RUI: Peatlands and Global Climate Change: Continued Comparative Studies of Northern and Southern Sites

RUI：泥炭地和全球气候变化：南北遗址的持续比较研究

• 批准号: 9408043
• 负责人: R. Kelman Wieder
• 金额: $ 50.51万
• 依托单位: Villanova University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-07-01 至 1998-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9408043&HistoricalAwards=false
• 关键词: RUI; Peatlands; Global; Climate; Change

Wieder Boreal and subarctic peatlands cover an estimated 346 million ha of the earth's land surface. They presently function as a net sink for atmospheric CO2 and as a substantial source of atmospheric CH4, an important greenhouse gas. Given predictions that climatic warming will be most pronounced in northern latitudes, the main goal of this research has been and will continue to be to gain insights into carbon balance in peatlands and gaseous exchanges of carbon between peatlands and the atmosphere. Field and laboratory studies will be undertaken to assess the historical development and the present function of peatlands. Numerous, relatively small, Sphagnum-dominated peatlands can be found along the axis to the Appalachian Mountains as far south as southern West Virginia. The Appalachian peatlands are of Quaternary age, with most having initiated peat accumulation 9,000-13,000 years ago. Within the Appalachian region, with decreasing latitude peat deposits become fewer in number, smaller in areal extent, thinner, and more highly decomposed. The Appalachian peat deposits have developed over thousands of years under climatic conditions that have been generally warmer than conditions in boreal and subarctic regions. Therefore, our research approach has been founded on the premise that comparisons between northern (cooler climate) and southern (warmer climate) peatland sites will provide insights into potential changes in boreal peatlands under predicted scenarios of global climate change. Specific objectives of this research are: to determine during long-term peat accumulation through chemical analysis of 210 Pb-dated peat cores collected from sites along a north to south gradient, to estimate turnover of photosynthetically fixed 14C in northern and southern sites to evaluate the effects of organic matter quality versus local climatic conditions on organic matter mineralization, to contrast spatial and temporal patterns in organic matter mineralization in peat in northern and southern sites, to determine the magnitude of within-site spatial variability in age/depth relationships, and to evaluate root exudation and root turnover as potential sources of labile organic matter fueling CO2 and CH4 production using laboratory mesocosm studies. Results obtained from these studies will provide insights into the carbon balance, peat accumulation/degradation, and exchange of greenhouse gases with the atmosphere under predicted scenarios of global climate change.

维德北方和亚北极泥炭地估计覆盖地球陆地表面 3.46 亿公顷。 它们目前充当大气二氧化碳的净汇和大气甲烷（一种重要的温室气体）的重要来源。 鉴于气候变暖在北纬地区最为明显的预测，这项研究的主要目标一直并将继续是深入了解泥炭地的碳平衡以及泥炭地与大气之间的碳气态交换。 将进行实地和实验室研究，以评估泥炭地的历史发展和当前功能。 沿着阿巴拉契亚山脉的轴线，一直到西弗吉尼亚州南部，都可以找到许多相对较小的、以泥炭藓为主的泥炭地。阿巴拉契亚泥炭地处于第四纪时代，大部分泥炭地在 9,000-13,000 年前就开始堆积。 在阿巴拉契亚地区，随着纬度的降低，泥炭沉积物的数量越来越少，面积越来越小，越来越薄，而且分解程度越来越高。 阿巴拉契亚泥炭沉积物是在比北方和亚北极地区温暖的气候条件下发展了数千年的。 因此，我们的研究方法的前提是，北部（气候较冷）和南部（气候较温暖）泥炭地地点之间的比较将有助于了解在全球气候变化预测情景下北方泥炭地的潜在变化。 这项研究的具体目标是：通过对从南北梯度站点收集的 210 个 Pb 测年泥炭岩心进行化学分析，确定长期泥炭积累过程，估计北部和南部站点光合固定 14C 的周转率，以评估有机质质量与当地气候条件对有机质矿化的影响，对比北部和南部泥炭地点有机质矿化的空间和时间模式，以确定地点内年龄/深度空间变异的程度关系，并利用实验室介层研究评估根系分泌物和根系周转作为不稳定有机物的潜在来源，促进二氧化碳和甲烷的产生。 这些研究获得的结果将为全球气候变化预测情景下的碳平衡、泥炭积累/退化以及温室气体与大气的交换提供见解。