The deep sea is a major sink for microplastic debris

The deep sea is a major sink for microplastic debris Lucy C. Woodall Anna Sànchez‐Vidal Miquel Canals Gordon Paterson Rachel Coppock Victoria A. Sleight Antoni Calafat Alex D. Rogers Bhavani E. Narayanaswamy Richard C. Thompson

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The deep sea is a major sink for microplastic debris 2014 Royal Society Open Science 10.1098/rsos.140317 woodall2014-the-deep-sea-is-a-major-sink-for-m woodall2014-the-deep-sea-is-a-major-sink-for-m.txt, the project's staged copy 51d33f57ee8f6f73529a312574cdbdd3e5d9a770 cc-by environmental-science

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0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them where the manufactured plastic that surveys cannot account for has gone, and whether deep-sea sediment holds it Quotation withheld because this record is not cleared for redistribution. how abundant and how widespread microplastic contamination is across a range of deep-sea depths and locations Quotation withheld because this record is not cleared for redistribution. microplastic fibres in all 12 sediment cores and all four coral samples from three oceans, at up to four orders of magnitude greater abundance per unit volume than heavily contaminated surface water - and the demonstration that the one previous deep-sea survey found little because it did not count fibres Quotation withheld because this record is not cleared for redistribution. existence Quotation withheld because this record is not cleared for redistribution. accumulation of plastic microfibres on the deep-sea floor - a repository large enough to bear on the missing-plastic budget, and unsampled until now Quotation withheld because this record is not cleared for redistribution. field-study field-study Quotation withheld because this record is not cleared for redistribution. a positively buoyant plastic floats when it enters the sea, and fouling by organisms and adherence of particles change its density over weeks to months until it sinks - so the compartment a plastic is found in is a function of how long it has been there buoyancy reversed by what grows on the particle Quotation withheld because this record is not cleared for redistribution. surface tension and currents hold most plastic at the surface; colonisation, adherence to phytoplankton and aggregation into marine snow bind fibres into larger, faster-settling particles, which is how a fibre reaches 3500 m aggregation as a delivery route Quotation withheld because this record is not cleared for redistribution. dense shelf water cascading, coastal storms, offshore convection and saline subduction all move large volumes of particle-loaded water downslope, carrying a full spectrum of grain sizes together with litter and contaminants, and submarine canyons concentrate the flow canyons as conduits for particle-loaded water Quotation withheld because this record is not cleared for redistribution. the fibres are the most numerous particle type in shallow habitats, so a protocol that does not enumerate fibres returns a low number from sediment that contains many - the difference between the two deep-sea reports is a decision about what to write down, and the authors demonstrated it on split samples rather than arguing it a recording rule deciding an abundance Quotation withheld because this record is not cleared for redistribution. no statistical comparison of abundance or composition between samples is possible - the authors name the lack of replicates, the small sample size and the methodological differences, and decline to make one Quotation withheld because this record is not cleared for redistribution. the four-orders-of-magnitude comparison with surface water is qualitative, because surface waters and sediments are sampled by different methods Quotation withheld because this record is not cleared for redistribution. whether fibres dominate sediment and fragments dominate the surface is a real distribution or an artefact of sampling method cannot be determined at present Quotation withheld because this record is not cleared for redistribution. the precise origin of individual microplastic debris cannot currently be established, although the polymer types point to diverse domestic and industrial sources Quotation withheld because this record is not cleared for redistribution. the coral samples were never quantitative - fibres were not extracted exhaustively and only presence or absence was recorded Quotation withheld because this record is not cleared for redistribution. rayon, which the authors state is not a plastic, is included in the counts and supplies 56.9% of the fibres reported Quotation withheld because this record is not cleared for redistribution. the 4 billion fibres per square kilometre figure is an extrapolation, offered on the most conservative estimates Quotation withheld because this record is not cleared for redistribution. few studies examine the biological effects of microplastics at all, so what this abundance implies for harm is not established here Quotation withheld because this record is not cleared for redistribution. particle-transport mechanisms carried from physical oceanography - cascading, convection, saline subduction, canyon funnelling and Taylor columns - to explain how a textile fibre reaches the abyssal floor Quotation withheld because this record is not cleared for redistribution. marine snow, a biological-oceanography construct for aggregated organic debris, used as the vehicle that makes a buoyant synthetic fibre settle Quotation withheld because this record is not cleared for redistribution. every preservation and processing fluid filtered through a 32 um sieve before use, and the fresh and salt water supplies sampled for an hour daily and screened for fibres eliminates: the laboratory's own water as the source of the fibres - a fibre that arrived in