LE3 .A278 2019

2019

Gibson, Glenys
Ferguson, Laura

Acadia University

Bachelor of Science

Honours

Biology

Biology

Plastic production has increased steadily since the 1950s; as a result,long-lasting plastic pollution persists in marine ecosystems including oceans, lakes, and small waterways. Plastic debris is manufactured or fragments into microplastics: pieces of plasticless than 5 mm to a few μm in diameter. Microplastics are a major ocean contaminant and environmental stressor for marine life. The model organism Carcinus maenas(Green Crab), a marine arthropod, was used to investigate the effects of ingested microplastics on the histology of the hepatopancreas, a digestive organ, using histochemistry to visualize potential changesin tissue structure. I investigated the potential effects of microplastics at low levels of exposure that were typical of concentrations found in the mid-Atlantic Ocean (1-2 particles / m3), and a higher concentration typical of coastal areas (100 particles/ m3). Controls included field-sampled crabs and laboratory cultured crabs without exposure to polystyrene. After six-weeks exposure, I compared the histology of the hepatopancreas using PAS-AB, Giemsa, Gomori’s Trichrome, H&E, and Nile Blue A to stain R absorptive, storage), F (precursor to B cells), and B (digestive enzymes) cells in the hepatopancreas tubules. Results demonstrated numbers of R cells significantly increased after exposure to a high concentration of microplastics. No significant differences were detected between field and control crabs and therefore indicate that tissue structure was not affected by lab culture. Additionally, no differences were detected in the abundance of F-cells or B-cells, likely because of their low numbers. These data suggest that levels of microplastics found in some coastal areas affect the structure of igestive tissue, through the numbers of R-cells, in these wide-spread scavengers.

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https://scholar.acadiau.ca/islandora/object/theses:3243