Assessment of marine debris on the coastal wetland of Martil in the North-East of Morocco

Baseline assessment of macrolitter on the coastline of Algeria: Fit-for-purpose data for tailor-made measures to navigate the Plasticene Age

Curbing the growing threat of marine litter requires reliable, coherent and fit-for-purpose data. The present study reports the findings of beach macrolitter surveys carried out in seventeen sites along the coastline of Algeria. The median litter density recorded along these sites amounted to 578 items per 100 m of coastline (range: 317-2684 items/100 m). Every surveyed beach exceeded the European threshold value of 20 items per 100 m of coastline by a significant margin. In addition, the evaluation conducted employing the Mediterranean threshold value of 130 items per 100 m of coastline indicated that each of the seventeen surveyed beaches resides within the non-Good Environmental Status spectrum. A significant proportion of the litter, accounting for 43 %, is attributed to food and beverage consumption-related items, highlighting the impact of single-use food packaging, including food and beverage containers resulting from unsustainable practices mainly by beach users and inadequate waste management.

Marine litter along the shores of the Persian Gulf, Iran

Plastic wastes -including cigarette butts (CBs)- are dangerous for marine ecosystems not only because they contain hazardous chemicals but also because they can finally turn into micro- or even nano-particles that may be ingested by micro- and macro-fauna. Even large pieces of plastics can trap animals. In this research, the pollution status of macroplastics (abundance, size, type, and colour) and cigarette butts (CBs, number/m2) on the northern coasts of the Persian Gulf has been investigated. A total of 19 stations were explored in Bushehr province (Iran), which covers a length equivalent to 160 km of the Persian Gulf coastline. Among the collected plastic waste (2992 items), disposable mugs were the most frequent (18 %). Plastics with sizes 5-15 cm were the most abundant, and the most common type of plastic was PET (P-value <0.05). The origin of most macroplastics was domestic (2269 items). According to the Index of Clean Coasts (ICC), most surveyed beaches were extremely dirty. The average number and density of CBs in this study were 220 and 2.45 items/m2, respectively. Household litter was the most abundant type of waste in the studied beaches, and this problem can be better managed by training and improving the waste disposal culture. In general, it is suggested that an integrated and enhanced management for fishing, sewage and surface water disposal, and sandy recreational beaches be implemented in Bushehr to control plastic waste.

Anthropogenic litter in a Mediterranean coastal wetland: A heterogeneous spatial pattern of historical deposition

Coastal wetlands represent areas that can testify historical accumulation of litter. We analyzed the anthropogenic litter deposited on the channel bottom of a coastal wetland area that experienced water stress due to extreme summer dryness after about 20 years. We hypothesize that the litter accumulated in the different areas over the years reflects the different social user categories (i.e., fishermen, beach users, hunters) and exposure to meteo-marine events. Our findings highlight that historically accumulated litter is composed of plastics (78.8 %), clothes (8.9 %), and glass (4.9 %). Moreover, litter concentration averages 53.6 items/ha in the 8 sectors. The most found categories were common household items (25.4 %), diverse (professional and consumer) items (24.2 %), and food and beverages packaging (21.4 %). Finally, litter diversity indices and the Detrended Correspondence Analysis showed sector and litter type similarities. We reported for the first time the presence of litter accumulated for 20 years testifying non-more occurring recreational activities.

Prioritising plastic pollution research in blue carbon ecosystems: A scientometric overview

The Blue Carbon Ecosystems (BCEs), comprising mangroves, saltmarshes, and seagrasses, located at the land-ocean interface provide crucial ecosystem services. These ecosystems serve as a natural barrier against the transportation of plastic waste from land to the ocean, effectively intercepting and mitigating plastic pollution in the ocean. To gain insights into the current state of research, and uncover key research gaps related to plastic pollution in BCEs, this study conveyed a comprehensive overview using bibliometric, altmetric, and literature synthesis approaches. The bibliometric analysis revealed a significant increase in publications addressing plastic pollution in BCEs, particularly since 2018. Geographically, Chinese institutions have made substantial contributions to this research field compared to countries and regions with extensive BCEs and established blue carbon science programs. Furthermore, many studies have focused on mangrove ecosystems, while limited attention was given to exploring plastic pollution in saltmarsh, seagrass, and multiple ecosystems simultaneously. Through a systematic analysis, this study identified four major research themes in BCE-plastics research: a) plastic trapping by vegetated coastal ecosystems, b) microbial plastic degradation, c) ingestion of plastic by benthic organisms, and d) effects of plastic on blue carbon biogeochemistry. Upon synthesising the current knowledge in each theme, we employed a perspective lens to outline future research frameworks, specifically emphasising habitat characteristics and blue carbon biogeochemistry. Emphasising the importance of synergistic research between plastic pollution and blue carbon science, we underscore the opportunities to progress our understanding of plastic reservoirs across BCEs and their subsequent effects on blue carbon sequestration and mineralisation. Together, the outcomes of this review have overarching implications for managing plastic pollution and optimising climate mitigation outcomes through the blue carbon strategies.

