Fire and Ice: Impacts of peatland disturbances on carbon cycling and water quality in catchments on the Taiga Plains.

火与冰：泥炭地扰动对针叶林集水区碳循环和水质的影响。

• 批准号: RGPIN-2016-04688
• 负责人: Olefeldt, David
• 金额: $ 2.48万
• 依托单位: University of Alberta
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=661173
• 关键词: Fire; Ice; Impacts; peatland; disturbances

Wildfire and permafrost thaw are two widespread disturbances that over the coming century are likely to significantly affect several functions of northern peatland-rich catchments, including carbon storage, methane emissions, runoff generation and water quality. The long term objectives of my research program are to further our understanding of the role of peatlands within catchments, in order to both assess vulnerability to climate change and to improve practices of peatland management and restoration. Over the next five year, this research program will focus on understanding the interactive effects on catchment functions from wildfire and permafrost in peatlands on the Taiga Plains of western Canada.***Northern peatlands within discontinuous permafrost zones, like the Taiga Plains, have since the end of the last glaciation accumulated a globally significant store of carbon in peat. A destabilization of this store due to climate change can cause substantial greenhouse gas emissions, constituting a feedback mechanism that would further accelerate climate change. The role of disturbances is a main obstacle for improving our projections of future peatland greenhouse gas emissions. ***The full impact of disturbances on catchment carbon cycling is however only understood once linkages between peatlands and downstream aquatic ecosystems also are considered. Peatlands are major sources of dissolved organic matter (DOM) to streams and lakes, where it in turn is partially degraded and emitted as greenhouse gases. Peatland DOM export also includes organic contaminants, including methylated metals. Altered peatland DOM export due to disturbances can therefore have cascading effects on both aquatic carbon cycling and water quality.***The research will be carried out at several peatland sites that represent sequences with regards to their time since permafrost thaw or fire. By studying changes along these sequences, we will discern long term disturbance effects. In particular, we will study I) how permafrost thaw affects greenhouse gas emissions and carbon storage in peatlands over decades to centuries; II) how fire affects permafrost stability and soil respiration in peatlands over years to decades; III) how fire and thaw in peatland-rich catchments alter catchment DOM export, including contaminants; and IV) how altered chemical composition of DOM due to disturbances alter its degradation in aquatic ecosystems.****This research will yield knowledge of how vulnerable the vast carbon stores in northern peatlands are to climate change, and how this could affect downstream aquatic ecosystems. The knowledge will inform and aid the development and implementation of policies at provincial, national and international levels that enhance climate change mitigation, and policies that protect and manage ecosystem services at the catchment scale.***

野火和永久冻土融化是两种广泛存在的扰动，在未来一个世纪可能会显著影响北部富含泥炭地的集水区的几种功能，包括碳储存、甲烷排放、径流产生和水质。我的研究计划的长期目标是进一步了解泥炭地在集水区中的作用，以便评估对气候变化的脆弱性，并改进泥炭地管理和恢复的做法。在接下来的五年里，该研究项目将重点了解加拿大西部泰加平原泥炭地野火和永久冻土层对集水区功能的相互作用。位于不连续永久冻土带内的北部泥炭地，如针叶林平原，自上次冰期结束以来，已经积累了全球重要的泥炭碳储量。由于气候变化而导致这一储备的不稳定可能导致大量温室气体排放，从而形成一种反馈机制，进一步加速气候变化。干扰的作用是改善我们对未来泥炭地温室气体排放预测的主要障碍。然而，只有考虑到泥炭地和下游水生生态系统之间的联系，才能了解干扰对集水区碳循环的全面影响。泥炭地是向河流和湖泊输送溶解有机物（DOM）的主要来源，而这些有机物在河流和湖泊中又被部分降解并作为温室气体排放。泥炭地DOM出口还包括有机污染物，包括甲基化金属。因此，干扰导致泥炭地DOM输出的改变会对水生碳循环和水质产生级联效应。***研究将在几个泥炭地地点进行，这些地点代表了自永久冻土融化或火灾以来的时间序列。通过研究这些序列的变化，我们将发现长期的干扰效应。特别是，我们将研究：(1)多年冻土融化如何影响数十年至数百年泥炭地的温室气体排放和碳储存；II)数年至数十年，火灾如何影响泥炭地的永久冻土稳定性和土壤呼吸；III)富含泥炭地的集水区的火灾和解冻如何改变集水区DOM输出，包括污染物；IV)干扰如何改变DOM的化学组成，从而改变其在水生生态系统中的降解。****这项研究将使人们了解北部泥炭地巨大的碳储量对气候变化有多脆弱，以及这将如何影响下游水生生态系统。这些知识将为省、国家和国际各级制定和实施加强减缓气候变化的政策以及保护和管理流域生态系统服务的政策提供信息和帮助