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Tracking plastics in the Mediterranean: 2D Lagrangian model
Abstract
Drift of floating debris is studied with a 2D Lagrangian model with stochastic beaching and sedimentation of plastics. An ensemble of >1010 virtual particles is tracked from anthropogenic sources (coastal human populations, rivers, shipping lanes) to environmental destinations (sea surface, coastlines, seabed). Daily analyses of ocean currents and waves provided by CMEMS at a horizontal resolution of 1/16° are used to force the plastics. High spatio-temporal variability in sea-surface plastic concentrations without any stable long-term accumulations is found. Substantial accumulation of plastics is detected on coastlines and the sea bottom. The most contaminated areas are in the Cilician subbasin, Catalan Sea, and near the Po River Delta. Also, highly polluted local patches in the vicinity of sources with limited circulation are identified. An inverse problem solution, used to quantify the origins of plastics, shows that plastic pollution of every Mediterranean country is caused primarily by its own terrestrial sources.
... Most plastic debris (80 %) comes from land-based sources such as single-use consumer items, with the remaining 20 % coming from shipping lanes and fishing vessels (Liubartseva et al., 2018). Wind and surface currents typically carry floating debris over long distances before it settles on the seafloor or accumulates onshorelines (Barnes et al., 2009;Cole et al., 2011;Derraik, 2002;Eriksen et al., 2014;Galgani et al., 2015). ...
... Some activities that lead to the generation of secondary MPs include the following: Dumping activities include tossing, dumping, or depositing plastic items on or near streets and stream basins, as well as directly accumulating along the shore. Liubartseva et al. (2018) noted that >70 % of plastic pollution on the Algerian coast came from terrestrial sources. The two basins, the El Saf-Saf and Kebir, serve as channels for collecting and transporting wastewater to the beaches in the study area. ...
... Ocean and waterway activities (fisheries and shipping): Twenty percent of marine plastic pollution in Algeria is related to shipping lanes (Liubartseva et al., 2018). ...
This paper describes the microplastic problems on five sandy beaches along the Skikda coastline (southwestern Mediterranean, northeastern Algeria), defining their magnitudes, spatial-temporal distributions, shapes, polymer types, impacts, and potential sources. The data presented in this study were collected during two field surveys in May (spring) and September (autumn/fall) of 2019. Overall, the average abundance of microplastics across all beaches was 6174 items/m2 in spring and 6183 items/m2 in autumn, representing the highest level of MPs ever reported in Algeria. The most common microplastic types found were fragments, pellets, foams and fibers, accounting for >98 % of the microplastic shapes collected in this study. Our findings highlight the persistence of MPs on the studied beaches and that environmental factors such as currents, wind directions, beaching, sedimentation, dunes, and fragmentation all significantly impact the distribution and accumulation of plastic debris on beaches.
... These results are unsurprising, as the Adriatic Sea is a known hotspot for marine debris in the Mediterranean basin Campanale et al., 2019;Gomiero et al., 2018;Palatinus et al., 2019). This is largely due to the significant plastic pollution transported across the Po River, which annually draws around 1350 t of plastic into the Mediterranean Sea (Liubartseva et al., 2018;Tsiaras et al., 2021). Additionally, plastic waste from Albanian rivers contributes to plastic pollution in the southern Adriatic Sea (Artegiani et al., 1997;Tsiaras et al., 2021;UNEP/ MAP, 2012). ...
... Morocco and Libya exhibit high rankings in total waste discard per capita (Dalberg and WWF Mediterranean Marine Initiative, 2019; Kaza et al., 2018). Furthermore, the Ceyahn and Seyahn rivers in Turkey, the Nile in Egypt, and the Vardar River, which flow into the Aegean Sea, are among the most polluted rivers in the region, thus serving as significant sources of plastic pollution entering into the sea (Liubartseva et al., 2018;Tsiaras et al., 2021). ...
... According to our data from the Spanish Mediterranean continental shelf sampled within the MEDIAS survey, Barcelona was one of the areas with the lowest abundance of macrofloating debris values (4.96 ± 2.35 items⋅km − 2 in 2021; 2.72 ± 4.71 items⋅km − 2 in 2022). However, a high abundance of macrofloating debris was expected in Barcelona due to its dense population, ranking as the second largest Mediterranean city with a large plastic input into the sea (1800 t per year; Dalberg and WWF Mediterranean Marine Initiative, 2019;Liubartseva et al., 2018). These findings are in keeping with the report by Garcia-Garin et al. (2020a, 2020b, who also reported a high level of macrofloating debris in the Ebro Delta. ...
... Most plastic debris (80 %) comes from land-based sources such as single-use consumer items, with the remaining 20 % coming from shipping lanes and fishing vessels (Liubartseva et al., 2018). Wind and surface currents typically carry floating debris over long distances before it settles on the seafloor or accumulates onshorelines (Barnes et al., 2009;Cole et al., 2011;Derraik, 2002;Eriksen et al., 2014;Galgani et al., 2015). ...
... Some activities that lead to the generation of secondary MPs include the following: Dumping activities include tossing, dumping, or depositing plastic items on or near streets and stream basins, as well as directly accumulating along the shore. Liubartseva et al. (2018) noted that >70 % of plastic pollution on the Algerian coast came from terrestrial sources. The two basins, the El Saf-Saf and Kebir, serve as channels for collecting and transporting wastewater to the beaches in the study area. ...
... Ocean and waterway activities (fisheries and shipping): Twenty percent of marine plastic pollution in Algeria is related to shipping lanes (Liubartseva et al., 2018). ...
... Türkiye is one of the major plastic pollution sources in the Mediterranean and the Black Sea (Liubartseva et al., 2018;Çevik et al., 2021;Strokal et al., 2022). Inadequate waste management infrastructure makes the Turkish rivers the main source of plastic pollution for the Mediterranean Sea. ...
... According to Gonzalez-Fernandez et al. (2021), Türkiye had the highest share (16.8%) of the total floating macro-litter loading to the marine environment (the Mediterranean and the Black Sea). In another study, it was estimated that areas with the highest concentrations of plastics (>20 g km −2 ) are represented in the Cilician Sea (NE Mediterranean coasts of Türkiye) (Liubartseva et al., 2018). In the same study, it is estimated that three of the top five major sources of plastic pollution in the Mediterranean Sea are Turkish rivers: the Ceyhan (5.1%), Seyhan (3.5%), and Buyuk Menderes Rivers (2.4%). ...
... The effluent of Seyhan WWTP flows into the Seyhan River. Therefore, as stated by Liubartseva et al. (2018), this is an important factor that makes the Seyhan River the river that carries the most plastic waste to the Mediterranean Sea. ...
This chapter examines the impact of plastic waste on the environment in Türkiye, a major importer and generator of plastic waste. Poor waste management exacerbates the harmful effects of plastic waste on the land, the seas, and the air. We analyze whether waste management litigation and practices in Türkiye are in conformity with the country’s obligations under the Basel Convention. We further evaluate the impact of Türkiye’s waste management on plastic waste in Turkish seas according to regional sea regimes in the Mediterranean and the Black Sea. Lastly, we consider the emissions from plastic waste in Türkiye and argue that they are detrimental for air quality and for the achievement of the objectives of the United Nations climate change regime. Türkiye struggles to manage the large amount of plastic waste it generates and imports. This chapter indicates that Türkiye’s plastic waste management practices have serious environmental consequences. These practices also raise concerns about the country’s ability to fulfill its commitments and obligations under the aforementioned multilateral environmental agreements. Considering the country’s position in ongoing Plastic Treaty negotiations, a significant improvement in plastic waste management seems unlikely. We suggest that Türkiye withdraws itself from being a subject of the transfer of plastic waste pollution and improves its waste management practices by focusing on the execution of domestic regulations that comply with international standards.
... employed by Critchell and Lambrechts (2016) is able to take into account beaching, settling, re-suspension/re-floating, degradation into micro-plastics and topographic effects on the wind in nearshore waters. Similarly, Liubartseva et al. (2018) proposed a 2D Lagrangian model integrated with algorithms of beaching and sedimentation of plastics to be solved using a Monte Carlo technique. Jalón-Rojas et al. (2019) introduced the 3D numerical model TrackMPD, which is able to include also the effects of the biofouling process on the micro-plastic buoyancy, using as representative parameters the biofilm thickness, density and growth rate. ...
... Kako et al., 2014;Critchell and Lambrechts, 2016;Iwasaki et al., 2017;Cardoso and Caldeira, 2021;Allison et al., 2022), enclosed seas (e.g. Carlson et al., 2017;Liubartseva et al., 2018;Li et al., 2018;Baudena et al., 2022;Murawski et al., 2022), and gulfs (e.g. Alosairi et al., 2020;Zayen et al., 2020). ...
... Table 2 reports the empirical coefficients of the rainfall DDF curve and the corresponding peak flow rates for T r equal to 2, 50 and 100 years. When plastic litter is released into the sea, whether directly or by the rivers, it spreads according to the local hydrodynamic circulation patterns, which may cause large sea surface plastic concentration, as demonstrated by the numerical investigation of Liubartseva et al. (2018). As shown in Fig. 1c, the mean direction of the sediment drift estimated from the analysis of the mean annual wave motion energy is about 50 • N (PRCEC, 2020), right towards the MPA. ...
Management of plastic litter in Marine Protected Areas (MPAs) is expensive but crucial to avoid harms to critical environments. In the present work, an open-source numerical modelling chain is proposed to estimate the seasonal pathways and fates of macro-plastics, and hence support the effective planning and implementation of sea and beach cleaning operations. The proposed approach is applied to the nearshore region that includes the MPA of Capo Milazzo (Italy). A sensitivity analysis on the influence of tides, wind, waves and river floods over the year indicates that seasonality only slightly affects the location and extension of the macro-plastic accumulation zones, and that beach cleaning operations should be performed in autumn. Instead, the influence of rivers on plastic litter distribution is crucial for the optimal planning of cleaning interventions in the coastal area.
... The observations indicated were roughly consistent for transport pathways of particles, although the beaching of plastics was not specified in the model. Another attempt to investigate the distribution of plastic debris was reported by Liubartseva et al. [31], who divided the simulated domain within the Mediterranean Sea into three distinct environmental compartments: the sea surface, the coastlines, and the seabed. The combination of the 2D Lagrangian particle tracking model together with wave-dependent currents calculated from a coupled hydrodynamic model highlighted the effect of Stokes drift in the transport of plastics [31]. ...
... Another attempt to investigate the distribution of plastic debris was reported by Liubartseva et al. [31], who divided the simulated domain within the Mediterranean Sea into three distinct environmental compartments: the sea surface, the coastlines, and the seabed. The combination of the 2D Lagrangian particle tracking model together with wave-dependent currents calculated from a coupled hydrodynamic model highlighted the effect of Stokes drift in the transport of plastics [31]. ...
... These models are not ideally suited for simulating plastic transport processes such as deposition, erosion, aggregation, and fragmentation. Moreover, the discrepancies among the aforementioned modelling results indicate that the realistic situation is highly complex and dynamic, owing in part to the fundamental mechanisms associated with external hydrological factors, such as transport by wave action [32], discharge [33], Stokes drift, beaching and sedimentation, buoyancy [31] in different aquatic environments, and even biological processes. However, the accuracy of numerical sim-ulations in capturing the advection and dispersion of microplastics has not undergone comprehensive validation. ...
