posted on 2021-11-23, 00:47authored byClara Leistenschneider, Patricia Burkhardt-Holm, Thomas Mani, Sebastian Primpke, Heidi Taubner, Gunnar Gerdts
Microplastic (MP)
pollution has been found in the Southern Ocean
surrounding Antarctica, but many local regions within this vast area
remain uninvestigated. The remote Weddell Sea contributes to the global
thermohaline circulation, and one of the two Antarctic gyres is located
in that region. 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. All putative MP were analyzed by attenuated
total reflection Fourier transform infrared (ATR-FTIR) spectroscopy.
MP was found in 65% of surface and 11.4% of subsurface samples, with
mean (±standard deviation (SD)) concentrations of 0.01 (±0.01
SD) MP m–3 and 0.04 (±0.1 SD) MP m–3, respectively, being within the range of previously reported values
for regions south of the Polar Front. Additionally, we aimed to determine
whether identified paint fragments (n = 394) derive
from the research vessel. 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. This revealed
that 45.5% of all recovered MP derived from vessel-induced contamination.
However, 11% of the measured fragments could be distinguished from
the reference paints via their elemental composition. This study demonstrates
that differentiation based purely on visual characteristics and FTIR
spectroscopy might not be sufficient for accurately determining sample
contamination sources.