DIATOMS ONLY. A sediment core is collected using a modified Kajak-Brinkhurst gravity corer (Glew 1988, 1989). The samples are extruded in the field, transported in whirlpack bags, and freeze-dried. For identification, Diatom slurries are prepared by oxidation of 0.2 g aliquots of sediment organic matter in hot 30% H2O2. Cleaned slurries were diluted, pipetted onto coverslips, air-dried, and mounted to microscope slides with Naphrax medium.