Year: 2024, 2024
Member of: Trent University Graduate Thesis Collection
Abstract: <p>A key knowledge gap in aeolian transport research concerns the adjustment of saltation processes to the extreme conditions found within high-latitude regions. A series of wind tunnel experiments were carried out under full climate control and over a wide range in humidity. Particle entrainment and transport within shearing flows of varied wind speed were monitored over beds of varied… more Year: 2024, 2024
Member of: Trent University Graduate Thesis Collection
Abstract: <p>This study examines the atmospheric (synoptic) controls on snowmelt and snow-free season carbon dioxide (CO2) fluxes at Daring Lake, Northwest Territories. Atmospheric circulation patterns were derived from 500 hPa geopotential height and classified using the self-organizing maps artificial neural network. Snowmelt timing was not found to be influenced by atmospheric circulation patterns… more Year: 2023, 2023
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): Brown, Rachel, Thesis advisor (ths): Aherne, Julian, Degree committee member (dgc): Koprivnjak, Jean-François, Degree committee member (dgc): Sager, Eric, Degree committee member (dgc): Lafleur, Peter, Degree granting institution (dgg): Trent University Abstract: <p>In this study, twenty lake catchments surrounding Iqaluit, Baffin Island, were assessed for trace element concentrations (Al, As, Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Sb, Se, THg, V, Zn) in lake water, catchment soil, lake sediment, and moss (Hylocomium splendens). Additionally, the sources of each trace element were determined through the positive matrix factorization (PMF) model and… more Year: 2023, 2023
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): Karl, Katrina Anna-Marie, Thesis advisor (ths): Aherne, Julian, Degree committee member (dgc): Sager, Eric, Degree committee member (dgc): Liang, Tanner, Degree committee member (dgc): Hickie, Brendan, Degree committee member (dgc): McKenna-Neuman, Cheryl, Degree granting institution (dgg): Trent University Abstract: <p>Plastic pollution is a growing concern, owing to its durability, ubiquity, and potential health impacts. The overall objective of this study was to assess the abundance and distribution of microplastics within Lake Scugog catchment, Ontario. This was fulfilled through two tasks (i) the development of a microplastic particle budget for the lake catchment, and (ii) the determination of the… more Year: 2023, 2023
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): Levasseur, Patrick, Thesis advisor (ths): Watmough, Shaun, Degree committee member (dgc): Aherne, Julian, Degree committee member (dgc): Sager, Eric, Degree committee member (dgc): Emilson, Erik, Degree granting institution (dgg): Trent University Abstract: <p>Mining and smelting degraded landscapes are characterised by heavily eroded soils that are acidic, contaminated with toxic metals, and depleted of essential nutrients. Regreening degraded landscapes has been proposed to support global carbon (C) mitigation measures and protect biodiversity. One of the world's largest regreening programs in the City of Greater Sudbury, Canada has… more Year: 2022, 2022
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Microplastics, plastic particles less than 5 mm in diameter, are ubiquitous in the environment. This study estimated the abundance of microplastics (MP) in atmospheric deposition from four background monitoring stations in Muskoka-Haliburton, south-central Ontario, Canada and quantified the fate of microplastics to three background headwater lake catchments in Muskoka-Haliburton.… more Year: 2022, 2022
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Maximum permitted SO2 emissions from an aluminum smelter in Kitimat, B.C., increased after modernization in 2015. An increase in acidic deposition can potentially acidify forest soils. Monitoring was conducted at two long-term soil monitoring plots at near (7 km) and far (41 km) sites downwind from the smelter. Change in soil properties was assessed between 2015 and 2018: for the near… more Year: 2022, 2022
Member of: Trent University Graduate Thesis Collection
