Citizen scientists reveal: Marine litter pollutes Arctic beaches and affects wild life

Arctic marine litter: Composition and sources investigated by citizen scientist "super-users"

Combating the challenge of marine litter requires an understanding of its distribution and accumulation for mitigative measures, and its sources for targeted preventative measures. The latter is generally not well assessed through most beach litter registration protocols available to citizen scientists. Deep Dives were specifically developed to provide management with additional relevant data on the sources of and behaviours leading to littering in the Arctic. In this project, the Deep Dive protocol was used as an add-on to the Norwegian national volunteer beach cleanup registration protocol. Litter was cleaned and registered from 9 locations in the Svalbard archipelago 2022-2023 in collaboration with two groups of citizen scientists: members of the Arctic Research Group and students from Svalbard Folkehøgskole. These were given specialised training as "super-users" to apply this more complex beach litter registration protocol. The experience of the volunteers was generally positive and the data quality good, although some need for additions to the training was highlighted to reliably categorise some challenging items. In the future, citizen scientists could contribute significantly to the collection of management-relevant data on marine litter in the Arctic provided adequate training, resources, and a user-friendly data registration portal.

Year-round spatial and temporal distribution of microplastics in water and sediments of an urban freshwater system (Jungnang Stream, Korea)

Streams and tributaries can play a significant role in the transport of inland microplastics to rivers and oceans; however, research on microplastics in these water bodies is limited compared to riverine and marine environments. Analyzing microplastic abundance at higher spatial and temporal resolutions is crucial to comprehend the dynamics of microplastics in these water bodies. Therefore, this study investigated year-round spatiotemporal variations of microplastics monthly in surface waters and sediments along the Jungnang Stream, one of the main tributaries to the Han River in South Korea. The mean concentration of microplastics in the stream was 9.8 ± 7.9 particles L-1 in water and 3640 ± 1620 particles kg-1 in sediment. Microplastic concentrations in surface waters during summer were significantly higher than in other seasons, positively linked to increased precipitation and river discharges. Polymer compositions mainly consisted of polyethylene, polypropylene, and polyethylene terephthalate, with the majority of microplastics detected smaller than 200 μm. Fragment-shaped microplastics were predominant over fibrous ones. The estimated annual input and output of microplastics through surface waters were 1.2-207 kg (2.7-150 billion particles) and 11.3-272 kg (17-769 billion particles), with the summer months contributing more than 70% of the total output. The greater microplastics output in the Jungnang Stream's waters compared to its receiving waters (Han River) indicates microplastics transport from water to other environmental compartments, such as sediments. These findings highlight the importance of investigating microplastic abundances in surface waters and sediments with temporal resolution, at least across different seasons. Such investigations offer valuable insights into the spatiotemporal occurrence and dynamic transport of microplastics, providing essential information for water management and the development of policies in freshwater ecosystems.

Rethinking ecological niches and geographic distributions in face of pervasive human influence in the Anthropocene

Species are distributed in predictable ways in geographic spaces. The three principal factors that determine geographic distributions of species are biotic interactions (B), abiotic conditions (A), and dispersal ability or mobility (M). A species is expected to be present in areas that are accessible to it and that contain suitable sets of abiotic and biotic conditions for it to persist. A species' probability of presence can be quantified as a combination of responses to B, A, and M via ecological niche modeling (ENM; also frequently referred to as species distribution modeling or SDM). This analytical approach has been used broadly in ecology and biogeography, as well as in conservation planning and decision-making, but commonly in the context of 'natural' settings. However, it is increasingly recognized that human impacts, including changes in climate, land cover, and ecosystem function, greatly influence species' geographic ranges. In this light, historical distinctions between natural and anthropogenic factors have become blurred, and a coupled human-natural landscape is recognized as the new norm. Therefore, B, A, and M (BAM) factors need to be reconsidered to understand and quantify species' distributions in a world with a pervasive signature of human impacts. Here, we present a framework, termed human-influenced BAM (Hi-BAM, for distributional ecology that (i) conceptualizes human impacts in the form of six drivers, and (ii) synthesizes previous studies to show how each driver modifies the natural BAM and species' distributions. Given the importance and prevalence of human impacts on species distributions globally, we also discuss implications of this framework for ENM/SDM methods, and explore strategies by which to incorporate increasing human impacts in the methodology. Human impacts are redefining biogeographic patterns; as such, future studies should incorporate signals of human impacts integrally in modeling and forecasting species' distributions.

Beach litter composition, distribution patterns and annual budgets on Novaya Zemlya archipelago, Russian Arctic

Beached macrolitter (>2,5 cm) abundance and composition in the Russian (Eastern) part of the Barents Sea and the adjacent part of the Kara Sea was assessed for 2021-2023. Average densities of beach litter on the coasts are 675 items/100 m and 37 kg/100 m (0.27 items/m2 and 0.015 kg/m2). Annual litter budgets for Cape Zhelaniya beaches are 0.49 items/m2 per year and 0.023 kg/m2 per year. The northernmost tip of Novaya Zemlya is shown to be a beach litter accumulation hot-spot on Novaya Zemlya archipelago, where litter is brought by surface currents and trapped by sea ice margins. Up to 80 % of beached marine macrolitter is made of plastics, originating from vessels. A certain accumulation strip of a beach was identified (14 m - 27.5 m distance from the waterline), and significance of the beach backshore was shown in litter accumulation. Beach litter accounting methodologies on the Arctic beaches are discussed.

Beached plastic and other anthropogenic debris in the inner Seychelles islands: Results of a citizen science approach

Masses of plastic and other anthropogenic debris on beaches of inner Seychelles and derived from 53 organised clean-ups have been analysed. Debris and plastic densities ranged from 0.0011 to 0.1622 kg m-2 and 0.0004 to 0.1179 kg m-2, respectively, and data from successive cleans of the same beach resulted in respective median accumulation rates of 0.0293 and 0.0137 g m-2 d-1. There was no dependence of density or accumulation on beach location/aspect or season, but there were significant inverse relationships with beach area. This effect was attributed to most debris and plastic being trapped on the backshore by rocks and vegetation, and the areal proportion of backshore increasing with decreasing beach size. Plastic is derived from local littering and more distal sources, with polyethylene terephthalate bottles, flip-flops and Styrofoam fragments making important contributions. Without intervention and an increased risk of coastal flooding with climate change, beached debris on Seychelles is predicted to increase.