Cigarette butt pollution in popular beaches of Morocco: Abundance, distribution, and mitigation measures

Cigarette butts pose a significant challenge in managing solid litter, with an estimated 4.5 trillion of them being discarded into the environment annually. This study investigated the pollution of eleven beaches along the Moroccan Mediterranean by cigarette butts compared to other types of marine litter between 2018 and 2023. Sampling was conducted using the visual survey technique according to a standardized protocol. A total of 50, 575 items were collected with cigarette butts (14.62 %) and plastic caps/lids drinks (10.93 %) being the most common. Our survey of eleven beaches revealed 7395 cigarette butts, giving an average density of 0.06/m2 comparable to other countries in the Mediterranean. The analysis of the results shows significant differences in the abundance cigarette butts according to the beach typology, seasonality, sediment type, and number of beach users. Moreover, the study discovered a decrease in beach pollution during the COVID-19 pandemic lockdown, resulting in less litter collected compared to pre- and post-pandemic periods. The Cigarette Butt Pollution Index was categorized as very low pollution in M'diq and Kaa Asrass, low pollution in Ksar Sghir, Fnideq, Amsa, Oued Laou, significant pollution in Martil and Nador and sever pollution in Saidia and Sababia. The CBPI was higher during summer and winter, significantly associated with the density levels of beach users. The study recommends immediate action by the local administration to prevent the potential pollution of groundwater and sand by toxic substances leached from cigarette butts.

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.

Binational survey using Mytilus galloprovincialis as a bioindicator of microplastic pollution: Insights into chemical analysis and potential risk on humans

Microplastic (MP) contamination in edible mussels has raised concerns due to their potential risk to human health. Aiming to provide valuable insights regarding the occurrence, physicochemical characteristics, and human health implications of MP contamination, in the present study, two nationwide surveys of MP contamination in mussels (Mytilus galloprovincialis) were conducted in Morocco and Tunisia. The results indicated that MP frequency ranged from 79 % to 100 % in all the analyzed samples. The highest MP density was detected in mussels from Morocco (gills "GI": 1.88 MPs/g ww^-1; digestive glands "DG": 0.92 MPs/g ww^-1) compared to mussels of Tunisia (GI: 1.47 MPs g^{- 1}; DG: 0.79 MPs g^{- 1}). No significant differences in MP density were found between the two organs (GI and DG) for both countries. MPs were predominantly blue and black fibers, and smaller than 1000 μm. Seven polymeric types were identified, of which PET, PP, and PE were the most abundant, accounting for >87 % of all samples. Scanning Electron Microscopy (SEM) coupled with Energy dispersive X-ray (EDX) showed that most MPs have noticeable signs of weathering and inorganic components on their surface. The highest MP daily intake was found in children, while the lowest was estimated in women and men. Moreover, the annual dietary exposure of MPs through mussel consumption was estimated to be 1262.17 MPs/year in Morocco and 78.18 MPs/year in Tunisia. The potential risk assessment of MPs in mussels based on the polymer hazard index (PHI) was estimated in the high-risk levels, implying that MPs may pose health risks to humans. Overall, this research suggests that the consumption of mussels represents a considerable MP exposure route for the Moroccan and Tunisian populations.

Occurrence, characteristics, and removal of microplastics in wastewater treatment plants located on the Moroccan Atlantic: The case of Agadir metropolis

Wastewater treatment plants (WWTPs) are some of the main sources of microplastics (MPs) in the environment. However, studies on the occurrence and removal efficiency of MPs in WWTPs are still scarce, especially in African countries. Thus, the aim of this work was to study the abundance of MPs in the influent and effluent of two WWTPs (Aourir and M'zar) from the Agadir metropolis (Moroccan Atlantic). The two WWTPs receive different wastewater inputs (domestic and industrial). In addition, the impacts of seasonality on the fate and removal efficiency were investigated. The results showed that the MPs abundance in the wastewater decreased from 188 MPs/L in the influent to 50 MPs/L in the effluent for Aourir WWTP (domestic inputs); while the abundance was greater in the M'zar WWTP (urban and industrial inputs) recording a mean value of 519 MPs/L and 86 MPs/L in the influent and effluent, respectively. MPs collected in the Aourir WWTP ranged from 290 to 3200 μm, while MPs from the M'zar WWTP, ranged from 330 to 4200 μm. Overall, the size range of 100-500 μm was the most abundant for both WWTPs. Fibers were the highest MPs morphotype found, followed by fragments. MP colors were mainly red, black, blue, and transparent for both treatment plants. Additionally, FTIR spectroscopy showed the presence of eight different polymers, mainly polyethylene (PE), polypropylene (PP), and polystyrene (PS). Seasonal variation analysis showed that MPs abundance in summer was significantly higher compared to other seasons. However, the comparison of the removal efficiency (RE) between the different seasons indicated that the winter season (74 %) recorded the highest RE for Aourir WWTP. Conversely, spring (87 %) recorded the highest RE for M'zar WWTP. SEM/EDX micrographs showed different degrees of weathering and chemical elements adhering to the surface of the MPs. The findings of the current study will serve as a baseline for future considerations about management strategies, wastewater reuse, as well as the understanding of the occurrence of microplastic pollution along the marine ecosystems of Morocco.