Abstract: <p>The following study measured dissolved organic carbon (DOC) and total mercury (THg) concentrations in acid sensitive lakes in the Republic of Ireland. Sixty-eight upland lakes and 48 lowland lakes were sampled for DOC; the upland lakes were additionally sampled for THg. Spatial variability of DOC was explained by regional precipitation and soil organic matter. A subset of lakes was… more Year: 2021, 2021
Member of: Trent University Graduate Thesis Collection
Abstract: <p>The Hudson Bay region is a sensitive environment, where anthropogenic (e.g., dams, diversions, and/or reservoirs) impacts have increased in recent decades, potentially influencing the functioning of the ecosystem. Dissolved organic matter (DOM) entering Hudson Bay comes from both terrestrial (allochthonous) and aquatic (autochthonous) sources. The chemical composition of DOM is important… more Year: 2021, 2021
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): McDonough, Andrew Michael, Thesis advisor (ths): Watmough, Shaun A, Degree committee member (dgc): Aherne, Julian, Degree committee member (dgc): Hutchinson, Tom, Degree committee member (dgc): Sager, Eric, Degree granting institution (dgg): Trent University Abstract: <p>In this study we seek to better understand the potential effects of short-term (5-year) N fertilization on jack pine forest biogeochemistry, vascular plant community composition and to project a temporal endpoint of nitrogen leaching below the major rooting zone. Aqueous ammonium nitrate (NH4NO3) was applied above the forest canopy across five treatment plots (20 x 80 m) four times… more Year: 2020, 2020
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): LeGrand, Matthew Cody LeGros, Thesis advisor (ths): Buttle, James M, Thesis advisor (ths): Metcalfe, Robert A, Degree committee member (dgc): Lafleur, Peter M, Degree committee member (dgc): Aherne, Julian, Degree granting institution (dgg): Trent University Abstract: <p>Water balance models calculate water storage and movement within drainage basins, a primary concern for many hydrologists. A Thornthwaite water balance model (H2OBAAS) has shown poor accuracy in predicting low flows in the Petawawa River basin in Ontario, so lake storage and winter snow processes were investigated to improve the accuracy of the model. Lake storage coefficients,… more Year: 2020, 2020
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Anthropogenic atmospheric emissions and subsequent deposition of nitrogen (N) can affect N-sensitive habitats and lead to shifts in plant species community composition. This study assessed the effects of N deposition on plant community composition for Jack pine forests across northwestern Canada and across a smaller subset of sites surrounding the Athabasca Oil Sands Region (AOSR) using… more Year: 2020, 2020
Member of: Trent University Graduate Thesis Collection
Abstract: <p>This study examined dissolved organic matter (DOM) and labile Mercury (from diffusive gradient in thin films (DGT)) in the Quesnel river, British and the Goose creek tributary of the Churchill river, Manitoba. DOM properties were measured with optical measurements of absorption coefficient (a254), spectral slopes (S275-295, SR) and fluorescence indices (HIX, BIX, FI). The DOC proxy… more Year: 2020, 2020
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Soils play a crucial role in ecosystem functioning, for example, soil minerals provide important provisioning and regulate ecosystem services. This study used major soil oxides from the North American Soil Geochemical Landscapes Project (n=560) to assess elemental associations and infer soil minerals through exploratory data analysis and to determined quantitative soil mineralogy using a… more Year: 2019, 2019
Member of: Trent University Graduate Thesis Collection
Abstract: <p>The spatial and temporal variation in atmospheric nitrogen dioxide (NO2), ammonia (NH3), and 17 elements (V, Cr, Fe, Ni, Cu, Zn, As, Cd, Pb, Mg, Al, Ca, Co, Se, Sb, Mn, and Na) were measured at 40 road side locations along a ~250 km traffic density gradient of 40,000–400,000 vehicles on the King's Highway 401, in Ontario, Canada. Elemental concentrations were measured over a year,… more Year: 2019, 2019
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Soil is an essential natural resource that supports provisioning services such as agriculture, silviculture, and mining. However, there is limited knowledge on forest soil properties across Canada. Digital soil mapping may be used to fill these data gaps, as it can predict soil properties in areas with limited observations. The focus of this study was to develop predictive maps of select… more Year: 2019, 2019
