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Full-Text Articles in Physical Sciences and Mathematics
The Effects Of Legacy Sulphur Deposition On Methylmercury Production In Northern Peatlands; Geochemical And Biological Considerations, Jennifer L. Blythe
The Effects Of Legacy Sulphur Deposition On Methylmercury Production In Northern Peatlands; Geochemical And Biological Considerations, Jennifer L. Blythe
Electronic Thesis and Dissertation Repository
Mercury is a ubiquitous element with a complex geochemical cycle. Aquatic ecosystems such as wetland soils convert inorganic mercury to organic, neurotoxic methylmercury though the activity of sulphate-reducing bacteria (SRB). Sulphate stimulates the activity of SRB, and the production of methylmercury in these environments. My aim was to investigate the effect that legacy sulphate has on Hg methylation in northern peatlands through a laboratory sulphate addition experiment with differentially sulphate-exposed peats and a field study of peatlands subjected to different levels of sulphate. Results from the laboratory study indicate that peatlands in regions of higher atmospheric sulphate deposition show enhanced …
Linking Mining Wastewater Discharge To Methylmercury Production In A Sub-Arctic Peatland, Lauren E. Twible
Linking Mining Wastewater Discharge To Methylmercury Production In A Sub-Arctic Peatland, Lauren E. Twible
Electronic Thesis and Dissertation Repository
It is well established that the addition of sulphate (SO42-) to peatlands increases methylmercury (MeHg) concentrations in pore waters via microbial methylation. Less information exists about the effects of different concentrations and sources of SO42- loading on MeHg production in remote, non- SO42- impacted regions like Canada’s north, where increased SO42- loadings come not from the atmosphere, but often from mining waste water and rock tailings. A three year field study (two years of loading; one year of recovery) examined the effects of simulated wastewater (containing 27.2 mg/L SO42- …
Methylmercury Production In Two Northern Fen Peatlands, Mikhail J. Mack
Methylmercury Production In Two Northern Fen Peatlands, Mikhail J. Mack
Electronic Thesis and Dissertation Repository
Northern peatlands provide conditions favourable for sulphate reducing bacteria, microorganisms responsible for producing methylmercury, an aquatic pollutant. An expected climate driven shift from moss- to sedge-dominance may alter mercury biogeochemistry. Observations from a moss-dominated poor fen and sedge-dominated intermediate fen were used to compare methylmercury to assess if contrasting plant communities, nutrients status and/or hydrologic regime control production. Chapter 2 compared porewater methylmercury and ancillary chemistry across two Northern Ontario fens. The lower water table, greater dissolved organic carbon, and lower pH in the poor fen resulted in 3.1 times greater methylmercury. Chapter 3, riparian zones in intermediate fen were …
Peatland-Stream Hydrological And Biogeochemical Connectivity In The James Bay Lowland, Ontario, Meghan Kline
Peatland-Stream Hydrological And Biogeochemical Connectivity In The James Bay Lowland, Ontario, Meghan Kline
Electronic Thesis and Dissertation Repository
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 …
Hydrology And Biogeochemistry Of A Bog-Fen-Tributary Complex In The Hudson Bay Lowlands, Ontario, Canada, Thomas A. Ulanowski
Hydrology And Biogeochemistry Of A Bog-Fen-Tributary Complex In The Hudson Bay Lowlands, Ontario, Canada, Thomas A. Ulanowski
Electronic Thesis and Dissertation Repository
The Hudson Bay Lowlands (HBL) contains 26 Gt C sequestered in a 2 meter thick layer of peat which blankets a quarter of Ontario, Canada. The hydrological and chemical influence of the HBL peatlands to surface waters is recognized, but information on peatland runoff processes and the evolution of groundwater through this vast, carbon-rich landscape remain scant. This study focused on elucidating the groundwater flow patterns of a bog-fen-tributary complex in the central region of the HBL, and estimating exports of groundwater, dissolved organic carbon (DOC), total (THg), and methyl (MeHg) mercury during the 2011 ice-free season. Hydrometric data, combined …