Microplastic contamination is a challenge in aquatic systems. Among these, floodplains exhibit their cyclical hydrological patterns with substantial fluctuations in water levels caused by annual floods or discharges from rivers into lakes. The influence of water level fluctuation on microplastics within complex floodplain systems has received limited attention in existing studies. This study employs hydrological data and a physics-based hydrodynamic model to assess the effects of water level fluctuations on the transport and redistribution of microplastics within Poyang Lake from 2018 to 2025. High spatiotemporal distribution variability in microplastic concentrations was found within the flood and drought periods. Furthermore, the residence rate of microplastics was assessed based on the microplastic concentration variations in the computational time. A gradual drop in the average discharge rate of microplastics was assessed at the outlet of Poyang Lake. The microplastics are more likely to drain into the Yangtze River in the high water-level period. Meanwhile, under the influence of hydrodynamics, local topography, and water level fluctuation, an accumulation of microplastics appears on the shallow shoals of the western and eastern regions of Poyang Lake, especially in the Gan River. Overall, by means of numerical simulation, the aim of our study is to serve as a reference and advance our understanding of the transportation patterns of microplastics at the aquatic–terrestrial interface.
... Previous studies have demonstrated that the presence of plastics is closely related to human activity, with their abundance significantly increasing near coastal areas (Franco et al., 2019). Barcelona, a major contributor to plastic pollution in the Mediterranean (Liubartseva et al., 2018), ranks second among urban areas with a contribution of 1.8 %. Previous studies have revealed that 90 % of marine litter in Barcelona consists of plastic, with the city's port exhibiting the highest plastic density along the Catalan coast (Llorca et al., 2020;Liubartseva et al., 2018;Balcells et al., 2023). ...
... Barcelona, a major contributor to plastic pollution in the Mediterranean (Liubartseva et al., 2018), ranks second among urban areas with a contribution of 1.8 %. Previous studies have revealed that 90 % of marine litter in Barcelona consists of plastic, with the city's port exhibiting the highest plastic density along the Catalan coast (Llorca et al., 2020;Liubartseva et al., 2018;Balcells et al., 2023). These findings underscore the significance of proximity in the accumulation of ocean debris and highlight the urgent need for more effective management of waste production and distribution in Barcelona. ...
The increase of plastic pollution represents a significant ecological threat, particularly in human-impacted environments. However, the effects of plastic ingestion by urban wildlife are less understood. This study investigates the presence of microplastic (MPs; plastic <5 mm in size) and macroplastics (MaPs, plastic >5 mm in size) in yellow-legged gull (Larus michahellis) chicks inhabiting the urban marine ecosystem of Barcelona (northeastern Spain). The stomach contents of 56 gull chicks were analysed, revealing the presence of MPs in 100 % of the individuals and MaPs in 19.64 % of individuals. Additionally, trophic analysis, through stomach content and stable isotope determination, identified links between diet and plastic ingestion, with diet diversity associated with higher MaP abundance. These results highlight the high presence of plastics in the early stages of an urban-dwelling wildlife species and open the potential role of the use of urban gull chicks as sentinels of marine and terrestrial pollution in urban coastal areas. The findings suggest that chicks can serve as bioindicators of plastic pollution, emphasizing the urgent need to address the high levels of plastic contamination in urban environments.
... High seasonal and inter-annual abundance and dispersal variability are indeed known for cetaceans and sea turtle species (e.g., Arcangeli et al. 2017, Arcangeli et al. 2019, Zampollo et al. 2022. Also, the accumulation/dispersion pattern of litter is highly variable in the Mediterranean basin, with a large transboundary dispersion and the absence of any formation of permanent large or local FML accumulations (i.e., Arcangeli et al. 2018, Liubartseva et al. 2018, Mansui et al. 2015, Macias et al. 2022. Marked seasonal and inter-annual variability with areas of FML accumulation was recognised mainly during summer/autumn, but with lower values indicating the gradual formation/disintegration of accumulation pattern also seen in June, October and November (Liubartseva et al. 2018). ...
... Also, the accumulation/dispersion pattern of litter is highly variable in the Mediterranean basin, with a large transboundary dispersion and the absence of any formation of permanent large or local FML accumulations (i.e., Arcangeli et al. 2018, Liubartseva et al. 2018, Mansui et al. 2015, Macias et al. 2022. Marked seasonal and inter-annual variability with areas of FML accumulation was recognised mainly during summer/autumn, but with lower values indicating the gradual formation/disintegration of accumulation pattern also seen in June, October and November (Liubartseva et al. 2018). A spatial stratification for potential exposure was also identified between offshore and coastal areas (Compa et al. 2019, Arcangeli et al. 2020. ...
Marine litter is a main threat for marine life, although the assessment of the associated risks has not yet been fully incorporated into area‑based management tools. Floating litter is detrimental to cetaceans and sea turtles, and thus, these organisms are considered an effective indicator of areas where litter accumulates. Increasing our ability to predict high‑exposure risk locations, i.e., where and when marine megafauna is exposed to the potential negative impacts of litter, is important for prioritising smart‑conservation planning and is an essential first step in characterising the risk of real injury/damage. However, Risk Exposure Assessment (REA) is still underrepresented as a standardised procedure. Here, a literature review framed the state‑of‑the‑art of REA approaches for cetaceans and sea turtles from floating litter supporting the standardisation of metrics and procedures. Of the 415 papers resulting from the literature search, the 23 selected (2011–2022) showed that 57% of the studies were conducted in the Western‑Mediterranean Sea, evidencing inconsistent geographical applications. While a variety of REA methodological approaches revealed high informational heterogeneity, main limits and future recommendations were identified regarding raw data availability, information bias, geographical gaps, target species selection and lack of standard protocol needed to assess trends to evaluate the effectiveness of mitigation measures. Ultimately, the study showed that a spatial‑contextual approach (possibly functional trait‑based) is needed to effectively support long‑term year‑round monitoring programmes, especially in still un‑surveyed regions.
... 50 may be specified or estimated based on some knowledge of the physical characteristics of the shoreline, or its exposure to wind and waves (Shen et al., 1987;Al-Rabeh et al., 2000;Zelenke et al., 2012). Liubartseva et al. (2018) used a similar stochastic approach, whereby the probability of mobilization of beached particles decays exponentially with time, i.e.: ...
Driftwood, which consists of fragments of wood transported by water, is abundant in many of the world’s coastal zones. The origins of coastal driftwood include inland and coastal forests, and industry (e.g., forestry and construction). Wood is thought to provide a number of ecosystem services in coastal zones and estuaries, including habitat, structure, nutrients, and carbon storage. These perceived benefits have led to the increasing utilization of wood in so-called nature-based shore protection and coastal restoration schemes. However, the evidence to support this practice is limited. Large quantities and accumulations of driftwood are known to be detrimental to the health and performance of some sensitive coastal ecosystems and nature-based features, such as newly establishing or restored salt marshes. Moreover, buoyant coastal driftwood (or “woody debris” when referring to negative impacts) mobilized by natural disturbances, such as tsunami or storm waves, poses hazards to communities, the environment, infrastructure, and other valued assets; and can incur substantial cleanup or mitigation costs. While the fate and transport of wood in fluvial systems or debris mobilized by tsunami has received substantial attention in the literature, comparatively few studies have investigated coastal driftwood transport and mobility in open-coast settings, where wind waves are an important driver. A thorough understanding of coastal driftwood fate and transport mechanisms and pathways is needed to inform risk management practice, and to weigh the risks and benefits of using wood in nature-based solutions, and implications for coastal structures.
This study characterized physical processes governing the transport and fate of coastal driftwood. Scale physical model experiments and optical tracking of model driftwood were conducted to quantify wave-driven transport and dispersion on a sandy shoreline with fringing reefs and various coastal structures. A numerical, Lagrangian particle-tracking model was developed to simulate driftwood transport in wave-dominated environments, and was validated using the experimental data. The physical and numerical modelling results provided unique insights to factors affecting coastal driftwood mobility, pertaining to driftwood characteristics (e.g., length, roughness, buoyancy), hydrodynamics (e.g., sea state parameters, wave-induced circulation, surf zone and swash zone dynamics), and coastal structures (e.g., length of groynes at the water line). The results highlighted the sensitivity of driftwood dynamics to surf zone and swash zone hydrodynamics, and the capabilities and limitations of two “state-of-the-art” nonlinear shallow water equations wave models (the reduced 2-layer XBeach non-hydrostatic model, and SWASH) as tools for simulating these processes were assessed. The numerical driftwood transport model (WOODRIFTSIM) incorporated a novel, physics-based beaching and washoff algorithm, which was used to assess the suitability of probabilistic formulae incorporated in several existing marine debris models, which typically assume an exponential decay in the probability of driftwood remobilization following a beaching event.
The findings from the study were synthesized to describe practical implications for the use of coastal driftwood in nature-based shore protection with respect to service life, quantity, stability, and effects on wave run-up and morphodynamics. Considerations for coastal structure design in regions with mobile driftwood were also discussed. Limitations of the work, and needs for further research to develop a more comprehensive understanding of coastal driftwood fate and transport were identified.
... Higher concentrations of microplastics along the coast may be linked to the claim that 80% of MPs come from land (Liubartseva et al., 2018). However, this is not certain as factors like currents and tides play a role. ...
Introduction
The Gulf of Trieste is prone to the accumulation of various pollutants and microplastics due to its geomorphological and hydrological characteristics. However, the distribution and sources of microplastics in this semi-enclosed area are poorly studied. The aim of our study was to determine the distribution and chemical composition of MP particles in the sediments of the Gulf of Trieste.
Methods
In this study, we collected 24 surface sediment samples using a Van Veen grab. Microplastics were extracted by density separation using NaCl. The size, shape, and color of the extracted microplastics were determined using an optical microscope, and the composition of the polymers was determined by Fourier transform infrared spectroscopy.
Results and discussion
The highest concentrations of up to 125 microplastic particles per 100 g dry sediment were found in coastal areas. Concentrations in the open sea were much lower, with an average of 3 particles per 100 g of sediment. Most of the microplastic was fibrous, made of polypropylene, 100–300 µm in size, and blue. This is the first study showing that microplastics are present in the sediments of the south-eastern part of the Gulf of Trieste. The findings suggest that microplastics exhibit a tendency to be retained within the sediment, leading to their accumulation primarily in a narrow coastal area rather than dispersing offshore. Our results will contribute to a better knowledge of the distribution and possible sources of plastics and microplastics in the Gulf of Trieste and even beyond in similar semi-enclosed marine areas.
... High-resolution data of environmental fields such as sea surface height (SSH) and currents in coastal regions provide valuable information for a range of coastal applications, including coastal management, marine aquaculture, and environmental monitoring (McCarthy et al., 2017). For instance, these data are essential for coastal flood protection (Seenath et al., 2016), coastal erosion assessment (Mentaschi et al., 2018), and pollutant tracking (Liubartseva et al., 2018). Detailed information about these data can facilitate coastal managers in decision-making and planning to mitigate the impacts of coastal hazards such as storm surges and erosion, especially in ecologically important regions like the Wadden Sea tidal flat system Jacob et al., 2023). ...
