Limnology and paleoecology of lakes

北极地区已多次被确定为全球环境变化研究的风向标。然而，由于缺乏长期数据，不可能确定许多生态系统变化的时间和幅度，也不可能检验假设、定义自然变率和评估模型。因此，必须使用间接替代方法，例如利用保存在湖泊沉积物中的信息（即古湖泊学）来解决许多科学和社会相关的问题。我在北极的26年研究项目与我们正在进行的古湖沼学研究相吻合，在此期间，我们记录了显著的湖沼学变化：随着气候变暖，北极的高池塘覆盖的冰越来越少，越来越浅，直到2006年7月，许多较小的地点最终完全干涸。我们将研究这些前所未有的生态变化如何影响北极生态系统，以及其他北极地区类似的古湖泊和生态变化。第二个新的研究领域将把我们的方法集中在亚北极泥炭地剖面上，它可能比北极湖泊沉积物提供更高的环境变化时间分辨率，并且可能与降水和蒸发比更密切相关。我们的主要焦点将是哈德逊湾低地地区的泥炭和永久冻土岩芯的样带，该地区对我们了解气候和环境变化至关重要。与以过程为基础的科学家合作，对15个湖泊进行平行的古湖泊学研究，将补充这个北方到亚北极的样带，并确定与气候有关的冰盖变化和/或热分层模式如何影响这些与温带和亚北极生态系统接壤的研究较少的地区的湖泊。最后，我们将开发和应用新的古湖泊学方法（主要基于无脊椎动物指标）来跟踪一个新的和以前未被认识到的影响世界各地软北方湖泊的环境问题：湖水钙浓度的下降。

Arctic regions have been repeatedly identified as bellwethers for the study of global environmental change. However, due to the lack of long-term data, it is impossible to determine the timing and magnitude of many ecosystem changes, and to test hypotheses, define natural variability, and evaluate models. Consequently, indirect proxy methods, such as using information preserved in lake sediments (i.e. paleolimnology) must be used to address many scientifically and socially-relevant questions. During my 26 year research program in the Arctic, which dovetails with our ongoing paleolimnological work, we have recorded marked limnological changes as high Arctic ponds become less ice-covered and shallower with warming until many of the smaller sites finally dried up totally in July 2006. We will study how these unprecedented ecological changes are affecting Arctic ecosystems, as well as comparable paleolimnological and ecological changes in other Arctic regions. A second new research area will focus our approaches on subarctic peatland profiles, which potentially offer higher temporal resolution of environmental change than Arctic lake sediments, and may be more closely linked to precipitation and evaporation ratios. Our main focus will be a transect of peat and permafrost cores from the Hudson Bay Lowlands region, which is a region that is critically important for our understanding of climatic and environmental change. A parallel paleolimnological study of 15 lakes, working in collaboration with process-based scientists, will complement this boreal to subarctic transect, and determine how climate-related changes in ice cover and/or thermal stratification patterns are affecting lakes in these poorly studied regions, bordering on temperate and sub-arctic ecosystems. Finally, we will develop and apply new paleolimnological methods (based largely on invertebrate indicators) to track a new and previously under-recognized environmental problem affecting softwater boreal lakes around the world: the decline in lakewater calcium concentrations.