Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Lakes (3)
- Phosphorus (3)
- Climate change (2)
- Eutrophication (2)
- Nitrogen (2)
-
- Nutrients (2)
- Rivers (2)
- Surface water (2)
- Acesulfame (1)
- Algae (1)
- Anthropogenic climate change (1)
- Artificial sweetener (1)
- Bedload (1)
- Borehole heat exchanger (1)
- Borehole thermal energy storage (1)
- Braiding (1)
- C-Q relationships (1)
- Carbon (1)
- Catchment (1)
- Cellular automata (1)
- Chlorinated solvents (1)
- Climate (1)
- Climate Change (1)
- Climate warming (1)
- Convective precipitation (1)
- Dehalococcoides spp. (1)
- Diatoms (1)
- Ecosystem health (1)
- Enhanced bioremediation (1)
- Extreme precipitation (1)
- Publication Year
- Publication
- Publication Type
Articles 1 - 15 of 15
Full-Text Articles in Earth Sciences
The Impacts Of Mid-Holocene Warming On Water Quality In A Southwestern Ontario Kettle Pond, Morgan E. Peicheff
The Impacts Of Mid-Holocene Warming On Water Quality In A Southwestern Ontario Kettle Pond, Morgan E. Peicheff
Undergraduate Student Research Internships Conference
No abstract provided.
Spatial And Temporal Variation Of Nutrients In The Great Lakes-St. Lawrence Basin: Implications For Primary Production In Stream Ecosystems, Nolan Pearce
Electronic Thesis and Dissertation Repository
Growing human populations and associated land use activities has increased the amount of nutrients delivered to surface waters. Eutrophication from the over-enrichment of nitrogen and phosphorus has degraded ecosystem conditions in streams, lakes, and coastal areas worldwide. Thus, the management of anthropogenic nutrient loading is a global concern. This thesis employed a combination of field and experimental research to provide watershed managers with information on the spatial and temporal patterns in stream nutrient enrichment, and the associated ecological effects of anthropogenic nutrient loading in the Great Lakes-St. Lawrence basin. Four studies were completed to address this research goal. First, I …
Quantification Of Septic System Contribution To Nutrient Loads In Surface Waters, Archana Tamang
Quantification Of Septic System Contribution To Nutrient Loads In Surface Waters, Archana Tamang
Electronic Thesis and Dissertation Repository
Freshwater systems worldwide are threatened by excessive nutrient (nitrogen and phosphorus) loading. This study evaluated the contribution of septic systems to stream nutrient loads in nine subwatersheds. Stream sampling was conducted during low and high discharge conditions, with samples analyzed for total phosphorus (TP), soluble reactive phosphorus (SRP), nitrate (NO3-N), and acesulfame (ACE; wastewater tracer). Higher septic effluent reached the subwatershed outlets during high discharge conditions. Subwatersheds with newer households had a lower percentage of septic effluent reaching the stream compared with subwatersheds with older households. Seasonal and event-based ACE concentration-discharge relationships revealed that the hydrological pathways delivering …
The Variability In The Morphological Active Width: Results From Physical Models Of Gravel‐Bed Braided Rivers, Sarah Peirce, Pauline Leduc, Peter Ashmore
The Variability In The Morphological Active Width: Results From Physical Models Of Gravel‐Bed Braided Rivers, Sarah Peirce, Pauline Leduc, Peter Ashmore
Geography & Environment Publications
The morphological active width, defined as the lateral extent of bed-material displacement over time, is a fundamental parameter in multi-threaded gravel-bed rivers, linking complex channel dynamics to bedload transport. Here, results are presented from 5 constant discharge experiments, and three event hydrographs, covering a range of flow strengths and channel configurations for which morphological change, bedload transport rates, and stream power were measured in a physical model. Changes in channel morphology were determined via differencing of photogrammetrically-derived digital elevation models (DEMs) of the model surface generated at regular intervals over the course of ~115 hours of experimental runs. Independent measures …
Expanding The "Active Layer", Peter Ashmore, Sarah Peirce, Pauline Leduc
Expanding The "Active Layer", Peter Ashmore, Sarah Peirce, Pauline Leduc
Geography & Environment Publications
