Do Microplastics in the Ocean Affect Scallops ? A conversation with WHOI scientist Scott Gallager

WHOI scientist Scott Gallager is making field observations and conducting lab experiments to explore the possible effects of microplastics in the ocean on marine organisms. Specifically, he’s looking at sea scallops at different life stages to determine if the tiny plastic fragments they ingest when filtering seawater stunt their growth. The work is part of WHOI’s Marine Microplastics Initiative, which is aimed at understanding the fate of “hidden” microplastics in the ocean and their impacts on marine life and human health.  (whoi.edu, Oceanus Magazine, 24/01/2019)

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Marine litter in stomach content of small pelagic fishes from the Adriatic Sea: sardines ( Sardina pilchardus) and anchovies ( Engraulis encrasicolus)

Marine litter impacts oceans and affects marine organisms, representing a potential threat for natural stocks of pelagic fish species located at the first levels of the marine food webs. In 2013–2014, on a seasonal basis, marine litter and microplastics in stomach contents from Sardinia pilchardus and Engraulis encrasicolus were evaluated. Selected species are plankitivores of great ecological and commercial importance in the Adriatic Sea. Collected data were correlated to possible factors able to affect ingested levels as well as species, season of sampling, biometry and sex of animals. Almost all tested samples (80 organisms for each species) contained marine litter (over 90% of samples from both species) and also microplastics; while any meso- or macroplastics were recorded. On average, recorded items were as follows: 4.63 (S. plichardus) and 1.25 (E. encrasicolus) per individual. Sardines evidenced a higher number of microplastics characterised by a smaller size than those recorded in anchovies. For sardines, sex, Gastro Somatic Index and sampling season showed negligible effects on the number of ingested litter; conversely, anchovies showed differences related with both sex of animals and dominant colour of ingested materials with prevalence for black and blue colours.

Monia Renzi, Antonietta Specchiulli, Andrea Blašković, Cristina Manzo, Giorgio Mancinelli, Lucrezia Cilenti, Environmental Science and Pollution Research, , Volume 26, Issue 3, pp 2771–2781

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Small microplastics as a main contributor to plastic mass balance in the North Atlantic subtropical gyre

Estimates of cumulative plastic inputs into the oceans are expressed in hundred million tons, whereas the total mass of microplastics afloat at sea is three orders of magnitude below this. This large gap is evidence of our ignorance about the fate of plastics, as well as transformations and sinks in the oceans. One of the current challenges consists of identifying and quantifying plastic particles at the microscale, the small microplastics (SMP, 25-1000 µm). The aim of the present study is to investigate SMP count and mass density at the sea surface in the North Atlantic subtropical gyre during the sea campaign Expedition 7th Continent. After isolation, SMP were characterized by micro-Fourier-transform infrared spectroscopy. Microplastic distribution was modeled by a wind-driven vertical mixing correction model taking into account individual particle properties (dimension, shape and density). We demonstrate that SMP buoyancy is significantly decreased compared to the large microplastics (LMP, 1-5 mm) and consequently more susceptible to vertical transport. The uncorrected LMP count density was between 13 000 and 174 000 pieces km-2, and was between 5 to 170 times more abundant for SMP. With a wind-driven vertical mixing correction, we estimated that SMP were 300 to 70 000 times more abundant than LMP. When discussing this in terms of weight after correction, LMP densities were between 50 to 1 000 g km-2, and SMP densities were between 5 and 14 000 g km-2.

Marie POULAIN, Matthieu J Mercier, Laurent Brach, Marion Martignac, Corinne Routaboul, Emile Perez, Marie Christine Desjean, and Alexandra ter Halle, Environ. Sci. Technol., Just Accepted Manuscript, December 21, 2018

Distribution and composition of floating macro litter off the Azores archipelago and Madeira (NE Atlantic) using opportunistic surveys