Occurrence and sources of microplastics on Arctic beaches: Svalbard

Plastic pollution is recognised as a major global environmental concern, especially within marine environments. The small size of microplastics (< 5 mm) make them readily available for ingestion by organisms in all trophic levels. Here, four beach sites in Adventfjorden on the west coast of Svalbard, were sampled with the aim of investigating the occurrence and abundance of microplastics on beaches to assess potential sources of microplastic pollution. High variability in microplastic amount, type and polymers were found at all sites ranging from means of 0.7 n/g (number) at the remotest site and 2.2 n/g (number) at the site closest to Longyearbyen. Statistical analyses suggested that patterns observed were linked to direct proximity to human activities through land uses and effluent discharge. These findings point to an increased importance of localised factors on driving elevated microplastic pollution in beach sediments over oceanic controls in remote but inhabited Arctic locations and have important implications for our understanding and future assessments of microplastic pollution in such settings.

Litter traps: A comparison of four marine habitats as sinks for anthropogenic marine macro-litter in Singapore

The potential for marine litter being trapped in biodiverse marine habitats such as mangrove forests, seagrass meadows and coral reefs is poorly understood. This study presents the first comprehensive investigation on the status of macro-litter across four marine habitats in Singapore during the two monsoonal seasons. Overall, litter density did not vary considerably between the southwest and the northeast monsoon. The litter density in terms of count was generally lower in seagrass meadows and coral reefs compared to mangroves and beaches. Plastic was the major type of litter found across most habitat types. Notably, many fishing-related items were found on coral reefs, while drinking straws were abundant at the mangrove strandlines during the southwest monsoon. Foam fragments and cigarette butts were common at the beach strandlines. These results suggest that mangroves among other habitats examined here should be prioritised for clean-up efforts in order to restore these critical coastal habitats.

Microplastics in stomach contents of juvenile Patagonian blennies (Eleginops maclovinus)

Microplastics are one of the major environmental issues that need to be addressed because they are starting to impact food chains and are also affecting human populations. The size, colour, form, and abundance of microplastics in young blennies of the species Eleginops maclovinus were examined in the current study. While the stomach contents of 70 % of the studied individuals contained microplastics, 95 % of them included fibres. Individual size and the largest particle size that can be eaten, which ranges between 0.09 and 1.5 mm present no statistical correlation. The quantity of particles taken in by each individual does not change with size. The most present microfibers colours were blue and red. Sampled fibres were analysed with FT-IR and no natural fibres were detected, proving the synthetic origin of the detected particles. These findings suggest that protected coastlines create conditions that favour the encounter of microplastics increasing local wildlife exposure to microplastics, raising the danger of their ingestion with potential physiological, ecological, economical and human health consequences.

Spatiotemporal distribution of microplastics in Miri coastal area, NW Borneo: inference from a periodical observation

The current study aims to investigate the spatiotemporal distribution of microplastics (MPs) in the Miri coast, targeting their occurrences, characterisation, and potential sources. For a periodical study, coastal sediments were collected from three different time intervals (monsoon, post-monsoon, and post-COVID) and subjected to stereomicroscope, ATR-FTIR, and SEM-EDX analyses. These results show a significant increase of MPs in post-COVID samples by approximately 218% and 148% comparatively with monsoon and post-monsoon samples, respectively. The highest concentration of MPs was detected near the river mouths and industrial areas where the waste discharge rate and anthropogenic activities dominate. Fibre-type MPs are the most abundant, with an average of nearly 64%, followed by fragments, films, microbeads, and foams. The most dominant polymer types were polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyester (PET). Overall, the current study shows a better understanding of MPs occurrence and potential sources in the Miri coastal area.

Assessing marine macrolitter on the coastline of the Asterousia Biosphere Reserve: Insights from a community-based study

Even in pristine and remote environments of the Mediterranean, marine litter is building up threatening habitats and species and inhibiting sustainable development. The present study reports the findings of beach litter surveys carried out by 250 local community members in nine sites along the coastline of the Asterousia Biosphere Reserve, situated in the southernmost end of Europe. The average recorded litter density along these sites amounted to 125 items per 100 meters of coastline (range: 22-510) and to 0.05 items per square meter of beach (range: 0.01-0.13). Only two of the nine surveyed beaches were found to be in good environmental status, in compliance with the European threshold value for beach litter. The other seven studied beaches surpassed the European threshold value. The primary sources of the litter identified in the study can be attributed to unsustainable practices and inadequate waste management by individuals, communities and municipalities using the coastal and marine environment. Additionally, unsustainable waste management practices within the agricultural sector were also found to be a significant contributor to marine litter pollution.

Marine plastic pollution in Morocco: state of the knowledge on origin, occurrence, fate, and management

Plastic pollution presents a major challenge facing stakeholders and decision-making worldwide. Plastics in the ocean damage biodiversity and marine ecosystem services that the blue economy relies upon. The present work analyses and reviews the literature on plastic pollution and the background knowledge about marine plastic pollution in Morocco. The economy of Morocco depends mainly on marine activities, including fisheries, tourism, and maritime trade. These sectors were identified as the main in-situ sources of plastics entering Moroccan coastal waters. The analysis results showed that the increasing abundance of plastics in such marine systems causes substantial economic loss to blue economy activities. In contrast, the lack of data on the plastic waste quantity entering Moroccan water is a limiting factor for assessing plastic pollution. This highlights the need for a risk assessment and more field investigations to value the weight impacts of marine activities generators of plastics on biodiversity and the economy. In addition, implementing laws and rules forbidding the disposal of plastic waste (PW) in public spaces, mainly beaches, and streets, is urgently needed. Raising awareness of plastic waste management and prioritizing improved waste collection, sorting, and management would boost Morocco's establishment and adoption of circular economy strategies. It is worth noting that while implementing the management projects and regulatory frameworks of plastic waste, considering their source and usage purpose is mandatory.

Utilising tourist-generated citizen science data in response to environmental challenges: A systematic literature review

There has been a proliferation of studies that have examined the impacts of public participation in Citizen Science (CS) that respond to environmental challenges and the recovery of ecosystems, endangered species or other important natural assets. However, comparatively few studies have explored how tourists may play a critical role in the generation of CS data and thus it has been posited that many potential opportunities remain unrealised. By systematically analysing studies that have utilised tourist-generated data in response to environmental challenges or issues, this paper seeks to establish an appraisal of what has so far been established in extant literature and to identify future possibilities for the inclusion of tourists in CS. Via our literature search, a total of 45 peer-reviewed studies were identified via the PRISMA search protocol. Our findings reveal numerous positive outcomes were reported that highlight the significant, yet largely untapped, potential of tourist integration in CS, with studies also offering a range of recommendations on how tourists could be included more effectively to expand scientific knowledge. Notwithstanding, several limitations were observed, and it is critical that future CS projects that utilise tourists for data collection purposes are acutely aware of the challenges they may encounter.

