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PLYMOUTH – Pollution from cellulose fibres such as cotton and linen made up 80 per cent of all deep-sea microfibres found in new research on Southern European seas. Perhaps surprisingly, polyester microfibres accounted for just 13 per cent of the 202 microfibres identified in 29 surface sediment samples analysed, while acrylic made up 4.5 per cent. The researchers presented new data on the distribution of microfibres after a widespread survey of seabed sediments in southern European seas including the northeast Atlantic Ocean (Cantabrian Sea), the Mediterranean Sea (Alboran Sea, Catalan Sea, Cretan Sea and Levantine Sea) and the Black Sea at depths from 42 m at the continental shelf to 3,500 m in the abyssal plain.

“The main type of microfibre found in seafloor sediments was thus essentially not plastic but cellulose fibres, that consisted of both dyed natural cellulose (cotton, linen) and manufactured fibres composed of regenerated cellulose, e.g. rayon,” says the paper.

It adds: “Our results show the dominance of cellulosic fibres over synthetic polymers. In contrast, synthetic fibres dominate the global fibre market, with 65 per cent of the share, while natural and man-made cellulosic fibres altogether comprise only a 35 per cent. Shedding of fibres is a relatively new concept in textile development and, to our knowledge, no studies have yet investigated microfibre shedding from cellulose vs. plastic textiles. Assuming a roughly equivalent release of fibres of each polymer to the aquatic environment, data suggest that polymer density is the key component controlling the spreading of microfibres to the deep.”

In the study, fibre length varied between 3 and 8 mm, and the most abundant colours were red (27 per cent), white (23 per cent), blue (21 per cent) and black (19 per cent). Fibre abundance ranged between 10 and 70 MF50 and averaged 34.8 ± 18.3 MF50, which is equivalent to 6,965 ± 3,669 microfibres m-2.

Further, microfibres abundances were found to be of the same order of magnitude as those reported in deep-sea sediments in the subpolar North Atlantic, the NE Atlantic and the SW Indian oceans, and significantly more abundant (2 to 8 orders of magnitude larger) than floating fibres in ocean surface and subsurface waters.

“Even though low floating microfibre abundances may be directly related to the relatively large (usually 330 μm) mesh size of the net, this is new evidence, after confirming deep-sea sediments as a major sink for microfibres,” says the paper.

“Around 20 per cent of the microfibres found had accumulated in the deep open sea beyond 2000m of water depth. The remoteness of the deep sea does not prevent the accumulation of microfibres, being available to become integrated into deep sea organisms.”

Citation: Sanchez-Vidal A, Thompson RC, Canals M, de Haan WP (2018) The imprint of microfibres in southern European deep seas. PLoS ONE 13(11): e0207033. https://doi.org/10.1371/journal.pone.0207033

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