RUI: Post-fire Nitrogen Cycling in Boreal Bogs - Critical Unknowns Explored

RUI：北方沼泽火灾后的氮循环——探索关键的未知因素

• 批准号: 1256985
• 负责人: R. Kelman Wieder
• 金额: $ 117万
• 依托单位: Villanova University
• 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: 2013-03-15 至 2018-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1256985&HistoricalAwards=false
• 关键词: RUI; Post; fire; Nitrogen; Cycling

This research is structured around a novel conceptual framework for how nitrogen (N) cycling in boreal bogs changes as a function of both time-since-fire and experimentally augmented N. Bog sites of different ages (time since the most recent fire) will receive elevated N inputs in simulated rainfall. New insights will be gained into: the importance of biological N2-fixation as a newly recognized major input of N into these bogs; the role of Sphagnum mosses, which cover the bog surface and are the major contributors to ongoing peat accumulation, as the gatekeepers of newly acquired N from either N2-fixation or rain and snow; and the linkages between N inputs and the ability of bogs to sequester both N and carbon (C) in the accumulating peat.Boreal peatlands cover only 3-4% of the Earth's land surface, yet store 25-30% of the world's soil C and 9-16% of the world's soil N in peat. Peatlands represent an ongoing net sink for atmospheric carbon dioxide. Bogs of western Canada persist at the dry end of the climatic gradient across which peatlands exist, and hence are especially sensitive to ongoing climate changes that include increasing temperature, as well as increasing wildfire frequency and severity. Further, in western Canada, atmospheric N deposition historically has been low, but is increasing because of N emissions from oil sands development in northern Alberta. Clarifying the linkages between N and C cycling in western Canadian bogs will enhance the ability to predict how N and C storage in peat may be influenced by ongoing climate change. The research will support graduate and undergraduate thesis students; the PIs will teach a Peatland Ecology course at the Meanook Biological Research Station, Alberta, Canada, in years 2 and 4 of the project.

这项研究围绕一个新颖的概念框架构建，该框架探讨了北方沼泽中的氮 (N) 循环如何随着火灾发生后的时间和实验性增强的氮的函数而变化。不同年龄（最近一次火灾以来的时间）的沼泽地点将受到影响模拟降雨中的氮输入增加。 将会获得新的见解：生物固氮作为新认识的氮进入这些沼泽的主要输入的重要性；泥炭藓的作用，覆盖沼泽表面，是持续泥炭积累的主要贡献者，作为从固氮或雨雪中新获得的氮的看门人；以及氮输入与沼泽在积累的泥炭中固存氮和碳 (C) 的能力之间的联系。北方泥炭地仅覆盖地球陆地表面的 3-4%，但却储存了世界土壤 C 的 25-30%世界土壤氮的 9-16% 存在于泥炭中。 泥炭地代表着大气二氧化碳的持续净汇。 加拿大西部的沼泽持续存在于泥炭地所在的气候梯度的干燥端，因此对持续的气候变化特别敏感，包括温度升高以及野火频率和严重程度的增加。 此外，在加拿大西部，大气中的氮沉积历史上一直很低，但由于阿尔伯塔省北部油砂开发的氮排放而增加。 澄清加拿大西部沼泽中氮和碳循环之间的联系将增强预测泥炭中氮和碳储存如何受到持续气候变化影响的能力。 该研究将为研究生和本科生论文学生提供支持；项目负责人将在项目的第二年和第四年在加拿大艾伯塔省米努克生物研究站教授泥炭地生态学课程。