Sediment cores were collected onboard the CCGS Amundsen during ArcticNet cruise 0502 (2005) using a box corer, penetrating the seafloor to a maximum of 50 cm. Samples were stored in a freezer (- 20 °C) onboard the Amundsen until the end of the cruise, then shipped to the Freshwater Institute (FWI), where they were maintained in storage at - 20 °C. Subsamples were processed at the University of Victoria Marine Micropaleontology Laboratory in October-November 2010. A gentle version of the standard palynological protocol was applied to oven-dried samples of known volume. Steps are as follows: (1) add 10 % hydrochloric acid in room temperature; (2) sieve with distilled water through a 120 micrometre and a 15 micrometre nitex mesh, retaining the fraction in between; (3) add 48% hydrofluoric acid in room temperature for 2-4 days followed by 20 minutes in 10 % hydrochloric acid; (4) sieve through precise 15 micrometre mesh with gentle sonication for 10-60 seconds. The final residue of samples was placed in sealed storage vials and stored in + 4 °C. Aliquots of residue were mounted in glycerine jelly on microscopic slides with cover slips. Dinoflagellate cysts are studied primarily with Zeiss Standard 20 microscope under bright-field oil-immersion and 500X and 1000X magnifications. At least 300 dinoflagellate cysts species and cyst types will be identified on each slide together with pollen, freshwater algae and other palynomorphs.