Church and Haschenburger (2017) make helpful distinctions around the issue of defining the active layer, with which we agree. We propose expanding discussion and definition of the ”active layer” in fluvial bedload transport to include the concept of the “morphological active layer”. This is particularly applicable to laterally unstable rivers (such as braided rivers) in which progressive morphological change over short time periods is the process by which much of the bedload transport occurs. The morphological active layer is also distinguished by variable lateral and longitudinal extent continuity over a range of flows and transport intensity. We suggest that the …
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 …
Channel Form And Processes In A Formerly Glaciated Terrain, Nathaniel Bergman
Channel Form And Processes In A Formerly Glaciated Terrain, Nathaniel Bergman
Electronic Thesis and Dissertation Repository
Despite that many places around the world in general, and North America in particular, were glaciated during the last ice age, relatively little is known about rivers that evolved over these landscapes once they deglaciated. These rivers are commonly categorized as alluvial with a glacial legacy, and often described as plain gravel-bed or sand-bed rivers. Alternatively, they are considered to be bedrock rivers when the glacial deposits were eroded and underlying rock was exposed. However, ignoring the glacial history of these rivers is scientifically wrong and they should be termed "semi-alluvial". This work shows that classification is important, not only …
Proportions Of Convective And Stratiform Precipitation Revealed In Water Isotope Ratios, Pradeep K. Aggarwal, Ulrike Romatschke, Luis Araguas-Araguas, Dagnachew Belachew, Fred J. Longstaffe, Peter Berg, Courtney Schumacher, Aaron Funk
Proportions Of Convective And Stratiform Precipitation Revealed In Water Isotope Ratios, Pradeep K. Aggarwal, Ulrike Romatschke, Luis Araguas-Araguas, Dagnachew Belachew, Fred J. Longstaffe, Peter Berg, Courtney Schumacher, Aaron Funk
Earth Sciences Publications
Tropical and midlatitude precipitation is fundamentally of two types, spatially-limited and high-intensity convective or widespread and lower-intensity stratiform, owing to differences in vertical air motions and microphysical processes governing rain formation. These processes are difficult to observe or model and precipitation partitioning into rain types is critical for understanding how the water cycle responds to climate changes. Here, we combine two independent data sets – convective and stratiform precipitation fractions, derived from the Tropical Rainfall Measuring Mission satellite or synoptic cloud observations, and stable isotope and tritium compositions of surface precipitation, derived from a global network – to show that …
Field Scale Application Of Nanoscale Zero Valent Iron: Mobility, Contaminant Degradation, And Impact On Microbial Communities, Chris M.D. Kocur
Field Scale Application Of Nanoscale Zero Valent Iron: Mobility, Contaminant Degradation, And Impact On Microbial Communities, Chris M.D. Kocur
Electronic Thesis and Dissertation Repository
This thesis began by verifying that nanoscale zero valent iron (nZVI) synthesis methods could be scaled up and implemented at the field scale in a safe manner. This led to successful demonstration of nZVI injection and mobility under constant head gravity injection into a contaminated utility corridor in Sarnia, Ontario. Where field studies have fallen short in the past was linking the somewhat qualitative field geochemical parameters to other evidence of nZVI transport. Definitive nZVI detection was elusive in previous field studies due to the highly reactive nature of the particles caused by their high surface area. nZVI was detected …
Exploration Of Spatial And Temporal Changes In Trophic Status Of Lakes In The Northern Temporal Forest Biome Using Remote Sensing, Aleksey Paltsev
Exploration Of Spatial And Temporal Changes In Trophic Status Of Lakes In The Northern Temporal Forest Biome Using Remote Sensing, Aleksey Paltsev
Electronic Thesis and Dissertation Repository
There is a critical need for detailed surveys of lakes covering large spatial (>100 km2) and temporal scales (decades) to determine if there is an increase in the magnitude and frequency of phytoplankton blooms. Remote sensing was used to: (1) develop a regression model that relates chlorophyll a (chl-a) as a proxy of lake phytoplankton biomass to Landsat TM and ETM+ optical reflectance (r2=0.85, p
Runoff Generation In A Tropical Dry Forest Watershed: Processes, Patterns And Connectivity, Kegan K. Farrick
Runoff Generation In A Tropical Dry Forest Watershed: Processes, Patterns And Connectivity, Kegan K. Farrick
