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.

Wieder Boreal和Subarctic泥炭地覆盖了地球陆地表面约3.46亿公顷。 目前，它们是大气CO2的净汇，也是大气CH 4（一种重要的温室气体）的重要来源。 鉴于预测气候变暖将在北方纬度最明显，这项研究的主要目标一直是并将继续是深入了解泥炭地的碳平衡和泥炭地与大气之间的碳气体交换。 将进行实地和实验室研究，以评估泥炭地的历史发展和目前的功能。 沿着沿着阿巴拉契亚山脉的中轴线，向南到西弗吉尼亚州南部，可以发现许多相对较小的泥炭地。阿巴拉契亚的泥炭地是第四纪的，大多数在9000 - 13000年前开始积累泥炭。 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，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，我们的研究方法已经建立在这样的前提下，北方（较冷的气候）和南方（较暖的气候）泥炭地的网站之间的比较，将提供洞察到潜在的变化，在北方泥炭地预测的全球气候变化的情况下。 这项研究的具体目标是：通过对从沿着南北梯度的地点收集的210个铅定年泥炭芯进行化学分析来确定长期泥炭积累期间，估计北方和南方地点光合固定的14 C的周转，以评估有机质质量与当地气候条件对有机质矿化的影响，对比北方和南方地点泥炭中有机物矿化的空间和时间模式，确定地点内年龄/深度关系的空间变异程度，并使用实验室围隔研究评估根系分泌物和根系周转作为促进CO2和CH 4产生的不稳定有机质的潜在来源。 从这些研究中获得的结果将有助于深入了解在预测的全球气候变化情景下的碳平衡、泥炭积累/退化以及温室气体与大气的交换。