Electronic Thesis and Dissertation Repository

Degree

Master of Science

Program

Geology

Supervisor

Dr. Brian Branfireun

Abstract

The Hudson-James Bay Lowlands are the second largest peatland dominated area on the planet, and are expected to be particularly vulnerable to future climate change. Changes in climate will affect peatland hydrology and biogeochemistry, impacting the aquatic ecosystems this region supports, however there is limited information about the hydrology and biogeochemistry of this landscape under current conditions. This thesis focuses on assessing the nature of hydrological and biogeochemical connectivity between a fen and 2nd order channel in the Central James Bay Lowland, Ontario. Specifically the study focuses on the role of preferential hydrological flowpaths in the riparian area, such as soil pipes and rivulets. We used water table-discharge relationships to examine the nature of hydrological connectivity between the fen and riparian area and identified thresholds of hydrological connectivity using these relationships. Once the storage thresholds in the near stream depression and fen have been met, peak flow can be generated in the soil pipes and rivulets, this occurs under wet antecedent conditions late in the fall. The study also identified that the riparian area is a likely dominant source of DOC and MeHg despite the extensive peatlands that dominate the upslope region, and that this area has a unique chemical signature from the fen. Furthermore late fall storm events with wet antecedent conditions were found to play an important role in solute transport from the soil pipes, with as much as >60% of the total solute load for one soil pipe occurring during a storm event which had a duration of only 17% of the monitoring period.

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