Plastic litter in coastal sand dunes: Degradation behavior and impact on native and non-native invasive plants

Pollution associated to marine plastic litter is raising increasing concerns due to its potential harmful effects on human health, biota, and coastal ecosystems. However, limited information is available on the degradation behavior of plastics, especially biodegradable ones, in dune habitats. Moreover, the effects of plastics on dune plant growth and ability to withstand environmental stresses and invasion by non-native plants have been largely neglected. This is a particularly relevant issue since biological invasions are major threats to dune ecosystems. In this 18-month study, we examined the degradation behavior of two plastic bags, non-biodegradable (NBP) or biodegradable/compostable (BP), in the dune environment by visual observations and analytical techniques. Concomitantly, we investigated the individual and combined effects of bag type and sand burial (no burial vs. partial burial) on the performance of a native dune plant (Thinopyrum junceum) and an invasive plant (Carpobrotus sp.) and on their interaction. NBP did not show relevant degradation signs over the experimental period as expected. BP exhibited gradual surface modifications and changes in chemical functionality and were almost disintegrated after 18 months. Bags and burial reduced independently T. junceum survival and growth, and most plants died within 8 months of plastic exposure. Bags and burial did not affect Carpobrotus survival. However, burial decreased Carpobrotus growth while NBP increased it. Both plastics increased Carpobrotus competitive ability, and no T. junceum plants survived to co-occurrent Carpobrotus, BP, and burial. These findings indicate that removing all littered plastics from beach-dune systems not only is critical to reduce plastic pollution but also to prevent further spread of invasive species in coastal dunes.

Marine beach litter monitoring strategies along Mediterranean coasts. A methodological review

Marine beach litter (MBL) represents a serious issue for marine life, coastal ecosystems, human health and several economical activities. The Mediterranean Sea is a semi enclosed basin particularly vulnerable to this problem. Its coasts are threatened by critical anthropogenic pressures that sum up with intensive fishing and shipping, and the slow turnover of its waters. In the last decades, several scientific and participative initiatives have been conducted to study, monitor and clean-up shorelines. These studies were generally characterized by differences in timing and frequency of the surveys, as well as in litter sampling, classification and analysis. This paper presents a systematic review of current literature concerning MBL monitoring strategies along the Mediterranean coasts. Scopus indexed studies are analysed to identify discrepancies and similarities among the applied protocols, understand where current gaps lie, and point out what would be needed to develop a basin-scale efficient monitoring for the Mediterranean Sea.

Marine macroinvertebrates fouled in marine anthropogenic litter in the Moroccan Mediterranean

The existence of floating marine litter in marine environments enhances the potential for the transport of fouling organisms using these substrates as vectors. In this study, we examined the fouling organisms on different types of litter stranded on two beaches of the Moroccan Mediterranean. The study revealed 13 fouling species belonging to 8 phyla (Arthropoda, Bryozoa, Annelida, Mollusca, Cnidaria, Echinodermata, Chlorophyta, and Ochrophyta) on marine litter. Rafting vectors were almost exclusively made up of plastics and could mainly be attributed to land-based sources. The most common fouling species were the crustacean Lepas pectinata, Lepas anatifera, Perforatus perforatus, and bryozoan species. More taxa were found on large litter than on small litter. Relative substratum coverage was highest for bryozoan sp. (31.0 %), green algae (29.0 %), Lepas anatifera (21.42 %), Lepas pectinata (17.8 %), and Perforatus perforatus (17.46 %). Our results suggest that the growing generation of plastic litter may enhance the probability of the introduction of non-native species into the Moroccan Mediterranean. Therefore, monitoring efforts are needed to identify vectors and the arrival of novel invasive species in this area.