... Allison et al., 2022;Cardoso and Caldeira, 2021;Critchell and Lambrechts, 2016;Iwasaki et al., 2017;Kako et al., 2014), enclosed seas (e.g. Baudena et al., 2022;Carlson et al., 2017;Li et al., 2018;Liubartseva et al., 2018;Murawski et al., 2022), and gulfs (e.g. Alosairi et al., 2020;Zayen et al., 2020). ...
A Lagrangian-particle tracking model, Delft3D-PART, combined with hydrodynamics models are used to investigate the fate and transport of buoyant plastics from Ba Lat river mouth in Red River Delta, northern Vietnam. It was found that during the dry season (Dec–Feb), 23 % (26.43 ton) of the plastics reached the shoreline while 76.1 % (68.3 ton) moved towards the coast further south of Red River Delta. During the wet season (Jun–Aug), 42 % (56.3 ton) were transported offshore away from the coast and 20 % (26.43 ton) distributed along the shore. The two bays adjacent to the river mouth are major hotspots with the intensity skewed towards the upwind side relative to the seasonal monsoon. This phenomenon is exacerbated by storm
events which reverse the typical transport and lead to formation of hotspots at the upwind side of the plastic source. Guidance of model results for targeted cleanup operations is discussed.
... Israel is a global and regional plastic pollution 'hotspot' , with a continuously growing rate of single-use plastic (SUP) consumption alongside increasing pollution in public spaces and the natural environment [121][122][123]. Daily plastic waste accumulation on Israel's coastline ranks 3rd highest in the Mediterranean, with 21 kg of plastic waste per kilometer of coastline [124] and is listed as a high pollution epicenter [125]. ...
Background
Israel is a regional "hotspot" of plastic pollution, with little discussion of potential adverse health effects from exposure to plastic. This review aims to stimulate discussion and drive policy by focusing on these adverse health effects.
Main body
Plastics are synthetic polymers containing additives which can leach from food- and beverage-contact plastic into our food and beverages, and from plastic textiles onto our skin. Plastics persist in the environment for generations, fragmenting into MNPs: Micro (1 micron–5 mm)-Nano (1 nm–1 micron)-Plastic, which contaminate our atmosphere, water, and food chain. MNP can enter the human body through ingestion, inhalation and touch. MNP < 10 microns can cross epithelial barriers in the respiratory and gastrointestinal systems, and fragments < 100 nm can cross intact skin, enabling entry into body tissues. MNP have been found in multiple organs of the human body. Patients with MNP in atheromas of carotid arteries have increased risk of a combined measure of stroke, cardiovascular disease, and death. Toxic additives to plastics include bisphenols, phthalates, and PFAS, endocrine-disrupting chemicals (EDCs) which cause dysregulation of thyroid function, reproduction, and metabolism, including increased risk of obesity, diabetes, endometriosis, cancer, and decreased fertility, sperm count and quality. Fetal exposure to EDCs is associated with increased rates of miscarriages, prematurity and low birth weight. There is likely no safe level of exposure to EDCs, with increasing evidence of trans-generational and epigenetic effects. There are several existing Israeli laws to reduce plastic use and waste. Taxes on single-use plastic (SUP) were recently cancelled. There are many gaps in regulatory standards for food-, beverage- and child- safe plastic. Existing standards are poorly enforced.
Conclusion
Reduction in production and use of plastic, promotion of recycling and reduction of leaching of toxic additives into our food and beverages are essential policy goals. Specific recommendations: Periodic monitoring of MNP in bottled beverages, food, indoor air; Strengthen enforcement of standards for food-, beverage-, and child-safe plastic; Renew tax on SUPs; National ban on SUP at public beaches, nature reserves and parks; Ban products manufactured with MNP; Increase research on sources and health outcomes of exposure to MNP and EDCs.
... In the Mediterranean Sea, the strong seasonal variability and intense mesoscale activity of surface currents prevent the formation of stable areas where plastic can concentrate (Millot and Taupier-Letage 2005;Pedrotti et al. 2022). Several models have suggested that seasonal plastic accumulation is influenced by proximity to sources such as large cities and rivers (Zambianchi et al. 2017;Liubartseva et al. 2018). However, these models do not match the field data. ...
... Particle tracking models (PTMs) can be used to track the potential dispersal of rafting marine NNS, according to the simulated circulation from a hydrodynamic model (Lett et al., 2008;Rothäusler et al., 2015;Garcia-Garcia et al., 2016;Casaucao et al., 2021;De-la-Torre et al., 2021). PTMs have been used previously to map the dispersion of marine litter on a global scale (Lebreton et al., 2012) and in more regional and local studies, such as in the Mediterranean (Liubartseva et al., 2018) or the Adriatic Sea (Liubartseva et al., 2016). These modelling methods can incorporate various oceanographic processes that contribute to the dispersal potential of rafters (e.g., tidal and residual currents, wind stress and wave climates; Demmer et al., 2022). ...
Marine species raft on floating litter, including various plastics, potentially spreading non-native species and threatening global marine habitats. Despite limited attention, Didemnum vexillum, an invasive colonial tunicate in Europe, colonised coasts of southwest Scotland (2009) and northeast Ireland (2012), likely transported via rafting. We studied D. vexillum survival and performance on three plastic types (Polyethylene, Polypropylene and Polystyrene) finding high survival rates over 42 days, with colonies thriving best on PS. Using these data, hydrodynamic and particle tracking models simulated dispersal from existing Irish Sea colonies, projecting potential rafting distances of up to ∼150 km for surface particles influenced by tide and wind, and half that for neutrally-buoyant mid-depth particles driven by tidal currents alone. Hence, the modelling supports the potential for dispersion of this species within the Irish Sea via rafting. This study highlights marine plastics as a vector that may facilitate widespread dispersal of non-native species.
... In the Mediterranean Sea, the strong seasonal variability and intense mesoscale activity of surface currents prevent the formation of stable areas where plastic can concentrate (Millot and Taupier-Letage 2005;Pedrotti et al. 2022). Several models have suggested that seasonal plastic accumulation is influenced by proximity to sources such as large cities and rivers (Zambianchi et al. 2017;Liubartseva et al. 2018). However, these models do not match the field data. ...
The archipelago of the Aeolian Islands in the Tyrrhenian Sea is a globally important natural laboratory. The archipelago, declared a UNESCO World Heritage Site for its unique geology and biodiversity, offers a unique opportunity to study plastic pollution. This study presents an initiative to assess the occurrence of plastic pellets on the beaches of five Aeolian Islands. It provides an insight into the polymer composition and the effects of degradation. Collected pellets were analyzed using stereomicroscopy and Fourier transform infrared spectroscopy (FTIR). Hierarchical cluster analysis (HCA) based on the results of the FTIR data has proved to be an effective statistical method in identifying different clusters corresponding to different degradation phases of the collected pellets. The infrared analysis identified polyethylene (80%) as the main polymer, with a small amount of polypropylene (20%). It was found that the surfaces of some pellets undergo changes during weathering that alter the polymer surfaces. By combining data on plastic pellets from the Aeolian Islands and surrounding coastal areas, we are gaining a more comprehensive understanding of the distribution patterns of microplastics. The results of the monitoring and characterization are expected to support the developing of waste management and remediation strategies for this environmentally sensitive region.
... Moving to smaller scales and confined basins, Liubartseva et al. (Liubartseva et al., 2018) attempted to simulate pathways and fate of plastic litter released into the Mediterranean Sea under the effect of waves and currents as predicted by a hydrodynamic-wave modelling system. They found that coastline plastic pollution is mainly caused by terrestrial sources of plastics, identifying the most contaminated areas in the proximity of the plastic debris sources. ...
The nearshore zone turns out to be the area with the higher concentration of plastic debris and, for this reason, it is important to know the processes that affect the transport and the fate of this type of litter. This study focuses on investigating the dynamics of various plastic types under several hydrodynamic conditions primarily induced by waves. 2D tests were carried out at the Hydraulic Laboratory of the University of Messina reproducing the main phenomena that occurred during the wave propagation on a planar beach. More than 200 different conditions were tested changing the wave characteristics, the water depth, the plastic debris characteristics (density and shape), and the roughness of the fixed bottom. In general, it can be observed that the reduction in particle displacement occurs due to: i) a decrease in wave steepness; ii) an increase in depth; iii) an increase in particle size; iv) an increase in plastic density. However, the experimental investigation shows that some plastic characteristics and bed roughness, even when hydraulically smooth, can alter these results. The experimental data analysis identified a criterion for predicting the short-term fate of plastic debris under wave action. This criterion to determine equilibrium conditions, based on an empirical relationship, takes into account the wave characteristics, the bed roughness and slope, and the weight of the debris.
... Simon-Sánchez et al. (2019) analysed MPs in the Ebro River and reported MP fibers to be the most common shape and with a mean abundance in surface waters of 3.5 ± 1.4 MPs⋅m − 3 , which represents an input of 2.14 × 10 9 MPs⋅yr − 1 into the Mediterranean Sea. On the other hand, because most marine currents run from north to south along the continental slope of the western Mediterranean coast (Font et al., 1995), it may be possible that MP pollution from the urban area of Barcelona (approximately 1800 tons annually; Liubartseva et al., 2018) are transported to the study area (Garcia-Garin et al., 2020) increasing its MP concentration. No significant differences were detected in the levels of MPs ingested by swordfish between the two sampling periods, although MP occurrence was higher in the recent period. ...
In this study, we aimed to quantify the presence of microplastics (MPs) in the stomachs of large pelagic fish (swordfish, Xiphias gladius, Linnaeus, 1758) sampled in the western Mediterranean Sea, and assess temporal trends (2011–2012 vs. 2017–2019) in MP ingestion. MPs were extracted from stomachs and characterized by μ-Fourier transform infrared spectroscopy. Results highlighted the ingestion of MP in 39 out of 49 stomachs analysed. Ingested MPs consisted mostly of small (<1 mm) fibers (88.6 %, mean ± standard deviation = 2.5 ± 6.1 particles per stomach), with a greater frequency of occurrence (FO) in the second period (FO = 90 %, 3.3 ± 8.0 particles per stomach). The predominant colours were purple, black and blue, and polyethylene terephthalate was the most frequently detected polymer. These results are crucial for the development of management actions aimed at the conservation of swordfish in the Mediterranean Sea and the prevention of health risks to humans.
... This transport is determined by ocean flows possessing preferred directions which are influenced by prevailing wind directions and mesoscale hydrodynamic structures like vortices, jets and fronts [26][27][28]. One of the challenges is the identification of the major pathways of particles such as the pathways of micro-and macro-plastics [29] and the locations where this litter concentrates in the ocean [30,31], the pathways of seeds to understand the distribution of plant species on different archipelagos in the world's ocean [32] or the pathways of larvae to get from spawning areas back to their reefs [33]. ...
The transport and distribution of organisms like larvae, seeds or litter in the ocean as well as particles in industrial flows is often approximated by a transport of tracer particles. We present a theoretical investigation to check the accuracy of this approximation by studying the transport of inertial particles between different islands embedded in an open hydrodynamic flow aiming at the construction of a Lagrangian flow network reflecting the connectivity between the islands. To this end we formulate a two-dimensional kinematic flow field which allows the placement of an arbitrary number of islands at arbitrary locations in a flow of prescribed direction. To account for the mixing in the flow we include a von K\'arm\'an vortex street in the wake of each island. We demonstrate that the transport probabilities of inertial particles making up the links of the Lagrangian flow network depend essentially on the properties of the particles, i.e. their Stokes number, the properties of the flow and the geometry of the setup of the islands. We find a strong segregation between aerosols and bubbles. Upon comparing the mobility of inertial particles to that of tracers or neutrally buoyant particles, it becomes apparent that the tracer approximation may not always accurately predict the probability of movement. This can lead to inconsistent forecasts regarding the fate of marine organisms, seeds, litter or particles in industrial flows.
