Paleoclimates and ecosystem dynamics in the Hudson Bay lowlands

加拿大北部广泛的泥炭形成湿地是生物多样性的重要储存库，也是全球重要的碳库。来自生物地球化学和古环境研究的证据表明，泥炭地的动态影响大气温室气体，从而影响气候系统。由于泥炭地对全球碳循环和气候的重要性，需要更多关于这些系统对气候或水文变化的敏感性的信息。例如，至关重要的是要知道地下水位位置或空气温度的变化幅度是产生湿地碳平衡从汇到源的转变所必需的。古生态记录提供了湿地系统过去变化的信息，可用于理解当代或未来的变化。该提案涉及对哈德逊湾低地泥炭和湖泊沉积物岩心的分析，哈德逊湾低地是加拿大最大但研究最少的湿地。这些岩心将用于确定冰川后隆升、植物演替、火和气候如何相互作用，从而产生湿地植物群落的变化。湖泊沉积物岩心将用于根据化石花粉颗粒和其他生物指标的组合进行定量气候重建。然后，这些基于代理的重建将与局部和区域尺度上的碳积累模型联系起来，并将整合到过去几千年全球尺度上的湿地动态综合中。

The extensive peat-forming wetlands of northern Canada are an important repository of biodiversity, and are a globally significant carbon pool. Evidence from biogeochemical and paleoenvironmental studies indicates that peatland dynamics affect atmospheric greenhouse gases, and thus, the climate system. Because of the importance of peatlands to the global carbon cycle and the climate, more information is needed on the sensitivity of these systems to climate or hydrological changes. For example, it is critical to know what magnitude of change in water table position or air temperature is necessary to produce a shift in the carbon balance of a wetland from sink to source. The paleoecological record provides information on past changes in wetland systems, which can be applied to understanding contemporary or future changes. This proposal involves the analysis of peat and lake sediment cores from the Hudson Bay Lowland, Canada's largest but most poorly studied wetland. These cores will be used to determine how post-glacial uplift, plant succession, fire and climate interact to produce changes in wetland plant communities. Lake sediment cores will be used to produce quantitative climate reconstructions, based on assemblages of fossil pollen grains and other biological indicators. These proxy-based reconstructions will then be linked to models of carbon accumulation both at local and regional scales, and will be integrated into syntheses of wetland dynamics over the past several millennia at the global scale.