In this study, we provide the first evidence of MP pollution in surface and subsurface water samples from the Weddell Sea. (28) The waters of the Weddell Sea remain uninvestigated.
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(26,27) To our knowledge, the Weddell Sea has received little investigation with regard to MP, with only three sediment samples from the northwestern portion of the Weddell Sea having been described by Van Cauwenberghe et al.
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It plays an important ecological role for endemic species, migrating seabirds, and marine mammals. Further studies on the occurrence and distribution of MP in the Southern Ocean, especially for less investigated areas, are crucial to evaluate which areas are vulnerable to MP pollution and accumulation, as well as identifying possible MP sources.īeing difficult to access due to its year-round sea ice coverage, the Weddell Sea is one of the most remote regions in Antarctica, with particularly low levels of human activity. (10,19,20) Highly variable MP concentrations found in Antarctic waters (9−11,21,22) and the fact that most studies south of 60°S are focusing on the Ross Sea (9,18,23) and the West Antarctic Peninsula (10,21,24,25) highlight that knowledge is still patchy and the problem of MP pollution in Antarctica is not well understood. (10) Once present in waters south of the ACC, MP may become trapped and accumulate in the Antarctic marine environment. (15−17) In the Ross Sea, potential MP emission from research stations was evidenced, (9,18) while shipping was identified as a MP source along the West Antarctic Peninsula. (12) Yet, it was shown that the ACC is not as impermeable as previously thought (13,14) and human activities, including tourism, fisheries, and research are increasing. Due to the strong Antarctic Circumpolar Current (ACC) and westerly polar winds, it is assumed that the passive north–south dispersal of drifting material and biota is hampered. (4−8) Even the most remote places were found to be polluted by MP, including the Southern Ocean surrounding Antarctica, (9−11) one of the most isolated places on earth with relatively low human activity. Microplastics (MP, <5 mm) (1) have been found to be ubiquitous around the globe in different marine compartments (2) and are considered as an emerging threat to marine biota (3) possibly interfering with feeding, reproductive performance, and survival. This study demonstrates that differentiation based purely on visual characteristics and FTIR spectroscopy might not be sufficient for accurately determining sample contamination sources. However, 11% of the measured fragments could be distinguished from the reference paints via their elemental composition. This revealed that 45.5% of all recovered MP derived from vessel-induced contamination.
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Environmentally sampled fragments ( n = 101) with similar ATR-FTIR spectra to reference paints from the research vessel and fresh paint references generated in the laboratory were further subjected to micro-X-ray fluorescence spectroscopy (μXRF) to compare their elemental composition. Additionally, we aimed to determine whether identified paint fragments ( n = 394) derive from the research vessel. MP was found in 65% of surface and 11.4% of subsurface samples, with mean (±standard deviation (SD)) concentrations of 0.01 (☐.01 SD) MP m –3 and 0.04 (☐.1 SD) MP m –3, respectively, being within the range of previously reported values for regions south of the Polar Front. All putative MP were analyzed by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. In the present study, we evaluate MP (>300 μm) concentration and composition in surface ( n = 34) and subsurface water samples ( n = 79, ∼11.2 m depth) of the Weddell Sea. The remote Weddell Sea contributes to the global thermohaline circulation, and one of the two Antarctic gyres is located in that region. Microplastic (MP) pollution has been found in the Southern Ocean surrounding Antarctica, but many local regions within this vast area remain uninvestigated.