Electronic Thesis and Dissertation Repository
The lack of understanding regarding the controls that govern runoff generation in tropical dry forests represent a critical gap in the hillslope and catchment hydrology literature. Tropical dry forests account for approximately 42% of the global tropical forests, but represent less than 1% of the forest hydrology literature. Three complementary studies were undertaken in a small tropical dry forest watershed, Mexico, to assess the controls that govern the retention and release of a rainfall in the catchment as runoff. In the first study, the high soil surface hydraulic conductivities, absence of a water repellent surface and low rainfall intensities during …
Hydrogeological And Thermal Sustainability Of Geothermal Borehole Heat Exchangers, S. Emad Dehkordi
Hydrogeological And Thermal Sustainability Of Geothermal Borehole Heat Exchangers, S. Emad Dehkordi
Electronic Thesis and Dissertation Repository
Assessment of the current approach taken by guidelines and design methods of vertical closed loop heat exchangers shows that often groundwater flow is either disregarded or is not methodically incorporated. The state of scientific research in this arena reveals that overlooking the groundwater flow in the design procedure may not always be a correct assumption. The significance of advective heat transport compared to conduction is defined by the groundwater flux or Darcy velocity which heavily depends on the hydraulic conductivity of the ground, followed by the hydraulic gradient which has a relatively limited range. A sensitivity analysis on ground and …
Topographic Influences On Trends And Cycles In Nutrient Export From Forested Catchments On The Precambrian Shield, Samson G. Mengistu
Topographic Influences On Trends And Cycles In Nutrient Export From Forested Catchments On The Precambrian Shield, Samson G. Mengistu
Electronic Thesis and Dissertation Repository
This dissertation explored topographic controls on spatial and temporal patterns in water yield and nutrient (carbon, nitrogen and phosphorus) export from forested headwater catchments in the Turkey Lakes Watershed in central Ontario, where other factors contributing to differences in water yield and nutrient export, including climate, geology, forest, and soils, are relatively constant. Topographic characteristics, including (a) hydrological flushing potential (expansion of water table into nitrate-N producing areas); (b) hydrological storage potential (area of wetlands, which can alternatively allow water and nutrients to bypass wetlands when storage capacity is filled with water or to trap them when not filled); and …
Coupled Heat And Water Transport In Frozen Soils, Ranjeet M. Nagare
Coupled Heat And Water Transport In Frozen Soils, Ranjeet M. Nagare
Electronic Thesis and Dissertation Repository
The effect of freezing on soil temperature and water redistribution was examined in four Mesocosms maintained at different initial water content profiles. An innovative experimental setup involving use of a frozen base layer acting as a proxy to permafrost beneath an active layer made up of packed and undisturbed peat cores was used. The experimental setup was successfully validated for its ability to maintain one dimensional change in temperature and soil water content in frozen soil. There was a substantial amount of water redistribution towards the freezing front, enough to create an impermeable frozen, saturated zone within 15 cm of …
Uncertainty Estimation Of Extreme Precipitations Under Climate Change: A Non-Parametric Approach, Tarana A. Solaiman
Uncertainty Estimation Of Extreme Precipitations Under Climate Change: A Non-Parametric Approach, Tarana A. Solaiman
Electronic Thesis and Dissertation Repository
Assessment of climate change impacts on hydrology at watershed scale incorporates (a) downscaling of global scale climatic variables into local scale hydrologic variables and (b) assessment of future hydrologic extremes. Atmosphere-Ocean Global Climate Models (AOGCM) are designed to simulate time series of future climate responses accounting for human induced green house gas emissions. The present study addresses the following limitations of climate change impact research: (i) limited availability of observed historical information; (ii) limited research on the detection of changes in hydrologic extremes; and (iii) coarse spatio-temporal resolution of AOGCMs for use at regional or local scale. Downscaled output from …