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

这项研究是围绕一个新的概念框架，如何氮（N）循环在北方沼泽的变化作为一个函数的时间，因为火灾和实验增加的N。 不同年龄的沼泽网站（时间，因为最近的火灾）将收到升高的N输入模拟降雨。 将获得新的见解：生物固氮的重要性，作为一个新认识到的主要输入N到这些沼泽的泥炭藓，覆盖沼泽表面的作用，是正在进行的泥炭积累的主要贡献者，作为看门人的新收购的N无论是固氮或雨和雪;以及氮输入与沼泽在积累的泥炭中隔离氮和碳（C）的能力之间的联系。北方泥炭地只覆盖地球陆地表面的3-4%，然而，世界土壤中25-30%的碳和9-16%的氮都储存在泥炭中。 泥炭地是大气二氧化碳的持续净吸收汇。 加拿大西部的沼泽持续存在于泥炭地存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，历史上大气氮沉降一直很低，但由于北方阿尔伯塔油砂开发的氮排放正在增加。 澄清加拿大西部沼泽N和C循环之间的联系，将提高能力，以预测如何N和C存储在泥炭可能会受到持续的气候变化。 该研究将支持研究生和本科生的论文; PI将在加拿大阿尔伯塔的Meanook生物研究站教授泥炭地生态学课程。

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.