Plastic Entanglement Poses a Potential Hazard to European Hedgehogs Erinaceus europaeus in Great Britain

A questionnaire to gather evidence on the plastic entanglement of the European hedgehog (Erinaceus europaeus) was sent to 160 wildlife rehabilitation centres in Great Britain. Fifty-four responses were received, and 184 individual admissions owing to plastic entanglement were reported. Death was the outcome for 46% (n = 86) of these cases. A high proportion of Britain's hedgehogs enter rehabilitation centres annually (approximately 5% of the national population and potentially 10% of the urban population), providing a robust basis for assessing the minimum impacts at a national level. We estimate that 4000-7000 hedgehog deaths per year are attributable to plastic, with the true rate likely being higher, since many entangled hedgehogs-in contrast to those involved in road traffic accidents-will not be found. Population modelling indicates that this excess mortality is sufficient to cause population declines. Although the scale of the impact is much lower than that attributable to traffic, it is nevertheless an additional pressure on a species that is already in decline and presents a significant welfare issue to a large number of individuals.

Anthropogenic litter in terrestrial flora and fauna: Is the situation as bad as in the ocean? A field study in Southern Germany on five meadows and 150 ruminants in comparison with marine debris

In contrast to the abundance of research on marine debris, terrestrial anthropogenic litter and its impacts are largely lacking scientific attention. Therefore, the main objective of the present study is to find out whether ingested litter produces pathological consequences to the health of domestic ruminants, as it does in their relatives in the ocean, the cetaceans. For this purpose, five meadows (49°18'N, 10°24'E) with a total survey area of 139,050 m² as well as the gastric content of 100 slaughtered cattle and 50 slaughtered sheep have been examined for persistent man-made debris in Northern Bavaria, Germany. All the five meadows contained garbage, and plastics were always part of it. Including glass and metal, 521 persistent anthropogenic objects were detected altogether, equalling a litter density of 3747 items per km². Of the examined animals, 30.0% of the cattle and 6.0% of the sheep harboured anthropogenic foreign bodies in their gastric tract. As in the case of cetaceans, plastics were the most dominant litter material. Bezoars had formed around plastic fibres of agricultural origin in two young bulls, whereas pointed metal objects were associated in cattle with traumatic lesions in the reticulum and the tongue. Of all the ingested anthropogenic debris, 24 items (26.4%) had direct equivalents in the studied meadows. Comparing with marine litter, 28 items (30.8%) were also present in marine environments and 27 items (29.7%) were previously reported as foreign bodies in marine animals. At least in this study region, waste pollution affected terrestrial environments and domestic animals, with clear equivalents in the marine world. Ingested foreign bodies produced lesions that may have reduced the animals' welfare and, regarding commercial purposes, their productivity.

Implications of Regurgitative Feeding on Plastic Loads in Northern Fulmars (Fulmarus glacialis): A Study from Svalbard

Procellariiform seabirds like northern fulmars (Fulmarus glacialis) are prone to ingest and accumulate floating plastic pieces. In the North Sea region, there is a long tradition to use beached fulmars as biomonitors for marine plastic pollution. Monitoring data revealed consistently lower plastic burdens in adult fulmars compared to younger age classes. Those findings were hypothesized to partly result from parental transfer of plastic to chicks. However, no prior study has examined this mechanism in fulmars by comparing plastic burdens in fledglings and older fulmars shortly after the chick-rearing period. Therefore, we investigated plastic ingestion in 39 fulmars from Kongsfjorden (Svalbard), including 21 fledglings and 18 older fulmars (adults/older immatures). We found that fledglings (50-60 days old) had significantly more plastic than older fulmars. While plastic was found in all fledglings, two older fulmars contained no and several older individuals barely any plastic. These findings supported that fulmar chicks from Svalbard get fed high quantities of plastic by their parents. Adverse effects of plastic on fulmars were indicated by one fragment that perforated the stomach and possibly one thread perforating the intestine. Negative correlations between plastic mass and body fat in fledglings and older fulmars were not significant.

Sources of marine debris for Seychelles and other remote islands in the western Indian Ocean

Vast quantities of debris are beaching at remote islands in the western Indian Ocean. We carry out marine dispersal simulations incorporating currents, waves, winds, beaching, and sinking, for both terrestrial and marine sources of debris, to predict where this debris comes from. Our results show that most terrestrial debris beaching at these remote western Indian Ocean islands drifts from Indonesia, India, and Sri Lanka. Debris associated with fisheries and shipping also poses a major risk. Debris accumulation at Seychelles is likely seasonal, peaking during February-April. This pattern is driven by monsoonal winds and may be amplified during positive Indian Ocean Dipole and El-Niño events. Our results underline the vulnerability of small island states to marine plastic pollution, and are a crucial step towards improved management of the issue. The trajectories used in this study are available for download, and our analyses can be rerun under different parameter choices.

Abundance and sources of plastic debris on beaches in a plastic hotspot, Nha Trang, Viet Nam

Viet Nam is challenged by extensive marine plastic pollution, however, remediation efforts are hampered by undefined sources to the coastal environment. This study surveyed the abundance, type, and source of beached plastic litter at seven beaches along the coast of Nha Trang, Viet Nam. A total of 4754 beached plastic litter items (>2 cm) yielded a mean abundance of 19.8 ± 19.5 items m^-2 corresponding to 116 ± 226 g DW m^-2. Our results demonstrate that plastic litter related to fishing and aquaculture constituted at least 62 % of the total by weight and 38 % by number, showing that these two sectors are responsible for a significant part of the plastic pollution along the coast. Hence, we argue that improved management of the fishing and aquaculture sectors could substantially reduce marine plastic pollution along Viet Nam's coast.

