Investigating the role of soil microbial processes in aquatic greenhouse gas emissions in Eastern Canadian permafrost landscapes

多年冻土融化产生的温室气体(GHG)排放是对全球变暖的一个重要潜在的积极反馈，但我们对控制这些排放的生物、地球化学和水文机制的了解仍然有限。最近的研究指出，水生环境(湖泊和池塘)是温室气体排放的热点，但永冻土碳对水生温室气体排放的贡献途径尚不清楚。目前，缺乏综合多年冻土景观中土壤和水环境中的微生物、生物地球化学和水文过程的研究，这一跨学科项目旨在解决这一问题。我们将研究加拿大东部代表连续和不连续永久冻土的生态系统中的这些过程。我们由FRQNT资助的研究项目侧重于(1)通过田间采样来表征微生物群落、有机质(OM)和通过土壤到水环境梯度的温室气体通量之间的关系，以及(2)通过培养实验确定微生物群落和温室气体通量之间的联系的控制机制。我们的团队在碳循环生物地球化学(Peter Douglas-McGill)、北极水生生态(Isabelle Laurion-INRS)、土壤微生物学(Cynthia Kallenbach-McGill)、微生物基因组学(Jérôme Comte-INRS)和营养生物地球化学(Roxane Maranger-University Montréal)方面拥有丰富的专业知识。来自NSERC Nova计划的新资金将促进与水文学家(Melissa Lafrenière-Queens)的合作，扩大研究计划，将重点放在有机物质、微生物和养分从土壤到池塘的水文运输的具体机制上。这将包括研究夏季降雨量和不同大小类别的有机物在控制土壤-池塘碳通量方面的作用。它还将促进对快速侵蚀的冲沟和永久冻土融化池塘在调动永久冻土碳库方面的潜力进行比较分析。这项新的资助研究将为土壤微生物学、水文学和永久冻土温室气体排放之间的机械联系提供关键的见解。

Greenhouse gas (GHG) emissions from thawing permafrost represent a major potential positive feedback to global warming, but our understanding of the biological, geochemical, and hydrological mechanisms controlling these emissions remains limited. Recent research points to aquatic environments (lakes and ponds) as hotspots of GHG emissions, but the pathways through which permafrost soil carbon contributes to aquatic GHG emissions remain unclear. Currently there is a lack of research integrating microbiological, biogeochemical, and hydrological processes in soils and aquatic environments in permafrost landscapes, which this interdisciplinary project aims to address. We will study these processes in ecosystems in Eastern Canada representing both continuous and discontinuous permafrost. Our FRQNT-funded research project focuses on (1) characterizing relationships between microbial communities, organic matter (OM), and GHG fluxes across soil to aquatic environmental gradients through field sampling and (2) identifying the mechanisms controlling linkages between microbial communities and GHG fluxes using incubation experiments. Our team comprises strong expertise in carbon cycle biogeochemistry (Peter Douglas- McGill), Arctic aquatic ecology (Isabelle Laurion-INRS), soil microbiology (Cynthia Kallenbach- McGill), microbial genomics (Jérôme Comte- INRS), and nutrient biogeochemistry (Roxane Maranger- Université de Montréal). New funding from the NSERC NOVA program will facilitate collaboration with a hydrologist (Melissa Lafrenière-Queens), broadening the research program to focus on specific mechanisms of hydrological transport of organic matter, microbes, and nutrients from soils to ponds. This will include examination of the role of summer rainfall and different size classes of organic matter in controlling soil-pond carbon fluxes. It will also facilitate a comparative analysis of rapidly eroding gullies with permafrost thaw ponds in terms of their potential for mobilizing permafrost carbon reservoirs. This new funding study will provide key insights into mechanistic linkages between soil microbiology, hydrology, and permafrost GHG emissions.