Toward a sustainable circular economy for cigarette butts, the most common waste worldwide on the coast

The circular economy is based on the maximum use of resources by reducing, reusing, and recycling the elements used. Currently, the items littered most frequently in the world are cigarettes butts (CB) as these debris are freely disseminated in the marine habitat, they are generally difficult to collect and very complex to recycle. Litter CB is a great social problem that generates excessive economic costs and serious environmental problems. CB is also not biodegradable and highly toxic to marine organisms and presents a distinctive mixture of physical and chemical contamination. However, little research has been done on the management and recycling of this dangerous waste. Several proposals have been made to incorporate this waste into high-volume articles of direct production or recycling, but collection logistics are lacking since the current system is inefficient, in addition to the poor environmental behaviour of citizens. This work presents a current synthesis of the CB problem from all its possible aspects in order to have a global vision of the life cycle of the CB, indicating both the known and the gaps in the knowledge of each of them, and intends to give a general outline of the steps to follow to try to end such a worrying problem at the global level.

Addressing the challenge of marine plastic litter in the Moroccan Mediterranean: A citizen science project with schoolchildren

In this study, based on data collected by citizen science, we studied the abundance, spatial and temporal distribution of marine litter in three beaches of the Moroccan Mediterranean. A total of 14,042 litter items were collected with an average abundance of 0.58 items/m². The most of litter were composed of anthropic polymeric materials, representing 74 % of the total litter collected. Plastics account for the majority of the items collected and are mainly caps/lids, crisp/sweet packets, plastic/polystyrene, cigarette butts and small plastic bags. Litter abundance displayed significant seasonal differences, with the highest during summer. Tourism and poor waste management practices are the major sources of plastic on the beaches surveyed. The use of the Clean Coast Index (CCI) and the Plastics Abundance Index (PAI) permits the classification of the three beaches in the Moroccan Mediterranean as a "moderately clean" coastal area with a "very high abundance" of plastics. In addition, the Hazardous Items Index (HII) allows classification of the region as highly polluted by hazardous litter. Best management measures are needed to promote the environmental quality of the beaches of the Moroccan Mediterranean.

Microplastics pollution in sediments of Moroccan urban beaches: The Taghazout coast as a case study

This work describes the spatiotemporal analysis of microplastics (MPs) pollution in sediments collected on a high urbanized beach located in Taghazout coast, central Atlantic part of Morocco. The study area is mainly composed of moderately well-sorted fine sands with an average density of MPs that ranged between 915 MPs/kg in 2018 and 1448 MPs/kg in 2019. The most polluted sites were in the south part of Taghazout coast, close to facilities of where beachgoers are often found. Microplastic Pollution Index (MPPI), Microplastic Impact Coefficient (CMPI), Agglomerative Hierarchical Clustering (AHC), and Multidimensional Scaling (MDS) revealed spatiotemporal variation of MPs pollution. Thus, the principal component analysis (PCA) showed a low correlation between the sediment characteristics (i.e., grain size, sorting, skewness) and MPs densities. Overall, the outputs of this baseline recommend implementing plastic management strategies to eliminate or at least minimize the collateral effects generated by MPs pollution in sediments of urbanized beaches.

Face masks related to COVID-19 in the beaches of the Moroccan Mediterranean: An emerging source of plastic pollution

During the COVID-19 pandemic, face masks became a common type of litter invading many different environments, including tourist beaches. However, the presence of face masks on beaches threatens the marine environment with a new form of plastic pollution. In this study, we monitored the occurrence and density of face masks on five tourist beaches along the Moroccan Mediterranean during five months starting from February until June 2021. A total of 321 face masks were recorded on the five beaches, 96.27% of which were single use. The mean density of face masks was 0.0012 ± 0.0008 m^-2. Recreational beaches were the most polluted in the study area. This is related to the important influx of beachgoers on urban beaches compared to resort beaches. With the large number of masks introduced on the beach, we hypothesize that microplastic pollution could increase drastically in the Moroccan Mediterranean in the coming years. Significant efforts are required to reduce this type of waste.

Microplastics pollution along the central Atlantic coastline of Morocco

This baseline study describes the microplastic (MPs) problem on seven beaches located on Agadir, central Atlantic coast of Morocco. Microplastics abundances (densities) ranged from 7680 MPs/kg to 34,200 MPs/kg above other world beaches. The following shapes were found: fibers, fragments, films, and pellets. Fibers were the dominant typology with a 73%. Polyethylene (PE) was the predominant polymer in all beaches with an average percentage of 59%, followed by Polypropylene (PP - 18%), Polystyrene (PS - 9%), Polyvinyl chloride (PVC - 8%), and Ethylene-vinyl acetate (EVA - 6%). Microplastics abundances presented in this work suggest continuous inputs of plastics of all sizes and types. Also, all observed shapes highlight a combination of sources (primary and secondary). Central Atlantic Moroccan beaches are currently affected by extreme values of MPs that demand urgent interventions to restore environmental quality.

