Estuarine Microplastics (MPs) are limited to know globally. By filtering subsurface water through 330 μm nets, MPs in Jiaojiang, Oujiang Estuaries were quantified, as well as that in Minjiang Estuary ...responding to Typhoon Soulik. Polymer matrix was analyzed by Raman spectroscopy. MP (<5 mm) comprised more than 90% of total number plastics. The highest MPs density was found in Minjiang, following Jiaojiang and Oujiang. Fibers and granules were the primary shapes, with no pellets found. Colored MPs were the majority. The concentrations of suspended microplastics determine their bioavailability to low trophic organisms, and then possibly promoting the transfer of microplastic to higher trophic levels. Polypropylene and polyethylene were the prevalent types of MPs analyzed. Economic structures in urban estuaries influenced on MPs contamination levels. Typhoon didn't influence the suspended MP densities significantly. Our results provide basic information for better understanding suspended microplastics within urban estuaries and for managerial actions.
•Suspended microplastic were investigated within three densely populated/developed urban estuaries, China.•Economical structures may contribute to the abundances of microplastic particles within the studied estuaries.•Typhoon Soulik didn't influence microplastic densities in the water column of Minjiang Estuary.•Microplastics (<5 mm in diameter) dominated more than 90% of the total plastic by number.
Suspended microplastics (MPs) levels were quantified within three urban estuaries, China. MPs densities were consistent with the urban economical structure, and that in Minjiang were unaffected by Typhoon.
•The quantity and composition of suspended microplastics are reported for the first time in China.•Microplastics (0.5–5mm) constituted more than 90% of total plastics by number of ...items.•Microplastics concentrations were spatially variable in the Yangtze Estuary.•Large rivers are contributed to the high MP abundances in the adjacent marine environment.•The most abundant plastics were fibres, while plastic spherules were rarely found.
Levels of microplastics (MPs) in China are completely unknown. This study characterizes suspended MPs quantitatively and qualitatively for the Yangtze Estuary and East China Sea. MPs were extracted via a floatation method. MPs were counted and categorized according to shape and size under a stereomicroscope. The MP densities were 4137.3±2461.5 and 0.167±0.138n/m3, respectively, in the estuarine and the sea samples. Plastic abundances varied significantly in the estuary. Higher densities in three sea trawls confirmed that rivers were the important sources of MP to the marine environment. Plastic particles (>5mm) were observed with a maximum size of 12.46mm, but MPs (0.5–5mm) constituted more than 90% by number of items. The most frequent geometries were fibres, followed by granules and films. Plastic spherules occurred sparsely. Transparent and coloured plastics comprised the majority of the particles. This study provides clues in understanding the fate and potential sources of MPs.
Plastic trash is common in oceans. Terrestrial and marine ecosystem interactions occur in the intertidal zone where accumulation of plastic frequently occurs. However, knowledge of the ...plastic-associated microbial community (the plastisphere) in the intertidal zone is scanty. We used high-throughput sequencing to profile the bacterial communities attached to microplastic samples from intertidal locations around the Yangtze estuary in China. The structure and composition of plastisphere communities varied significantly among the locations. We found the taxonomic composition on microplastic samples was related to their sedimentary and aquatic origins. Correlation network analysis was used to identify keystone bacterial genera (e.g. Rhodobacterales, Sphingomonadales and Rhizobiales), which represented important microbial associations within the plastisphere community. Other species (i.e. potential pathogens) were considered as hitchhikers in the plastic attached microbial communities. Metabolic pathway analysis suggested adaptations of these bacterial assemblages to the plastic surface-colonization lifestyle. These adaptations included reduced “cell motility” and greater “xenobiotics biodegradation and metabolism.” The findings illustrate the diverse microbial assemblages that occur on microplastic and increase our understanding of plastisphere ecology.
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•The information of plastic-associated microbial community in the intertidal zone is scanty.•Microbial communities attached plastics discriminates among three intertidal ecosystems around the Yangtze estuary, China.•Keystone species were Alphaproteobacteria, Gammaproteobacteria, Flavobacteriia, Acidobacteria and Cyanobacteria.•Putatively pathogenic species acts as hitchhikers on microplastic particles.
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•Sunlight can remove microplastics from the sea surface.•The type of plastic influences how rapidly microplastics photo-degrade.•Microplastics dissolve at the sea surface due to ...sunlight-driven photochemistry.•Dissolved organic carbon is produced as microplastics photo-dissolve in sunlight.•Photo-produced dissolved organic carbon impacts marine bacteria.
