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Articles 1 - 4 of 4
Full-Text Articles in Physical Sciences and Mathematics
Paleolimnological Reconstruction Of Hydrologic Change In The Slave River And Great Slave Lake During The Past Millennium, Matthew Ennis
Paleolimnological Reconstruction Of Hydrologic Change In The Slave River And Great Slave Lake During The Past Millennium, Matthew Ennis
Theses and Dissertations (Comprehensive)
The Slave River Delta (SRD), NWT, represents a pivotal node in the upper Mackenzie Basin watershed and is a productive northern wetland landscape with a rich natural and cultural heritage. Concerns over environmental consequences of natural and anthropogenic-driven decline in river discharge as well as climate variability have prompted hydroecological sstudies to improve understanding of how this ecosystem functions over time and space. However, long-term natural hydrological variability of the Slave River system is not well documented and needs to be further developed. In order to provide a temperal context for understanding and evaluating the impacts of climate variability and …
Spatial And Temporal Patterns In Nitrous Oxide Flux From Agricultural Soil In Southern Ontario, Michelle E. Zurbrigg
Spatial And Temporal Patterns In Nitrous Oxide Flux From Agricultural Soil In Southern Ontario, Michelle E. Zurbrigg
Theses and Dissertations (Comprehensive)
This research examines spatial and temporal variations in N2O flux from agricultural clay loam in corn-wheat and corn-oat rotations in southern Ontario. Gas samples are collected by the chamber method following significant precipitation events, thaw events, fertilization events, and otherwise every two weeks over a two-year period. Crop type appears to influence the magnitude of N2O emisions, whereas N2O fluxes do not otherwise seem to vary by landscape position. The seasonal pattern of in situ N2O flux at Strawberry Creek (SC) indicates that the highest N2O emissions are occuring during …
Plant Isotopes As Indicators Of N Cycling Processes In Agricultural Fields, Eric Thuss
Plant Isotopes As Indicators Of N Cycling Processes In Agricultural Fields, Eric Thuss
Theses and Dissertations (Comprehensive)
When nitrogen (N) availability exceeds biological demand, excess N, especially nitrate (NO3), may subsequently pollute ground and surface water. Agricultural practices in Southern Ontario typically supplement soils with organic and inorganic nutrients to aid in crop development, and employ various management techniques to limit nutrient loss. Excess N has several potential fates, which are controlled by the net effects of numerous N cycling reactions in the soil that are often difficult to measure directly. N cycling in soils is controlled in large part by soil moisture, as it affects microbial activity and soil redox conditions. Stable isotope geochemistry …
Carbon Dioxide Exchange In A Permafrost-Dominated Boreal Wetland In The Northwest Territories, Canada, Andrea J. Kenward
Carbon Dioxide Exchange In A Permafrost-Dominated Boreal Wetland In The Northwest Territories, Canada, Andrea J. Kenward
Theses and Dissertations (Comprehensive)
Northern boreal wetland complexes are substantial reservoirs for carbon and play a crucial role in both regional and global carbon budgets but they are showing significant signs of impact by climate change. This study examined the carbon dioxide flux of a high boreal wetland during the snowmelt and growing season of 2008 in Scotty Creek Basin, located near Fort Simpson (61°18'N, 121°18'W), Northwest Territories. This basin is not only responding to shifts in atmospheric temperatures, but it is also under additional pressure from increasing permafrost degradation. A dynamic closed-system chamber was used to monitor and quantify mid-day total respiration (R …