https://hdl.handle.net/10388/13378

Ankley, Phillip J 2021. Using zooplankton metabarcoding for the ecotoxicological assessment of remediation practices for a simulated petroleum spill in a boreal lake.

After oil spills occur, regulators require adequate information to select best practices to minimize impacts on environments and to remediate target freshwater ecosystems. Zooplankton are valuable indicators of structure and function of aquatic ecosystems since they play pivotal roles in biochemical cycles while stabilizing food webs. Traditional identification of zooplankton can be costly and time-consuming, while also being difficult to standardize. Compared with classification of individuals by identification, based on visual inspection of morphology, metabarcoding of DNA and or RNA has promise for cost-effective high-throughput and benchmarkable biomonitoring of zooplankton communities. These identification methods were applied in the context of assessing responses of the zooplankton community exposed to simulated spills of diluted bitumen (dilbit), with concurrent exposure of experimental remediation practices of enhanced monitored natural recovery and shoreline cleaner application. The objective of this study was also to apply DNA and RNA metabarcoding of zooplankton for ecotoxicological assessment and compare it with traditional morphological identification in experimental shoreline enclosures in a boreal lake. Metabarcoding detected 77.4% of the morphologically identified boreal zooplankton taxa down to the genus level, with a total of 24 shared genera. Metabarcoding-based relative abundance of shared genus also served as an acceptable proxy for biomass inferred by morphological identification at the genera-level. Overall, both DNA and RNA metabarcoding determined significant differences between genera richness between the no treatment enclosure and shoreline cleaner application, while morphological identification determined no difference. DNA metabarcoding determined overall differences in community composition between no treatment and treatments, shoreline cleaner application and enhanced monitored natural recovery, while RNA metabarcoding and morphological identification determined differences between one or the other. Shoreline cleaner application overall seemed to have the greatest effect on zooplankton communities relative to enhanced monitored natural recovery, regardless of zooplankton identification method. Both metabarcoding and morphological identification were able to discern the differences between the two experimental remediation practices. Metabarcoding of zooplankton can provide informative results for ecotoxicological assessment of remediation practices of dilbit, advancing our knowledge of best practices for remediating oil-impacted aquatic ecosystems while serving to accelerate the assessment of at-risk freshwater ecosystems.

Masters, University of Saskatchewan, Next Generation Solutions

https://hdl.handle.net/10388/13378