... Allison et al., 2022;Cardoso and Caldeira, 2021;Critchell and Lambrechts, 2016;Iwasaki et al., 2017;Kako et al., 2014), enclosed seas (e.g. Baudena et al., 2022;Carlson et al., 2017;Li et al., 2018;Liubartseva et al., 2018;Murawski et al., 2022), and gulfs (e.g. Alosairi et al., 2020;Zayen et al., 2020). ...
... The study by Liubartseva et al. (2018) also relied on simplified parameterisation, including vertical displacement, which affected the reliability of emphasising the crucial influence of coastal area kinematics on microplastic fate. Additionally, Maximenko et al. (2012) adopt a stochastic modelling approach to study marine debris pathways using historical trajectories of drifting buoys. ...
Microplastics in the environment are considered complex pollutants as they are chemical and corrosive-resistant, non-biodegradable and ubiquitous. These microplastics may act as vectors for the dissemination of other pollutants and the transmission of microorganisms into the water environment. The currently available literature reviews focus on analysing the occurrence, environmental effects and methods of microplastic detection, however lacking a wide-scale systematic review and classification of the mathematical microplastic modelling applications. Thus, the current review provides a global overview of the modelling methodologies used for microplastic transport and fate in water environments. This review consolidates, classifies and analyses the methods, model inputs and results of 61 microplastic modelling studies in the last decade (2012–2022). It thoroughly discusses their strengths, weaknesses and common gaps in their modelling framework. Five main modelling types were classified as follows: hydrodynamic, process-based, statistical, mass-balance and machine learning models. Further, categorisations based on the water environments, location and published year of these applications were also adopted. It is concluded that addressed modelling types resulted in relatively reliable outcomes, yet each modelling framework has its strengths and weaknesses. However, common issues were found such as inputs being unrealistically assumed, especially biological processes, and the lack of sufficient field data for model calibration and validation. For future research, it is recommended to incorporate macroplastics’ degradation rates, particles of different shapes and sizes and vertical mixing due to biofouling and turbulent conditions and also more experimental data to obtain precise model inputs and standardised sampling methods for surface and column waters.
... As discussed in the previous chapter, the improvement of sea surface currents estimation is of key importance for a wide range of applications, including climate modeling [94], vessel routing [31], and pollution tracking [92]. Furthermore, it is known that knowledge of the small scale of sea surface current is critically important for wave forecasting [5], which is an important topic for maritime safety reasons. ...
This thesis focuses on the assimilation of surface ocean currents from AIS data. This problem is an ill-posed inverse problem that falls within the scope of data assimilation. The main contribution of this thesis is to propose a new variational formulation for the assimilation of surface ocean currents from AIS data and the use of deep learning techniques to solve the associated assimilation problem. Different learning paradigms (supervised or unsupervised) are studied on real and simulated datasets, demonstrating significant gains in reconstruction performance compared to the state of the art. The ability of AIS data to estimate total currents is evaluated, as well as the possible synergies between AIS and altimetric data for reconstruction. Finally, the quantification of uncertainties associated with data assimilation problems is investigated. A new family of generative models based on the transport of the measure on divergence-free fields is proposed: these models have the property of conserving volumes, which allows extending the calculation of Shannon's differential entropy to families of complex probability distributions. Their generative capacity and their application to ill-posed inverse problems are evaluated on toy datasets.
... The beaching or grounding itselfif relevant for the type of particle under considerationcan then be obtained from a Lagrangian parameterization that accounts for all known unresolved processes occurring at the subgrid scale that are ultimately responsible for pushing particles ashore (Pawlowicz, 2021). There is an increasing number of, for example, marine plastic dispersal studies with basic implementations of this approach (Onink et al., 2019;Ypma et al., 2022;Kaandorp et al., 2023;Vogt-Vincent et al., 2023;Liubartseva et al., 2018;van der Mheen et al., 2020). Yet, the existing 685 grounding parameterizations still need further refinement and validation based on data from dedicated grounding experiments with customized surface drifters (Pawlowicz, 2021). ...
Numerical simulations of marine surface particle dispersal are a crucial tool for addressing many outstanding issues in physical oceanography with societal relevance, such as marine plastic pollution. However, the quality of these Lagrangian simulations depends on the ability of the underlying numerical model to represent the prevailing ocean circulation features. Here, we investigate how simulated marine surface particle dispersal changes, if the – often omitted or only approximated – impact of wind-generated surface waves on the upper ocean circulation is considered. We use velocity fields from a high-resolution coupled ocean-wave model simulation and a complementary stand-alone ocean model simulation for the Mediterranean Sea to answer the following questions: 1) How does the explicit representation of waves impact the simulated surface particle dispersal, and what is the relative impact of Stokes drift and wave-driven Eulerian currents? 2) How accurately can the wave impact be approximated by the commonly applied approach to advect particles with non wave-driven Eulerian currents and Stokes drift from stand-alone ocean and wave models? We find that the representation of surface waves tends to increase the simulated mean Lagrangian surface drift speed in winter through a dominant impact of Stokes drift, and to decrease the mean Lagrangian surface drift speed in summer through a dominant impact by wave-driven Eulerian currents. Furthermore, simulations that approximate the surface wave impact by including the Stokes drift (but ignoring the wave-driven Eulerian currents) do not necessarily yield a better estimate of the surface particle dispersal patterns with explicit representation of the wave impact than simulations that do not include any surface wave impact. Our results imply that – whenever possible – velocity fields from a coupled ocean-wave model should be used for surface particle dispersal simulations.
... Among the different regions of the world's ocean, the Mediterranean Sea is considered one of the most impacted areas by plastics, as due to its semi-enclosed structure tends to hold on the plastics ending up in the basin (Eriksen et al., 2014;Coźar et al., 2015). Efforts made to estimate the plastics' quantity that enters the Mediterranean Sea and to simulate their pathways and fate have led to considerably varying results (e.g., Jambeck et al., 2015;Liubartseva et al., 2018;Kaandorp et al., 2020). More recently, Tsiaras et al. (2021), taking into account only major land-based sources of plastics, have estimated the total annual plastics load at 17,600 tons and the total amount of plastics floating on the surface layer and in the water column of the Mediterranean at 3,842 tons. ...
Plastic additives include a wide range of pollutants, added throughout the production process of plastics aiming to improve their properties. Given that they are not chemically bound to the plastic items, they can easily migrate in the marine environment allowing their uptake by marine organisms and accumulation in their tissues. Representatives of Phthalic acid esters (PAEs) and bisphenols have been characterized for their ability to impact not only marine organisms but also humans via fish and seafood consumption. In this study, a liquid-liquid method was applied to determine the concentrations of selected PAEs and Bisphenol A (BPA) in the tissues of E.encrasicolus, S.pilchardus, B.boops, and M.barbatus from two important divisions of fisheries (North Aegean and the Western Ionian Seas, thereof NAS and IOS respectively) of the Mediterranean Sea. The level of contamination varied among the different species and geographical locations. DEHP (bis(2-ethylhexyl) phthalate) had the highest mean concentrations of the examined PAEs for all four species examined. Statistically significant differences in DEHP mean concentrations were observed between the tissues of B.boops (collected from NAS) and S.pilchardus (from IOS) (p < 0.05, Wilcoxon rank test). DIDP (di-isodecyl phthalate) was the following most common PAEs, although no statistically significant differences were presented between sites, species, and tissues. DINP (di-isononyl phthalate) was recorded only in the GIT of E.encrasicolus (from NAS), while the rest of the examined PAEs were presented in a smaller subset of the samples. Noticeably, the parent diester DBP and the metabolic monoester MNBP were concurrently detected in a part of the analyzed samples. The level of risk via fish consumption, based on the Estimated Daily Intake and the Target Hazard Quotient (THQ), showed that the PAEs and BPA had a low likelihood of a negative effect occurring for every scenario that was examined, although THQ for BPA indicated there was a higher likelihood than PAEs of an adverse effect to be presented. The results of this study highlighted the need for future efforts focusing on the factors affecting plastic additives occurrences in the marine environment, especially for marine organisms intended for consumption.
... Numerical models, especially those coupling Lagrangian particle tracking with ocean circulation models, are extensively employed to assess and forecast changing environmental conditions (Liubartseva et al., 2018). However, many Lagrangian tracking models suffer from compatibility issues, frequently supporting only the output data of specific hydrodynamic models. ...
This study examines the interannual and seasonal variations in the distribution of radioactive materials released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) accident in the surface layer of the Kuroshio Extension (KE). Focusing on the contrasting flow conditions in 2015 (southward) and 2021 (northward) – significant oscillatory phases of the KE’s mean flow axis – the research analyzes the impact of seasonal variations on particle transport pathways. The findings reveal distinct seasonal patterns: summer releases primarily follow the eastward KE movement, while winter releases exhibit a southward trajectory. The study further quantifies the transport timescales, demonstrating that particles can reach the Luzon Strait within 10 months, subsequently diverging northward along the Kuroshio and northwestward along the Kuroshio Branch Current, potentially entering the South China Sea within 13 months. This research contributes valuable insights into the seasonal dynamics governing the dispersion and transport of Fukushima-derived radioisotopes in the surface ocean, highlighting the crucial role of the KE in influencing their trajectories.
... The Mediterranean Sea, and especially its western basin, seems to be an area of plastic accumulation (Pham et al., 2014;Sharma et al., 2021). Moreover, Spain is the second leading country on dumping plastics into the Mediterranean (126 tons/day) (UNEP/MAP, 2015), and Barcelona is the third major plastic debris contributing city (1787 tons/year) (Liubartseva et al., 2018;Sharma et al., 2021). Therefore, the high values of AIs observed in the present study are in accordance with the high pollution levels that characterize the Mediterranean area due to its anthropogenic pressure, as already seen in other benthic and pelagic species off the Catalan coast (Carreras-Colom et al., 2018Muns-Pujadas et al., 2023;Rodríguez-Romeu et al., 2020, 2022. ...
The small-spotted catshark (Scyliorhinus canicula) is a bottom-dwelling elasmobranch that represents the most discarded catch in terms of biomass in the Catalan coast (NW Mediterranean). Potential impacts affecting its population and food safety implications have been assessed in three localities along the Catalan coast. Distinct indicators were integrated, such as biological data, ingested anthropogenic items (plastic and cellulose-like items), parasitological indices, trace metal concentrations and histopathology using liver as target organ. Although high ingestion rates of fibres and levels of some heavy metals, they do not seem negatively affected by any major pathology nor by the current levels of pollutants. Small-scale differences among localities and depths were found and discussed. No zoonotic parasites were found. Encysted larvae of Grillotia adenoplusia and, above all, the levels of Hg found in the musculature, that are well over the European Commission limits, rise concerns regarding human consumption of S. canicula in this region.
