<p> Cost data from different marine and pipeline scenarios were analyzed under changing world oil price and discount assumptions to determine a minimum economic scale for Beaufort Sea - Mackenzie Delta hydrocarbon development. Environmental and socio-economic impacts were included to supplement the purely economic analysis. </p> <p> The minimum economic scale project, a sixteen-inch pipeline through the Mackenzie Valley, was found to be marginally economic. When environmental and social costs were assumed to be internalized by the companies involved, and federal government exploration and development incentives disregarded, the minimum scale project was found to yield a negative internal rate of return. </p> / Thesis / Bachelor of Arts (BA)

No description available.

The main objective of this study was to describe the overflow of freshwater onto the sea ice surface in the Mackenzie Delta and to investigate the hydraulic behaviour of the upwelling and strudel events. This study was performed from the analysis of data collected during field investigations, from satellite images and from experimental laboratory studies. A forecasting method using the water level in the Mackenzie River was formulated to predict the overflow initiation about five days before its occurrence. The physical modelling of a strudel flow through a circular hole established a relation between the overflow depth and the discharge coefficient. Velocity measurements of the free-surface vortex using an Acoustic Doppler Velocimeter found that velocities at the vortexs core were influenced by its vorticity. Finally, predictions of maximum strudel scour, which are of great importance for the determination of burial depth of pipelines, were predicted from published impinging jet experiments. / Water Resources Engineering

Climate warming has the potential to alter the structure and function of Arctic ecosystems in ways that are not fully understood. Polygonal terrain is a widespread permafrost feature of Arctic landscapes that is likely to be impacted by warming ground temperatures. This is of particular relevance in the uplands in the Mackenzie Delta region, where high-centre ice wedge polygon fields comprise 10% of the terrestrial landscape, and mean annual ground temperatures have increased between 1 and 2°C over the last 40 years (Burn and Kokelj 2009). I used broad-scale airphoto analysis and fine-scale field studies to investigate the impacts and possible trajectories of ice wedge degradation in the upland tundra north of Inuvik, NWT. Field investigations were undertaken to characterize biotic and abiotic conditions and feedbacks in stable and degrading high-centre polygons. Field surveys were conducted along transects which crossed three polygon micropositions (centres, edges and troughs) and targeted a degradation sequence from stable troughs to ice wedge melt ponds. I measured surface microtopography, active layer depth, water depth, plant community composition, soil gravimetric moisture, late winter snow depth, and shallow annual ground temperatures. Field data showed that ice wedge degradation drove increases in soil moisture, standing water depth, ground surface collapse, ground temperature, and active layer thaw and snow pack compared to stable troughs. These changing abiotic conditions drove the shift from mesic upland tundra plant communities to unvegetated melt ponds. Interactions between abiotic and biotic factors in degrading troughs increase ground temperature and contribute to positive feedbacks for ice wedge degradation. Analysis of broad-scale factors affecting ice wedge degradation involved the mapping of high-centre polygon distribution across the study area and the distribution of ice wedge melt ponds using high-resolution aerial photographs from 2004. Recent changes in melt pond area were also mapped using imagery dating from 1972. Thermokarst activity in polygonal terrain adjacent to anthropogenic disturbances was also assessed. Polygon fields were more abundant and larger in the northern part of the study area, where ground temperature conditions were most favourable for ice wedge formation. Spatial variation in polygonal terrain density was also related to topography, drainage, and the distribution of lacustrine sediments. Melt pond mapping and assessment of thermokarst at anthropogenic disturbances showed that ice wedges at higher latitudes are more susceptible to degradation primarily because these areas are underlain by larger and more abundant ice wedges. Melt pond mapping confirmed that the polygonal fields north of 69.4°N have shown both large increases and decreases in area, and that polygons in the south have been relatively stable in recent decades. The increased thaw sensitivity of polygonal terrain at higher latitudes has implications for soil carbon dynamics, terrestrial ecosystems, and the planning and maintenance of infrastructure as air and ground temperatures continue to increase. / Graduate / 0329 / 0372 / 0388

No description available.