Assessment of national beach litter composition, sources, and management along the Indian coast - a citizen science approach

The present study evaluates the Pan-India beach litter density (items/m²), weight (kg/m²), composition (%), and probable sources based on the citizen science approach. A total of 33 beaches in 2019 and 30 beaches in 2021 were studied. Based on density, the national beach litter average was 0.475± 0.51 and 0.3 ± 0.4 items/m² in 2019 and 2021, respectively. Plastic was the dominant litter type (65 % in 2019; 74 % in 2021) and Single-Use Plastics (SUPs) were predominant. Based on Clean-Coast Index, six beaches in 2019 and three beaches in 2021 are classified as "extremely dirty". The principal (∼60 %) sources of litter were tourism and public littering. Improving solid waste management, stringent implementation of environmental legislation, leveraging the polluter pays principle, monitoring the effectiveness of SUPs ban, generating awareness, and beach clean-up at regular intervals by engaging the public, educational, and non-governmental organizations will improve and sustain the cleanliness of beaches.

Thrushes (Aves: Passeriformes) as indicators of microplastic pollution in terrestrial environments

Microplastic pollution is one of the leading global conservation issues. The aim of this study was to investigate the occurrence of microplastics in the gastrointestinal tracts of Common Blackbirds Turdus merula (N = 16) and Song Thrushes Turdus philomelos (N = 18), songbirds with exceptionally terrestrial lifestyles and a wide distribution range. We searched for microplastics of over 100 μm in size and assessed whether their contamination differed regarding the age of the birds and the time of year. We used birds that had died as a result of collision with anthropogenic infrastructure, which were sampled during wildlife monitoring of anthropogenic infrastructures and citizen science projects in north-eastern Poland. We found that all the analysed individuals contained microplastic in their gastrointestinal tracts, which were classified as fibers, fragments, films and pellets. A total number of 1073 microplastics were observed, mostly consisting of fibers (84 %) and films (10 %) below 1 mm in size. The dominant colours of microplastics were transparent (75 %) and brown (14 %). The species average microplastic concentration was higher in Song Thrushes (40.1) than Common Blackbirds (21.9), however the difference was not statistically significant. Moreover, we found no seasonal or age-related differences in microplastic ingestion in either species. While our results show a ubiquity of microplastics in terrestrial environments, they also indicate that thrushes have the potential to be used as indicators of microplastic pollution in terrestrial ecosystems.

Beach litter contamination of the Turkish middle Black Sea coasts: Spatial and temporal variation, composition, and possible sources

Marine litter is one of the biggest environmental problems nowadays. Sinop, is located in the heart of Türkiye's Black Sea coast, has a small population, and is a popular fishing and tourist destination. In this study, marine litter amount, composition, and possible sources were investigated, and seasonal comparisons were made between in Sinop beaches. Marine litter amount was found as 0.29-7.67 items·m^-2 and 3.46-49.09 g·m^-2 and beaches were classified as moderate to extremely dirty. Plastics were the highest ratio (88.14-98.46 %) and "plastic pieces 2.5> <50 cm" were the major litter type. The major possible litter source was improper waste disposal (33.36 %) and litter items originated from mainly land-based sources (74.13 %). The result of this study shows that there is a significant litter problem on the coasts. The solution of this problem can be possible to take rational measures against marine litter pollution with education and management policies.

Sources and management of marine litter pollution along the Bay of Bengal coast of Bangladesh

Marine debris is often detected everywhere in the oceans after it enters the marine ecosystems from various sources. Marine litter pollution is a major threat to the marine ecosystem in Bangladesh. A preliminary study was conducted to identify the sources of marine litter (plastics, foamed plastic, clothes, glass, ceramic, metals, paper, and cardboard) along the Bay of Bengal coast. From the observations, the range of abundance of the collected marine litter was 0.14-0.58 items/m². From the ten sampling sites, the highest amount of marine litter was observed for aluminium cans (3500), followed by plastic bottles (3200). The spatial distribution pattern indicated that all the study areas had beach litter of all types of materials. The present investigation showed that plastics were the dominating pollutants in the marine ecosystem in Bangladesh. The clean-coast index (CCI) value indicated that the Cox's Bazar coast was clean to dirty class. The abundance, distribution, and pollution of marine litter along the coastal belts pose a potential threat to the entire ecosystem. This study will help come up with ways to manage and get rid of marine litter along the coast in an effective way.

Plastic burdens in northern fulmars from Svalbard: Looking back 25 years

The northern fulmar Fulmarus glacialis ingests a larger number of (micro)plastics than many other seabirds due to its feeding habits and gut morphology. Since 2002, they are bioindicators of marine plastics in the North Sea region, and data are needed to extend the programme to other parts of their distribution areas, such as the Arctic. In this study, we provide data on ingested plastics by fulmars collected in 1997 in Kongsfjorden, Svalbard. An extraction protocol with KOH was used and for half of the birds, the gizzard and the proventricular contents were analysed separately. Ninety-one percent of the birds had ingested at least one piece of plastic with an average of 10.3 (±11.9 SD) pieces. The gizzards contained significantly more plastics than the proventriculus. Hard fragments and polyethylene were the most common characteristics. Twelve percent of the birds exceeded the EcoQO value of 0.1 g.

Plastic pollution of four understudied marine ecosystems: a review of mangroves, seagrass meadows, the Arctic Ocean and the deep seafloor

Plastic pollution is now a worldwide phenomenon affecting all marine ecosystems, but some ecosystems and regions remain understudied. Here, we review the presence and impacts of macroplastics and microplastics for four such ecosystems: mangroves, seagrass meadows, the Arctic Ocean and the deep seafloor. Plastic production has grown steadily, and thus the impact on species and ecosystems has increased, too. The accumulated evidence also indicates that plastic pollution is an additional and increasing stressor to these already ecosystems and many of the species living in them. However, laboratory or field studies, which provide strong correlational or experimental evidence of ecological harm due to plastic pollution remain scarce or absent for these ecosystems. Based on these findings, we give some research recommendations for the future.

Microplastics in atmospheric dust samples of Sistan: sources and distribution

In this work, the amount and physical and chemical characteristics of airborne microplastics (MPs) pollution in dust samples in Sistan, located in the eastern part of Iran, is reported. Sampling stations were selected according to the wind direction and population density. MPs were collected by a static dust sampler and analyzed by optical microscopy and FT-IR spectroscopy. Results showed that the distribution frequency of MPs in residential and non-residential areas was 6 to 11 pieces per 100 g (pcs/100 g) with an average abundance of 9.8 pcs/100 g. Fragmented MPs were approximately consisted 64% of total MPs and their sizes were in the range of 0.9-3.8 mm. Polyethylene (49%), polystyrene (21%) and polyester (18%) were the main MPs presented in the dust samples. It was observed that population density and wind direction were the most important parameters affecting MPs pollution in dust.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40201-022-00833-y.

