Meeting Abstract
A major environmental stressor facing marine organisms is the near-ubiquitous glut of microplastics in ocean ecosystems. We investigated the effects of microplastics on the histology of the bivalve mollusc Mytilus edulis, filter feeders that are highly abundant in coastal ecosystems. Our objective was to determine if microplastics are taken up into tissues at high risk of exposure (e.g., gills, hepatopancreas) and to use histochemistry to look for tissue-level effects. We exposed mussels to polystyrene particles (5 micrometer diameter) at a low concentration that is typical of water samples of the mid-Atlantic Ocean (1-2 particles/ m3) and at a higher concentration characteristic of some coastal areas (100x low). Controls included field-sampled mussels and mussels cultured in the lab but without polystyrene exposure. After a six-week exposure, we compared the histology of the gills and hepatopancreas in paraffin section using histochemistry. We examined potential changes in basic tissue structure (Hematoxylin and Eosin, Gomori trichrome), mucin production and distribution of hemocytes (periodic-acid Schiff-Alcian Blue), as well as classic indicators of immune responses including lipofuscin production and melanisation (Nile Blue). Preliminary results suggest that polystyrene exposure, even at these low concentrations, was associated with several stress-related responses in both organ systems.
