PALEOLIMNOLOGICAL INVESTIGATION OF LAKES AND PONDS ON BANKS ISLAND, N.W.T., CANADIAN HIGH ARCTIC

The Canadian High Arctic is a distinct region of our planet, and with the need to better understand the far reaching effects of high arctic climate change, comes the demand for continued long-term monitoring of the High Arctic. However, this is a difficult region to monitor on a frequent basis due to financial and logistical constraints, and relatively little ecological baseline data exists for many areas throughout the High Arctic. The situation is slowly being rectified through limnological and paleolimnological investigations that allow for the acquisition of both baseline and historical limnic data from the myriad of lakes (depth>2m) and ponds (depth<2m) that dot the landscape of the High Arctic. Lake and pond sediments preserve many biological indicators that can serve as proxy indicators of past environmental changes. More specifically, in the oligotrophic lakes and ponds of the High Arctic, diatoms (class Bacillariophyceae) often are a significant part of the algal community. Their fossilized siliceous remains are used as bioindicators in our investigations of past physical and chemical limnic conditions.

In the High Arctic, surface sediment samples (~ top 1cm) represent an integrated sample of diatom communities, both spatially (i.e. from various habitats) and temporally (i.e. last few years of deposition). A quantitative relationship between the dominant surface sediment diatom assemblages and present-day limnic properties can be established in order to produce environmental reconstruction models. This study focuses on the development of a calibration set for Banks Island, N.W.T., and the application of this environmental reconstruction model to 3 lacustrine cores from Banks Island. Cores were retrieved from the following sites: (a) 34cm core from lake BK-AH (73º35.57N, 119º35.01W), (b) 6.0 cm core from pond BK-3 (73º11.583N, 119º38.091W), and (c) 10 cm core from pond BK-5 (73º12.732N, 119°34.452W). Generally, core findings show a shift from greater diatom diversity in the top sections to a dominance of two to three key species throughout the remainder of the core. The calibration set construction is currently in progress, however all results to date, including general trends driving species variance amongst the sampled sites, and core stratigraphies are described in this poster presentation.