The distribution and composition of macro litter floating around oceanic islands is poorly known, especially in the North Atlantic. Due to its isolated location at the fringe of the North Atlantic subtropical gyre, the Azores archipelago has recently been proposed as a potential retention zone for floating litter. To further investigate this assumption, opportunistic surveys from pole-and-line tuna fishing boats were performed from 2015 to 2017 to document (1) the distribution and (2) the composition of the floating macro litter present off the Azores and Madeira islands. Among the 2406 visual transects, 482 floating debris were recorded and were mainly composed of general plastic user items (48%), plastic packaging (21%) and derelict fishing gears (18%). Average number of debris per transect was 0.19 ± 0.5, with a total number ranging between 0 and 5 items per transect. For the majority of transects (84%), no debris was observed, 13% of the transects contained a single item, and only 3% contained more than one item. Although debris between 2.5 and 5 cm were recorded, 93% of the debris were larger than 5 cm. The GLMs showed strong effect of the observer (p < 0.001) and the standardized densities accounting for the observer bias were higher (1.39 ± 0.14 items.km-2) than the observed densities (0.78 ± 0.07 items.km−2). Debris densities were however relatively low and tended to aggregate around the Central group of the Azores (standardized mean: 0.90 ± 0.20 items.km−2). Our findings therefore suggest that most of the debris might originate from far away land-based sources and from fishing activities. This study highlights the potential of fisheries observer programs to obtain cost-effective information on floating macro debris that are essential to support the implementation of the European Marine Strategy Framework Directive.

P. Chambault, F. Vandeperre, M. MAchete and al., Marine Environmental Research, Volume 141, October 2018, Pages 225-232

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High levels of microplastic pollution in the sediments and benthic organisms of the South Yellow Sea, China

Microplastics, emerging contaminants in the ocean, are thought to sink and accumulate in sediments, and thus may pose a potential ecological risk to benthic communities. In this study, abundances and characteristics of microplastics in sediments and benthic organisms from the South Yellow Sea were investigated. First, we optimized the sediment sampling for microplastic analysis and found that the top layer (0–5 cm) had the highest abundance, and microplastic abundances decreased significantly with increase in sediment depth. The abundance of microplastics was 560–4205 n/kg dry weight in the surface sediments (the topmost 3 cm) of 14 sites and 1.7–47.0 n/g wet weight in the tissues of benthic organisms. Moreover, microplastic abundances in sediments and benthic organisms were both positively correlated with water depth. Fibers, transparent microplastics, and small microplastics (<0.5 mm) were the most dominant types in sediments and organisms. FTIR analysis showed that polypropylene (PP, 31%), polyester (PE, 24%), nylon (19%), and polystyrene (PS, 15%) were the most abundant polymers in sediments. The results of SEM showed rough surfaces and obvious cracks on the microplastics isolated from sediments. In addition, characteristics of microplastics in Ophiura sarsii, Crangon affinis, and Acila mirabilis were compared. Our results demonstrate that a comprehensive investigation of microplastics in sediments and benthic communities will help to fully understand the ecological risk of microplastic pollution.

J. Wang, M. Wang, S. Ru and al., Science of The Total Environment, Volume 651, Part 2, 15 February 2019, Pages 1661-1669

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Evidence that the Great Pacific Garbage Patch is rapidly accumulating plastic

Ocean plastic can persist in sea surface waters, eventually accumulating in remote areas of the world’s oceans. Here we characterise and quantify a major ocean plastic accumulation zone formed in subtropical waters between California and Hawaii: The Great Pacific Garbage Patch (GPGP). Our model, calibrated with data from multi-vessel and aircraft surveys, predicted at least 79 (45–129) thousand tonnes of ocean plastic are floating inside an area of 1.6 million km2; a figure four to sixteen times higher than previously reported. We explain this difference through the use of more robust methods to quantify larger debris. Over three-quarters of the GPGP mass was carried by debris larger than 5 cm and at least 46% was comprised of fishing nets. Microplastics accounted for 8% of the total mass but 94% of the estimated 1.8 (1.1–3.6) trillion pieces floating in the area. Plastic collected during our study has specific characteristics such as small surface-to-volume ratio, indicating that only certain types of debris have the capacity to persist and accumulate at the surface of the GPGP. Finally, our results suggest that ocean plastic pollution within the GPGP is increasing exponentially and at a faster rate than in surrounding waters.

L. Lebreton, B. Slat, F. Ferrari, and al., Scientific Reports, volume 8, Article number: 4666 (2018)

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Plastic pollution: Scientists identify two more potential ‘garbage patch’ zones in world’s oceans

Study attempts to locate remaining 99% of plastic unaccounted for by conventional surveys.

An attempt to locate millions of tons of “missing” plastic in the world’s oceans has thrown up two locations that may contain enormous, previously unreported patches of debris.

Plastic has risen to the top of the environmental agenda after scientists sounded the alarm about the potential impact it as having on marine life.

Best estimates suggest 10 million tons of plastic are dumped in the sea every year. (…) (Theindependent, 13/09/2018)

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