Land-water linkages and the biogeochemistry and ecology of Arctic aquatic ecosystems

河流和湖泊是周围景观的强大整合者。陆地上的变化不可避免地被流经景观的水捕获，最终被输送到水生环境。因此，水生生态系统既捕捉到发生在广阔空间尺度上的变化，又受到变化的影响。这在北方尤其重要，因为覆盖加拿大陆地一半的永久冻土正在整个北极地区融化。因此，目前被“锁定”（隔离）在永久冻土中的成分正变得可以在土壤中发生反应并从土壤中释放出来，并运输到水生环境。在加拿大西部北极经历大规模永久冻土滑坡的地点工作，本研究将研究永久冻土融化如何改变溶解无机碳和有机碳（DIC， DOC）的土地-水通量，以及这种变化对更大的碳(C)循环的影响。碳酸氢盐通常是水生DIC池的主要成分，它主要是由化学风化作用产生的，即溶解在水中的二氧化碳与土壤的矿物成分发生反应，导致原始的二氧化碳“固定”为碳酸氢盐。除了光合作用，风化作用是陆地上两种主要的二氧化碳封存机制之一。相比之下，永久冻土土壤中有机碳的含量大约是目前大气中有机碳含量的两倍，因此，从融化的永久冻土中动员起来的DOC在被细菌或阳光降解后，代表着未来二氧化碳的来源。尽管探索永久冻土融化的碳动力学的研究几乎完全集中在有机碳的降解上，但我们的早期工作表明，在新融化的矿物土壤中，风化作用的增加可能会缓和永久冻土融化时有机碳释放的二氧化碳的影响。该研究将对加拿大西部北极地区永久冻土融化对无机和有机碳循环的平衡作用进行独特的同步调查，并培训多名南部人员和北部居民。由于永久冻土融化释放了许多成分，这项工作也将加强对永久冻土融化对北方淡水的社会经济和环境影响的理解。

Rivers and lakes are powerful integrators of the landscapes that surround them. Changes on land are inevitably captured by water flowing across landscapes, which is ultimately delivered to aquatic environments. Thus, aquatic ecosystems both capture, and are affected by, change occurring across broad spatial scales. This is particularly important in the north because permafrost - the permanently frozen ground that covers about half of Canada's landmass - is thawing throughout the Arctic. Thus, constituents currently 'locked away' (sequestered) in permafrost are becoming available for reaction within and liberation from soils, and transport to aquatic environments. Working at sites experiencing massive permafrost slumping in the western Canadian Arctic, this research will examine how permafrost thaw changes the land-to-water flux of dissolved inorganic and organic carbon (DIC, DOC), and the implications of this change for the larger carbon (C) cycle. Bicarbonate, which is typically the main component of the aquatic DIC pool, is largely produced by chemical weathering, whereby CO2 dissolved in water reacts with the mineral component of soils, causing the original CO2 to become 'fixed' as bicarbonate. Alongside photosynthesis, weathering is one of two main sequestration mechanisms for CO2 on land. In contrast, permafrost soils contain about twice as much organic C as currently exists in the atmosphere as CO2, and thus DOC mobilized from thawing permafrost represents a future CO2 source, following its degradation by bacteria or sunlight. Although research exploring the C dynamics of permafrost thaw has focused almost exclusively on organic C degradation, our early work has shown that increased weathering in newly-thawed mineral soils may temper the effect of CO2 release from organic C as permafrost thaws. This research will undertake a unique, concurrent investigation of the counterbalancing effects of permafrost thaw on inorganic and organic C cycling in the western Canadian Arctic, and train multiple southern personnel and northern residents. Because of the many constituents released as permafrost thaws, this work will also bolster understanding of the socio-economic and environmental effects of permafrost thaw on northern freshwaters.