The spatiotemporal dynamics, distribution, and characteristics of beached plastics along the remote south coast of Western Australia

Understanding the accumulation mechanism for beached plastics is important for marine debris research. Similar to the global accumulation pattern for beached plastics, we find that along the remote south coast of Western Australia (SCWA) white, hard, microplastics dominate the microplastic pollution accumulating on beaches. We estimate that along the SCWA, plastics are present at a density of 2.01 items·m^-2, but also find that the density of plastic pollution is higher at the eastern end of bays. Significantly fewer plastics were found after easterly winds (austral summer-prevailing winds), and regional physical ocean process, including the Leeuwin Current, and the Ekman transport effect may be relevant to the rate of plastic accumulation on SCWA beaches.

Abundance and composition of marine litter on the coasts of the Dardanelles (Canakkale Strait, Turkey)

The amount of human-origin litter in sea surface water, sediment, and beaches has been increasing for decades. Initially described in marine coastal systems in the 1960s, marine litter (ML) is nowadays commonly observed in all marine systems. There is even a gigantic island consisting of garbage in the gyre area of the Atlantic Ocean. In relation to this significant problem, ML was collected from seven stations on beaches along the Dardanelles for the first time in the period May 2017-May 2018 and was seasonally and regionally analyzed in terms of densities and weights. ML was categorized by material type (plastic, rubber, paper, etc.) and field of use (mixed packaging wastes, personal use products, fishing wastes, etc.). Total numbers and weights of ML during the study were 5751 items and 115.7 kg in an area of 15,980 m², respectively. Density and weight of ML ranged from 0.050 to 1.182 items/m² and from 0.446 to 78.46 g/m², respectively. The main ML component was plastic items in terms of both density (90.95%) and weight (53.76%) according to material type. Additionally, mixed packaging wastes (MPW) were the most common ML items in terms of density (82.14%) and weight (49.38%) according to usage. According to the clean-coast index, while Kilya (St.2) and Kepez (St.5) beaches were dirty, Seddulbahir (St.1) beach was clean. The beaches in other stations were neither dirty nor clean (medium) according to the index. At the end of the study, suggestions for a regional strategy were made.

Industrialised fishing nations largely contribute to floating plastic pollution in the North Pacific subtropical gyre

The subtropical oceanic gyre in the North Pacific Ocean is currently covered with tens of thousands of tonnes of floating plastic debris, dispersed over millions of square kilometres. A large fraction is composed of fishing nets and ropes while the rest is mostly composed of hard plastic objects and fragments, sometimes carrying evidence on their origin. In 2019, an oceanographic mission conducted in the area, retrieved over 6000 hard plastic debris items > 5 cm. The debris was later sorted, counted, weighed, and analysed for evidence of origin and age. Our results, complemented with numerical model simulations and findings from a previous oceanographic mission, revealed that a majority of the floating material stems from fishing activities. While recent assessments for plastic inputs into the ocean point to coastal developing economies and rivers as major contributors into oceanic plastic pollution, here we show that most floating plastics in the North Pacific subtropical gyre can be traced back to five industrialised fishing nations, highlighting the important role the fishing industry plays in the solution to this global issue.

Marine litter and climate change: Inextricably connected threats to the world's oceans

The global issues of climate change and marine litter are interlinked and understanding these connections is key to managing their combined risks to marine biodiversity and ultimately society. For example, fossil fuel-based plastics cause direct emissions of greenhouse gases and therefore are an important contributing factor to climate change, while other impacts of plastics can manifest as alterations in key species and habitats in coastal and marine environments. Marine litter is acknowledged as a threat multiplier that acts with other stressors such as climate change to cause far greater damage than if they occurred in isolation. On the other hand, while climate change can lead to increased inputs of litter into the marine environment, the presence of marine litter can also undermine the climate resilience of marine ecosystems. There is increasing evidence that that climate change and marine litter are inextricably linked, although these interactions and the resulting effects vary widely across oceanic regions and depend on the particular characteristics of specific marine environments. Ecosystem resilience approaches, that integrate climate change with other local stressors, offer a suitable framework to incorporate the consideration of marine litter where that is deemed to be a risk, and to steer, coordinate and prioritise research and monitoring, as well as management, policy, planning and action to effectively tackle the combined risks and impacts from climate change and marine litter.

Citizen science in marine litter research: A review

Citizen science (CS) can help to tackle the emerging and worldwide problem of marine litter (ML), from collecting data to engaging different stakeholders. We reviewed what and how the scientific literature is reporting CS on ML to identify possible gaps to be improved. The 92 search results (separate occasions when 48 different CS initiatives were discussed across 85 publication records) revealed an under-representation of studies in developing regions. Most search results focused on the science of ML, whilst information regarding citizen scientists was commonly vague or missing, preventing critical analysis of good practices on this aspect. The studies concentrated on the shoreline and did not harmonize types and sizes of items collected, thus precluding data meta-analyses. The standardisation of CS methods and approaches and the detailed report of aspects related to citizen scientists are essential to support the science we need for the advances in CS efforts to face ML.

First documentation of plastic ingestion in the arctic glaucous gull (Larus hyperboreus)

Arctic wildlife is facing multiple stressors, including increasing plastic pollution. Seabirds are intrinsic to marine ecosystems, but most seabird populations are declining. We lack knowledge on plastic ingestion in many arctic seabird species, and there is an urgent need for more information to enable risk assessment and monitoring. Our study aimed to investigate the occurrence of plastics in glaucous gulls (Larus hyperboreus) breeding on Svalbard. The glaucous gull is a sentinel species for the health of the arctic marine ecosystem, but there have been no studies investigating plastic occurrence in this species since 1994. As a surface feeder and generalist living in an area with high human activity on Svalbard, we expected to find plastic in its stomach. We investigated for plastic >1 mm and documented plastic ingestion for the first time in glaucous gulls, with a frequency of occurrence of 14.3% (n = 21). The plastics were all identified as user plastics and consisted of polypropylene (PP) and polystyrene (PS). Our study provides new quantitative and qualitative data on plastic burden and polymer type reported in a standardized manner establishing a reference point for future research and monitoring of arctic gulls on national and international levels.

