Impacts of Talik Microbial Geochemistry on a Changing Permafrost Landscape

点击翻译按钮获取中文摘要

The proposed research program takes an interdisciplinary approach to investigate the hydrology, geochemistry, and microbiology of taliks under lakes and ponds, defined as a layer or body of unfrozen ground in permafrost regions. These taliks are hydrologically connected to surface waters but are poorly understood due to long periods of extensive ice cover and inherent difficulty in accessing them. While permafrost creates an effective barrier that can isolate microbial communities within taliks, climate warming in the Arctic at twice the global mean is contributing to decreases in both the distribution and thickness of permafrost that will diminish these barriers and lead to talik expansion, which is of great concern when considering the microbial respiration of vast reserves of soil organic carbon in permafrost and associated methane release from thermokarst lakes. The Arctic is also experiencing dramatic hydrological and hydrogeological changes leading to a rapidly evolving interrelationship between surface waters and groundwaters. This is affecting the partitioning of water stored above and below ground and connectivity of surface waters with subsurface environments due to changing hydrologic flowpaths, and physicochemical conditions. These climate-related impacts will strongly influence talik environments, but the degree and extent of these impacts on microbial diversity and biogeochemistry and their subsequent future interconnectivity with surface waters are unknown. HQP-led projects will generate new knowledge about the extent and composition of taliks under lakes and ponds at three field sites in continuous and discontinuous permafrost regions. It will identify and map these taliks and their interconnectedness with other subsurface feature, measure and compare the thermal, hydrogeochemical, and microbial properties of these taliks, and determine how talik properties influence adjacent aqueous and sedimentary environments such as overlying waters or nearshore settings. HQP will conduct extensive fieldwork at these sites and become proficient in techniques in geophysics, geochemistry, metagenomics, and microscopy. In addition to new knowledge generated through the scientific work of 19 HQP, this program will directly benefit northern communities that are concerned about the impacts of climate warming on freshwater environments. In addition, Canadian citizens will directly benefit by having a better understanding of the Arctic terrestrial landscape through these efforts. Their knowledge will help society understand how climate warming is impacting the Arctic and will guide present and future policymakers in their determination for how Canada addresses global climate change. Finally, through the development of HQP-led projects that include 5 northern community members, this work will help to empower these communities to understand and prepare for future hydrological and geochemical changes as a result of climate warming.