... Considering the population demography of the Nile River countries that prefer living around the river's banks, a drastic quantity of plastic waste is discarded directly into the river (Ramzi and El-Nahry, 2015). An estimation indicates that approximately 6.8% of the Mediterranean Sea's plastic garbage (6772 metric tons per year) comes from this river (Liubartseva et al., 2018). Importantly, the problem of plastic waste is exaggerated due to poor solid waste management (Abdellatif et al., 2021). ...
... In the present study, the comparison was therefore done by abundance of the marine plastic debris washed ashore on the Indian Ocean beaches. However, plastic fluxes (abundance per beach area × time of accumulation) might be more appropriate than the present study as adopted by Liubartseva et al. (2018) and Prevenios et al. (2018) in the Mediterranean Sea. ...
... Finally, note that the methodology employed here could be also used in future studies to assess the contaminant potential along major shipping lanes, as it was done for plastics in Liubartseva et al. (2018). ...
... Virtual Lagrangian trajectories have been employed by several authors to determine the exposure or distribution of marine pollution (Delpeche-Ellmann and Soomere, 2013;Liubartseva et al., 2018;Mohtar et al., 2018;van Sebille et al., 2015), demonstrating the effectiveness of this tool as a complementary instrument to fieldwork (Hurlburt and Hogan, 2000;Werner et al., 2007). In a real case like the one presented here, the combination of forward and backward simulations provides a comprehensive explanatory vision, enhancing our understanding of oceanic connectivity and plastic transport (Cardoso and Caldeira, 2021;Mohtar et al., 2018;Sala et al., 2015). ...
... The spatial distribution of MPs in seabed sediment and sea surface can vary due to ocean currents and proximity to pollution sources (Jaubet et al., 2021;Lorenz et al., 2019). Several MP distribution models have been proposed in relation to circulation in the Mediterranean Sea (Liubartseva et al., 2018;Politikos et al., 2020;Tsiaras et al., 2021), along with local variations of MPs in areas of heterogeneous anthropogenic pressures (Lefebvre et al., 2019;Marrone et al., 2021;Tsangaris et al., 2020). In this context, the island of Zakynthos, located in the eastern Mediterranean Sea, is exposed to different anthropogenic pressures. ...
... Plastic contamination has been documented in all the marine coastal areas considered in this study [47,63]. In particular, the Cilician Sea is one of the most contaminated coastal areas; in addition, the Gulf of Izmir in Turkey and the Bay of Thessaloniki in Greece can also be considered hot spots for the release of plastics into the marine environment [64]. The huge contamination in these areas is mainly attributed to an anthropogenic input linked to the high use of plastic by the local population, coupled with incorrect disposal and limited recycling (around 20% in Greece and 40% in Turkey) [65]. ...
We characterized the presence of plastics in different organs of the gilthead seabream (Sparus aurata) and European seabass (Dicentrarchus labrax) from some off-shore aquaculture facilities of the Mediterranean Sea. Plastics were detected in 38% of analyzed fish. Higher contamination was observed in fish from Turkey and Greece with respect to Italy, without significant differences between the geographical areas. Plastics accumulated mostly in the gastrointestinal tract and, to a lower extent, in the muscle, which represents the edible part of fish. Based on the particle detected, a maximum amount of 0.01 plastic/g wet weight (w.w.) can occur in muscles, suggesting a low input for humans through consumption. A large portion of the particles identified was represented by man-made cellulose-based fibers. The characterization of the polymeric composition suggests that plastics taken up by fish can have land-based and pelagic origins, but plastics can be introduced also from different aquaculture practices.
... Moreover, the previous studies that explored the entire area were primarily concerned with the tidal influence and neglected the overall transport characteristics, especially seasonal characteristics. Given the predominance of positively buoyant microplastics in marine environments, several studies have utilized two-dimensional (2D) (Lebreton et al., 2012;Liubartseva et al., 2018) and three-dimensional (3D) models to simulate their transport processes in the ocean, resulting in favorable outcomes. However, vertical processes are extremely important for the transport and distribution of microplastics (J. ...
Elucidating the mechanisms governing microplastic transport and spatial distribution in offshore waters is essential to microplastic control. However, current research on microplastic transport in the China Seas is largely restricted to small-scale investigations, which do not provide a comprehensive result. Therefore, in this study, we used the Regional Ocean Modeling System (ROMS) combined with the Lagrangian Transport (LTRANS v.2) model to investigate how microplastics are transported around the China Seas during different seasons and under climatological river discharge. Our findings showed that the microplastic pathways and spatial distributions exhibit marked seasonal variations controlled by circulation patterns in the China Seas, river discharge values, and the characteristics of the microplastic materials. Floating microplastics exhibited the longest transport distance in summer, when microplastics from the Pearl River could be transported up to 1375.8 km through the Tokara and Tsushima straits. The heavy pollution areas in summer were located in the South Yellow Sea and East China Sea, mainly resulting from the contribution of the Yangtze River (>66%). In autumn and winter, more than three-quarters of the microplastics beached off the south-central Chinese coast. In addition, simulating the vertical velocity of the water prolonged the time required for microplastics to reach the open ocean, thereby reducing the amount of microplastics entering the Pacific Ocean by 6% compared to the simulation without the vertical velocity of the water in summer. Microplastics with higher densities were generally transported shorter distances. The transmission distances of PET and PS were two orders of magnitude smaller than that of PE. This study enhances knowledge of the sources and fates of offshore microplastics and provides scientific support for offshore microplastic control.
... Various aspects of the problem related to the mechanisms of pollution dispersion have been studied by many authors, for example [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. However, questions regarding the horizontal dispersion of admixtures under the effect of external velocity fields still remain poorly understood. ...
In the framework of a three-layer quasi-geostrophic model, within the f-plane approximation, a numerical investigation has been conducted on the influence of a guyot on the motion of surface and subsurface patches of passive admixture advected by vertically homogeneous zonal currents. The possibility of partial trapping of the admixture by a quasi-stationary topographic vortex in the vicinity of the guyot has been demonstrated. The role of the initial localization (both horizontally and vertically) in the resulting pattern of pollution distribution has been revealed.
... The flux onto the coastlines is bigger than the flux to the bottom in the Mediterranean. This can lead to significant plastic accumulation in coastal areas (Liubartseva et al., 2018;Gündogdu and Cevik, 2019). ...
This study aimed to evaluate the abundance and diversity of macro- and microplastics in sand samples collected during summer and winter from eight different beaches used for recreational purposes located on the South Aegean coasts of Türkiye. According to the results, microplastic in fiber shape was dominant on all the beaches. The highest microplastic abundance was determined at Ölüdeniz Kumburnu Beach (360.00 ± 237.66 particles kg-1 dw) in summer and at Aktur Beach (358.33 ± 397.24 particles kg-1 dw) in winter. A significant positive correlation was found in the winter between microplastic amounts and wind speed. The study area is an important touristic center faraway from major cities and industrial areas. Thus, plastic pollution in this area may be the result of tourism activities in the summer, discharge waters from wastewater treatment plants or transportation by meteorological factors (like waves, wind or river flows).
... All these activities, together with some of the largest Italian rivers flowing in this area, represent potential ML sources. The Po River, for example, has been recently included in the top 10 list of plastic litter inputs in the Mediterranean Sea (Liubartseva et al. 2018). Regarding seafloor ML, some studies have already been conducted in the Adriatic Sea using both toothed dredges, locally named "rapido", and other trawls for ML collection Strafella et al. 2019). ...
Although the seafloor is an important sink for marine litter, its less accessible environment makes seafloor litter the least studied component. Nevertheless, detailed monitoring of its composition and spatial distribution is urgently needed to develop appropriate mitigation strategies in areas exposed to multiple anthropogenic pressures, such as the Adriatic Sea. Commercial fisheries such as bottom trawls can serve as an opportunistic platform for collecting data on seafloor litter and help researchers in addressing the lack of data through Fishing for Litter initiatives. In this study, the crews of twelve trawlers from two Italian Adriatic ports collected seafloor litter as part of their Fishing for Litter initiatives. In addition to the classical scheme, the collected litter was sorted on board into different bags, and speed, duration and geographical coordinates of each haul were recorded to allow an assessment of both densities and spatial distribution. More than 600 kg of litter was removed from the seafloor by the fishers in approximately 1 month and characterised by the researchers on the docks. Most of the found items were made of synthetic polymers and related to packaging, fisheries and aquaculture activities. Abandoned, lost or discarded fishing gear and mussel nets were identified as of particular concern in the maritime compartment of Chioggia and Civitanova Marche, respectively. Three hotspots for marine litter were identified: near the Venice lagoon, in the centre of the northern basin and at greater depth in the central Adriatic. This study provides a detailed picture of the spatial distribution and composition of seafloor litter in the areas studied and highlights the importance of increased cooperation between fishermen and scientists to improve the identification of hotspots and sources while removing marine litter from the seafloor and raising awareness of the problem.
Plastic pollution in the Mediterranean region and Sea raises serious concerns for ecosystem and human health. Plastic dispersal from Mediterranean watersheds in Southern Europe, Northern Africa and Middle-East, and Nile basin is complex due to the different (mis-)managed waste streams, population dynamics and climate. In this study, an environmental plastics mass budget and box-model is proposed for the Mediterranean region based on recent observations. We use this model to explore plastics dispersal under different OECD plastic production and waste management policy scenarios toward the end of the 21st century. We find that the current Mediterranean marine plastic stock (sea surface, water column, sandy beach and sediments) of 7 million metric tons (Mt, median, IQR 3–15 Mt) in 2015 constrains continental plastic runoff to 0.31 Mt y-1 (median, IQR 0.14–0.57 Mt y-1). The total marine plastics stock would increase 4-fold by 2060 under a business-as-usual scenario, reaching 26 Mt (median, IQR 13–48 Mt). Implementation of the OECD Global Ambition policy scenario, that targets near-zero new plastics waste leakage, would not significantly lower this stock (25 Mt, median, IQR 12–44 Mt) by 2060. This is because marine litter remote sensing observations attribute most, 0.27 Mt y-1 (88 %), of recent plastic runoff to Southern Europe, where high rainfall will continue to mobilize legacy plastic waste from land to sea, regardless of low leakage targets. About 1.5 % of all Mediterranean legacy plastic waste reached the marine environment, meaning that most plastic waste still resides on land (361 Mt, 76 %). Moreover, in the marine environment, 83 % of plastic mass resides in shelf sediments (median 6 Mt, IQR 2–14 Mt), which are fragile ecosystems that host most of the Mediterranean Sea biodiversity, and are not easy to clean up. This underlines the necessity to address upstream legacy plastic waste on land. Land-based remediation scenarios modelled here show that total plastic runoff from land to sea can be reduced 2-fold (0.22 Mt y-1, IQR 0.16–0.27 Mt y-1) compared to the business-as-usual scenario in 2060, and significantly reduce the total plastic stock in the marine environment.
