Paleolimnological assessment of nutrient enrichment on diatom assemblages in a priori defined nitrogen- and phosphorus-limited lakes downwind of the Athabasca Oil Sands, Canada

Date
2017-04-14
Authors
Laird, Kathleen R.
Das, Biplob
Hesjedal, Brittany
Leavitt, Peter R.
Mushet, Graham R.
Scott, Kenneth A.
Simpson, Gavin L.
Wissel, Bjorn
Wolfe, Jared
Cumming, Brian F.
Journal Title
Journal ISSN
Volume Title
Publisher
PAGEpress
Abstract

As the industrial footprint of the Athabasca Oil Sands Region (AOSR) continues to expand, concern about the potential impacts of pollutants on the surrounding terrestrial and aquatic ecosystems need to be assessed. An emerging issue is whether recent increases in lake production downwind of the development can be linked to AOSR activities, and/or whether changing climatic conditions are influencing lake nutrient status. To decipher the importance of pollutants, particularly atmospheric deposition of reactive nitrogen (Nr), and the effects of climate change as potential sources of increasing lake production, lakes from both within and outside of the nitrogen deposition zone were analyzed for historical changes in diatom assemblages. Lake sediment cores were collected from a priori defined nitrogen (N) - and phosphorus (P) - limited lakes within and outside the N plume associated with the AOSR. Diatom assemblages were quantified at sub-decadal resolution since ca. 1890 to compare conditions prior to oil sands expansion and regional climate warming, to the more recent conditions in each group of lakes (Reference and Impacted, N- and P-limited lakes). Analyses of changes in assemblage similarity and species turnover indicates that changes in diatom assemblages were minimal both within and across all lake groups. Small changes in percent composition of planktonic taxa, particularly small centric taxa (Discostella and Cyclotella species) and pennate taxa, such as Asterionella formosa and Fragilaria crotonensis, occurred in some of the lakes. While these changes were consistent with potential climate effects on algal growth, water column stability and other factors; the timing and direction of biotic changes were variable among sites suggesting that any apparent response to climate was lake dependent. The absence of a consistent pattern of diatom changes associated with receipt of reactive nitrogen or intrinsic nutrient-limitation status of the lake suggest that downwind AOSR emissions had no demonstrable effect on diatom composition.

Description
©Copyright Kathleen R. LAIRD et al., 2017. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Keywords
Athabasca oil sands, nitrogen deposition, diatom assemblages, nutrient limitation
Citation
Laird, Kathleen R., Biplob Das, Brittany Hesjedal, Peter R. Leavitt, Graham R. Mushet, Kenneth A. Scott, Gavin L. Simpson, Bjorn Wissel, Jared Wolfe, and Brian F. Cumming. 2017. “Paleolimnological Assessment of Nutrient Enrichment on Diatom Assemblages in a Priori Defined Nitrogen- and Phosphorus-Limited Lakes Downwind of the Athabasca Oil Sands, Canada”. Journal of Limnology 76 (3). https://doi.org/10.4081/jlimnol.2017.1598
Collections