Paleoclimates and ecosystem dynamics in the Hudson Bay lowlands

加拿大北方广阔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。地球化学和古环境研究的证据表明，泥炭地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，必须知道地下水位位置或空气温度的变化幅度，才能使湿地的碳平衡从汇向源转变。古生态记录提供了有关湿地系统过去变化的信息，这些信息可用于了解当代或未来的变化。该提案涉及分析来自加拿大最大但研究最少的湿地哈德逊湾低地的泥炭和湖泊沉积物岩心。这些核心将被用来确定冰后隆起，植物演替，火灾和气候如何相互作用，以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粒和其他生物指标的组合进行定量气候重建。这些基于代理的重建将与当地和区域尺度的碳积累模型联系起来，并将被整合到过去几千年来全球尺度的湿地动态合成中。

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.