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%，在寒冷的气候环境中发挥着至关重要的作用，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方方面面，包括：基础设施、植被生产力(绿化和褐化)、湖泊和河流以及土壤生物地球化学循环。微生物分解正在退化的永久冻土中储存的有机碳，正在促进全球气候-碳系统的积极反馈。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是否存在地面冰。地面冰(特别是过剩的冰)控制着永久冻土退化的速度，这是由于冰的高潜热，以及融化冰冻冻土潜在反馈的复杂性质。因此，有必要提高我们对影响复杂的多年冻土系统中不同地貌和不同尺度的地冰空间和垂直分布的因素的认识，以便更好地评估极地地区正在进行的环境变化。为了对这一评估做出贡献，我的研究计划集中在调查物理和(生物)地球化学过程，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。在接下来的五年里，我的研究的主要目标是：(1)量化和预测连续多年冻土中冰和热通量的垂直分布；(2)量化酸排水扰动对活动层和冻土的温度、水的流动性和生物地球化学的影响；(3)量化退化的冰楔景观对当地地形、植被、水文和水质的影响；以及(4)在加拿大培养一支在冻土相关专题方面具有高素质人才的临界人数。研究将主要在：(1)育空地区中部的墓碑领地公园；(2)育空地区北部的鹰平原；以及(3)努纳武特埃尔斯米尔岛上的尤里卡湾低地。这些地点的范围从冻土带环境中的温暖持续多年冻土到极地沙漠环境中的寒冷持续多年冻土。拟议的研究方案将导致对永久冻土沉积物中地面冰垂直分布的第一次定量估计，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排水和放出的热量的内部反馈，有助于开发适当的热虹吸技术，以消除所需的地热，使数百个废弃的尾矿保持冻结，并防止土著传统土地上的环境灾难。最后，这项研究将改进对受冰楔多边形地形退化影响地区的水质的评估，这有助于在不断变化的北极管理水资源。