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): Blanchard, Dane Alexander, Thesis advisor (ths): Aherne, Julian, Degree committee member (dgc): Watmough, Shaun, Degree committee member (dgc): Sager, Eric P.S., Degree committee member (dgc): McKenna Neuman, Cheryl L, Degree granting institution (dgg): Trent University Abstract: <p>Recent developments at an aluminum (Al) smelter in Kitimat, BC resulted in a permitted increase of 27 to 42 tonnes of sulphur dioxide (SO2) emissions per day. Gaseous SO2 is a pollutant known to contribute to acidic deposition through processes of wet and dry deposition and can additionally react in-atmosphere to form particulate sulphate (pSO42-). Between June 2017 to October 2018, an… more Year: 2019, 2019
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Microfibres, which are threadlike particles < 5 mm, are the most common type of microplastic reported in the environment. However, few studies have focused on their abundance in background natural environments. This study assessed the abundance of microfibres in rainfall samples (from four precipitation monitoring stations) and across three headwater lake catchments that were in… more Year: 2018, 2018
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): Levasseur, Patrick, Thesis advisor (ths): Watmough, Shaun, Degree committee member (dgc): Aherne, Julian, Degree committee member (dgc): Eimers, Catherine, Degree committee member (dgc): Whitfield, Colin, Degree granting institution (dgg): Trent University Abstract: <p>In 2012, the Rio Tinto aluminum smelter in Kitimat, British Columbia increased sulphur dioxide (SO2) emissions from 27 to 42 tonnes/day. An initial study was conducted to investigate the effect of the increased sulphur (S) deposition on forest soils. A key uncertainty of the initial study was mineral surface area estimations that were applied to critical load calculations. The current… more Year: 2018, 2018
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): Cowden, Phaedra, Thesis advisor (ths): Aherne, Julian, Degree committee member (dgc): Watmough, Shaun, Degree committee member (dgc): Sager, Eric, Degree committee member (dgc): Canners, Richard, Degree granting institution (dgg): Trent University Abstract: <p>Atmospheric pollutant deposition poses a risk to ecosystem health; therefore, monitoring the spatial and temporal trends of deposition is integral to environmental sustainability. Although moss biomonitoring is a common method to monitor various pollutants in Europe, offering a cost-effective approach compared to traditional methods of monitoring, it is rarely used in Canada. The focus… more Year: 2018, 2018
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Threats such as climate change and increased anthropogenic activity such as shipping, are expected to negatively affect the Arctic. Lack of data on Arctic systems restricts our current understanding of these sensitive systems and limits our ability to predict future impacts. Lakes and ponds are a major feature of the Arctic landscape and are recognized as 'sentinels of change… more Year: 2017, 2017
Member of: Trent University Graduate Thesis Collection
Abstract: <p>A catchment-based study was carried out at three remote acid sensitive Irish lakes to determine concentrations of Hg and POPs and to investigate the factors governing the partitioning of these pollutants in various environmental matrices. Both Hg and POPs are an environmental concern due to their ability to travel long distances via atmospheric transport and their tendency to accumulate… more Year: 2016, 2016
Member of: Trent University Graduate Thesis Collection
Abstract: <p>This study assesses the bioavailable metal (Cu, Ni, Zn, Pb) species in the Athabasca-Mackenzie watersheds using diffusive gradient in thin films (DGT) devices. Metal toxicity is not only based on the concentration of metal in natural waters, but also on the nature of metal species. Four main forms in aquatic systems are: free ion, inorganic species, DOM bound (humic) species and metal… more Year: 2015, 2015
Member of: Trent University Graduate Thesis Collection
