Marine litter disrupts ecological processes in reef systems

Marine litter (ML) contaminates essentially all global coastal and marine environments and drives multiple ecosystem-level effects. Although deleterious effects of ML on several organisms have been investigated in the last years, this information tends to be dispersed or underreported, even in marine biodiversity hotspots such as reef ecosystems. Two are the main goals of this paper: (i) to integrate and synthesize current knowledge on the interactions of ML and reef organisms, and (ii) to evaluate the multiple disruptions on the ecological processes in reef systems. We report here ML-driven ecological disruptions on 418 species across eight reef taxa, including interactions that were previously not addressed in detail, and evaluate their major conservation implications. These results can help raise awareness of global impacts on the world’s reefs by highlighting ML associations in different reef systems around the world, and can aid in ML input reduction and marine management.

Gustavo F. de Carvalho-Souza, Marcos Llope, Moacir S. Tinôco, Diego V. Medeiros, Rodrigo Maia-Nogueira, Cláudio L.S. Sampaio, Marine Pollution Bulletin, Volume 133, August 2018, Pages 464–471

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Styrene impairs normal embryo development in the Mediterranean mussel (Mytilus galloprovincialis)

This study analysed the effects of styrene, a main monomer in plastic manufacturing and acknowledged to be amongst the most common plastic leachates, on early embryo development of the Mediterranean mussel. Embryotoxicity tests showed that styrene impaired normal embryo development at concentrations (0.01 μg/L–1 mg/L) encompassing the environmental range. Occurrence of normal D-veligers was significantly reduced up to 40% of the total, and larval size was reduced of about 20%. D-veligers grown in the presence of styrene (0.1 and 10 μg/L) showed significant reduction of total Multixenobiotic resistance (MXR) efflux activity that was not apparently related to transcriptional expression of genes encoding P-glycoprotein (ABCB) and Mrp (ABCC), the two main ABC transporters of embryonal MXR system. Indeed, ABCB transcription was not affected by styrene, while ABCC was up-regulated. At these same concentrations, transcriptional profiles of 15 genes underlying key biological functions in embryo development and potential targets of adverse effects of styrene were analysed. Main transcriptional effects were observed for genes involved in shell biogenesis and lysosomal responses (down-regulation), and in neuroendocrine signaling and immune responses (up-regulation). On the whole, results indicate that styrene may affect mussel early development through dysregulation of gene transcription and suggest the possible conservation of styrene mode of action across bivalve life cycle and between bivalves and humans, as well as through unpredicted impacts on protective systems and on shell biogenesis.

Rajapaksha Haddokara Gedara Rasika Wathsala, Silvia Franzellitti, Morena Scaglione,
Elena Fabbri, Aquatic Toxicology, Volume 201, August 2018, Pages 58-65

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Investigating microplastic trophic transfer in marine top predators

Microplastics are highly bioavailable to marine organisms, either through direct ingestion, or indirectly by trophic transfer from contaminated prey. The latter has been observed for low-trophic level organisms in laboratory conditions, yet empirical evidence in high trophic-level taxa is lacking. In natura studies face difficulties when dealing with contamination and differentiating between directly and indirectly ingested microplastics. The ethical constraints of subjecting large organisms, such as marine mammals, to laboratory investigations hinder the resolution of these limitations. Here, these issues were resolved by analysing sub-samples of scat from captive grey seals (Halichoerus grypus) and whole digestive tracts of the wild-caught Atlantic mackerel (Scomber scombrus) they are fed upon. An enzymatic digestion protocol was employed to remove excess organic material and facilitate visual detection of synthetic particles without damaging them. Polymer type was confirmed using Fourier-Transform Infrared (FTIR) spectroscopy. Extensive contamination control measures were implemented throughout. Approximately half of scat subsamples (48%; n = 15) and a third of fish (32%; n = 10) contained 1–4 microplastics. Particles were mainly black, clear, red and blue in colour. Mean lengths were 1.5 mm and 2 mm in scats and fish respectively. Ethylene propylene was the most frequently detected polymer type in both. Our findings suggest trophic transfer represents an indirect, yet potentially major, pathway of microplastic ingestion for any species whose feeding ecology involves the consumption of whole prey, including humans.

S. E. Nelms, T. S. Galloway, B. J. Godley and al., Environmental Pollution, Volume 238, July 2018, Pages 999-1007

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Why is the global governance of plastic failing the oceans?