Personal protective equipment (PPE) pollution associated with the COVID-19 pandemic along the coastline of Agadir, Morocco

The increasing use of personal protective equipment (PPE) as a sanitary measure against the new coronavirus (SARS-CoV-2) has become a significant source of many environmental risks. The majority of the governments enforce the use of PPE in public areas, such as beaches. Thus, the use and disposal of PPE have compromised most solid waste management strategies, ultimately leading to the occurrence of PPE polluting the marine environment. The present study aimed to monitor the PPE pollution associated with COVID-19 along the coastline of Agadir, Morocco. In parallel, the influence of the activities carried out in each sampled beach before and after the lockdown break was reported. Overall, a total number of 689 PPE items were identified, with a mean density of 1.13 × 10^-5 PPE m^-2 (0-1.21 × 10^-4 PPE m^-2). The majority of the PPE items found were face masks (96.81%), out of which 98.4% were surgical masks and 1.6% were reusable cloth masks. The most polluted sites were the beaches with recreational activities, followed by surfing, and fishing as the main activity. Importantly, PPE density increased significantly after lockdown measures. Additionally, the discarded PPE sampled in the supralittoral zone was higher than PPE recorded in the intertidal zone. This confirms that PPE items are driven by the beachgoers during their visit. PPE items are a source of microplastic and chemical pollutants, a substrate to invasive species colonization, and a potential threat of entanglement, ingestion, and/or infection among apex predators. In the specific case of Agadir beaches, significant efforts are required to work on the lack of environmental awareness and education. It is recommended to improve beach cleaning strategies and to penalize incorrect PPE disposal. Additional alternatives may be adopted, as the involvement of biodegradable materials in PPE manufacturing, recycling through pyrolysis, and encouraging reusable and washable masks.

Anthropogenic litter along a coastal-wetland gradient: Reed-bed vegetation in the backdunes may act as a sink for expanded polystyrene

We investigated the accumulation of litter along a transition gradient from the dunal beaches (B), to the backdunes (BD), to the channels of a coastal wetland (W), considering both the total litter and a sub-category represented by expanded polystyrene (EPS). Using a removal sampling technique carried out in spring (April and May), we hypothesized that: (i) the total accumulation of litter decreases progressively from the dunes to the backdunes to wet environments while (ii) the lighter polystyrene concentrates in the BD-W fringe where the Phragmites australis reedbeds can have a sink role for this polymer. The total litter density showed a significant decrease along the gradient B-BD-W in both months, with an evident collapse between BD and W. Analogously, EPS showed a significant difference in density along the B-BD-W gradient in both months, although with a different pattern: a maximum in the BD and a significant collapse between BD and W. The presence of backdune hygrophilous vegetation (Phragmites australis' reedbeds) may act as a sink trapping all types of litter in both cases (total litter and EPS). The different accumulation pattern between total litter and the EPS is due to the lower specific weight of the latter polymer: while the generic litter tends to decrease quantitatively moving away from the sea, the lighter EPS is removed by the winds and pushed towards the land, beyond the dune, where it is trapped by the vegetation, thus showing a peak in density in the backdunes. No significant differences were observed between the litter density in the two months (before and after the removal) either considering the total litter and only EPS. This may suggest a continuous supply of litter from the sea, highlighting how clean-ups actions should be carried out with a higher frequency rather than monthly. This may be even more valid in the period of greater frequency of intense weather-marine events (autumn-winter) when a greater quantity of litter is deposited. These are the first data for the Mediterranean regarding a specific role of wetland hygrophilous vegetation as a sink for anthropogenic litter, mainly expanded polystyrene.

What remains on the beach after tourists leave? The case of Abaís beach (Sergipe, Brazil)

The study evaluated the characteristics of marine litter disposed of by tourists on the Abaís beach (state of Sergipe, Brazil), during the dry (December/2017, January/2018, and February/2018) and rainy (May/2018, June/2018, and July/2018) months. Litter was collected on a Sunday of each month after the tourists left. The values of abundance (9.71 ± 2.03 items/m), weight (21.07 ± 16.04 g/m), volume (0.58 ± 0.25 L/m), richness (33 litter groups) and plastic percentage (75.07 ± 4.81%) were higher in the dry months compared to the rainy ones (2.01 ± 2.80 items/m; 5.08 ± 6.01 g/m; 0.17 ± 0.16 L/m; 22 litter groups; and 68.62 ± 5.98% of plastic, respectively). Considering the tourist importance of the Abaís beach to Sergipe state, it is crucial to develop effective cleaning actions, environmental awareness campaigns for tourists, residents and traders, as well as to establish restrictive public legal instruments to promote reduction, reuse, and recycling of the marine litter.

