Rapidly changing climates in northern Canada make the western Hudson Bay region an area of high importance for paleoenvironmental studies. Long-term changes in assemblages of diatoms (microscopic algae) were analyzed from lake sediment cores from Baker Lake, Nunavut, and Lake AT01, northern Ontario, to track responses to past environmental changes. Diatom assemblages dating to 6700 years ago in AT01 were initially characterized by cold- tolerant Fragilarioid assemblages, but shifted to an assemblage dominated by large benthic species and Cymbella diluviana consistent with the timing of the Holocene Thermal Maximum after 6300 years BP. A possible drainage event in Lake AT01 may have added significant hydrologic control on the diatom assemblages. The post-industrial period is marked by the largest compositional shifts in both records. Assemblages during the 20th century are indicative of reduced ice cover and enhanced thermal stratification linked to a climate regime shift noted in Hudson Bay since the mid-1990’s.
| Identifer | oai:union.ndltd.org:TORONTO/oai:tspace.library.utoronto.ca:1807/30595 |
| Date | 07 December 2011 |
| Creators | Friel, Charlotte |
| Contributors | Finkelstein, Sarah A. |
| Source Sets | University of Toronto |
| Language | en_ca |
| Detected Language | English |
| Type | Thesis |
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