Trophic transfer of microplastics in urban and rural coastal ecosystems

Description

Microplastics, small pieces of plastic less than five millimetres long, have permeated the oceans including seawater and sediment, posing a major threat to marine life and ecosystems. However, there is little information about the extent to which these pollutants accumulate and transfer through food webs, or whether proximity to urban area is a factor in the ingestion of microplastics across trophic levels. Many aquatic organisms can ingest microplastics, though each retains and accumulates them at a different rate. Potential health effects may include reduced body condition, lower reproductive success, and changes in feeding preferences. To address these knowledge gaps, we will quantify the uptake of microplastics in important bivalve species, and investigate the transfer and bioaccumulation of these pollutants through a model food chain.

Filter-feeding bivalves such as manila clams and pacific oysters may be particularly sensitive to ingesting microplastics, making them excellent model organisms for studying food web transfer and the bioaccumulation of microplastics. This research will measure microplastic concentrations and the chemical (isotopic) signatures of species at various levels of the food web to determine whether these pollutants accumulate as they move up the food web. The carbon and nitrogen signatures of each species are necessary to verify the proposed marine food chain, particularly for an ecosystem with many prey species and generalist predators. To determine the degree of bioaccumulation and biomagnification across different levels of the food web, we will quantify the number and type of microplastics in the gut and tissue of several species. The findings of this study will contribute to global knowledge about the impacts of microplastics in Canadian marine ecosystems.

Program Name

National Contaminants Advisory Group (NCAG)

Year(s)

2018 – 2020

Ecoregion(s)

Pacific: Strait of Georgia, Southern Shelf

Principal Investigator(s)

Dr. Francis Juanes
Professor, Department of Biology
University of Victoria