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反应，并将仪器温度记录放在长期的角度，我们将使用多代理古矿物学方法从加拿大北极东部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，并对产生的时间序列进行分析，以便能够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至千年尺度的湖泊参数数量变化记录网络，这将使我们能够更好地了解加拿大东北部自然环境变化的范围，并使我们能够探索与冰川后生态系统演替有关的北部地貌的基本问题。 到目前为止，在我们的研究中，我们开发了新的分析技术和替代指示生物(硅藻和摇蚊)的传递函数，这对魁北克北部(努纳维克)、拉布拉多和南安普顿岛(努纳武特)的全新世气候和环境变异性产生了新的见解。在下一笔发现赠款的期限内，我们将把我们的生物地层学时间序列方法扩展到努纳武特的福克斯盆地地区(65°-70°N；71°-85°W)，该地区位于近几十年来湖泊和冰冻圈显示明显变暖迹象的北极高地和尚未检测到这些变化的亚北极地区(努纳维克和拉布拉多)之间。建立在古湖沼学和当代湖湖学之间紧密联系的基础上，我们对北方湖泊和池塘过去变化的解释将与对这些生态系统今天功能的研究结合起来。我们将特别关注在新形成的景观中更好地了解湖泊早期演化过程中的湖泊条件及其对水生生物群的影响。因此，我们将研究比洛特岛(73°N)上退缩冰川前面的湖泊的情况，这些湖泊与北方湖泊历史上的早期发展阶段有密切联系。

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.