scholarly journals Increased size and relative abundance of migratory fishes observed near the Athabasca oil sands

FACETS ◽  
2017 ◽  
Vol 2 (2) ◽  
pp. 833-858 ◽  
Author(s):  
Tim J. Arciszewski ◽  
Kelly R. Munkittrick ◽  
Bruce W. Kilgour ◽  
Heather M. Keith ◽  
Janice E. Linehan ◽  
...  
Keyword(s):  
Oil Sands ◽  
Cumulative Effect ◽  
Field Studies ◽  
White Sucker ◽  
Athabasca Oil Sands ◽  
Data Set ◽  
Arctic Grayling ◽  
Normal Ranges ◽  
The Status ◽  
Relative Abundances

Responses to chemical and physical stressors are commonly expected among organisms residing near the Athabasca oil sands. Physiological effects have been observed in fishes during field studies; but further effects associated with development are not clear or consistent among species. For instance, data from a fish fence in 2009 show declines in the relative abundances of some species, including Arctic grayling ( Thymallus arcticus). In contrast, increases were seen in white sucker ( Catostomus commersoni). This divergence suggests incomplete understanding of the status of fishes residing near the oil sands. However, an important challenge limiting understanding is the lack of reliable baseline or reference data. To overcome this challenge, we used iterative normal ranges and a historical data set (electrofishing surveys done from 1987 to 2014) to determine if changes have occurred in fishes captured in the lower Athabasca River. These analyses revealed clear increases in the lengths of white sucker and walleye ( Sander vitreus) and their relative abundances during the spawning season. The occurrence of these changes may be associated with overwintering location, but reduced fishing pressure in Lake Athabasca, eutrophication, or a cumulative effect may explain the form of changes detected in this study.

Micro and Macro-level Analysis of Crop Diversification: Evidence from an Agrarian State West Bengal

2020 ◽  
pp. 489-499
Keyword(s):  
Crop Production ◽  
West Bengal ◽  
Farming Systems ◽  
Field Studies ◽  
Farming System ◽  
Structure Questionnaire ◽  
Crop Diversification ◽  
The Status ◽  
Block Level ◽  
Diversified Farming Systems

The farming system in West Bengal is being shifted by integration between the set of cash crops and the main food harvest process. This change in diversified farming systems, where smallholders have a production base in rice can complement production; affect technical efficiency and farm performance. The goal of this study was to investigate the status of crop diversification on smallholders in West Bengal. First, crop diversification regions were developed in West Bengal based on the Herfindahl index, which were categorized into three regions. Three sample districts were studied separately at the block level, and 915 small farmers from 41 sample villages of 9 sample blocks were interviewed through a good structure questionnaire for field studies from the sample districts. West Bengal was gradually moving towards multiple crop production. Furthermore, increasing rice production reduced the marginal use of inputs for the production of other crops. Farming and other vital factors such as HYVs area to GCA, average holding size and per capita income in some districts of West Bengal can be identified as determinants of crop diversification.

scholarly journals The Effects of Plume Episodes on PAC Profiles in the Athabasca Oil Sands Region

2021 ◽  
pp. 117014
Author(s):  
Narumol Jariyasopit ◽  
Tom Harner ◽  
Cecilia Shin ◽  
Richard Park
Keyword(s):  
Oil Sands ◽  
Athabasca Oil Sands ◽  
Athabasca Oil Sands Region

scholarly journals Identifying Reservoir Features via iSOR Response Behaviour

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 427
Author(s):  
Jingyi Wang ◽  
Ian Gates
Keyword(s):  
Oil Sands ◽  
Gravity Drainage ◽  
Athabasca Oil Sands ◽  
Steam Chamber ◽  
Heterogeneous Reservoirs ◽  
Steam Assisted Gravity Drainage ◽  
Response Behaviour

To extract viscous bitumen from oil sands reservoirs, steam is injected into the formation to lower the bitumen’s viscosity enabling sufficient mobility for its production to the surface. Steam-assisted gravity drainage (SAGD) is the preferred process for Athabasca oil sands reservoirs but its performance suffers in heterogeneous reservoirs leading to an elevated steam-to-oil ratio (SOR) above that which would be observed in a clean oil sands reservoir. This implies that the SOR could be used as a signature to understand the nature of heterogeneities or other features in reservoirs. In the research reported here, the use of the SOR as a signal to provide information on the heterogeneity of the reservoir is explored. The analysis conducted on prototypical reservoirs reveals that the instantaneous SOR (iSOR) can be used to identify reservoir features. The results show that the iSOR profile exhibits specific signatures that can be used to identify when the steam chamber reaches the top of the formation, a lean zone, a top gas zone, and shale layers.

Surfactants in Athabasca Oil Sands Slurry Conditioning, Flotation Recovery, and Tailings Processes

Surfactants ◽  
2000 ◽  
pp. 365-430 ◽  
Author(s):  
Laurier L. Schramm ◽  
Elaine N. Stasiuk ◽  
Mike MacKinnon
Keyword(s):  
Oil Sands ◽  
Athabasca Oil Sands ◽  
Flotation Recovery

Syndepositional architecture of the northern Athabasca Oil Sands Deposit, northeastern Alberta

2015 ◽  
Vol 52 (1) ◽  
pp. 21-50 ◽  
Author(s):  
Paul L. Broughton
Keyword(s):  
Oil Sands ◽  
Linear Chain ◽  
Upper Devonian ◽  
Karst Collapse ◽  
Athabasca Oil Sands ◽  
Northern Margin ◽  
Sea Level Fluctuations ◽  
Salt Dissolution ◽  
Half Graben ◽  
Spatio Temporal

Salt dissolution collapse-subsidence is proposed as the dominant tectono-stratigraphic control on the deposition of major sand trends across the northern Athabasca Oil Sands Deposit. Salt removal along linear dissolution trends 200 m below in the Prairie Evaporite (Middle Devonian) halite beds resulted in the collapse of the overlying Upper Devonian strata. The collapse-induced differential subsidence of the fault blocks formed the floor underlying the McMurray deposits in the 50 km long V-shaped Bitumount Trough extending across the northern area of the Athabasca Oil Sands Deposit. The lower and middle-upper McMurray sand trends filled the accommodation created by collapses of a linear chain of Upper Devonian fault blocks along the northern margin of the western Trough. A pair of tens-of-metres thick and 20–30 km long sand trends developed parallel in overlying accumulations of the lower and middle-upper McMurray Formation (Aptian). This half-graben tilted northward as the dissolution trend in the underlying Prairie Evaporite salt scarp widened, and the scarp margin was deeply embayed. Salt dissolution-induced structures were the principal control that located the large sand complexes exploited by bitumen mining projects. Earlier models of McMurray architecture interpreted the underlying karst collapse to have been largely pre-Cretaceous. This new architectural model reinterprets the spatio-temporal balance between erosion at the pre-Cretaceous surface and within the buried salt beds. Extensive salt removal resulted in collapse of the underlying hypogene karst during the late Aptian age. This resulted in the over-thickened multi-kilometres long McMurray sand trends. The underlying karst collapse resulted in unstable deposition surfaces along the sub-Cretaceous trough floors. This tectono-stratigraphic architecture, called the syndepositional model in this study, is proposed as an alternative to two other models, one of which proposes that deeply incised channel valleys and fills resulted from multiple significant sea-level fluctuations, while the other proposes that stacked parasequences accumulated along overlying shallow channels that meandered across a stable fluvio-estuarine coast.

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