The Mackenzie Delta region of the Northwest Territories, Canada, has experienced rapid climate warming in the past century resulting in rapidly thawing permafrost in this region. This thesis examines spatial and temporal changes to sediment organic carbon and mercury flux in lakes from thermokarst regions by comparing sediment cores from lakes with and without retrogressive thaw slumps on their shorelines. We show that sediments from lakes with permafrost thaw slump development on their shorelines (slump lakes) had higher sedimentation rates as well as lower total Hg, methyl mercury (MeHg), and labile OC fractions when compared to lakes where thaw slumps were absent. Total Hg and MeHg concentrations in sediments were correlated with total organic carbon (TOC), S2 (labile algal-derived OC), and inferred chlorophyll a content, indicating an association between autochthonous organic carbon and Hg in these sediments. Correlations between mercury and S2 in these study lakes generally support the hypothesis that algal-derived materials correlate with Hg concentration in sediments. We observed higher S2 concentrations in reference lakes than in slump lakes, likely due to uninterrupted algal production, lower dilution by flux of inorganic matter, and possibly better anoxic preservation in reference lakes compared to slump lakes. It is evident that thaw slump development in this thermokarst region increases inorganic sedimentation in lakes, while decreasing concentrations of organic carbon and associated Hg and MeHg in sediments.

The Mackenzie Delta region of the Northwest Territories, Canada, has experienced rapid climate warming in the past century resulting in rapidly thawing permafrost in this region. This thesis examines spatial and temporal changes to sediment organic carbon and mercury flux in lakes from thermokarst regions by comparing sediment cores from lakes with and without retrogressive thaw slumps on their shorelines. We show that sediments from lakes with permafrost thaw slump development on their shorelines (slump lakes) had higher sedimentation rates as well as lower total Hg, methyl mercury (MeHg), and labile OC fractions when compared to lakes where thaw slumps were absent. Total Hg and MeHg concentrations in sediments were correlated with total organic carbon (TOC), S2 (labile algal-derived OC), and inferred chlorophyll a content, indicating an association between autochthonous organic carbon and Hg in these sediments. Correlations between mercury and S2 in these study lakes generally support the hypothesis that algal-derived materials correlate with Hg concentration in sediments. We observed higher S2 concentrations in reference lakes than in slump lakes, likely due to uninterrupted algal production, lower dilution by flux of inorganic matter, and possibly better anoxic preservation in reference lakes compared to slump lakes. It is evident that thaw slump development in this thermokarst region increases inorganic sedimentation in lakes, while decreasing concentrations of organic carbon and associated Hg and MeHg in sediments.

The Mackenzie Delta region of the Northwest Territories, Canada, has experienced rapid climate warming in the past century resulting in rapidly thawing permafrost in this region. This thesis examines spatial and temporal changes to sediment organic carbon and mercury flux in lakes from thermokarst regions by comparing sediment cores from lakes with and without retrogressive thaw slumps on their shorelines. We show that sediments from lakes with permafrost thaw slump development on their shorelines (slump lakes) had higher sedimentation rates as well as lower total Hg, methyl mercury (MeHg), and labile OC fractions when compared to lakes where thaw slumps were absent. Total Hg and MeHg concentrations in sediments were correlated with total organic carbon (TOC), S2 (labile algal-derived OC), and inferred chlorophyll a content, indicating an association between autochthonous organic carbon and Hg in these sediments. Correlations between mercury and S2 in these study lakes generally support the hypothesis that algal-derived materials correlate with Hg concentration in sediments. We observed higher S2 concentrations in reference lakes than in slump lakes, likely due to uninterrupted algal production, lower dilution by flux of inorganic matter, and possibly better anoxic preservation in reference lakes compared to slump lakes. It is evident that thaw slump development in this thermokarst region increases inorganic sedimentation in lakes, while decreasing concentrations of organic carbon and associated Hg and MeHg in sediments.

