Hydrology and mercury biogeochemistry of the Hudson Bay lowland

绝大多数关于泥炭地和地表水质量的研究都是在小型集水区进行的，通常具有高度简化的水平衡，这当然适用于泥炭地在汞的命运和运输中的作用的调查。我们对小泥炭地中汞循环的认识是基于过程的，但没有人试图将其扩展到世界上更大的泥炭地系统中。哈德逊湾低地（HBL）是世界上第二大连续泥炭地，总面积约32万平方公里，是世界上任何地方因气候变化而遭受年平均气温上升最显著的地区。缺乏面向过程的水文和水质数据意味着，气候变化对HBL泥炭地水文和生物地球化学过程的潜在巨大影响以及随后对汞循环的变化是未知的。鉴于汞循环对北方生态系统和社区的重要性，这是一个重大的知识缺口。通过对HBL南部断续带和北部连续冻土带的水文和汞生物地球化学研究，我希望：1)阐明HBL泥炭地对哈德逊/詹姆斯湾主要支流的水收支、总汞（THg）和甲基汞（MeHg）的贡献；2)在不同的地面冰条件下，对HBL广泛的泥炭地中控制甲基汞生产和运输的过程进行机械洞察；3)将基于景观的泥炭地流域过程模型应用于HBL广泛的泥炭地流域。研究结果将为该地区的土地利用管理和北部社区提供重要指导，该地区正面临越来越大的资源开采压力，并为更北部河流的潜在水文和生物地球化学变化提供见解，因为气候变化开始影响永久冻土的范围。

The vast majority of research on peatlands and surface water quality has been done in small catchments, often with highly simplified water balances, and this certainly applies to investigations of the role of peatlands in mercury fate and transport. There have been no attempts to scale up the process-based knowledge that we have about Hg cycling in small peatlands to the larger extensive peatland systems of the world. The Hudson Bay Lowlands (HBL) is the second largest contiguous peatland in the world, with a total area of approximately 320 000 sq km. The HBL is in a region that is likely to be subjected to the most significant increases in annual average temperature due to climate change of anywhere in the world. The absence of process-oriented hydrological and water quality data means that the potentially dramatic impacts of a changing climate on the hydrological and biogeochemical processes of the peatlands of the HBL and the subsequent changes to the mercury cycle are unknown. Given the importance of the mercury cycle to northern ecosystems and communities, this is a significant knowledge gap. By undertaking research on the hydrology and mercury biogeochemistry in both the southern discontinuous and northern continuous permafrost zones of the HBL, I hope to: 1) elucidate the contributions of the HBL peatlands to the budget of water, total mercury (THg) and methylmercury (MeHg) of major tributaries of Hudson/James Bay; 2) gain mechanistic insight into the processes that control MeHg production and transport in the extensive peatlands of the HBL with varying ground ice conditions, and; 3) apply a landscape-based model of peatland-watershed processes to the extensive peatland watersheds of the HBL. Research findings will provide important guidance for land-use management and northern communities in a region that is coming under increasing pressure for resource extraction, and offer insights into the potential hydrological and biogeochemical alterations of the more northern rivers as climate change begins to impact the extent of permafrost.