Paleoenvironmental implications of diatom assemblages in a large middle arctic watershed: Sanagak Lake and the Lord Lindsay River, Boothia Peninsula, Nunavut

An assessment of the recent (∼150 years) fossil diatom assemblage and contemporary river diatom (lotic) assemblage of Sanagak Lake and its major source of inflow, the Lord Lindsay River, was undertaken. In addition, isolating specific taxa that show a strong affinity for the lotic environment generated an opportunity to interpret stratigraphic changes in these species in terms of past hydrological change. Together, these records contribute to current knowledge on the character and manifestation of recent ecological changes being documented in high latitude freshwater ecosystems.; Results of diatom analyses indicate a gradual decline in benthic relative to planktonic taxa since the late-1800s, and a sudden increase in the planktonics Asterionella formosa Hassal, Stephanodiscus minutulus (Kutzing) Cleve & Moller, and Cyclotella atomus Hustedt beginning in the late-1980s. Comparing the timing of the increase in planktonics to other studies documenting similar changes in high latitude lakes and ponds reveals a positive correlation between the apparent onset of the change and maximum lake depth (r2 = 0.77), suggesting that lake volume influences ecosystem response. (Abstract shortened by UMI.)...