent fractionation factor/isotopic effect, allows ultra-clean as well as species and/or size specific diatom samples to be analysed in palaeoenvironmental research down to seasonal timescale resolution. By further altering the inner dimensions of the commercially available capillary tubes, (3.5–150 \upmu m) this technique can be extended for use with other microfossils including radiolaria (30 \upmu m to 1 mm), pollen (6–100 \upmu m) and phytolith samples (1–200 \upmu m).