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Campbell Lake


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Location

Strathcona BC
Canada

Campbell Lake


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Location

AB
Canada

Association of postfire peat accumulation and microtopography in boreal bogs


Year: 2005

Abstract:
Peatlands accumulate organic matter as peat because of disproportionate rates of production and decomposition. However, peat accumulation heterogeneity has not been well studied along the microtopographic gradient (hummocks vs. hollows), particularly with respect to fire. Fire affects peatland species composition by differentially removing vegetation and resetting succession, resulting in peat accumulation changes. We examined peat accumulation and microtopography in two historically burned bogs in Alberta, Canada. Measurements of current and historic microtopography were made, and cores were collected along the gradient to identify depth of peat accumulated since fire, as well as to assess properties of the accumulated peat. Current microtopography is significant and correlated with the immediate postfire surface relief. However, differences in the magnitude of variability between sites suggests that differential rates of growth between features are exacerbated between sites and reflected in bog microtopography. Rates of organic matter accumulation, ranging from 156 to 257 g.m^sup -2^.year^sup -1^, were elevated but comparable to published rates of recent accumulation. Organic matter content and accumulation rate were greater for hummocks than hollows at Athabasca bog, but the difference between features diminished at Sinkhole Lake, suggesting that the pattern and properties of peat accumulation and microtopography postfire may be attributable to differences in site conditions.

Correlation of the Campbell strandlines along the northwestern margin of glacial Lake Agassiz


Author(s): Rayburn, J. A.

Year: 1997

Abstract:
The Upper and Lower Campbell strandlines of glacial Lake Agassiz, were correlated from Dauphin, Manitoba northwestward toward the Clearwater River to determine if Lake Agassiz could have overflowed through a northwestern outlet at the Clearwater River into the Mackenzie River drainage basin. The results suggest that the Upper Campbell extended only as far as 350 km southeast of the Clearwater River Two lines of evidence suggest that waters of Upper Campbell-level Lake Agassiz were blocked from reaching the northwestern outlet. They are the termination of the Upper Campbell strandline on the northwestern side of the Wapawekka Hills, in north-central Saskatchewan, and a rapid rise in elevation of the Upper Campbell strandline from the southern side of the Hills to the northern side. The Lower Campbell beach, extends farther to the northwest, possibly reaching the northwestern outlet. A high-resolution differential GPS survey along the correlated Campbell strandlines has allowed the construction of isobases across the western side of the Lake Agassiz basin. The new isobase information indicates that there was more post-glacial rebound in the northwestern region than previously estimated. This reconstruction indicates that, immediately following deglaciation, the Clearwater Spillway may have been below the southern outlet of Lake Agassiz, and acted as a temporary outlet for the lake. It is concluded that the northern side of the Wapawekka Hills was the location of the Keewatin ice margin while the lake remained at the Upper Campbell level. Sometime after 9,350 BP, rapid ice retreat in the northwest exposed the northwestern outlet, allowing a rapid lowering of Lake Agassiz, and temporarily halting drainage through the Mississippi River system. Subsequent rapid isostatic rebound in the northwest would have raised the elevation of the northwestern outlet, causing its abandonment and reopening the southern outlet. (Abstract shortened by UMI.)

Mercury trends in colonial waterbird eggs downstream of the oil sands region of Alberta Canada


Year: 2013

Abstract:
Mercury levels were measured in colonial waterbird eggs collected from two sites in northern Alberta and one site in southern Alberta, Canada. Northern sites in the Peace-Athabasca Delta and Lake Athabasca were located in receiving waters of the Athabasca River which drains the oil sands industrial region north of Fort McMurray, Alberta. Temporal trends in egg mercury (Hg) levels were assessed as were egg stable nitrogen isotope values as an indicator of dietary change. In northern Alberta, California and Ring-billed Gulls exhibited statistically significant increases in egg Hg concentrations in 2012 compared to data from the earliest year of sampling. Hg levels in Caspian and Common Tern eggs showed a nonstatistically significant increase. In southern Alberta, Hg concentrations in California Gull eggs declined significantly through time. Bird dietary change was not responsible for any of these trends. Neither were egg Hg trends related to recent forest fires. Differences in egg Hg temporal trends between northern and southern Alberta combined with greater Hg levels in eggs from northern Alberta identified the likely importance of local Hg sources in regulating regional Hg trends. Hg concentrations in gull and Common Tern eggs were generally below generic thresholds associated with toxic effects in birds. However, in 2012, Hg levels in the majority of Caspian Tern eggs exceeded the lower toxicity threshold. Increasing Hg levels in eggs of multiple species nesting downstream of the oil sands region of northern Alberta warrant continued monitoring and research to further evaluate Hg trends and to conclusively identify sources.

Metals and polycyclic aromatic hydrocarbons in colonial waterbird eggs from Lake Athabasca and the Peace-Athabasca Delta Canada


Year: 2011

Abstract:
In 2009, aquatic bird eggs from a variety of species were collected from three sites in northern Alberta, Canada. Two sites were located in receiving waters of the Athabasca River, which drains the oil sands industrial region north of Fort McMurray, Alberta. The third site, located on the Peace River, was remote from the influence of the Athabasca River. Levels of mercury, arsenic, and polycyclic aromatic hydrocarbons (PAHs) were measured in the eggs along with nitrogen stable isotopes (δ¹⁵N) as an indicator of bird trophic position. Levels of As and PAHs in eggs were low, whereas Hg was measureable in all samples. Egg Hg levels increased with δ¹⁵N values (a proxy of food web trophic position); however, some eggs exhibited Hg levels greater than expected based on trophic position. These eggs were from sites in receiving waters of the Athabasca River, namely, Mamawi Lake and Egg Island. Levels of Hg in egg pools were correlated with naphthalene levels, perhaps indicating a common source of contamination. Temporal comparison of Hg levels in California gull (Larus californicus) eggs from the Lake Athabasca colony indicated that egg Hg burdens increased 40% from 1977 to 2009. More research is required to evaluate temporal trends in levels of environmental contaminants and to identify sources.

Risking rupture: Integral accidents and in/security in Canada's bitumen sands


Author(s): Greaves, W.

Year: 2013

Abstract:
The expansion of unconventional hydrocarbon development in Western Canada is one of the most contentious issues in contemporary Canadian politics. Although widely studied, little attention has been paid to the framing of Alberta's bitumen sands within distinct and incompatible discourses of energy and environmental security. This essay examines these discourses using the tools of securitization analysis, asking the basic questions of what each presents as needing to be secured, from what, and by what means. Presented with two sets of socially constructed in/ security claims related to the bitumen sands and proposed pipeline expansion, the author suggests the social theory of Paul Virilio provides a useful intervention into securitization analysis that allows the material implications of these discourses to be clarified and assessed. Drawing upon Virilio's critical account of technological progress and his theory of accidents, this essay proposes that conventional accounts of "energy security" in the bitumen sands cannot result in meaningful conditions of security because they remain premised upon continued and expanded hydrocarbon consumption in an era of anthropogenic climate change.