Diatom assemblage changes in shallow lakes of the Athabasca Oil Sands Region are not tracking aerially deposited contami
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ORIGINAL PAPER
Diatom assemblage changes in shallow lakes of the Athabasca Oil Sands Region are not tracking aerially deposited contaminants Nell Libera . Jamie C. Summers . Kathleen M. Ru¨hland . Joshua Kurek . John P. Smol
Received: 22 October 2019 / Accepted: 23 May 2020 Ó Springer Nature B.V. 2020
Abstract The Athabasca Oil Sands Region (AOSR) in northeast Alberta contains Canada’s largest reserve of hydrocarbons, and the third largest in the world. Extraction and processing operations generate contaminants and nutrients that are aerially deposited across the region. However, structured environmental monitoring efforts were only initiated decades following the establishment (1967) and escalation (* 1980) of commercial operations. We examined whether diatom assemblages preserved in 210Pb-dated
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10933-020-00136-y) contains supplementary material, which is available to authorized users. N. Libera (&) J. C. Summers K. M. Ru¨hland J. P. Smol Paleoecological Environmental Assessment and Research Lab (PEARL), Department of Biology, Queen’s University, Kingston, ON K7L 3N6, Canada e-mail: [email protected]
sediment cores retrieved from strategically selected lakes have responded to aerial deposition of contaminants. The relative amount of contaminant inputs was tracked using sedimentary dibenzothiophene (DBT) concentrations and DBT enrichment factors, which are established proxies for AOSR activities. We observed no relationship between diatom assemblage changes and DBT enrichment. The nature of the diatom changes differed among lakes, regardless of DBT enrichment, suggesting that diatom responses were related to site-specific conditions. Moreover, diatom assemblage changes at several sites tracked trends in whole-lake primary production. Collectively, these records indicate that regional warming is likely the primary driver of recent diatom assemblage changes in these shallow, closed-basin lakes. Keywords Sediments Alberta Polycyclic aromatic compounds Dibenzothiophenes Climate change
J. C. Summers e-mail: [email protected] K. M. Ru¨hland e-mail: [email protected]
Introduction
J. P. Smol e-mail: [email protected]
The hydrocarbon deposits in Alberta, Canada, are the third largest in the world, encompassing 142,000 km2 and holding an estimated total of 170 billion barrels of extractable crude oil (Government of Alberta 2017). The Athabasca Oil Sands Region (AOSR), near the city of Fort McMurray (Fig. 1), hosts the largest of
J. Kurek Department of Geography and Environment, Mount Allison University, Sackville, NB E4L 1A7, Canada e-mail: [email protected]
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J Paleolimnol
Alberta’s bitumen deposits (Alberta Energy Regulator 2015). Bitumen deposits have been mined since the introduction of the commercial oil sands industry in 1967, and heavily exploited since the subsequent acceleration in production, at a rate of 100,000 barrels/day ca. 1980 (Can
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