the rinse would be indistinguishable from one that arrived from the seafloor · outcome: held Quotation withheld because this record is not cleared for redistribution. the spectra of the actual waterproofs and laboratory gloves used during collection and processing added to the FT-IR reference library, so that a fibre shed from them would be identified as such rather than as an unknown polymer eliminates: the investigators' own equipment as the source of the identified polymers - without the spectra in the library a glove fibre matches nothing and is simply an unmatched particle · outcome: held Quotation withheld because this record is not cleared for redistribution. all residue sediment checked for the larger plastic particles the previous deep-sea study described, not only for the fibres this study was looking for eliminates: this protocol having simply traded one blind spot for another - the check asks whether the particles the other method counts were present and missed · outcome: held Quotation withheld because this record is not cleared for redistribution. two extraction methods used by two independent teams, with the specific gravities of the separating substances reported against each other - 1.2 for NaCl, 1.16 for Ludox eliminates: either laboratory's separation chemistry as the source of the result, to the extent that a float separation is characterised by its density · outcome: partial Quotation withheld because this record is not cleared for redistribution. their own deep-sea samples split and run through both this protocol and the protocol of the one previous deep-sea study, rather than comparing published numbers eliminates: a real difference between sites as the explanation of the disagreement with the previous report - the same sediment cannot differ from itself · outcome: held Quotation withheld because this record is not cleared for redistribution. damp filter paper exposed to the laboratory air whenever samples were open, as a check on airborne contamination during processing eliminates: airborne microplastic fibres settling into the samples during processing - the whole finding is fibres in deep-sea sediment, and the laboratory air is the rival source · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. natural fibre clothing only, with 100% cotton coats and headwear and latex gloves, for all laboratory processing and for the JC76T cruise eliminates: synthetic fibres shed from the handlers' own clothing, which would be indistinguishable from the microplastic being counted · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. FT-IR acceptance thresholds on the spectral quality index - 0.7 and above accepted, 0.6 to 0.7 inspected individually, below 0.6 rejected eliminates: false polymer identifications from poor-quality FT-IR spectra, with the middle band inspected by hand rather than accepted or dropped wholesale · outcome (stated by the tagger, no quotation): held Quotation withheld because this record is not cleared for redistribution. microplastics microplastics Quotation withheld because this record is not cleared for redistribution. microfibres microfibres Quotation withheld because this record is not cleared for redistribution. Rayon Rayon Quotation withheld because this record is not cleared for redistribution. polyester polyester Quotation withheld because this record is not cleared for redistribution. missing fraction missing fraction Quotation withheld because this record is not cleared for redistribution. deep-sea sediments deep-sea sediments Quotation withheld because this record is not cleared for redistribution. marine snow marine snow Quotation withheld because this record is not cleared for redistribution. dense shelf water cascading dense shelf water cascading Quotation withheld because this record is not cleared for redistribution. quality index quality index Quotation withheld because this record is not cleared for redistribution. specific gravities specific gravities Quotation withheld because this record is not cleared for redistribution. octocorals octocorals Quotation withheld because this record is not cleared for redistribution. deep-sea microplastic abundance - UNDER THE PREVIOUS PROTOCOL: very low, from a method that did not enumerate fibres at all Quotation withheld because this record is not cleared for redistribution. deep-sea microplastic abundance - UNDER THIS PROTOCOL, ON THE SAME SPLIT SAMPLES: substantially greater, with the other method shown to underestimate Quotation withheld because this record is not cleared for redistribution. the reported count - AS A COUNT OF FIBRES: 13.4 pieces per 50 ml, 1.4 to 40 across the cores, every one of them fibrous in shape Quotation withheld because this record is not cleared for redistribution. the reported count - AS A COUNT OF PLASTIC: a minority of it, since rayon is 56.9% of the fibres and the authors state that rayon is not a plastic Quotation withheld because this record is not cleared for redistribution. the comparison with surface water - AS THE ABSTRACT PUTS IT: up to four orders of magnitude more abundant per unit volume than contaminated sea-surface waters Quotation withheld because this record is not cleared for redistribution. the comparison with surface water - AS THE DISCUSSION QUALIFIES IT: qualitative, because different methods sample the two compartments Quotation withheld because this record is not cleared for redistribution. critiques → routine environmental monitoring of plastic debris, which has produced little evidence of the expected increase and leaves temporal trends unresolved in most datasets because microplastics were not included Quotation withheld because this record is not cleared for redistribution. qualifies → the one previous report of microplastics in the deep sea, whose very low abundance is attributed here to a protocol that did not enumerate fibres - tested on split samples, not asserted Quotation withheld