Collaborative Research: P2C2: Contributions of northern cold-climate peatlands and lakes to abrupt changes in atmospheric methane during the last deglaciation

合作研究：P2C2：北部寒冷气候泥炭地和湖泊对末次冰消期大气甲烷突变的贡献

• 批准号: 1304408
• 负责人: Todd Sowers
• 金额: $ 4.02万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1304408&HistoricalAwards=false
• 关键词: Collaborative; Research; P2C2; Contributions; northern

The proposed research integrates studies in a range of disciplines (paleoecology, climate, biogeochemistry, geomorphology, geology) to understand the timing, magnitude, and overall contribution of northern cold-climate peatlands and lakes to rapid increases in atmospheric methane (CH4) concentrations (AMC) during the last deglaciation. The study will use comprehensive paleoecological records of northern peatland and lake development to document their past spatial and temporal patterns of CH4 emission. This will enable better prediction of future emissions from northern ecosystems, particularly as surface permafrost thaws under scenarios of climate warming. Specifically, the PIs propose to: (1) Synthesize new and existing peatland, thermokarst-lake, kettle-lake and other post-glacial lake initiation data, as well as compiling such data from regions that no longer support peatlands or permafrost, such as on formerly exposed continental shelf and along southern margins of ice sheets, to gain knowledge of timing of these AMC sources during the last deglaciation; (2) analyze new and existing peat macrofossil data to estimate past CH4 flux from northern high latitude peatland regions as they evolved from high- CH4 emitting fens to lower- CH4 emitting bogs during the Holocene; (3) use novel stable isotope approaches and 14C dating to constrain the magnitude and timing of permafrost-derived hydrogen and carbon in CH4 from northern peatlands and lakes that formed when ground ice melted; and (4) compare their bottom-up reconstructions of past CH4 emissions and their isotope values from peatlands and thermokarst lakes with top-down modeling of global atmospheric CH4 sources based on recent, higher resolution data of interhemispheric CH4 isotope (13C, D, 14C) gradients recorded in Greenland and Antarctic ice cores.Methane is a potent greenhouse gas. Its global warming potential is many times that of carbon dioxide. Therefore, in order to develop scenarios of future climate change, it is important to be able to estimate how much methane will be released to the atmosphere due to permafrost degradation. This project will constrain that number.

拟议的研究整合了一系列学科（古生态学，气候，地球化学，地貌学，地质学）的研究，以了解北方寒冷气候泥炭地和湖泊的时间，规模和整体贡献，在最后一次冰消期大气甲烷（CH 4）浓度（AMC）的快速增加。这项研究将利用北方泥炭地和湖泊发展的全面古生态记录，记录其过去的空间和时间模式的甲烷排放。这将有助于更好地预测北方生态系统未来的排放量，特别是在气候变暖的情况下地表永久冻土融化时。具体而言，研究所建议：（1）综合新的和现有的泥炭地、热岩溶湖、壶湖和其他冰后期湖泊形成数据，并汇编来自不再支持泥炭地或永久冻土的地区的此类数据，如以前暴露的大陆架和沿着冰盖南部边缘，以了解这些AMC源在末次冰消期间的时间;（2）分析新的和现有的泥炭宏体化石数据，估算北方高纬度泥炭地在全新世从高甲烷排放沼泽向低甲烷排放沼泽演化过程中的甲烷通量;（3）使用新的稳定同位素方法和14 C测年来限制永久冻土的规模和时间-来自北方泥炭地和湖泊的甲烷中的氢和碳，这些泥炭地和湖泊是在地面冰融化时形成的;（4）将泥炭地和热岩溶湖泊的CH 4排放及其同位素值的自下而上的重建与自上而下的重建进行比较，基于格陵兰和南极冰芯记录的最近的、更高分辨率的半球间CH 4同位素（13 C、D、14 C）梯度数据，对全球大气CH 4源进行了向下建模。 它的全球变暖潜力是二氧化碳的许多倍。 因此，为了制定未来气候变化的情景，重要的是能够估计有多少甲烷将由于永久冻土退化而释放到大气中。 该项目将限制这一数字。