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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=708909
• 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.

野火和冻土融化是两种广泛的干扰，在未来世纪可能会显着影响北方泥炭地丰富的集水区，包括碳储存，甲烷排放，径流产生和水质的几个功能。我的研究计划的长期目标是进一步了解泥炭地在集水区的作用，以评估气候变化的脆弱性，并改善泥炭地管理和恢复的做法。在接下来的五年里，这项研究计划将侧重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相互影响。 北方不连续的永久冻土带内的泥炭地，如泰加平原，自末次冰期结束以来，已经在泥炭中积累了全球重要的碳储存。由于气候变化造成的这种储存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。扰动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，只有在考虑泥炭地和下游水生生态系统之间的联系之后，才能理解干扰对集水区碳循环的全面影响。泥炭地是河流和湖泊中溶解有机物（DOM）的主要来源，在那里它又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，扰动导致泥炭地DOM输出的改变可能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进行，这些泥炭地代表了自永久冻土融化或火灾以来的时间序列。通过研究沿着这些序列的变化，我们将辨别长期的扰动影响。特别是，我们将研究I）多年冻土融化如何影响几十年到几个世纪的泥炭地温室气体排放和碳储存; II）火灾如何影响多年冻土稳定性和泥炭地土壤呼吸; III）泥炭地丰富的集水区的火灾和融化如何改变集水区DOM输出，包括污染物;和IV）由于扰动而改变的DOM化学组成如何改变其在水生生态系统中的降解。 这项研究将有助于了解北方泥炭地巨大的碳储量对气候变化的脆弱性，以及这将如何影响下游的水生生态系统。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在流域范围保护和管理生态系统服务的政策提供信息和帮助。