because this record is not cleared for redistribution. extends → Van Cauwenberghe et al., with which this paper is offered jointly as the first evidence of global sinks for microplastic debris - the same study it corrects on method Quotation withheld because this record is not cleared for redistribution. qualifies → its own headline comparison - the four-orders-of-magnitude figure is qualitative, and no statistical comparison between samples is attempted Quotation withheld because this record is not cleared for redistribution. critiques → the field's methodological inconsistency, which the authors say must be fixed before robust temporal and spatial comparisons are possible at all Quotation withheld because this record is not cleared for redistribution. Rayon —contrasted-with→ polyester Rayon polyester differs in: how much of the reported abundance each supplies, and whether it is a plastic · the relation itself is separately evidenced · strength of the relation: 0.95 · differs in (stated by the tagger, no quotation): how much of the reported abundance each supplies, and whether it is a plastic · the relation stated: rayon supplies more than twice the count polyester does, and only one of the two is a plastic Quotation withheld because this record is not cleared for redistribution. microfibres —contrasted-with→ deep-sea sediments microfibres deep-sea sediments differs in: whether the compartment or the sampling method produces the size distribution · the relation itself is separately evidenced · strength of the relation: 0.9 · differs in (stated by the tagger, no quotation): whether the compartment or the sampling method produces the size distribution · the relation stated: sediment studies find mostly fibres while sea-surface studies find mostly larger fragments, and which is real cannot yet be decided Audit 2026-09-28: DOUBTFUL - read against its span and kept, but the span contrasts sediment with sea-surface studies; the endpoints are loose. Quotation withheld because this record is not cleared for redistribution. FT-IR confirmed microplastic fibres in all 12 sediment samples and all coral samples. FT-IR confirmed microplastic fibres in all 12 sediment samples and all coral samples. Quotation withheld because this record is not cleared for redistribution. rayon, which the authors state is not a plastic, supplies 56.9% of the fibres counted as microplastics rayon, which the authors state is not a plastic, supplies 56.9% of the fibres counted as microplastics Quotation withheld because this record is not cleared for redistribution. On split samples, the other study's method underestimated microplastic concentration relative to this study's fibre-recording approach. On split samples, the other study's method underestimated microplastic concentration relative to this study's fibre-recording approach. Quotation withheld because this record is not cleared for redistribution. deep-sea sediment carries about four orders of magnitude more microplastic per unit volume than heavily contaminated surface water, on a comparison the authors call qualitative deep-sea sediment carries about four orders of magnitude more microplastic per unit volume than heavily contaminated surface water, on a comparison the authors call qualitative Quotation withheld because this record is not cleared for redistribution. no statistical comparison between samples is attempted, for lack of replicates and consistency of method no statistical comparison between samples is attempted, for lack of replicates and consistency of method Quotation withheld because this record is not cleared for redistribution. whether sediment holds fibres and the surface holds fragments is a real distribution or a sampling artefact cannot be determined whether sediment holds fibres and the surface holds fragments is a real distribution or a sampling artefact cannot be determined Quotation withheld because this record is not cleared for redistribution. a man-made non-plastic polymer, included in this paper's microplastic counts by a stated decision because it is semi-synthetic and widely reported in the marine environment Rayon Quotation withheld because this record is not cleared for redistribution. the FT-IR spectral match score used to accept or reject an identification - accepted at 0.7 and above, inspected by hand between 0.6 and 0.7, rejected below 0.6 quality index Quotation withheld because this record is not cleared for redistribution. rayon's share of the total number of fibres seen - the majority of the reported count, and not a plastic 56.9% Quotation withheld because this record is not cleared for redistribution. polyester's share OF THE REMAINING fibres, i.e. of the non-rayon fraction, not of the total 53.4% Quotation withheld because this record is not cleared for redistribution. the range of plastic microfibre abundance across the sediment cores, in pieces per 50 ml 1.4 to 40 Quotation withheld because this record is not cleared for redistribution. fibres per square kilometre of Indian Ocean seamount sediment, extrapolated on the most conservative estimates 4 billion Quotation withheld because this record is not cleared for redistribution. the specific gravity of the Ludox-TM 40 separation, against 1.2 for the NaCl one - the number the two teams' comparability rests on 1.16 Quotation withheld because this record is not cleared for redistribution. mean mean Quotation withheld because this record is not cleared for redistribution. microplastic abundance microplastic abundance Quotation withheld because this record is not cleared for redistribution. quality index quality index Quotation withheld because this record is not cleared for redistribution.

The full text of this article is not redistributable, so it is not included here. The evidence sentences are withheld with it; the tag layer and its grounding status remain. The article itself is at https://doi.org/10.1098/rsos.140317.