Physical Sciences and Mathematics Commons^™

Rethinking Holocene Ecological Relationships Among Caribou, Muskoxen, And Human Hunters On Banks Island, Nwt, Canada: A Stable Isotope Approach, Jordon S. Munizzi

Electronic Thesis and Dissertation Repository

This dissertation explores the ecology of caribou (Rangifer tarandus spp.) and muskoxen (Ovibos moschatus), and its relevance to human hunters on Banks Island, NWT, Canada, over the last 4000 years, primarily through the isotopic analysis of modern and archaeological faunal remains.

First, we establish baseline carbon and nitrogen isotope relationships between modern vegetation and caribou and muskox bone collagen using Bayesian mixing models. The models indicate that dwarf shrub (Salix arctica) does not contribute significantly to bone collagen isotopic compositions in either species, while sedges and yellow lichen (Cetraria tilesii) do. These findings …

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 (SO₄^2-) to peatlands increases methylmercury (MeHg) concentrations in pore waters via microbial methylation. Less information exists about the effects of different concentrations and sources of SO₄^2- loading on MeHg production in remote, non- SO₄^2- impacted regions like Canada’s north, where increased SO₄^2- 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 SO₄^{2- …}

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 …