This capstone analysis aims to find the environmental impact caused by textile industry activities throughout their life cycle in the Mediterranean Sea. The analysis aims to allow related stakeholders to provide solutions across the Mediterranean region. The research methodology chosen is to analyst data gained from three observations and secondary data available on the Life Cycle Assessment (LCA), that aligns with the framework of ISO 14040. This LCA method allows the analysis to cover cradle-to-grave stages and find the most impactful part of the textile industry on the health of the Mediterranean Sea. As textile industries create various types of waste throughout the life cycle, it is important to do deep academic research on this topic. The analysis of the waste by the textile industry's production processes on the Mediterranean Sea is important as though the size of the sea is small compared to others, it is home to various marine biodiversity and plays a role in climate change. The data can be used by stakeholders in Europe, such as France, Spain, Monaco and Italy; the North of Africa, such as Egypt, Morocco, and Tunisia; and the western part of Asia, such as Turkey, to create solutions that will allow them to address waste-related environmental issues. Stakeholders in the textile industry are responsible for the environmental impact. Textile management must prioritize the Mediterranean Sea's environmental impact on their business models. While governments in Mediterranean countries have already been creating regulations around the Mediterranean Sea to protect its health, the impact would not be impactful if all stakeholders did not participate. In the end, the study suggests that circular economy can be their main goal and that corporate social responsibility (CSR) frameworks can be instrumental in encouraging textile companies to invest in addressing waste management processes. The concept of CSR can be used for textile companies to invest and pay more attention to the waste process.
With the expansion of human settlements and the environmental changes brought on by human activity and pollutants, toxicology and risk assessment of piscine species is becoming increasingly of interest to scientists involved in environmental research and connected disciplines. This book focuses specifically on environmental risk assessment in fish species from different zoogeographical regions of the world.
Fish Species in Environmental Risk Assessment Strategies is an ideal companion to toxicologists and ecologists interested in risk assessment in the environments of ichthyic fauna, particularly those with an interest in the deleterious impact introduced by human activity. The book is also of interest to those working in conservation biology, biological invasion, biocontrol, habitat management and related disciplines.
The transport and distribution of organisms such as larvae, seeds, or litter in the ocean as well as particles in industrial flows is often approximated by a transport of tracer particles. We present a theoretical investigation to check the accuracy of this approximation by studying the transport of inertial particles between different islands embedded in an open hydrodynamic flow aiming at the construction of a Lagrangian flow network reflecting the connectivity between the islands. To this end, we formulate a two-dimensional kinematic flow field which allows the placement of an arbitrary number of islands at arbitrary locations in a flow of prescribed direction. To account for the mixing in the flow, we include a von Kármán vortex street in the wake of each island. We demonstrate that the transport probabilities of inertial particles making up the links of the Lagrangian flow network essentially depend on the properties of the particles, i.e., their Stokes number, the properties of the flow, and the geometry of the setup of the islands. We find a strong segregation between aerosols and bubbles. Upon comparing the mobility of inertial particles to that of tracers or neutrally buoyant particles, it becomes apparent that the tracer approximation may not always accurately predict the probability of movement. This can lead to inconsistent forecasts regarding the fate of marine organisms, seeds, litter, or particles in industrial flows.
A Lagrangian particle tracking module within a hydrodynamic model in Environmental Fluid Dynamic Code Plus
(EFDC+) was used to track the movements of large floating marine carcasses. This research used data from six
GPS-tagged drifters collected in April 2017 by NOAA to conduct a sensitivity analysis and calibration on the
Lagrangian particle tracking module. These analyses investigate the influence of specific parameters, notably
wind drag and number of vertical layers in the model. Changing these parameters resulted in observable changes
in the trajectories of tracked particles. The results of the sensitivity experiments were compared using the Skill
Score statistic. Adding wind drag to the LPT was a pivotal alteration, augmenting the model predictive capabilities by increasing the Skill Score value from 0.23 to 0.47. Further tests examined the impact of varying wind
drag coefficients (A and B) which are the slope and y-intercept of a linear equation used to describe overall drag
coefficient (CD) as a function of wind velocity. These coefficients are employed in EFDC + software and altering
them revealed that coefficient A has a larger impact on the model predictions compared to coefficient B. Finally,
the transition from a 2D to a 3D model had a more significant impact on the results compared to increasing the
number of vertical layers in the 3D configuration. However, the findings indicated that changing the model from
2D to 3D may not yield a large enough improvement in accuracy that would justify the additional computational
demands associated with a 3D model when running long periods of time (several years). The study results have
valuable implications for developing accurate and precise models of hydrodynamic systems emphasizing the
importance of wind in LPT models and the efficiency of 2D vs 3D models for LPT simulations in the Mississippi
Sound area.
The transport mechanisms of floating marine debris in coastal zones remain poorly understood due to complex geometries and the influence of coastal processes, posing difficulties in incorporating them into Lagrangian numerical models. The numerical model LOCATE overcomes these challenges by coupling Eulerian hydrodynamic data at varying resolutions within nested grids using Parcels, a Lagrangian particle solver, to accurately simulate the motion of plastic particles where a high spatial coverage and resolution are required to resolve coastal processes. Nested grids performed better than a coarse-resolution grid when analysing the model's dispersion skill by comparing drifter data and simulated trajectories. A sensitivity analysis of different beaching conditions comparing spatiotemporal beaching patterns demonstrated notable differences in the land–water boundary detection between nested hydrodynamic grids and high-resolution shoreline data. The latter formed the basis for a beaching module that parameterised beaching by calculating the particle distance to the shore during the simulation. A realistic debris discharge scenario comparison around the Barcelona coastline using the distance-based beaching module in conjunction with nested grids or a coarse-resolution grid revealed very high levels of particle beaching (>91.5%) in each case, demonstrating the importance of appropriately parameterising beaching at coastal scales. In this scenario, high variability in particle residence times and beaching patterns was observed between simulations. These differences derived from how each option resolved the shoreline, with particle residence times being much higher in areas of intricate shoreline configurations when using nested grids, thus resolving complex structures that were undetectable using the coarse-resolution grid. LOCATE can effectively integrate high-resolution hydrodynamic data within nested grids to model the dispersion and deposition patterns of particles at coastal scales using high-resolution shoreline data for shoreline detection uniformity.
Microplastics (MPs), which are small plastic particles measuring less than 5 mm in size, have emerged as a significant environmental concern in marine ecosystems worldwide. The presence of MPs in aquatic environments has increased due to the contributions from anthropogenic and terrestrial sources, raising concerns about their abundance in aquatic organisms. MPs primarily originate from the photo-degradation of larger plastic debris (macroplastics), with their release into the environment often occurring through the breakdown of additive compounds. The ingestion of MPs poses eco-toxicological risks to marine organisms, causing damage to the gastrointestinal (GI) tracts and stomachs of affected organisms. Approximately 80 % of MPs originate from terrestrial sources, which can be classified as either primary sources, such as those generated during the production of skincare products, tires, and the use of MPs as carriers for pharmaceutical products, or secondary sources resulting from the improper disposal of plastics near coastal areas and water bodies. The issue of MPs and their potential effects on the marine ecosystem demands significant attention. In conclusion, this review provides a comprehensive overview of the vulnerability of microplastics in marine environments, consolidating the current understanding of their sources, distribution, fate, and ecological impacts. It emphasizes the urgent need for ongoing research and proactive measures to mitigate the potential long-term consequences of microplastic pollution on marine ecosystems and the essential services they provide.
Although plastic is ubiquitous in marine systems, our current knowledge of transport mechanisms is limited. Much of the plastic entering the ocean sinks; this is intuitively obvious for polymers such as polystyrene (PS), which have a greater density than seawater, but lower density polymers like polyethylene (PE) also occur in sediments. Biofouling can cause large plastic objects to sink, but this phenomenon has not been described for microplastics < 5 mm. We incubated PS and PE microplastic particles in estuarine and coastal waters to determine how biofouling changes their sinking behavior. Sinking velocities of PS increased 16% in estuarine water (salinity 9.8) and 81% in marine water (salinity 36) after 6 weeks of incubation. Thereafter sinking velocities decreased due to lower water temperatures and reduced light availability. Biofouling did not cause PE to sink during the 14 weeks of incubation in estuarine water, but PE started to sink after six weeks in coastal water when sufficiently colonized by blue mussels Mytilus edulis, and its velocity continued to increase until the end of the incubation period. Sinking velocities of these PE pellets were similar irrespective of salinity (10 vs. 36). Biofilm composition differed between estuarine and coastal stations, presumably accounting for differences in sinking behavior. We demonstrate that biofouling enhances microplastic deposition to marine sediments, and our findings should improve microplastic transport models.
This work describes the first step towards a fully coupled modelling system composed of an ocean circulation and a wind wave model. Sensitivity experiments are presented for the Mediterranean Sea where the hydrodynamic model NEMO is coupled with the third-generation wave model WaveWatchIII (WW3). Both models are implemented at 1/16° horizontal resolution and are forced by ECMWF 1/4° horizontal resolution atmospheric fields. The models are two-way coupled at hourly intervals exchanging the following fields: sea surface currents and temperature are transferred from NEMO to WW3 by modifying the mean momentum transfer of waves and the wind speed stability parameter, respectively. The neutral drag coefficient computed by WW3 is then passed to NEMO, which computes the surface stress. Five-year (2009–2013) numerical experiments were carried out in both uncoupled and coupled mode. In order to validate the modelling system, numerical results were compared with coastal and drifting buoys and remote sensing data. The results show that the coupling of currents with waves improves the representation of the wave spectrum. However, the wave-induced drag coefficient shows only minor improvements in NEMO circulation fields, such as temperature, salinity, and currents.
The role of riverine freshwater inflow on the Central Mediterranean Overturning Circulation (CMOC) was studied using a high-resolution ocean model with a complete distribution of rivers in the Adriatic and Ionian catchment areas. The impact of river runoff on the Adriatic and Ionian Sea basins was assessed by a twin experiment, with and without runoff, from 1999 to 2012. This study tries to show the connection between the Adriatic as a marginal sea containing the downwelling branch of the anti-estuarine CMOC and the large runoff occurring there. It is found that the multiannual CMOC is a persistent anti-estuarine structure with secondary estuarine cells that strengthen in years of large realistic river runoff. The CMOC is demonstrated to be controlled by wind forcing at least as much as by buoyancy fluxes. It is found that river runoff affects the CMOC strength, enhancing the amplitude of the secondary estuarine cells and reducing the intensity of the dominant anti-estuarine cell. A large river runoff can produce a positive buoyancy flux without switching off the antiestuarine CMOC cell, but a particularly low heat flux and wind work with normal river runoff can reverse it. Overall by comparing experiments with, without and with unrealistically augmented runoff we demonstrate that rivers affect the CMOC strength but they can never represent its dominant forcing mechanism and the potential role of river runoff has to be considered jointly with wind work and heat flux, as they largely contribute to the energy budget of the basin. Looking at the downwelling branch of the CMOC in the Adriatic basin, rivers are demonstrated to locally reduce the volume of Adriatic dense water formed in the Southern Adriatic Sea as a result of increased water stratification. The spreading of the Adriatic dense water into the Ionian abyss is affected as well: dense waters overflowing the Otranto Strait are less dense in a realistic runoff regime, with respect to no runoff experiment, and confined to a narrower band against the Italian shelf with less lateral spreading toward the Ionian Sea center.
