Hydrology and mercury biogeochemistry of the Hudson Bay lowland

点击翻译按钮获取中文摘要

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.