The Cell Biology And Ecology Of Heterotrophic Eukaryotes In A Tailings Reclamation Site In Northern Alberta

Abstract

The wastewater products from the bitumen extraction process, called tailings, are contained in pits which cover over 77km2 of the Northern Albertan landscape. Reclaiming these tailings is an essential part of the life cycle of oil sands mines. One method under development converts tailings ponds into end-pit lakes (EPLs). EPLs contain a layer of tailings capped with freshwater, which, over time, are projected to resemble natural lakes in the Northern Alberta boreal forest region. The first full-scale EPL in the Athabasca Oil Sands is Base Mine Lake (BML) on the Syncrude mine site. I carried out an initial assessment of the eukaryotic microbial population of BML in 2015, two years after BML was water capped. Using eDNA sequencing, I was able to identify a substantial heterotrophic flagellate population in BML. I continued this eDNA study over four years (2015-2018) and observed changes the community over time. After addition of alum to BML in early 2016, photosynthetic eukaryotes returned over the subsequent summers. There was also a substantial increase in species richness in the heterotrophic eukaryotes, though there were no clear trends associated with any variables other than time. One group that exhibited an increase in species richness over time was the ciliates. This phylum has been noted as a potential source of bioindicators, but little is known about the diversity of their cell biology. I ran a comparative genomic analysis on species across the diversity of the ciliates and identified substantial variation in the membrane trafficking components across each class. The results of this analysis suggest that the traditional model organisms for ciliates, all of which are found in the class Oligohymenophorea, may not be representative of ciliate diversity and additional model organisms or analysis may be necessary to determine resistance or sensitivity of specific ciliate classes or species to anthropogenic disturbance.