The Mackenzie Delta region of the Northwest Territories, Canada, has experienced rapid climate warming in the past century resulting in rapidly thawing permafrost in this region. This thesis examines spatial and temporal changes to sediment organic carbon and mercury flux in lakes from thermokarst regions by comparing sediment cores from lakes with and without retrogressive thaw slumps on their shorelines. We show that sediments from lakes with permafrost thaw slump development on their shorelines (slump lakes) had higher sedimentation rates as well as lower total Hg, methyl mercury (MeHg), and labile OC fractions when compared to lakes where thaw slumps were absent. Total Hg and MeHg concentrations in sediments were correlated with total organic carbon (TOC), S2 (labile algal-derived OC), and inferred chlorophyll a content, indicating an association between autochthonous organic carbon and Hg in these sediments. Correlations between mercury and S2 in these study lakes generally support the hypothesis that algal-derived materials correlate with Hg concentration in sediments. We observed higher S2 concentrations in reference lakes than in slump lakes, likely due to uninterrupted algal production, lower dilution by flux of inorganic matter, and possibly better anoxic preservation in reference lakes compared to slump lakes. It is evident that thaw slump development in this thermokarst region increases inorganic sedimentation in lakes, while decreasing concentrations of organic carbon and associated Hg and MeHg in sediments.

With the rising demand for fossil fuels, Northern Canada has seen an unprecedented increase in petrochemical development. These developments are often associated with emissions of PAHs, a group of hydrophobic organic contaminants that are known to be carcinogenic and otherwise harmful to humans. Due to their hydrophobic nature, PAHs tend to bind to organic matter and can be produced through both anthropogenic and natural processes, making them ubiquitous in the environment. Therefore, in addition to impacts from petrochemical developments, changes to climatic conditions, such as increased forest fire disturbance and primary production also have the potential to alter delivery of organic carbon (OC) and PAHs to ecosystems. However, very little is known as to how the combined stressors of climate change and petrochemical development may affect environmental deposition of these contaminants. The concentrations and composition of parent and alkyl PAHs were analysed in radiometrically-dated sediment cores from lakes with one of four different types of petrochemical development in their catchments: (1) in-situ oil sands extraction (Cold Lake, AB); (2) open-pit oil sands extraction (Fort McMurray, AB); (3) abandoned conventional natural gas exploration (Mackenzie Delta Uplands, NWT); and (4) conventional gas and oil extraction (Cameron Hills, NWT). PAH deposition to lake sediments was also compared to climate reconstructions using climate proxies (diatom assemblages, inferred chlorophyll a and its diagenetic products, and Rock Eval carbon fractions as well as %OC). PAH sources were differentiated between potential pyrogenic and petrogenic origin over a period that extends to pre-industrial times using ratios of specific PAHs that can be traced to their potential source. Sediment cores from Cold Lake, AB showed concentrations of the sum of alkyl PAHs greater than those of parent PAHs, while all other cores show the reverse trend. A comparison of the % change of PAH concentrations from pre-development to post-development sediments between the four regions, showed that the greatest increase in concentrations of PAHs occurred in the Athabasca oil sands region. PAH profiles in the conventional regions have been historically dominated by mixed sources (pyrogenic PAHs from general background atmospheric inputs and petrogenic PAHs from the surrounding hydrocarbon-rich soils). While cores from the Fort McMurray area show a clear shift from pyrogenic sources (primarily wood and coal burning) in earlier sediments to petrogenic sources in more modern sediments, and the Cold Lake cores show some shifting sources to those dominated by pyrogenic sources in modern sediments. Organic carbon was significantly correlated with the sum of parent PAHs in 2 out of the 6 NWT cores that were examined for climate change impacts, while all other PAH parameters (concentration and composition) do not correlate significantly with any of the climate proxies. Establishing background concentrations and sources of PAHs in aquatic ecosystems is essential for understanding the natural environmental variations in these contaminants. Moreover, as both petrochemical activity and impacts from climate change are predicted to intensify in the future, studies such as this one allow us to build a solid understanding of how PAH deposition to northern lakes has responded to the warming climate and whether PAHs have been altered as a result of petrochemical activity.