Skip To Content

Patterson Lake


View Larger Map

Location

Rossburn MB
Canada

Patterson Lake


View Larger Map

Location

Division No. 18 SK
Canada

Climate cycles drive aquatic ecologic changes in the Fort McMurray region of northern Alberta, Canada


Year: 2015

Abstract:
Understanding ecologic response to climate cycles will aid in defining current and future ecological changes associated with climate change and allow for a differentiation between climate-driven versus anthropogenic driven environmental stresses. The paleoecological record from a northern Canadian lake located 40 km east of the Athabasca Oil Sands operation records a benthic stress-induced ecological response to climate cycles such as the El Niño Southern Oscillation (ENSO), the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO). Arcellacea (testate lobose amoebae) preserved in a freeze core obtained from “ALE”, an upland lake in Northeastern Alberta, Canada, were used to reconstruct climate and associated benthic response since 1875 A.D. ALE is situated in a boreal wetland environment where inorganic sediment delivery is overwhelmingly dominated by surface overland flow transport during spring melt. Arcellacea are benthic protists that are excellent indicators of aquatic ecology. Relationships between arcellacean family groupings which represent either healthy or stressed environmental conditions were compared to instrumental climate indices. Modeling using wavelet analysis identified strong ENSO cycles in all arcellacean proxies and weaker PDO cycles in only the healthy ecosystem indicator. The ENSO phenomenon in the tropical Pacific Ocean drives the largest interannual variation in climate across western Canada, and in the study region has been associated with fluctuations in winter precipitation and temperature. The healthy ecosystem indicators decreased in response to positive El Niño and PDO conditions, which are characteristic of decreased precipitation and therefore nutrient input to boreal lakes. The relationship between arcellaceans and climate anomalies shows that climate driven variations in nutrient input influence boreal aquatic ecology. The link between aquatic ecology and climate has significant implications on oil sands risk assessment and the determination of reclamation endpoints.

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.

Relationship between ecological indicators (Arcellacea) total mercury concentrations and grain size in lakes within the Athabasca oil sands region, Alberta


Year: 2014

Abstract:
Industrial mercury (Hg) sources associated with the processing of Athabasca oil sands (AOS), Alberta, Canada, may pose an environmental risk to nearby water bodies via either waterborne or airborne transport. Using a dataset derived from 63 lakes in the area, this study investigates the relationships between total-Hg (THg), organic matter, grain size, and lake ecology as measured by environmentally sensitive arcellacean (testate lobose amoebae) communities. The lakes studied include 59 lakes within a 75 km radius of the operations, plus four distal lakes ~150 km from the main industrial operations. Hg transport to the lakes is primarily through airborne pathways. The four distal lakes in the Peace–Athabasca Delta (~150 km downstream of the AOS operations) were examined to determine if the operation is emitting potential waterborne inputs, in addition to airborne inputs, and to identify any associated impact to those ecosystems. Total mercury in lakes close to the AOS were similar to values recorded in lakes farthest away. THg was most closely linked to the silt fraction, suggesting much of the Hg in these lakes is minerogenic in origin, either adsorbed and/or lattice-bound. THg is not statistically related to organic matter as has been observed in other Canadian lakes. The ecologic response to THg levels was investigated via the distribution of key indicator species and, or species diversity (Shannon diversity index). The spatial extent of arcellacean ecosystem stress in the study lakes did not correlate with THg concentrations. This is perhaps due to the generally low THg levels found in these lakes, all except one had THg concentrations lower than current CCME guidelines. While these findings may rule out any direct link between THg concentrations in the lakes and observed Arcellacea faunas, ecosystem stress unrelated to THg was observed northeast of the AOS, which warrants further examination. The results of this research suggest that the natural lake arcellacean faunas in the region are not being significantly impacted by current THg concentrations.

Relationship between ecological indicators (Arcellacea), total mercury concentrations and grain size in lakes within the Athabasca oil sands region, Alberta


Year: 2014

Abstract:
Industrial mercury (Hg) sources associated with the processing of Athabasca oil sands (AOS), Alberta, Canada, may pose an environmental risk to nearby water bodies via either waterborne or airborne transport. Using a dataset derived from 63 lakes in the area, this study investigates the relationships between total-Hg (THg), organic matter, grain size, and lake ecology as measured by environmentally sensitive arcellacean (testate lobose amoebae) communities. The lakes studied include 59 lakes within a 75 km radius of the operations, plus four distal lakes ~150 km from the main industrial operations. Hg transport to the lakes is primarily through airborne pathways. The four distal lakes in the Peace–Athabasca Delta (~150 km downstream of the AOS operations) were examined to determine if the operation is emitting potential waterborne inputs, in addition to airborne inputs, and to identify any associated impact to those ecosystems. Total mercury in lakes close to the AOS were similar to values recorded in lakes farthest away. THg was most closely linked to the silt fraction, suggesting much of the Hg in these lakes is minerogenic in origin, either adsorbed and/or lattice-bound. THg is not statistically related to organic matter as has been observed in other Canadian lakes. The ecologic response to THg levels was investigated via the distribution of key indicator species and, or species diversity (Shannon diversity index). The spatial extent of arcellacean ecosystem stress in the study lakes did not correlate with THg concentrations. This is perhaps due to the generally low THg levels found in these lakes, all except one had THg concentrations lower than current CCME guidelines. While these findings may rule out any direct link between THg concentrations in the lakes and observed Arcellacea faunas, ecosystem stress unrelated to THg was observed northeast of the AOS, which warrants further examination. The results of this research suggest that the natural lake arcellacean faunas in the region are not being significantly impacted by current THg concentrations.