Trillions of plastic fragments are afloat at sea, yet they represent only 1–2% of the plastics entering the ocean annually. The fate of the missing plastic and its impact on marine life remains largely unknown. To address these unknowns, we irradiated post-consumer microplastics (polyethylene, PE; polypropylene, PP; and expanded polystyrene, EPS), standard PE, and plastic-fragments collected from the surface waters of the North Pacific Gyre under a solar simulator. We report that simulated sunlight can remove plastics from the sea surface. Simulated sunlight also fragmented, oxidized, and altered the color of the irradiated polymers. Dissolved organic carbon (DOC) is identified as a major byproduct of sunlight-driven plastic photodegradation. Rates of removal depended upon polymer chemistry with EPS degrading more rapidly than PP, and PE being the most photo-resistant polymer studied. The DOC released as most plastics photodegraded was readily utilized by marine bacteria. However, one sample of PE microplastics released organics or co-leachates that inhibited microbial growth. Thus, although sunlight may remove plastics from the ocean’s surface, leachates formed during plastic photodegradation may have mixed impacts on ocean microbes and the food webs they support.
The role of rivers as a major transport pathway for all sizes of plastic debris into the ocean is widely recognized. Global modelling studies ranked the Changjiang River as the largest contributor of ...plastic waste to the marine environment, but these estimates were based on insufficient empirical data. To better understand the role of rivers in delivering terrestrial plastic debris to the ocean, the spatial and temporal patterns of microplastics (MP) in the Changjiang Estuary (CE) and the East China Sea (ECS) were studied based on surface water samples in February, May, and July 2017. A total of 3225 MP (60–5000 μm) were identified by Fourier-transform infrared (FTIR) spectrometry. MP abundance in July was higher than in February and May due to higher river discharge. Density stratification in CE significantly influenced the surface MP abundances. A temporal accumulation zone within the river-sea interface for plastics was indicated by stations with apparently higher abundances in the river plume. Fibers were the most common MP (>80%) over three months. Small MP (<1000 μm) composed 75.0% of the total plastics on average. The average mass of MP was 0.000033 g/particle, which was two orders of magnitude lower than the empirical mass in literature. Without considering tidal effects, we estimate 16–20 trillion MP particles, weighing 537.6–905.9 tons, entered the sea through the surface water layer of the Changjiang River in 2017. These findings of this study provide reliable information on MP waste in a large river, which should be considered in further studies for estimating the riverine plastic loads.
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•MP abundance and size exhibited distinct seasonality in the Changjiang Estuary.•A ‘Patchiness’ in distribution of MP were observed in the Changjiang River plume.•The water density stratification impacted suspended microplastic abundances.•MP in our study averagely weighed 0.000033 g.•The annually MP load in the top layer of the Changjiang River is 537.6–905.9 tons.
Marine aggregates incorporate particles from the environment, including microplastic (MP). The characteristics of MP in aggregates and the role of aggregates in linking MP with marine organisms, ...however, are poorly understood. To address these issues, we collected aggregates and blue mussels, Mytulis edulis, at Avery Point, CT, and analyzed samples with microspectrometers. Results indicate that over 70% of aggregates sampled harbored MP (1290 ± 1510 particles/m3). Fifteen polymer types were identified, with polypropylene, polyester and synthetic-cellulose accounting for 44.7%, 21.2% and 10.6%, respectively, of the total MP count. Over 90% of MP in aggregates were ≤1000 μm, suggesting that aggregations are a sink for this size fraction. Although size, shape, and chemical type of MP captured by mussels were representative of those found in aggregates, differences in the sizes of MP in pseudofeces, feces and digestive gland/gut were found, suggesting size-dependent particle ingestion. Over 40% of the MP particles were either rejected in pseudofeces or egested in feces. Our results are the first to identify a connection between field-collected marine aggregates and bivalves, and indicate that aggregates may play an important role in removing MP from the ocean surface and facilitating their transfer to marine food webs.