A circulation model is coupled to a Lagrangian particle-tracking model to simulate the transport floating litter particles in the Aegean Sea, Greece (Eastern Mediterranean). Considering different source regions and release dates, simulations were carried out to explore the fate and distribution of floating litter over 1990–2009, taking into account the seasonal and interannual variability of surface circulation. Model results depicted recurrently high concentrations of floating litter particles in the North Aegean plateau, the Saronikos Gulf, and along Evia and Crete islands. Modeled transport pathways of floating litter demonstrated that source regions are interconnected, with Saronikos Gulf being a main receptor of litter from other sources. Notably higher percent of litter exit (~35%) than enter the model domain (~7%) signified that Aegean Sea seems to act as a source rather than receptor of floating litter pollution in the Eastern Mediterranean Sea. Beached litter was found around 10%, mostly located in the western part of the Aegean Sea. This is the first modeling study to explore the transport of floating marine litter in Greek waters.
The Mediterranean Sea is greatly affected by marine litter. In this area, research on the impact of plastic debris (including microplastics) on biota, particularly large filter-feeding species such as the fin whale (Balaenoptera physalus), is still in its infancy. We investigated the possible overlap between microplastic, mesoplastic and macrolitter accumulation areas and the fin whale feeding grounds in in a pelagic Specially Protected Area of Mediterranean Importance (SPAMI): the Pelagos Sanctuary. Models of ocean circulation and fin whale potential habitat were merged to compare marine litter accumulation with the presence of whales. Additionally, field data on microplastics, mesoplastics, and macrolitter abundance and cetacean presence were simultaneously collected. The resulting data were compared, as a multi-layer, with the simulated distribution of plastic concentration and the whale habitat model. These data showed a high occurrence of microplastics (mean: 0.082 items/m², STD ± 0.079 items/m²) spatial distribution agreed with our modeling results. Areas with high microplastic density significantly overlapped with areas of high macroplastic density. The most abundant polymer detected in all the sampling sites was polyethylene (PE), suggesting fragmentation of larger packaging items as the primary source. To our knowledge, this is the first study in the Pelagos Sanctuary in which the simulated microplastic distribution has been confirmed by field observations. The overlap between the fin whale feeding habitat and the microplastic hot spots is an important contribution for risk assessment of fin whale exposure to microplastics.
Concern about marine litter has been rising in the last decades, triggered by the discovery of the great mid-ocean garbage patches. The Mediterranean Sea is strongly affected by the presence of floating litter, as it has a very high amount of waste generated annually per person that eventually ends up in its waters, with plastic objects accounting for a large percentage of all manmade debris. In principle, the basin looks very vulnerable to possible accumulation of floating debris, since its dynamics is characterized by an inward surface flow of water from the Atlantic hampering surface floating items from being flushed out. Yet, no evidence of permanent litter accumulation areas has been reported so far in the Mediterranean. In this paper we utilized the largest available set of historical Lagrangian data gathered in the Mediterranean Sea to estimate the probability of debris particles to reach different subareas of the basin, with the main objective of singling out possible retention areas. Climatological reconstructions of the time evolution of litter distribution in the basin carried out on the basis of observed Lagrangian displacements suggest a general tendency of floating matter to collect in the southern portion of the basin, and in particular a long term accumulation in the southern and southeastern Levantine basin, areas not yet sampled by marine litter observation campaigns, whose targeted organization we strongly recommend at the end of this paper.
The Cilician Basin located in the Northeastern Mediterranean is a region that is affected by a diversity of anthropogenic pressures and is further expected to suffer from negative economic, environmental and social impacts of coastal litter. To provide a baseline for litter management plans, the standing crop of coastal macro-litter was sampled on 13 beaches following MSFD guidelines. Environmental predictors characterizing beach use and potential land based litter point sources in the vicinity of the beaches were related to litter densities to identify litter sources. The average litter density was 0.92 ± 0.36 items/m2. Litter items resulting from convenience food consumption and smoking made up more than half of the total litter collected, while agricultural, industrial, fishing activities together contributed only 6% of the total number of items. Plastic items on average constituted more than 80% of the dominant material type. Percentages of the litter transported with currents from neighbouring countries (transboundary litter) varied from 0 – 4.23% between beaches. Direct deposition on the beaches was identified as the main method for transport of items to the coastal environment. Our results show poor local awareness and underline the need for educational programs that can help reduce coastal litter. © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey.
Microplastic debris floating at the ocean surface can harm marine life. Understanding the severity of this harm requires knowledge of plastic abundance and distributions. Dozens of expeditions measuring microplastics have been carried out since the 1970s, but they have primarily focused on the North Atlantic and North Pacific accumulation zones, with much sparser coverage elsewhere. Here, we use the largest dataset of microplastic measurements assembled to date to assess the confidence we can have in global estimates of microplastic abundance and mass. We use a rigorous statistical framework to standardize a global dataset of plastic marine debris measured using surface-trawling plankton nets and coupled this with three different ocean circulation models to spatially interpolate the observations. Our estimates show that the accumulated number of microplastic particles in 2014 ranges from 15 to 51 trillion particles, weighing between 93 and 236 thousand metric tons, which is only approximately 1% of global plastic waste estimated to enter the ocean in the year 2010. These estimates are larger than previous global estimates, but vary widely because the scarcity of data in most of the world ocean, differences in model formulations, and fundamental knowledge gaps in the sources, transformations and fates of microplastics in the ocean.
Contamination levels by plastic debris, trace elements and persistent organic pollutants were assessed and related to macrobenthic diversity within soft bottoms of Grand Harbour (Malta, Central Mediterranean). Sediment toxicity was evaluated by ecotoxicological method, deploying Bacteria (Vibrio fischeri), Echinodermata (Paracentrotus lividus) and Crustacea (Corophium orientale). Univariate analysis (Pearson's test) was used to test relationships between biodiversity indices, pollutants and grain size. A multivariate approach (PERMANOVA) was applied to investigate for any significant differences among sampling stations concerning plastic abundances and to test the relationship between infaunal abundances and pollutant concentrations (the BIOENV test). Significant differences in the plastic abundances were found between sampling stations. The lowest value for Shannon-Wiener biodiversity index was associated to the highest sediment pollution level. Multivariate analyses suggest that MBT and TBT were factors that most influenced macrozoobenthic abundance and biodiversity. The bivalve Corbula gibba and the introduced polychaete Monticellina dorsobranchialis were the most abundant found species.
The dynamic behavior of coastal litter is followed on Israeli beaches. Subsequently, the impact of the coastal geomorphology on litter dynamics is examined. Six prototype sampling beaches of different morphology were selected. The position, number, composition and nature of all the litter pieces, within a 50 m beach front, were recorded on each beach. Strips of litter concentration were demarcated and their movement was mapped along shore-normal transects. All items were tagged in situ, each beach strip by a different color. These sampling procedures enabled to define inflow, outflow, transfer, storage and reemergence of buried litter. We also calculated the litter budget at each site, traced litter movement through the beach and calculated the residence time and the turnover period. The littered area in all beaches, over the entire study period, was less than one percent. The widest beaches were the most littered. Specific beach morphology, as ridge and runnel, made the backshore an efficient trap for the litter. The results show that the narrower the beach the higher its litter flux. The narrowest sandy beach showed the highest range of dynamics. The litter is spread and organized in distinct strips. Their pattern reflects the specific beach depositional dynamics. The Israeli Mediterranean coast is homogeneous in its high mobility of litter, shown by a similar input and output of litter items and by the almost balanced budget of litter on each studied site. Turnover time, i.e., the time needed to replace the total litter on each beach, is only a few months long and less than half a year. This high mobility of the litter means poor persistence and a good self-cleaning capacity. The data suggests that the Israeli beaches are essentially a transfer route for the litter, which migrates along and finally seems to bypass them.
The processes of transport, diffusion and transformation of surface oil in
seawater can be simulated using a Lagrangian model formalism coupled with
Eulerian circulation models. This paper describes the formalism and the
conceptual assumptions of a Lagrangian marine surface oil slick numerical model and
rewrites the constitutive equations in a modern mathematical framework. The
Lagrangian numerical representation of the oil slick requires three different
state variables: the slick, the particle and the structural state variables.
Transformation processes (evaporation, spreading, dispersion and coastal
adhesion) act on the slick state variables, while particle variables are
used to model the transport and diffusion processes. The slick and particle
variables are recombined together to compute the oil concentration in water,
a structural state variable. The mathematical and numerical formulation of
oil transport, diffusion and transformation processes described in this
paper, together with the many simplifying hypothesis and parameterizations,
form the basis of a new, open source Lagrangian surface oil spill model,
the so-called MEDSLIK-II, based on its precursor MEDSLIK (Lardner et al., 1998, 2006; Zodiatis et al., 2008a).
Part 2 of this paper describes the applications of
the model to oil spill simulations that allow the validation of the model
results and the study of the sensitivity of the simulated oil slick to
different model numerical parameterizations.
Concentrations of floating plastic were measured throughout the Mediterranean Sea to assess whether this basin can be regarded as a great accumulation region of plastic debris. We found that the average density of plastic (1 item per 4 m2), as well as its frequency of occurrence (100% of the sites sampled), are comparable to the accumulation zones described for the five subtropical ocean gyres. Plastic debris in the Mediterranean surface waters was dominated by millimeter-sized fragments, but showed a higher proportion of large plastic objects than that present in oceanic gyres, reflecting the closer connection with pollution sources. The accumulation of floating plastic in the Mediterranean Sea (between 1,000 and 3,000 tons) is likely related to the high human pressure together with the hydrodynamics of this semi-enclosed basin, with outflow mainly occurring through a deep water layer. Given the biological richness and concentration of economic activities in the Mediterranean Sea, the affects of plastic pollution on marine and human life are expected to be particularly frequent in this plastic accumulation region.
Drifter observations and satellite-derived sea surface height data are used to quantitatively study the surface geostrophic circulation of the entire Mediterranean Sea for the period spanning 1992-2010. After removal of the wind-driven components from the drifter velocities and low-pass filtering in bins of 1 degrees x 1 degrees X 1 week, maps of surface geostrophic circulation (mean flow and kinetic energy levels) are produced using the drifter and/or satellite data. The mean currents and kinetic energy levels derived from the drifter data appear stronger/higher with respect to those obtained from satellite altimeter data. The maps of mean circulation estimated from the drifter data and from a combination of drifter and altimeter data are, however, qualitatively similar. In the western basin they show the main pathways of the surface waters flowing eastward from the Strait of Gibraltar to the Sicily Channel and the current transporting waters back westward along the Italian, French, and Spanish coasts. Intermittent and long-lived subbasin-scale eddies and gyres abound in the Tyrrhenian and Algerian Seas. In the eastern basin, the surface waters are transported eastward by several currents but recirculate in numerous eddies and gyres before reaching the northward coastal current off Israel, Lebanon, and Syria and veering westward off Turkey. In the Ionian Sea, the mean geostrophic velocity maps were also produced separately for the two extended seasons and for multiyear periods. Significant variations are confirmed, with seasonal reversals of the currents in the south and changes of the circulation from anticyclonic (prior to 1 July 2007) to cyclonic and back to anticyclonic after 31 December 2005.
An assessment of hazard stemming from operational oil ship discharges in the Southern Adriatic and Northern Ionian (SANI) Seas is presented. The methodology integrates ship traffic data, the fate and transport oil spill model MEDSLIK-II, coupled with the Mediterranean Forecasting System (MFS) ocean currents, sea surface temperature analyses and ECMWF surface winds. Monthly and climatological hazard maps were calculated for February 2009 through April 2013. Monthly hazard distributions of oil show that the zones of highest sea surface hazard are located in the southwestern Adriatic Sea and eastern Ionian Sea. Distinctive “hot spots” appear in front of the Taranto Port and the sea area between Corfu Island and the Greek coastlines. Beached oil hazard maps indicate the highest values in the Taranto Port area, on the eastern Greek coastline, as well as in the Bari Port area and near Brindisi Port area.
