Plastic pollution in Antarctica and the Southern Ocean has been recorded in scientific literature since the 1980s; however, the presence of microplastic particles (<5 mm) is less understood. Here, we aimed to determine whether microplastic accumulation would vary among Antarctic and Southern Ocean regions through studying 30 deep-sea sediment cores. Additionally, we aimed to highlight whether microplastic accumulation was related to sample depth or the sediment characteristics within each core. Sediment cores were digested and separated using a high-density sodium polytungstate solution (SPT) and microplastic particles were identified using micro-Fourier-transform infrared spectroscopy (μFTIR). Microplastic pollution was found in 93% of the sediment cores (28/30). The mean (±SE) microplastics per gram of sediment was 1.30 ± 0.51, 1.09 ± 0.22, and 1.04 ± 0.39 MP/g, for the Antarctic Peninsula, South Sandwich Islands, and South Georgia, respectively. Microplastic fragment accumulation correlated significantly with the percentage of clay within cores, suggesting that microplastics have similar dispersion behavior to low density sediments. Although no difference in microplastic abundance was found among regions, the values were much higher in comparison to less remote ecosystems, suggesting that the Antarctic and Southern Ocean deep-sea accumulates higher numbers of microplastic pollution than previously expected.
Bibliographical noteFunding Information:
E.M.C. is supported by the Department for Agriculture, Environment, and Rural Affairs, Northern Ireland. E.M.C. gratefully thanks Dave Williams and Hazel Clarke for their technical assistance, Prof. Jochen Koop for facilitating the μFTIR analysis at the Federal Institute of Hydrology, BfG, Koblenz, Germany, and Dr Jason Kirby for facilitating the microplastic analysis at Liverpool John Moores University. K.L. acknowledges support from the British Antarctic Survey Polar Science for Planet Earth Programme funded by The Natural Environment Research Council NC-Science and NERC grant NE/R012296/1 for JR17003a. We thank Prof Gerhard Bohrmann, Marum at University of Bremen, Germany for the invitations to join the research cruises M134 (KL) and PS119 (KL, JDS). This work was supported by the Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou). We also thank the late Briar Dick for stimulating discussion.
© 2020 American Chemical Society.
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- sediment grain size
- Southern Ocean
- synthetic polymers
ASJC Scopus subject areas
- Environmental Chemistry