A Survey of Marine Coastal Litters around Zhoushan Island, China and Their Impacts

Rapid development of the economy increased marine litter around Zhoushan Island. Social-ecological scenario studies can help to develop strategies to adapt to such change. To investigate the present situation of marine litter pollution, a stratified random sampling (StRS) method was applied to survey the distribution of marine coastal litters around Zhoushan Island. A univariate analysis of variance was conducted to access the amount of litter in different landforms that include mudflats, artificial and rocky beaches. In addition, two questionnaires were designed for local fishermen and tourists to provide social scenarios. The results showed that the distribution of litter in different landforms was significantly different, while the distribution of litter in different sampling points had no significant difference. The StRS survey showed to be a valuable method for giving a relative overview of beach litter around Zhoushan Island with less effort in a future survey. The questionnaire feedbacks helped to understand the source of marine litter and showed the impact on the local environment and economy. Based on the social-ecological scenarios, governance recommendations were provided in this paper.

Trajectory of coastal wetland vegetation in Xiangshan Bay, China, from image time series

Coastal wetland vegetation is crucial for providing multiple ecosystem services. However, accurate assessment of wetland vegetation is problematic due to the challenging coastal environment. Using Xiangshan Bay (XB) in China as a typical case study, we developed a time series biological phenological approach to classifying coastal wetland vegetation using Landsat time-series images from 1984 to 2018. The results demonstrate that the total vegetation area of coastal wetlands in XB in 2018 was ~85.3 km². The interannual dynamics of coastal wetland vegetation area in XB in the last 35 years can be divided into three periods: increasing volatility (1984-1998), decreasing (1999-2004), and increasing volatility (2005-2018). Our results emphasize the potential of the use of the time-series biological phenological approach for monitoring coastal wetland vegetation, which can contribute to the sustainable management of coastal ecosystems.

A snapshot of the litter problem along the Viña del Mar - Concón coastal strip, Valparaíso region, Chile

Along the Viña del Mar - Concón coastal strip 11,894 litter items were collected, and grouped into 48 different categories (11 litter typologies). The average litter abundance was 0.25 items/m², plastic items, and cigarette butts being the most common. Hazardous litter can be found along the entire study area, reaching 28.9% (3438 items of 11,894 total items collected distributed in 14 different categories), and an average of 0.071 items/m². The application of environmental evaluation indices based on litter data, allows categorizing the study area as a clean-moderate coastal strip with some presence of hazardous litter items, and unsatisfactory environmental conditions. Studied sectors were statistically grouped into three specific types that ranged from sectors in optimal environmental conditions (Group A) to sectors in adverse environmental conditions (Group C). The typology and magnitudes of litter found along the study area suggest a combination of sources that mainly include direct activities on the beach (recreational and smoking-related) as well dumping. In the same way, sanitary waste, ocean/waterway items, and items related to surfing activities were observed. Strategies for litter management and environmental quality improvement need to be developed and enforced.

Marine debris in Moroccan Mediterranean beaches: An assessment of their abundance, composition and sources

Morocco is well known for its attractive Mediterranean beaches, which play an important economic role. With the fast development and growth, these beaches have become more contaminated by marine debris. This paper examined the abundance, composition and marine debris sources on five beaches in the Moroccan Mediterranean during 2019 four seasons. A total of 7839 marine debris were collected from the five beaches with a total weight of 231 kg. The average density of the debris collected was 0.20 ± 0.098 items/m². Polymer materials constituted the majority of debris found, with a percentage of 71.36%, followed by paper/cardboard (11.50%), metal (5.77%), processed wood (5.34%), cloth/textile (2.51%) and glass/ceramics (1.76%). Human recreational activities were the main source of debris (70.13%), followed by smoking-related (13.98%). Debris density appears to be particularly influenced by beach users. Awareness campaigns are needed for beach users to improve the quality of the beaches.

Combined effect of plastic litter and increased atmospheric nitrogen deposition on vegetative propagules of dune plants: A further threat to coastal ecosystems

Large amounts of non-biodegradable plastics are currently deposited on beach-dune systems, and biodegradable plastics could enter these already declining habitats in coming years. Yet, the impacts of plastics on vegetative recruitment, a plant strategy playing a key role in dune stabilization, are unknown. Whether these pollutants interact with increased atmospheric nitrogen (N) deposition, a major global driver of plant biodiversity loss, in affecting plant communities of such nutrient-poor habitats, and how plant-plant interactions mediate their effects need to be explored. In a one-year field experiments, we examined individual and combined effects of plastic (non-biodegradable, biodegradable), N deposition (ambient, elevated) and biotic condition (no interaction, interaction with a conspecific or with a hetero-specific) on the colonization success and growth of vegetative propagules of dune plants. Thinopyrum junceum and Sporobolus pumilus were chosen as models because they co-occur along Mediterranean dunes and differ in ecological role (dune- vs. non dune-building) and photosynthetic pathway (C3 vs. C4). For both species, survival probability was reduced by non-biodegradable plastic and elevated N by up to 100%. Thinopyrum junceum survival was also reduced by S. pumilus presence. Elevated N and biodegradable plastic reduced T. junceum shoot biomass when grown alone and with a conspecific, respectively; these factors in combination mitigated their negative individual effects on root biomass. Biodegradable plastic increased S. pumilus shoot and root biomass, and in combination with elevated N caused a greater biomass investment in belowground (root plus rhizome) than aboveground organs. Non-biodegradable plastic may be a further threat to dune habitats by reducing plant colonization. Biodegradable plastic and increased N deposition could favour the generalist S. pumilus and hinder the dune-building T. junceum. These findings highlight the urgency of implementing measures for preventing plastic deposition on beaches and reducing N input.