Microplastics (MP; 1 μm to 1 mm) of various shapes and compositions are ingested by numerous marine animals. Recently, proposals have been made to adopt bivalve molluscs as bioindicators of MP ...pollution. To serve as indicators of MP pollution, however, the proposed organisms should ingest, without bias, the majority of plastic particles to which they are exposed. To test this premise, eastern oysters, Crassostrea virginica, and blue mussels, Mytilus edulis, were offered variously sized polystyrene microspheres (diameters 19–1000 μm) and nylon microfibers (lengths 75–1075 × diameter 30 μm), and the proportion of each rejected in pseudofeces and egested in feces was determined. For both species, the proportion of microspheres rejected increased from ca. 10–30% for the smallest spheres to 98% for the largest spheres. A higher proportion of the largest microsphere was rejected compared with the longest microfiber, but similar proportions of microfibers were ingested regardless of length. Differential egestion of MP also occurred. As a result of particle selection, the number and types of MP found in the bivalve gut will depend upon the physical characteristics of the particles. Thus, bivalves will be poor bioindicators of MP pollution in the environment, and it is advised that other marine species be explored.
Trillions of plastic debris fragments are floating at sea, presenting a substantial surface area for microbial colonization. Numerous cultivation-independent surveys have characterized ...plastic-associated microbial biofilms, however, quantitative studies addressing microbial carbon biomass are lacking. Our confocal laser scanning microscopy data show that early biofilm development on polyethylene, polypropylene, polystyrene, and glass substrates displayed variable cell size, abundance, and carbon biomass, whereas these parameters stabilized in mature biofilms. Unexpectedly, plastic substrates presented lower volume proportions of photosynthetic cells after 8 weeks, compared to glass. Early biofilms displayed the highest proportions of diatoms, which could influence the vertical transport of plastic debris. In total, conservative estimates suggest 2.1 × 10
to 3.4 × 10
cells, corresponding to about 1% of the microbial cells in the ocean surface microlayer (1.5 × 10
to 1.1 × 10
tons of carbon biomass), inhabit plastic debris globally. As an unnatural addition to sea surface waters, the large quantity of cells and biomass carried by plastic debris has the potential to impact biodiversity, autochthonous ecological functions, and biogeochemical cycles within the ocean.
Cyanobacterial blooms are becoming potent agents of natural selection in aquatic ecosystems because of their high production of some toxins and increased frequency in recent decades with ...eutrophication and climate change. Maternal exposure to the toxic Microcystis aeruginosa significantly increased the intrinsic rates of population increase, average life span, and net reproductive rates of a clone of the planktonic grazer Daphnia carinata in an offspring environment where cyanobacteria were present, but not for two additional clones. Offspring from mothers exposed to M. aeruginosa had lower intrinsic rates of population increase, average life span, and net reproductive rates than individuals from unexposed mothers when fed exclusively a green alga. These results suggest that benefits, costs, and clonal variations of maternal effects of inducible tolerance should be considered when trying to understand ecological consequences of cyanobacterial blooms since they can shape the trophic interactions between cyanobacteria and daphnids.
•Maternal exposure to Microcystis aeruginosa significantly increased the offspring tolerance in a Daphnia carinata clone.•Another two clones, however, failed to response to maternal exposure.•Offspring from exposed mothers had lower fitness when fed exclusively a green alga.
Capsule: Maternal exposure to the toxic Microcystis aeruginosa increased offspring fitness in one of three Daphnia carinata clones and carried a cost.
The level of contamination by microscopic anthropogenic litter (0.5–5mm) in terrestrial ecosystems is not well understood. After chemical digestion in 10% KOH, microscopic anthropogenic litter from ...the gastrointestinal tracts of 17 terrestrial birds was identified and categorized under a stereomicroscope based on its physical properties and melting tests. In total, 364 items from 16 birds were identified as microscopic anthropogenic litter, ranging in size from 0.5 to 8.5mm. No relationship between plastic load and body condition was found. Natural fibers, plastic fibers and fragmented plastics represented, respectively, 37.4% (136 items), 54.9% (200 items) and 7.7% (28 items) of total litter items. Small sample sizes limited our ability to draw strong conclusions about the metabolism of natural fibers, but the decline in the proportion of natural fibers from the esophagus to stomach to intestine suggested that they may be digestible. Particles smaller than 5mm represented more than 90% of the total number of pollutant items. Particles with colors in the mid-tones and fibrous shapes were overwhelmingly common particles. The results reflect pollution by microscopic anthropogenic litter in the terrestrial ecosystem of the study area. Microscopic natural fibers, which may disperse and adsorb chemical pollutants differently from microplastic and may pose an even greater risk, are in urgent need of further research.
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•Microscopic litter in the digestive tracts of terrestrial birds is firstly studied.•Natural fibers (136 items) accounted for 37.4% of the total microscopic litter.•Two hundred fibers and 28 fragments were classified as microplastic particles.•Microscopic litter was ubiquitous in the terrestrial ecosystem of the study area.
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