Spatial variation of plastic debris on important turtle nesting beaches of the remote Chagos Archipelago, Indian Ocean

We report Anthropogenic Marine Debris (AMD) in Chagos Archipelago in the Indian Ocean, globally amongst the most isolated island groups. AMD on 14 island beaches in five atolls were surveyed in 2019 using two techniques: Marine Debris Tracker (MDT) along littoral vegetation and photoquadrats in open beach. Over 60 % of AMD in both beach zones was composed of plastics, especially bottles and fragments (mean = 44.9 %, 27.2 %, range = 16.5-73.2 %, 4.8-55.9 % respectively in vegetation; mean = 28.7 %, 31.5 %, range = 17.7-40.7 %, 11.6-60.0 % respectively in open beach). The density of plastic debris in littoral vegetation (MDT data: 1995 bottles, 3328 fragments per 100 m²) was 10-fold greater than in open beach (photoquadrat data: 184 bottles, 106 fragments per 100 m²). Significant latitudinal variation in vegetation AMD occurred (8-fold greater in southern atolls, p = 0.006). AMD varied within island zones: most debris observed on oceanside beaches (oceanside vs lagoon, W = 365, p < 0.001; ocean vs island tip, W = 107, p = 0.034). Standardisation of surveys using the open-source MDT App is recommended. Debris accumulation hotspots overlapped with sea turtle nesting habitat, guiding future beach clean-up prioritisation.

Plastics in the environment as potential threat to life: an overview

Plastics have become inevitable for human beings in their daily life. Million tons of plastic waste is entering in oceans, soil, freshwater, and sediments. Invasion of plastics in different ecosystems is causing severe problems to inhabitants. Wild animals such as seabirds, fishes, crustaceans, and other invertebrates are mostly effected by plastic entanglements and organic pollutants absorbed and carried by plastics/microplastics. Plastics can also be potentially harmful to human beings and other mammals. Keeping in view the possible harms of plastics, some mitigation strategies must be adopted which may include the use of bioplastics and some natural polymers such as squid-ring teeth protein. This review focuses on the possible sources of intrusion and fate of plastics in different ecosystems, their potential deleterious effects on wildlife, and the measures that can be taken to minimize and avoid the plastic use.

The Citizen Science Paradox

Citizen science (CS) is now very popular in ecology. The number of scientific publications referencing CS has increased steadily over the past 15 years, with more than 1150 publications today. However, the multiplicity of research involved suggests that this number is highly underestimated. Based on this paradox, a literature review on CS shows that while its formalization in 2009 facilitated its referencing, about 70% of the publications are not referenced using CS as keyword. To understand this under-representation, an analysis of 149 publications related to the famous Christmas Bird Count program shows that this underestimation is not mainly related to the diversity of keywords used to describe CS, but rather to the fact that CS is mainly considered as a method (four publications out of five). The results also show that taking into account the whole text of a publication would represent a substantial improvement for the analysis of scientific databases, whatever the field of research.

Occurrence of ingested human litter in winter arctic foxes (Vulpes lagopus) from Svalbard, Norway

The aim of this study is to assess the occurrence of human litter ingested by arctic foxes (Vulpes lagopus) caught in Svalbard, Norway, in winter when scavenging is at its highest. Twenty arctic fox stomachs and intestines were examined for human litter and plastic using the protocol from the Oslo-Paris Convention (OSPAR) for monitoring plastic ingestion by the northern fulmar (Fulmarus glacialis) (human litter and plastic >1 mm). The arctic foxes had ingested human litter at a low frequency (15%, 3 out of 20 foxes). Despite the low sample size, we do not regard ingestion of human litter as an immediate threat to the arctic fox population in Svalbard.

Quantity and type of coastal debris pollution in Taiwan: A rapid assessment with trained citizen scientists using a visual estimation method

Ongoing monitoring of the distribution and composition of coastal debris is a prerequisite for efficient management and cleanups. Therefore, we conducted a rapid assessment of coastal debris along the 1210 km coastline of Taiwan using a visual estimation method. Forty-nine citizen scientists were intensively trained to correctly identify the volume and types of debris. At 121 sampling locations randomly placed along Taiwan's coastline, the citizen scientists recorded the pollution level and the three most abundant debris types within a 100-m transect during four surveys in 2018-2019. Averaging over the four surveys, the mean amount of coastal debris was estimated to be 406.6 kg/km, and the three most abundant debris types were plastic bottles, foamed plastics, and fishing nets and ropes. Using a statistical test which avoids spatial pseudoreplication, we showed that north-facing coastlines had significantly higher pollution levels than the other coastlines, which we suggest is deposited there during strong winter winds. We also showed that fishery-related debris was a much more important part of coastal debris when the volume of it was determined instead of just the number of items. Mean pollution levels were further associated with wind speed, coastline type, and the distance to presumed pollution sources. Our results compare well with similar surveys conducted in Japan and South Korea. In each country, the debris was highly aggregated, which means it was concentrated in a few highly polluted localities. Therefore, the visual estimation method can effectively guide cleanup efforts to the most polluted areas and also reliably generate long-term monitoring data.

Beach debris quantity and composition around the world: A bibliometric and systematic review

Anthropogenic pollution of marine ecosystems caused by beach debris has become a serious environmental concern in the last few decades. Regarding the raising production of beach debris, the present work aimed to summarize the quantity and quality of beach debris reported from different beach areas of the world. Also, a bibliometric analysis was used to analyze research trends and upgrade knowledge in this research area. Using Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA), the eligible papers reviewed regarding beach debris abundance along with their composition from 2010, which were extracted from the Scopus database. The results of the study showed that plastic items represented the dominant material (61.25%), followed by food (5.88%), wood (5.78%), metals (5.2%), and glass (5%). Further, the beaches studied were classified into three degrees, including highly polluted (31.5 items/m2), moderate polluted (3.47 items/m2), and low polluted (0.37 items/m2), based on the average abundance of debris.

Baseline Marine Litter Surveys along Vietnam Coasts Using Citizen Science Approach

Marine litter is a significant threat to the marine environment, human health, and the economy. In this study, beach litter surveys along Vietnamese coasts were conducted in a local context to quantify and characterize marine litter using the modified GESAMP marine litter monitoring guideline. A total of 21,754 items weighing 136,820.2 g was recorded across 14 surveys from September 2020 to January 2021. Plastic was the most abundant type of litter by both quantity (20,744 items) and weight (100,371.2 g). Fishing gear 1 (fishing plastic rope, net pieces, fishing lures and lines, hard plastic floats) and soft plastic fragments were the most frequently observed items (17.65% and 17.24%, respectively). This study not only demonstrates the abundance and composition of marine litter in Vietnam, it also provides valuable information for the implementation of appropriate preventive measures, such as the redesign of collection, reuse, and recycling programs, and informs policy and priorities, with a focus on action and investment in Vietnam. Moreover, insights from this study indicate that citizen science is a useful approach for collecting data on marine litter in Vietnam.