Density and composition of surface and buried plastic debris in beaches of Senegal

Debris poses a series of problems to marine life and human well-being. However, estimates of density and characteristics of debris found on beach surfaces and buried in the sand are patchy on a global scale and absent for West Africa. Here we investigate the density of surface and buried debris accumulated in two beaches with contrasting levels of urbanisation in Senegal, West Africa. We also describe type, colour, weight, size, and possible source of the 1766 items collected. The average density of debris buried at a depth of 10 cm (48.75 items/m²) was 25 times higher than that observed at the surface (1.92 items/m²). Plastics accounted for 97.62% of the items. Plastic bags and clothing plastic were the most common types, whereas white and transparent were the most common colours. Most items originated from mixed sources, i.e. beach users and land-based sources (51.30%). Debris density in the urbanised site was 20 times higher than that in the non-urbanised site. Debris density can, therefore, be largely underestimated when sampling only on the beach surface. Our study provides the first findings for future research on beach debris in Senegal.

Plastic pollution on the Mediterranean coastline: Generating fit-for-purpose data to support decision-making via a participatory-science initiative

Plastic pollution is a global problem and reliable, coherent and comparable data are essential for targeted mitigation strategies. Throughout the years Mediterranean NGOs have significantly contributed to providing data and information on the temporal and spatial distribution of marine litter found stranded on beaches; thus participatory-science campaigns are an essential tool to fill in the marine litter knowledge gaps. The present study reports the findings of beach litter surveys carried out by 7 NGOs in 23 sites along the coastline of the Mediterranean. The average litter density per site varied from 53 items/100 m to 6,660 items/100 m, with a median of 451 items/100 m. The majority of litter items were made of artificial/anthropogenic polymer materials accounting for 90% of all litter collected. Litter from shoreline sources accounted for 38%. Single-use plastics (SUPs) accounted for 38% of all items recorded ranging from 18.6% to 66.9% for the different beaches. 30% of the investigated beaches had more than 50% of SUPs of the total items recorded, thus providing baseline information and supporting evidence for the Single-Use Plastics Directive.

Marine Microbial Assemblages on Microplastics: Diversity, Adaptation, and Role in Degradation

We have known for more than 45 years that microplastics in the ocean are carriers of microbially dominated assemblages. However, only recently has the role of microbial interactions with microplastics in marine ecosystems been investigated in detail. Research in this field has focused on three main areas: (a) the establishment of plastic-specific biofilms (the so-called plastisphere); (b) enrichment of pathogenic bacteria, particularly members of the genus Vibrio, coupled to a vector function of microplastics; and (c) the microbial degradation of microplastics in the marine environment. Nevertheless, the relationships between marine microorganisms and microplastics remain unclear. In this review, we deduce from the current literature, new comparative analyses, and considerations of microbial adaptation concerning plastic degradation that interactions between microorganisms and microplastic particles should have rather limited effects on the ocean ecosystems. The majority of microorganisms growing on microplastics seem to belong to opportunistic colonists that do not distinguish between natural and artificial surfaces. Thus, microplastics do not pose a higher risk than natural particles to higher life forms by potentially harboring pathogenic bacteria. On the other hand, microplastics in the ocean represent recalcitrant substances for microorganisms that are insufficient to support prokaryotic metabolism and will probably not be microbially degraded in any period of time relevant to human society. Because we cannot remove microplastics from the ocean, proactive action regarding research on plastic alternatives and strategies to prevent plastic entering the environment should be taken promptly.

Exposure of coastal dune vegetation to plastic bag leachates: A neglected impact of plastic litter