On some measures, the global governance of plastic is improving. Curbside recycling and community cleanups are increasing. Companies like Toyota, Walmart, and Procter & Gamble are reducing waste to landfill. And all around the world, as research consolidates and activism intensifies, towns, cities, and legislatures are banning some uses of plastic, such as for grocery bags and as microbeads in consumer products. Yet the amount of plastic flowing into the oceans is on track to double from 2010 to 2025. Why? Partly, the dispersal, durability, and mobility of microplastics make governance extremely hard. At the same time, the difficulty of governing plastic has been rising as production accelerates, consumption globalizes, pollution sources diversify, and international trade obscures responsibility. As pressures and complexities mount, the global governance of plastic – characterized by fragmented authority, weak international institutions, uneven regulations, uncoordinated policies, and business-oriented solutions – is failing to rein in marine plastic pollution. In large part, as this article demonstrates, this governance landscape reflects industry efforts to resist government regulation, deflect accountability, and thwart critics, coupled with industry advocacy of corporate self-regulation and consumer responsibility as principles of governance. These findings confirm the need for more hard-hitting domestic regulation of industry as well as an international plastics treaty to scale up local reforms.

Peter Dauvergne, Global Environmental Change, Volume 51, July 2018, Pages 22-31

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Spatial occurrence and effects of microplastic ingestion on the deep-water shrimp Aristeus antennatus

Microplastic (MP) ingestion has been reported in a wide variety of organisms, however, its spatial occurrence and effects on wild populations remain quite unknown. The present study targets an economically and ecologically key species in the Mediterranean Sea, the shrimp Aristeus antennatus. 39.2% of the individuals sampled had MP in their stomachs, albeit in areas close to Barcelona city the percentage reached values of 100%. Overall, MP ingestion was confirmed in a wide spatial and depth (630–1870 m) range, pointing out the great dispersion of this pollutant. The benthophagous diet and close relationship with the sea bottom of A. antennatus might enhance MP exposure and ultimately lead to accidental ingestion. Detailed analysis of shrimps’ diet revealed that individuals with MP had a higher presence of endobenthic prey. Microplastic fibers are probably retained for long periods due to stomach’s morphology, but no negative effects on shrimp’s biological condition were observed.

E. Carreras-Colom, M. Constenla, A. SolerMembrives and al., Marine Pollution Bulletin, Volume 133, August 2018, Pages 44-52

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Multi-temporal surveys for microplastic particles enabled by a novel and fast application of SWIR imaging spectroscopy – Study of an urban watercourse traversing the city of Berlin, Germany

Highlights

• Fast semi-automated identification of microplastics by SWIR imaging spectroscopy.

• Areally extensive multi-temporal sampling survey.

• Analysis of rainstorm related microplastic input to watercourse.

• Evidence of an urban area as a source of microplastic pollution.

L. K. Schmidt, M. Bochow, H. K. Imhof and al., Environmental Pollution, Volume 239, August 2018, Pages 579–589

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Human footprint in the abyss: 30 year records of deep-sea plastic debris

This study reports plastic debris pollution in the deep-sea based on the information from a recently developed database. The Global Oceanographic Data Center (GODAC) of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) launched the Deep-sea Debris Database for public use in March 2017. The database archives photographs and videos of debris that have been collected since 1983 by deep-sea submersibles and remotely operated vehicles. From the 5010 dives in the database, 3425 man-made debris items were counted. More than 33% of the debris was macro-plastic, of which 89% was single-use products, and these ratios increased to 52% and 92%, respectively, in areas deeper than 6000 m. The deepest record was a plastic bag at 10898 m in the Mariana Trench. Deep-sea organisms were observed in the 17% of plastic debris images, which include entanglement of plastic bags on chemosynthetic cold seep communities. Quantitative density analysis for the subset data in the western North Pacific showed plastic density ranging from 17 to 335 items km−2 at depths of 1092–5977 m. The data show that, in addition to resource exploitation and industrial development, the influence of land-based human activities has reached the deepest parts of the ocean in areas more than 1000 km from the mainland. Establishment of international frameworks on monitoring of deep-sea plastic pollution as an Essential Ocean Variable and a data sharing protocol are the keys to delivering scientific outcomes that are useful for the effective management of plastic pollution and the conservation of deep-sea ecosystems.

S. Chiba, H. Saito, R. Fletcher and al., Marine Policy, Available online 6 April 2018, In Press

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