Are Tourists Willing to Pay for a Marine Litter-Free Coastal Attraction to Achieve Tourism Sustainability? Case Study of Libong Island, Thailand

Coastal areas around the world are under increasing environmental pressures from marine litter. In particular, tourism in coastal tourist areas suffers with waste littering on the coast, as well as in the water. Therefore, substantial costs are required for the handling of marine litter in order to achieve sustainable development in the tourism sector. The introduction of an entrance fee as an economic tool is a feasible way to provide alternative financing, in addition to limited government funding. The objective of this study was to estimate tourists’ willingness to pay (WTP) for visiting a marine litter-free coastal attraction, and examine the factors affecting the WTP. A questionnaire was employed using a single-bound dichotomous choice method on Libong Island, Thailand, between September and December 2020. A logistic model was used to estimate the WTP of the 1655 respondents. The mean WTP obtained is THB 92.24 per person per visit (approximately USD 3). The expected benefit of charging an entrance fee is THB 27.52 million (USD 0.88 million) for 2019. The factors influencing WTP are bid amount, age, education, monthly income, marine litter perception, and environmentally responsible behaviors. Associated initiatives were recommended to achieve coastal destination sustainability, including regular clean-up operations at beaches, seagrass beds, and surrounding waters; the placement and maintenance of litter facilities; and the promotion of marine litter awareness and environmentally responsible behaviors.

A review of plastic pollution in aquatic ecosystems of Turkey

Turkey is one of the major plastic pollution sources in the Mediterranean and the Black Sea. This review summarizes present information, data, and legislation on plastic pollution in Turkish aquatic ecosystems. According to results derived from reviewed studies, both macro- and microplastic pollutions were documented in Turkish aquatic ecosystems. Most of the studies on plastic pollution in Turkish waters were performed in the marine environment while only four were conducted in freshwater environments. Spatially, the majority of these studies, which were on levels in the marine environment, were conducted on the northeastern Mediterranean coasts of Turkey, especially Iskenderun and Mersin Bays. Additional studies were carried out on either the ingestion/presence/impact of microplastics by/to aquatic organisms or the entanglement of marine organisms in plastics. There were also studies assessing the microplastic content of commercial salt, and another has reported microplastic presence in traditional stuffed mussels sold in Turkish streets. Some studies were conducted on microplastic presence and/or their removal in wastewater treatment plants in Mersin, Adana, Mugla, and Istanbul cities. Macro- and microliter loading from a few Turkish rivers to the sea was also estimated. All these investigations indicate that Turkish aquatic environments have significant plastic pollution problems, which were also underlined by the legislative studies. The need for further studies in this field still exists, especially in freshwater environments.

Wave fetch and distance from the ocean determine the distribution of macroplastics in the intertidal zone of central Spitsbergen, Arctic

In this study, we estimated the variety and distribution of macroplastics in the central part of Spitsbergen, Svalbard archipelago, Arctic. All marine litter photos were georeferenced, then identified using the OSPAR (2010) classification guide. The majority (90% of all objects) of marine debris was macroplastic with average number in the study area being 2.0 ± 0.4 objects per 100 m. It was determined that the full variety of macroplastic categories in the study area can be found after surveying approx. 8 km of coastline. Correlation analysis showed that the amount of macroplastic accumulated on the beaches decreases with distance from the open ocean and increases with wave fetch. When zoning the entire study area on the basis of a cluster analysis of the distribution of macroplastics, it was found that the geographical proximity of the sections is less important than the wave fetch.

Trans-polar drift-pathways of riverine European microplastic

High concentrations of microplastic particles are reported across the Arctic Ocean–yet no meaningful point sources, suspension timelines, or accumulation areas have been identified. Here we use Lagrangian particle advection simulations to model the transport of buoyant microplastic from northern European rivers to the high Arctic, and compare model results to the flux of sampled synthetic particles across the main entrance to the Arctic Ocean. We report widespread dispersal along the Eurasian continental shelf, across the North Pole, and back into the Nordic Seas; with accumulation zones over the Nansen basin, the Laptev Sea, and the ocean gyres of the Nordic Seas. The equal distribution of sampled synthetic particles across water masses covering a wide time frame of anthropogenic influence suggests a system in full saturation rather than pronounced injection from European sources, through a complex circulation scheme connecting the entire Arctic Mediterranean. This circulation of microplastic through Arctic ecosystems may have large consequences to natural ecosystem health, highlighting an ever-increasing need for better waste management.

Evaluating Canada's single-use plastic mitigation policies via brand audit and beach cleanup data to reduce plastic pollution

Single-use plastics (SUPs) represent a major threat to marine environments and require proactive policies to reduce consumption and mismanagement. Many SUP management strategies exist to reduce SUP use and mitigate environmental impacts, including extended producer responsibility (EPR), deposit-return schemes, SUP bans or taxes, and public outreach and education. This study analyzed brand audit and beach cleanup data in four densely populated Canadian cities (Vancouver, Toronto, Montréal, Halifax) and a remote island (Sable Island) to determine efficacy of ongoing SUP mitigation measures. Cities were found to have similar litter type proportions, and six brands were found to disproportionally contribute to Canadian SUP litter, comprising 39% of branded litter collected. Results confirm that current Canadian SUP management appears to be insufficient to address leakage of SUPs into the environment. Recommendations to strengthen SUP management strategies and mitigate plastic pollution are recommended to improve future Canadian SUP reduction policies.

Spatio-temporal variation of microplastic pollution in the sediment from the Chukchi Sea over five years

Sediment has been considered as an important sink for microplastics (MPs), but there are limited reports about the spatial and temporal variability of MPs in sediment from the Arctic Ocean. Furthermore, understanding is lacking on the correlation between Arctic sea ice variation and MP abundance in sediment. This study aimed to assess the MP contamination in the sediment from the Chukchi Sea over five years through three voyages (in 2016, 2018, and 2020). The MP abundances in the sediments from the Chukchi Plateau and Chukchi Shelf over five years ranged from 33.66 ± 15.08 to 104.54 ± 28.07 items kg^-1 dry weight (DW) and 20.63 ± 6.71 to 55.64 ± 22.61 items kg^-1 DW, respectively. The MP levels from the Chukchi Sea were lower than those from the Eastern Arctic Ocean. Our findings suggest that the Chukchi Plateau is an accumulation zone for fibers related to fishing gear and textiles under the dual influence of the Pacific and Atlantic Ocean currents. However, the reduction of these fibers in the sediment from the Chukchi Shelf might be related to bottom currents, sediment resuspension, and biomass. Moreover, the MP abundance in the sediment from the Chukchi Sea was positively correlated with the reduction of Arctic sea ice, suggesting that the melting sea ice contributes to the increase in MP levels in the sediment. The increase in blue MPs from the Chukchi Plateau over time might be attributed to melting sea ice or intense fishing activity, whereas the increase of the smallest MPs in this region could be owing to the breakdown of larger plastics during long-distance transport or the easier settlement of smaller MPs. Further time-series investigations are urgently required to improve the understanding of the environmental fate and transport of MPs among the different Arctic environmental compartments.

