Page 6 - Shimadzu Journal vol.7 Issue1

Environmental Analysis

Microplastics and synthetic particles ingested by deep-sea amphipods
in six of the deepest marine ecosystems on Earth

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A.J. Jamieson , L.S.R. Brooks , W.D.K. Reid , S.B. Piertney , B.E. Narayanaswamy and T. D. Linley 1
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Affiliations:
1 Marine Sciences- School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, Tyne and Wear, NE1 7RU, UK
Institute of Biological and Environmental Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK.
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3 Scottish Association for Marine Science, Scottish Marine Institute, Oban, Argyll, PA37 1QA, UK
*Corresponding Author: Jamieson, A.J. email: alan.jamieson@ncl.ac.uk
Abstract
Whilst there is now an established recognition of microplastic pollution in the oceans, and the detrimental effects this may have on
marine animals, the ocean depth at which such contamination is ingested by organisms has still not been established. Here we detect the
presence of ingested microplastics in the hindguts of Lysianassoidea amphipod populations, in six deep ocean trenches from around the
Pacific Rim (Japan, Izu-Bonin, Mariana, Kermadec, New Hebrides and the Peru-Chile trenches), at depths ranging from 7000 m to 10,890
m. This illustrates that microplastic contaminants occur in the very deepest reaches of the oceans. Over 72% of individuals examined (65
of 90) contained at least one microparticle. The number of microparticles ingested per individual across all trenches ranged from 1 to 8.
The mean and standard error of microparticles varied per trench, from 0.9 ± 0.4 (New Hebrides Trench) to 3.3 ± 0.7 (Mariana Trench). A
subsample of microfibres and fragments analysed using FTIR were found to be a collection of plastic and synthetic materials (Nylon,
polyethylene, polyamide, polyvinyl alcohol, polyvinylchloride, often with inorganic filler material), semi synthetic (rayon and lyocell) and
natural fibre (ramie). Notwithstanding, this study reports the deepest record of microplastic ingestion, indicating that anthropogenic
debris is bioavailable to organisms at some of the deepest locations in the Earth’s oceans.

Keywords: microplastic; hadal; trench; microfibre; marine; pollution; Hirondellea; Eurythenes

Introduction
There is now an established appreciation of microplastic pollution Microplastics, defined as being between 0.1 µm and 5mm [19] , are
in our oceans and the detrimental effects this has on marine of particular concern in marine environments because they may be
organisms [1-3] . An estimated 322 million tonnes of plastic are similar or smaller in size to prey or particles selected for ingestion
produced annually , with more than 5 trillion plastic pieces by marine organisms. Some microplastics are produced for
[4]
weighing over 250,000 tons currently floating on the surface . In industrial processes [20, 21] while others have originated from the
[5]
2010 alone, 4.8-12.7 million tonnes were released into the ocean break-up of larger items through UV light and physical abrasion [21,
and this is set to increase by an order of a magnitude by 2025 . 22] . The size of microplastics makes them bioavailable, which
[6]
As such, plastics represent arguably the clearest indicator of facilitates entry into the food chain at various trophic levels and
mankind’s detrimental impact on the oceans and an obvious bioaccumulation [23-25] .
[7]
signature of the Anthropocene. A research priority is now to Microplastic ingestion has been observed in a wide range of taxa
characterise the extent of microplastic and semi-synthetic fibre including: plankton [26] , bivalves [27, 28] , crustaceans [29, 30] ,
pollution in the oceans and the consequences this has on marine echinoderms [8, 9] , fishes [31-35] , elasmobranchs [36] and cetaceans [1, 37] .
life. The investigation of microplastic ingestion by marine The extent of the adverse effects on marine biota are not fully
organisms has largely focused on shallow water habitats given the understood despite being known to negatively affect ~700
ease of sampling these locations yet we know very little about marine species, predominantly through ingestion, decreased
their ingestion in the deep sea [7-9] . This begs the questions of how nutrition from intestinal blockage or decreased mobility . There is
[3]
pervasive and ubiquitous microplastic pollution is within the deep also the potential for plastics to act as a vector for pollutants
sea, and does it extend to full ocean depth? including persistent organic pollutants (e.g. polychlorinated
The majority of plastic present in the oceans can be observed biphenyls) [38, 39] . The downstream impacts at an ecosystems level
[9]
floating on the surface . The degradation and fragmentation of on the physical and toxicological impacts of microplastic ingestion
plastics will ultimately result in sinking to the underlying deep-sea still remains unclear [39-41] .
habitats, where opportunities for dispersal become ever more The major pathways for plastics to the oceans are diverse and
limited [7,9,11] . Marine plastic litter has now been observed in range from river and estuary transport [42] to atmospheric fallout [43] .
numerous locations in the deep sea [12-16] . The deepest recorded The result is microplastics are observed globally in coastal [27, 44] ,
plastic item was plastic bag at 10,898 m in the Marina Trench [16] open ocean [45] , pelagic [46] , benthic [47] and deep-sea habitats [13, 48, 49] .
while in the Ryukyu Trench off Japan at depths greater than There are only a few records of microplastics in deep-sea
7000m, discarded items were found with increasing frequency sediments [7, 13, 49] with the deepest point being 5768m on the upper
towards the trench axes [17] . This reflects the ‘depocentre’ function margins of the Kuril-Kamchatka Trench [13] . Currently, the deepest
otherwise positively associated with surface derived food recorded occurrence of microplastic ingestion by deep-sea
[9]
supply [18] . organisms is 2200 m depth in the North Atlantic with no

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