Impacts of climatic change and environmental stress on aquatic ecosystems

为了探索北部淡水生态系统及其流域对气候变化的潜在响应，并将仪器温度记录置于长期视角，我们将使用多代理古河流学方法从加拿大东部北极地区的湖泊沉积物档案中生成详细的古气候和古环境记录。将对这些记录进行综合，并对所得的时间序列进行分析，以便与格陵兰岛的冰芯数据以及周围海洋环境的古海洋学数据进行区域比较。我们的中心目标是建立一个十年-千年尺度的湖泊参数定量变化记录网络，这将更好地了解加拿大东北部自然环境变化的范围，并使我们能够探索有关北部景观冰川后生态系统演替的基本问题。

To explore the potential responses of northern freshwater ecosystems and their watersheds to climate change and to place instrumental temperature records into a long-term perspective, we will use a multi-proxy paleolimnological approach to generate detailed paleoclimatic and paleoenvironmental records from lake sediment archives in the eastern Canadian Arctic. These records will be synthesized and the resulting time series analyzed to allow regional comparisons with ice core data from Greenland as well as with paleoceanographic data from surrounding marine environments. Our central objective is to generate a network of decadal-millennial scale records of quantitative variations in limnological parameters that will provide a better understanding of the range of natural environmental variability in northeastern Canada, and allow us to explore fundamental questions concerning postglacial ecosystem succession in northern landscapes. In our research to date we have developed new analytical techniques and transfer functions for proxy indicator organisms (diatoms and chironomids) that have generated new insights into Holocene climatic and environmental variability in northern Québec (Nunavik), Labrador and Southampton Island (Nunavut). Over the term of the next Discovery grant, we will extend our biostratigraphical time-series approach into the Foxe Basin region of Nunavut (65°-70°N; 71°-85°W), which occupies a key position between the High Arctic where lakes and the cryosphere show signs of pronounced warming in recent decades, and the Subarctic (Nunavik and Labrador) where these changes are not yet detectable. Building on strong links between paleolimnology and contemporary limnology, our interpretations of past changes in northern lakes and ponds will be combined with research into the present-day functioning of these ecosystems. We will focus especially on developing a better understanding of limnological conditions during early lake evolution in newly formed landscapes and their repercussions on aquatic biota. We will therefore examine the conditions in lakes in front of retreating glaciers on Bylot Island (73°N) that have affinities with early developmental phases in the history of northern lakes.