Abstract: <p>The emission of acid precursors by large point sources in Western Canada</p><p>(such as the Athabasca Oil Sands Region) has prompted studies into the possible impact to downwind aquatic and terrestrial ecosystems. Sensitivity of catchments to acidic deposition was estimated for the total lake population of northern Saskatchewan (n=89,947) using regression kriging. Under the… more Year: 2015, 2015
Member of: Trent University Graduate Thesis Collection
Abstract: <p>(MRC) in central Ontario was carried out to determine the range and spatial distribution of soil Ca weathering rates, and investigate the relationships between lake Ca and soil and catchment attributes. The MRC is acid-sensitive, and has a long history of impacts from industrial emission sources in Ontario and the United States. Small headwater catchments were sampled for soil and… more Year: 2015, 2015
Member of: Trent University Graduate Thesis Collection
Abstract: <p>In this study, the influence of N deposition on the vegetation community of semi-natural oak woodlands in Ireland was assessed through national and regional scale analysis of forest plot data. At both scales, Canonical Correspondence Analysis suggested that N deposition was a predictor of community composition, although site-specific soil characteristics were the strongest predictors of… more Year: 2015, 2015
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): Celsie, Alena Kathryn Davidson, Thesis advisor (ths): Mackay, Donald, Thesis advisor (ths): Parnis, Mark, Degree committee member (dgc): Hickie, Brendan, Degree committee member (dgc): Mackay, Donald, Degree committee member (dgc): Parnis, Mark, Degree committee member (dgc): Aherne, Julian, Degree granting institution (dgg): Trent University Abstract: <p>Models of partitioning, uptake, and toxicity of neutral organic chemicals in fish</p><p>Alena Kathryn Davidson Celsie</p><p>A novel dynamic fugacity model is developed that simulates the uptake of chemicals in fish by respiration as applies in aquatic toxicity tests. A physiologically based toxicokinetic model was developed which calculates the time-course of… more Year: 2015, 2015
Member of: Trent University Graduate Thesis Collection
Abstract: <p>The reliability and performance of four passive sampler membrane coatings specific to nitrogen dioxide (NO2) were evaluated through co-exposure at multiple Ontario Ministry of Environment and Climate Change (OMOECC) active monitoring stations. All four coatings performed relatively similar under a wide range of meteorological conditions, notably showing exposure-specific atmospheric… more Year: 2015, 2015
Member of: Trent University Graduate Thesis Collection
Abstract: <p>Decreasing lake calcium (Ca) concentration, in lakes located in base poor</p><p>catchments of the Muskoka River Watershed (MRW) in south-central Ontario, is a well- established acid-rain driven legacy effect threatening the health and integrity of aquatic ecosystems that can be compounded by additional Ca removals through forest harvesting. The objectives of this thesis were… more Year: 2014, 2014
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): Johnson, James Anthony, Thesis advisor (ths): Aherne, Julian, Degree committee member (dgc): Watmough, Shaun A, Degree committee member (dgc): Huber, Christian, Degree committee member (dgc): Cummins, Thomas, Degree granting institution (dgg): Trent University Abstract: <p>The objective of this thesis was to assess the influence of anthropogenic sulphur (S) and nitrogen (N) deposition, and harvesting on soil acidity and calcium (Ca<super>2+</super>), magnesium (Mg<super>2+</super>), potassium (K<super>+</super>) and N soil pools in plantation forest soils in Ireland. The response to reductions in anthropogenic S… more Year: 2014, 2014
Member of: Trent University Graduate Thesis Collection
Name(s): Creator (cre): Balch, Jordan, Thesis advisor (ths): Gueguen, Celine, Degree committee member (dgc): Hickey, Brendan, Degree committee member (dgc): Thompson, Matthew, Degree committee member (dgc): Aherne, Julian, Degree granting institution (dgg): Trent University Abstract: <p>The efficacy of the diffusive gradients in thin films (DGT) passive samplers to provide accurate measurements of free metal ions and those complexed with dissolved organic matter (DOM) was investigated. DOM controls the diffusive properties of DOM-complexed metal species in natural systems. Knowing the diffusion coeiffiecent (D) for DOM of different molecular weights (MW) and the major… more