The presence of plastic bags on coastal dunes worldwide is well documented. Plastic bags contain additives that during rainfall events can leach out from bags into sand dune and be absorbed by seeds and roots of plants. Dune plants play a fundamental role in dune system formation, yet the possible impact of bag leaching on their establishment and development has been neglected. We assessed in laboratory whether (i) not biodegradable bags (high-density polyethylene, PE) and new generation of compostable bags (Mater-bi®, MB) would influence via leaching water chemical/physical properties and (ii) leachates would affect germination and seedling growth using Thinopyrum junceum and Glaucium flavum as models. Leachates were obtained from different amounts of not-exposed and bags exposed to beach or marine conditions simulating various pollution degrees (none, low, intermediate and high pollution). All water variables were affected by leaching. The magnitude of these alterations depended on bag type and environmental exposure. Seeds of T. junceum treated with the high concentration of marine-exposed MB bag leachate germinated later than controls while those of G. flavum treated with the remaining leachates germinated earlier. For both species, leachates from the low concentration of PE and MB marine-exposed bags increased seed germinability. A short radicle was observed in T. junceum seedlings treated with not-exposed MB bag leachates. Glaucium flavum seedlings treated with beach- and marine-exposed PE bags and not-exposed MB bags leachates showed a greater below-aboveground length ratio and those grown with the low concentration of not-exposed PE bag leachate had a longer hypocotyl compared to controls. Leachates from the high concentration of PE and MB bag caused seedling anomalies in both species. These findings indicate that not biodegradable and compostable bags may interact with abiotic/biotic factors and affect via leaching germination phenology, seedling establishment and plant interactions with consequences on dune community structure.

Adverse effects of non-biodegradable and compostable plastic bags on the establishment of coastal dune vegetation: First experimental evidences

Non-biodegradable and compostable plastic bags on beaches negatively affect the development of coastal dune vegetation by drastically reducing seedling emergence and growth.

Quantity and spatial distribution of seafloor marine debris in the Moroccan Mediterranean Sea

This paper qualifies, quantifies and localizes seafloor marine debris (SMD) in the Moroccan portion of the Mediterranean Sea. Six scientific trawl surveys were conducted by the Moroccan Institute of Fisheries Research from 2012 to 2015 between Cape Spartel (5°W) and Saidia (2°W), during which a total of 497 kg of SMD has been collected. Statistical analysis show that the mean abundance differed between surveys, generally ranging from 26 ± 68 to 80 ± 133 kg/km². A typology of SMD indicates that plastic represented 73% of the debris collected, followed by rubber (12%), textile (8%), metal (3%), glass (0.32%), and some unidentified materials (2.70%). Analysis of results shows that the abundance and the distribution of SMD were strongly influenced by the local anthropogenic activities and by rivers inputs. The movements and accumulations in the open sea were also shown to be influenced by the geomorphology and the hydrodynamics of the basin.

Plastic cigar tips debris: Exploring use and disposal issues for Lake Erie beaches

Great Lakes states are increasingly faced with questions regarding how plastic debris is impacting marine and coastal ecosystems. This is especially evident along the southern beaches of Lake Erie, where high population and industrial development have contributed to the plastics problem. In Ohio, the most common items found are cigarettes and other smoking related materials, including plastic cigar tips. Given the growing awareness of the issue, and the impact of plastics on beaches throughout the Great Lakes, a focus group convened to investigate strategies to help address the problem. The group was comprised of individuals with practical knowledge of plastic cigar tip use and disposal issues, including representatives of government agencies, nongovernmental organizations, community groups, and local academic institutions. This report represents the exploratory results of the focus group, complete with information regarding the what, why, and how of plastic cigar tip debris in the region, guidance on the material and social barriers to sustaining desired behaviors (cessation of use by minors and/or proper disposal), strategies to overcome those barriers, and suggestions for management and policy actions moving forward. Group members suggest that a combination of education and government-supported financial incentives may be the most effective approach, with community-based positive messaging backed by local taxes on smoking items that have plastic tips and rebates or other rewards for properly disposing of debris.

Collected marine litter - A growing waste challenge

Marine litter, in particular plastic debris, poses a serious threat to marine life, human health and the economy. In order to reduce its impact, marine litter collections such as beach clean-ups are frequently conducted. This paper presents a systematic review of temporal developments, geographical distribution, quantities and waste treatment pathways of collected marine litter. Results from over 130 studies and projects highlight the worldwide increase in collection efforts. Many of these are in wealthy countries that do not primarily contribute to the problem. Over 250 thousand tonnes, have already been removed, but there is little or no information available regarding how this waste is treated or used post collection. This paper highlights the need for a whole-system quantitative assessment for the collection and waste treatment of marine litter, and identifies the challenges associated with utilising this waste in the future.

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

Recent data indicate accumulation areas of marine litter in Arctic waters and significant increases over time. Beaches on remote Arctic islands may be sinks for marine litter and reflect pollution levels of the surrounding waters particularly well. We provide the first quantitative data from surveys carried out by citizen scientists on six beaches of Svalbard. Litter quantities recorded by cruise tourists varied from 9-524gm^-2 and were similar to those from densely populated areas. Plastics accounted for >80% of the overall litter, most of which originated from fisheries. Photographs provided by citizens show deleterious effects of beach litter on Arctic wildlife, which is already under strong pressure from global climate change. Our study highlights the potential of citizen scientists to provide scientifically valuable data on the pollution of sensitive remote ecosystems. The results stress once more that current legislative frameworks are insufficient to tackle the pollution of Arctic ecosystems.