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

野火和冻土融化是两种广泛存在的干扰，在接下来的一个世纪里，可能会对北部泥炭地丰富的集水区的几个功能产生重大影响，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加深我们对泥炭地在流域内的作用的理解，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实践。在接下来的五年里，这项研究计划将专注于了解加拿大西部泰加平原泥炭地野火和永久冻土对集水功能的交互影响。 位于不连续永久冻土地带的北部泥炭地，如泰加平原，自上一次冰川结束以来，在全球范围内积累了大量的泥炭碳储量。由于气候变化导致的这家商店的不稳定可能导致大量温室气体排放，构成一种反馈机制，将进一步加速气候变化。干扰的作用是改善我们对泥炭地未来温室气体排放预测的主要障碍。 然而，只有在考虑泥炭地与下游水生生态系统之间的联系时，才能了解干扰对流域碳循环的全面影响。泥炭地是河流和湖泊溶解有机物质(DOM)的主要来源，在那里它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，由于干扰而改变的泥炭地DOM出口可能会对水生碳循环和水质产生级联效应。 这项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，我们将辨别出长期的扰动效应。特别是，我们将研究i)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)火如何影响多年至数十年泥炭地的永冻土稳定性和土壤呼吸；iii)富泥炭地集水区的火和融化如何改变集水区DOM的出口，包括污染物；以及IV)由于干扰而改变DOM的化学成分如何改变其在水生生态系统中的退化。 这项研究将产生关于北部泥炭地巨大的碳库对气候变化的脆弱性，以及这可能如何影响下游水生生态系统的知识。这些知识将为省、国家和国际各级加强减缓气候变化的政策以及在流域范围内保护和管理生态系统服务的政策的制定和实施提供信息和帮助。

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.