The ecological fate of microplastic in the nearshore environment of South Georgia, a sub-Antarctic island

Buckingham, Jack

Abstract

Microplastic is a marine pollutant of global concern which has managed to penetrate remote regions. This thesis describes the first comprehensive assessment of microplastics in the nearshore environment of South Georgia, an island in the sub-Antarctic region of the South Atlantic and Southern Ocean. The following samples were collected and analysed for their microplastic contents: seawater sampled from the coast and offshore, wastewater from land-based human habitation, precipitation, zooplankton, fish (Lepidonotothen larseni, Gobionotothen gibberifrons, Patagonotothen guntheri, and Gymnoscopelus bolini), and scats from two breeding populations of higher predators (Arctocephalus gazella and Pygoscelis papua), which were also examined for their dietary composition.
The concentration of microplastic in seawater was 0.58 ± 5.17 particles L-1 (mean ± standard deviation, median = 0, range = 0 – 4), higher than many other records of microplastics in surface seawater from the Southern Ocean. There was little similarity between the type of microplastics retrieved from seawater, wastewater (0.55 ± 3.00 L-1 mean ± s.d., median = 0.33, range = 0 – 2.33) and precipitation (1.55 ± 3.21 L-1 mean ± s.d., median = 1.16, range = 0 – 2.33). The microplastic concentration in zooplankton was 1.6 ± 1.6 particles per 15 g, and microplastic was found in every year examined with no significant change in concentration over time. Two microplastics were retrieved from fish, and the concentration in higher predators was 0.04 ± 0.05 particles g-1 (mean ± s.d., median = 0.025, range = 0 – 0.1) of scat in A. gazella and 0.08 ± 0.09 particles g-1 (mean ± s.d, median = 0.05, range = 0 – 0.25) of scat in P. papua, greater than abundances recorded from the Antarctic Peninsula, but lower than reports from lower latitudes. Morphometric analysis of hard parts suggested fish and crustacean diets but little evidence of the trophic transfer of microplastics into predators from their prey.
South Georgia is a biodiversity hotspot, the site of one of the world’s largest marine protected areas and has commercial importance from fishing and tourism. This thesis aims to contribute knowledge of the scale of anthropogenic stress on the region and produce a baseline, in terms of findings and best methodological practices, for any future research or monitoring of this pollutant in this region. Although wider ecological questions remain, the extent of microplastic in South Georgia nearshore waters has been quantified for the first time.

Citation

Buckingham, J. The ecological fate of microplastic in the nearshore environment of South Georgia, a sub-Antarctic island. (Thesis). University of Hull. https://hull-repository.worktribe.com/output/4347844

• Thesis Type: Thesis
• Deposit Date: Aug 2, 2023
• Publicly Available Date: Aug 7, 2023
• Keywords: Geography ; Environment
• Public URL: https://hull-repository.worktribe.com/output/4347844
• Additional Information: Energy & Environment Institute,; University of Hull
• Award Date: Jul 5, 2023