Phytoplankton Ecology in an Oilsands End Pit Lake

• Published in: ARPHA Conference Abstracts
• Main Authors: Furgason,Chantel, Smirnova,Angela, Dacks,Joel, Dunfield,Peter
• Format: Conference Object
• Language: English
• Published: Pensoft Publishers 2023
• Subjects: mine reclamation; community analysis; gene sequencing; Mine Lake; Beaver Creek
• Online Access: https://doi.org/10.3897/aca.6.e108385; https://aca.pensoft.net/article/108385/

Alberta oilsands mining and extraction have produced over 1 trillion litres of tailings wastewater (AER 2021) containing several compounds of concern (Cossey et al. 2021). End-pit lakes are a low-cost, long-term proposed strategy of tailings reclamation that sequester tailings in a mined-out pit under a freshwater cap. Through dilution and biogeochemical processes, the water cap should over time develop into a functional ecosystem integrable with the local watershed (Cossey et al. 2021, Saborimanesh 2021). Established in 2012, Base Mine Lake is currently the only full-scale pilot end pit lake developed by the Alberta oilsands industry and requires further investigation to validate end pit lakes as a tailings reclamation technology (Cossey et al. 2021). The first stage of reclamation requires the development of a phytoplankton community, which serves as the base of the aquatic food web (CEMA 2012).The primary objective of this study was to characterize the phytoplanktxon community over time in BML from 2016 to 2021 to determine how community composition and abundances shift over seasons and years. Characterization used Illumina gene sequencing targeting 16S rRNA, 18S rRNA, and 23S rRNA gene amplicons, giving relative abundance data over time for phytoplankton. Cell count data was used to verify gene sequencing results. The phytoplankton community composition and diversity in Base Mine Lake was compared to those of a freshwater reservoir and a tailings pond.Analysis of gene sequencing data revealed that major genera of phytoplankton included Cryptomonas (Cryptophyceae), Choricystis (Trebouxiophyceae), Euglena (Euglenales), and Synechococcus (Synechococcales), all of which appear to exhibit seasonal blooms during 2016-2021 (Fig. 1). Sequencing analysis also indicated that Base Mine Lake and its freshwater input source Beaver Creek Reservoir shared many of the same genera but different strains/species of those genera. This suggested that the distinct conditions in each aquatic site may have selected for distinct ...