The meeting Connecting Early Career Canadian Freshwater Microplastics Researchers hosted by the University of British Columbia occurred on March 9th and 10th, 2022. The meeting successfully brought together 15 early career researchers from across Canada from 11 different universities and 5 provinces. Over the course of the meeting, we heard presentations from 11 researchers who shared either their research findings or plans for future research. The topics shared included the characterization and quantification of microplastics in water and biota samples, the effects of microplastics on various organisms and levels of biological organization, and the use of models to understand the fate of microplastics in food webs. Looking forward, the future research plans which were shared will evidently (and excitingly!) address key knowledge gaps in the field of freshwater microplastics research. On the second meeting day, we heard from our keynote speaker, a fellow early career researcher and PhD Candidate at the University of Rome ‘Roma Tre’, Alessandra Cera, who shared her recently published review on the global occurrence of microplastics in freshwater biota. The meeting was concluded by a networking event in which researchers were randomly assigned to smaller groups of 3-4 to freely discuss and exchange ideas, knowledge, and perspectives on microplastics research.
Natasha K (University of British Columbia) presented data on microplastic characterization and quantification of 8 lakes across British Columbia. She found similar concentrations across lakes in both water and zooplankton samples, however she is awaiting Raman spectroscopy data and therefore only reported on suspected microplastics at this time. She plans to correct her concentrations with the Raman data and to further investigate if land-use or proximity to urbanization affected the concentrations or particle types observed at each lake.
Madelaine (Carleton University) presented data on characterizations of microplastics in water and sediment from the Yellowknife River and Yellowknife Bay. Preliminary analysis has found fragments to be the dominant particle morphology and blue to be the dominant colour. Madelaine plans to finish processing her samples from last summer, complete polymer analysis, and sample additional sites in Yellowknife in 2022.
Gen (McGill University) presented her research using community modules to study the fate of microplastics in freshwater food webs. To determine how microplastics are incorporated into food webs, she used a representative freshwater food web including round gobies, gammarids and Quagga mussels. Through carefully designed microbead exposure experiments, she found different trophic levels have different dose-response relationships and species interactions can add to the body burden of microplastics. Future directions include exposing all species to microbeads simultaneously to mimic an environmentally realistic scenario.
Miguel (Concordia) presented his research on the impacts of microplastics on the development, behaviour, and cognition of juvenile convict cichlids. He exposed cichlids to different microplastic exposure scenarios via trophic transfer, as he fed the fish brine shrimp which had been exposed to varying concentrations of microspheres. He completed foraging and cognitive trials to observe behavioural differences between treatments and is currently analyzing the data.
Cody (Lakehead University) presented his research on the impacts of microplastics on the metabolic rates of yellow perch. His research is part of the in-lake limnocorral mesocosm experiment occurring at the IISD Experimental Lakes Area (ELA). Cody performed body measurements and respiratory tests on fish which had been exposed to microplastics in the limnocorrals. His initial results did not show a significant effect of microplastics on metabolic rates, but he is continuing this research again this summer with larger sample sizes.
Kennedy (University of Toronto) presented her research where she found that environmental microplastics induced transgenerational impacts on fathead minnows while pre-consumer microplastics did not. To determine transgenerational impacts, she conducted a chronic exposure experiment where she measured reproductive output and impacts to the offspring. She found that both types of microplastics had limited effects at the individual level on the parent generation, but environmental microplastics changed reproductive output, altered the viability of eggs, and resulted in larval deformities. Overall her research illustrates the need to consider microplastics as both a physical and chemical stressor.
Colleen (McMaster University) presented her MSc research from Western University where she quantified microplastics in White Sucker and Common Carp from the Upper Thames River. She found that body mass was related to the amount of fragments, fibers, and tire wear particles that were found in the fish. She also found that both species had similar body burdens of microplastics and that land use was correlated to the amount of fragments and tire wear particles found in the fish. Her research is a part of a long-term study in the Thames River, Ontario.
Desiree (University of Manitoba) presented her preliminary results on the effects of microplastics on freshwater zooplankton communities. Her research is part of the pELAstics project occurring at the IISD ELA. For her experiment, she examined the effects of different microplastic types and concentrations (which were dosed in the limnocorrals) on zooplankton species richness and community composition. She found that zooplankton abundance was positively correlated with microplastic concentration at one month of exposure, potentially due to additional nutrition from biofilm present on the microplastics, but then saw no effect at 10 weeks. She also found that species richness was positively correlated with microplastics at day 5 of exposure. Next steps include continuing to analyze data, quantify microplastic ingestion by the zooplankton, and investigate species-specific responses.
Quinn (McMaster University) presented her research on the toxicity and accumulation of microplastics in freshwater macroinvertebrates including pulmonate snails, oligochaete worms, and larval mayflies. Her experiment exposes macroinvertebrates to aged microfibers for varying exposure times. So far, she found that there was no effect of microplastics on survival or reproduction, however the experiment is still in progress.
Natasha N (Queen’s University) presented her future plans to examine the effects of microplastics on litter-associated macroinvertebrates. She is also participating in the pELAstics project at the IISD ELA, but her research will utilize open bottom corrals to investigate the effects of microplastic exposure on benthic invertebrates as well as the indirect effects on zooplankton and other organisms living within depth of the corrals. To examine microplastic effects on benthic ecosystem processes, she will add litterbags to the corrals. She is still working on the methodology and plans for her experiments to begin this summer.
Yaryna (University of Guelph) presented her research testing the impacts of microplastics on juvenile freshwater mussels (Lampsilis siliquoidea). She used various microplastic types for the toxicity tests on juvenile mussels. Currently, she has found that for 10μm and 100μm polystyrene spheres, there is no significant difference in growth over 28 days and no mortality in any of the treatments. There is more processing to finish and moving forward, she plans to complete chronic testing with the juveniles, re-run acute toxicity tests, and perform tests with adult mussels.
Alex (Carleton University) presented his research examining if ringed seals and walruses showed evidence of microplastic ingestion in the Canadian Arctic. Alex found only microfibers, and the mean amount of particles in his blanks and stomachs were similar. Because of this his results indicate no microplastics >80 μm were detected in either animal, as it cannot be accurately determined if the microplastics found in the animals were indeed introduced via ingestion or if they were introduced through procedural contamination. His research provides insight into detection limits and emphasizes the need for QA/QC, and also provides context for quantifying and characterizing microplastic pollution in larger aquatic mammals.