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Full-Text Articles in Physical Sciences and Mathematics
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 …
Climatic Controls On The Porewater Chemistry Of Mid-Continental Wetlands, Zeno Francis Levy
Climatic Controls On The Porewater Chemistry Of Mid-Continental Wetlands, Zeno Francis Levy
Dissertations - ALL
Wetlands develop where climate and physiography conspire to maintain saturated soils at the land surface, support diverse plant and animal communities, and serve as globally important sinks for atmospheric carbon. The chemistry of wetland porewaters impacts near-surface biological communities and subsurface biogeochemical processes that influence carbon cycling in the environment. Wetland porewater chemistry is a dynamic byproduct of complex hydrogeological processes that cause meteoric waters to enter groundwater systems (recharge) or groundwater to flow to the land surface (discharge). Changes in climate can alter subsurface hydraulic gradients that determine the recharge and discharge functions of wetlands, which in turn control …
Impact Of Linear Disturbances On A Discontinuous Permafrost Peatland Environment, Michael Braverman
Impact Of Linear Disturbances On A Discontinuous Permafrost Peatland Environment, Michael Braverman
Theses and Dissertations (Comprehensive)
Permafrost is ground that remains at or below 0°C for at least two consecutive years (PIWP, 2012). In the continuous permafrost zone its thickness may exceed 300 m, in lower latitudes, permafrost thickness is progressively decreasing, its occurrence becomes discontinuous and eventually sporadic (PIWP, 2012). At the southern fringe of permafrost in northwestern Canada, just about few meters. In subarctic peatlands permafrost is one of the main elements governing the hydrological processes. Being very thin and with temperature just fractions of the degree below 0oC, it is very vulnerable to any changes in soil temperature and water content. …
Permafrost Thaw Induced Changes To Runoff Generation And Hydrologic Connectivity In Low-Relief, Discontinuous Permafrost Terrains, Ryan Connon
Theses and Dissertations (Comprehensive)
Recent climate warming in northwestern Canada is occurring at an unprecedented rate in recorded history and has resulted in the widespread thaw of permafrost. Where present, permafrost exerts a significant control on local hydrology, and disappearance of permafrost threatens to change the hydrology of northern basins. In the peatlands that characterise the southern distribution of permafrost in low relief terrain, permafrost takes the form of forested peat plateaus and is interspersed by permafrost-free wetlands (i.e. channel fens and flat bogs). Previous field studies have found that channel fens serve as the drainage network and route water to the basin …