Permafrost in a changing climate: geohazard risk assessment and biogeochemical impacts on the environment.

气候变化中的永久冻土：地质灾害风险评估和对环境的生物地球化学影响。

• 批准号: RGPIN-2022-03209
• 负责人: Lacelle, Denis
• 金额: $ 2.19万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=754766
• 关键词: Permafrost; changing; climate; geohazard; risk

Permafrost occupies 40-50% of Canada's landmass and plays a crucial role in cold-climate environments since it affects physical, geomorphological, hydrological, and biological processes. Global warming and permafrost degradation are impacting all aspects of the landscape, including: infrastructure, vegetation productivity (greening and browning), lakes and rivers, and soil biogeochemical cycles. The microbial decomposition of stocks of organic carbon in degrading permafrost is contributing to a positive feedback in the global climate-carbon system. However, the extent of all of these changes is strongly dependent on the presence of ground ice in permafrost sediments. Ground ice (particularly excess ice) controls the rate of permafrost degradation, due to the high latent heat of ice, and the complex nature of potential feedbacks of thawing icy permafrost. Therefore, there is a need to improve our knowledge on the factors influencing the spatial and vertical distribution of ground ice in the complex permafrost system across different landscapes and at different scales to better assess the ongoing environmental changes in polar regions. To contribute to this assessment, my research program is centered on the investigation of physical and (bio)geochemical processes that shape and define the permafrost environments in the Canadian Arctic and Antarctica within a system approach framework. Over the next five years, the main goals of my research are to: (1) Quantify and predict the vertical distribution of ice and heat fluxes in continuous permafrost; (2) Quantify the effects of acid drainage disturbances on temperatures, mobility of water, and biogeochemistry of the active layer and permafrost; (3) Quantify the effect of degrading ice wedge landscapes on local topography, vegetation, hydrology and water quality; and (4) develop a critical mass of highly qualified personnel in permafrost-related topics in Canada. The research will take place mainly at: (1) Tombstone Territorial Park, central Yukon; (2) Eagle Plains, northern Yukon; and (3) Eureka Sound Lowlands on Ellesmere Island, Nunavut. These sites range from warm continuous permafrost in tundra setting to cold continuous permafrost in a polar desert environment. The proposed research program will lead to the production of the first quantitative estimate of the vertical distribution of ground ice in permafrost sediments which could be used to mitigate geohazard risks. A better understanding of the internal feedback of acid drainage and heat released during oxidation of sulphides could help develop proper thermosyphons technology to remove required ground heat to keep hundreds of abandoned tailings frozen and prevent environmental disaster on Indigenous traditional lands. Finally, the research will lead to improved assessment of the water quality from areas affected by degradation of ice wedge polygonal terrain which can help manage water resources in a changing Arctic.

永久冻土占加拿大陆地面积的40-50%，在寒冷气候环境中起着至关重要的作用，因为它影响着物理、地貌、水文和生物过程。全球变暖和永久冻土退化正在影响景观的各个方面，包括：基础设施、植被生产力（绿化和褐变）、湖泊和河流以及土壤生物地球化学循环。在退化的永久冻土中，微生物对有机碳储量的分解有助于全球气候-碳系统的正反馈。然而，所有这些变化的程度在很大程度上取决于永久冻土沉积物中地面冰的存在。由于冰的高潜热和永久冻土融化的潜在反馈的复杂性，地面冰（特别是过量冰）控制着永久冻土退化的速度。因此，有必要提高我们对影响不同景观和不同尺度的复杂多年冻土系统中地面冰空间和垂直分布的因素的认识，以更好地评估极地地区正在发生的环境变化。为了对这一评估做出贡献，我的研究计划集中在物理和（生物）地球化学过程的调查上，这些过程在系统方法框架内塑造和定义了加拿大北极和南极洲的永久冻土环境。在未来5年，我的主要研究目标是：(1)量化和预测连续多年冻土的冰通量和热通量的垂直分布；(2)量化酸性排水扰动对温度、水的流动性以及活动层和永久冻土的生物地球化学的影响；(3)量化冰楔景观退化对当地地形、植被、水文和水质的影响；(4)在加拿大培养与永久冻土相关主题的高素质人才。研究将主要在以下地点进行：(1)育空地区中部的墓碑领土公园；(2)育空北部鹰平原；(3)努纳武特埃尔斯米尔岛的尤里卡峡湾低地。这些地点范围从冻土带设置的温暖连续永久冻土到极地沙漠环境中的寒冷连续永久冻土。拟议的研究计划将导致对永久冻土沉积物中地面冰垂直分布的首次定量估计，这可用于减轻地质灾害风险。更好地了解硫化物氧化过程中酸性排放和热量释放的内部反馈，有助于开发适当的热虹吸技术，以去除所需的地热，使数百个废弃尾矿保持冻结，防止土著传统土地上的环境灾害。最后，该研究将有助于改善受冰楔多边形地形退化影响地区的水质评估，从而有助于管理不断变化的北极地区的水资源。