Distribution and transport of microplastic and fine particulate organic matter in urban streams

Plastic litter is accumulating in ecosystems worldwide. Rivers are a major source of plastic litter to oceans. However, rivers also retain and transform plastic pollution. While methods for calculating particle transport dynamics in rivers are well established, they are infrequently used to quantify the transport and retention of microplastics (i.e., particles < 5 mm) in flowing waters. Measurements of microplastic movement in rivers are needed for a greater understanding of the fate of plastic litter at watershed and global scales, and to inform pollution prevention strategies. Our objectives were to (1) quantify the abundance of microplastics within different river habitats and (2) adapt organic matter "spiraling" metrics to measure microplastic transport concurrent with fine particulate organic matter (FPOM). We quantified microplastic and FPOM abundance across urban river habitats (i.e., surface water, water column, benthos), and calculated downstream particle velocity, index of retention, turnover rate, and spiraling length for both particle types. Microplastic standing stock was assessed using a habitat-specific approach, and estimates were scaled up to encompass the study reach. Spatial distribution of particles demonstrated that microplastics and FPOM were retained together, likely by hydrodynamic forces that facilitate particle sinking or resuspension. Microplastic particles had a higher downstream particle velocity and lower index of retention relative to FPOM, suggesting that microplastics were retained to a lesser degree than FPOM in the study reaches. Microplastics also showed lower turnover rates and longer spiraling lengths relative to FPOM, attributed to the slow rates of plastic degradation. Thus, rivers are less retentive of microplastics than FPOM, although both particles are retained in similar locations. Because microplastics are resistant to degradation, individual particles can be transported longer distances prior to mineralization than FPOM, making it likely that microplastic particles will encounter larger bodies of water and interact with various aquatic biota in the process. These empirical assessments of particle transport will be valuable for understanding the fate and transformation of microplastic particles in freshwater resources and ultimately contribute to the refinement of global plastic budgets.

Combining citizen and conventional science for microplastics monitoring in the White Sea basin (Russian Arctic)

The study presents the results of the field expedition in the Russian Arctic held by a group of NGO members, scientists and volunteers in summer-autumn 2020 in the Arkhangelsk Region (Russia). The survey showed microplastics presence in 7 out of 13 remote and sparsely inhabited locations in lakes, rivers and coastal areas of the White Sea basin, with microplastic particle average concentration 1.14 part/m³, that is in agreement with other recent regional studies. Mostly PE, PET and PVC were found. A simple, cheap and easy-to-use microplastics monitoring protocol was developed and tested to be used by volunteers in remote Arctic communities. Video-lectures and tutorials are available online in an open-aсcess mode. 200 volunteers from polar communities are trained in microplastic sampling and litter separation, learning about microplastic pollution, including local residents, schoolchildren and students.

Marine debris database development using international best practices: A case study in Vietnam

Marine debris, particularly plastic debris is a ubiquitous global pervasive problem. The international community recognizes that a reduction in plastic debris density is central to sustainable ocean use based on reduction performance metrics. Although many national databases already exist or are being developed, an internationally accepted index of plastic debris density does not currently exist. Standardized methods for monitoring marine debris can help inform policy decisions to reduce sources marine debris and support mitigation effectiveness. Vietnam recently committed to addressing marine debris nationally and internationally and developed ambitious targets to manage and reduce ocean plastic debris, yet Vietnam does not currently have a national marine debris monitoring database. This study identified international best practices and standards; developed a marine plastic database for accurate, efficient information gathering, management, and reporting; and developed a centralized database platform for future marine plastic debris management in Vietnam that can be adapted for other jurisdictions.

Quantifying Marine Plastic Debris in a Beach Environment Using Spectral Analysis

Marine plastic debris (MPD) is a globally relevant environmental challenge, with an estimated 8 million tons of synthetic debris entering the marine environment each year. Plastic has been found in all parts of the marine environment, including the surface layers of the ocean, within the water column, in coastal waters, on the benthic layer and on beaches. While research on detecting MPD using remote sensing is increasing, most of it focuses on detecting floating debris in open waters, rather than detecting MPD on beaches. However, beaches present challenges that are unique from other parts of the marine environment. In order to better understand the spectral properties of beached MPD, we present the SWIR reflectance of weathered MPD and virgin plastics over a sandy substrate. We conducted spectral feature analysis on the different plastic groups to better understand the impact that polymers have on our ability to detect synthetic debris at sub-pixel surface covers that occur on beaches. Our results show that the minimum surface cover required to detect MPD on a sandy surface varies between 2–8% for different polymer types. Furthermore, plastic composition affects the magnitude of spectral absorption. This suggests that variation in both surface cover and polymer type will inform the efficacy of beach litter detection methods.

Positively buoyant but sinking: Polymer identification and composition of marine litter at the seafloor of the North Sea and Baltic Sea

Different litter types accumulate in all marine environments. Plastics are of special interest because of their high abundance and possible threats to marine organisms. Polymer type is crucial for their distribution and fate in marine environments. Seafloor litter abundance and composition in the Baltic and North Sea were analysed based on three sampling campaigns according to the protocol of ICES International Bottom Trawl Survey. Polymers were identified via attenuated total reflection-Fourier transform infrared spectroscopy. General litter abundances differed significantly between the Baltic and North Sea with 9.6 items/km² and 70.7 items/km², respectively. Plastic built the dominating litter group in both seas (62.2% and 91.3%, respectively). Polymer identification revealed clear dominance of polyethylene, polypropylene and polyamide. Most polymers were positively buoyant in seawater (89.5%), thereby excluding polymer density as the main driver of vertical plastic litter transportation. Plastics at the seafloor basically reflected the entirety of polymers entering marine environments.