The present study aims to analyse the local and regional variability in the density and typology of marine debris on fishing grounds on the northern Mediterranean continental shelf, and to test relationships between marine litter and trawl fishing activity. Moreover, the colonization of plastics was examined in order to study the importance of plastics as a source of impact on marine communities and their further environmental implications. This study surveyed 11 sites, associated with trawling grounds and subjected to different levels of fishing intensity, located in four areas of the Mediterranean: one in Italy, the Central Tyrrhenian coast, one in Greece, the eastern Ionian coast, and two in Spain, the Murcian and Catalan coasts. Samples were collected during an oceanographic cruise undertaken from the 21 May to the 24 June 2009. Results showed geographical variation in the density of marine debris which ranged from 0 to 405 pieces per hectare in the surveyed areas, plastics being the dominant components. Variability within sites was higher than between areas, indicating small-scale patchiness in the distribution of the debris over the seafloor. Though the study areas were within trawling grounds, the density of debris was not significantly correlated with fishing effort. More than 30% of plastics were between 10 and 20 cm width/length, and more than 40% of the plastics were colonized by a biofilm of microorganisms, suggesting indirect effects on benthic communities.
Ocean models need over-ocean atmospheric forcing. However, such forcing is not necessarily provided near the land-sea boundary because 1) the atmospheric model grid used for forcing is frequently much coarser than the ocean model grid, and 2) some of the atmospheric model grid over the ocean includes land values near coastal regions. This paper presents a creeping sea-fill methodology to reduce the improper representation of scalar atmospheric forcing variables near coastal regions, a problem that compromises the usefulness of the fields for ocean model simulations and other offshore applications. For demonstration, atmospheric forcing variables from archived coarse-resolution gridded products—the 1.125° 1.125° 15-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-15) and 1.0° 1.0° Navy Operational Global Atmospheric Prediction System (NOGAPS)—are used here. A fine-resolution (1/25° 1 /25° cos(lat)), (longitude latitude) (3.2 km) eddy-resolving Black Sea Hybrid Coordinate Ocean Model (HYCOM) is then forced with/without sea-filled atmospheric variables from these gridded products to simulate monthly mean climatological sea surface temperature (SST). Using only over-ocean values from atmospheric forcing fields in the ocean model simulations significantly reduces the climatological mean SST bias (by 1°-3°C) and rms SST difference over the seasonal cycle (by 2°-3°C) in coastal regions. Per- formance of the creeping sea-fill methodology is also directly evaluated using measurements of wind speed at 10 m above the surface from the SeaWinds scatterometer on the NASA Quick Scatterometer (QuikSCAT) satellite. Comparisons of original monthly mean wind speeds from operational ECMWF and NOGAPS products with those from QuikSCAT give basin-averaged rms differences of 1.6 and 1.4 m s1, respectively, during 2000-03. Similar comparisons performed with sea-filled monthly mean wind speeds result in a much lower rms difference (0.7 m s1 for both products) during the same time period, clearly confirming the accuracy of the methodology even on interannual time scales. Most of the unrealistically low wind speeds from ECMWF and NOGAPS near coastal boundaries are appropriately corrected with the use of the creeping sea fill. Wind speed errors for ECWMF and NOGAPS (mean bias of 2.5 m s1 with respect to QuikSCAT during 2000-03) are substantially eliminated (e.g., almost no bias) near most of the land-sea boundaries. Finally, ocean, atmosphere, and coupled atmospheric-oceanic modelers need to be aware that the creeping sea fill is a promising methodology in significantly reducing the land contamination resulting from an improper land-sea mask existing in gridded coarse-resolution atmospheric products (e.g., ECMWF).
The aim of this study is to produce future scenarios on the river inputs of water and nutrients (nitrate and phosphate) into the Mediterranean and Black Sea. They are based on the four contrasting scenarios that were developed by the Millenium Ecosystem Assessment (MEA) for the years 2030 and 2050 and implemented in a spatially explicit manner into the IMAGE model. We first identified the major drivers of the river fluxes by regression analyses, then tested the retained models against the past evolutions between 1970 and 2000, and finally applied the models to the MEA scenarios. For nutrients, the considered river data mainly refer to the large rivers for which long-term time series exist (Rhone, Po, Ebro, and Danube). Here, recent trends were principally driven by fertilizer spreads (NO3, PO4), together with urban wastewater releases (PO4). Future trends remain in the envelope of the observed variability during the last 40 years, both for the large rivers and, when extrapolated to the basin scales, also for the entire Mediterranean and Black Sea. At regional scales, however, the budgets considerably change. In the northern parts of the Mediterranean drainage basin, they uniformly tend to decrease, but they may strongly increase in the south and east. Water discharge is examined on a basis of 37 rivers, showing that this parameter is clearly linked to the evolution of climate. Because of the ongoing evolution toward dryer and warmer conditions, we predict a significant trend of decreasing freshwater fluxes for the future, which already started in the past. Regional hot spots for this decrease are the drainage basin of the Alboran Sea and, when also considering the inhabitant specific water fluxes, the basins of the Aegean and north Levantine seas.
Marine litter has been defined as solid materials of human origin discarded at sea, or reaching the sea through waterways. The effect of marine debris on wildlife, tourism and human health is well documented and there is considerable scientific literature about plastic litter in the sea and over the seabed, mostly highlighting the possible impact on marine mammals and tourism. Dispersal of marine and terrestrial organisms on floating objects has biogeographical and ecological interest. For some species, extension of their geographical range is more likely to be related to transport of mature individuals on floating rafts than to the active or passive dispersal of reproductive propagules. Variability and variety of rafting materials has increased dramatically in recent years and marine litter has been used widely as a raft by ‘hitch-hiking’ species. This paper reports on the benthic invertebrates living on marine debris transported by wind and surface currents over the western Mediterranean Sea. Plastics accounted for the major item of debris because of poor degradability, however glass, cans, fishing nets and polyurethane containers, were also found. Macro-benthos living on raft material comprised mainly molluscs, polychaetes and bryozoans. Large fish were found commonly below large plastic bags. Estimations of the distances that may be covered by hitch-hiking species and the contribution of rafting to the theoretical dispersal of species is provided.
A global ocean circulation model is coupled to a Lagrangian particle tracking model to simulate 30 years of input, transport and accumulation of floating debris in the world ocean. Using both terrestrial and maritime inputs, the modelling results clearly show the formation of five accumulation zones in the subtropical latitudes of the major ocean basins. The relative size and concentration of each clearly illustrate the dominance of the accumulation zones in the northern hemisphere, while smaller seas surrounded by densely populated areas are also shown to have a high concentration of floating debris. We also determine the relative contribution of different source regions to the total amount of material in a particular accumulation zone. This study provides a framework for describing the transport, distribution and accumulation of floating marine debris and can be continuously updated and adapted to assess scenarios reflecting changes in the production and disposal of plastic worldwide.
Between 2014 and 2016 a total of 43 microplastic samples were collected at six sampling stations in the eastern section of the Gulf of Lion (located in the northwestern Mediterranean Sea), as well as upstream of the Rhône River. Microplastics were found in every sample with highly variable concentrations and masses. Concentrations ranged from 6 · 10³ items km⁻² to 1 · 10⁶ items km⁻² (with an average of 112 · 10³ items km⁻²), and mass ranged from 0.30 g km⁻² to 1018 g km⁻² DW (mean 61.92 ± 178.03 g km⁻²). The samples with the highest and lowest microplastic count originate both from the Bay of Marseille. For the Bay of Marseille, it is estimated that the total microplastic load consist of 519 · 10³ -101 · 10⁶ items weighing 0.07-118 kg. Estimations for daily microplastic transport by the Northern Current and the Rhône River, two important hydrologic features of the northwestern Mediterranean Sea, range from 0.18 to 86.46 t and from 0.20 to 21.32 kg, respectively. Particles < 1 mm² clearly dominated sampling stations in the Northern Current, the Rhône River and its plume (52, 53 and 61%, respectively), suggesting a long exposure time in the environment. Items between 1 mm² and 5 mm² in size were the most abundant microplastics in Marseille Bay (55%), which suggests coastal pollution sources or the removal of smaller particles from surface waters e.g. by ballasting owing to the presence of epibionts.
Marine litter is a major source of pollution in the Mediterranean basin, but despite legislative
requirements, scant information is available for the ongoing assessment of this threat.
Using higher size classes as proxy for litter distribution, this study gave a synoptic estimation of
the amount, composition, and distribution of floating macro-litter in the Mediterranean. The
average amount of macro-litter was in a range of 2-5 items/km2, with the highest in the Adriatic
basin. Seasonal patterns were present in almost all study areas and were significant in the
Ligurian Sea, Sardinian-Balearic basin, and Central Tyrrhenian Sea. Plastic accounted for more
than 80% of litter in all areas and seasons, with the highest proportion in the Adriatic Sea,
Ligurian Sea, and Sicilian-Sardinian Channels; in the Bonifacio Strait, Tyrrhenian Sea, and
Sardinian-Balearic basin, litter composition was instead more diverse. Spatial analysis
suggested an almost homogeneous distribution of litter without evident regular aggregation
zones.
We assessed amounts, composition and net accumulation rates every ~. 15. days of beach macro litter (≥. 2.5. cm) on 4 Mediterranean beaches, on Corfu island, N. Ionian Sea, taking into account natural and anthropogenic drivers. Average net accumulation rate on all beaches was found 142. ±. 115. N/100. m/15. d. By applying a Generalized Linear Model (GzLM) it was shown that sea transport is the dominant pathway affecting the amount and variability in beach litter loadings. Principal Component Analysis (PCA) on compositional data and indicator items discerned two more pathways of beach litter, i.e. in situ litter from beach goers and wind and/or runoff transport of litter from land. By comparing the PCA results to those from a simple item to source attribution, it is shown that regardless their source litter items arrive at beaches from various pathways. Our data provide baseline knowledge for designing monitoring strategies and for setting management targets.
The Mediterranean is an ecosystem that faces more and more
microplastic pollution every day. This causes the whole Mediterranean to
face the negative effects of plastic pollution. This study examines the
state of plastic debris and fouling organisms found on it in one of the
areas most affected by plastic pollution, Mersin Bay. As a result, a
total of 3.88kg plastic (mean=0.97 kg; n=120; 2670 item/km2; 86.3 kg/km2)
was collected and based on the ATR-FTIR analysis, it was determined that
this total contained 9 types of plastics. 17 different fouling species
belonging to 6 phylum (Annelida, Arthropoda, Bryozoa, Chordata, Cnidaria,
Mollusca) 7 class and 11 order were discovered on plastics. Spirobranchus
triqueter, Hydroides sp. and Neopycnodonte cochlear were the most
abundant species. In the end, the example of Mersin Bay shows that
plastic debris as a substrate can contain a very high diversity of life
just like natural substrates.
The composition, spatial distribution and source of marine litter in the Spanish Southeast Mediterranean were assessed. The data proceed from a marine litter retention programme implemented by commercial trawlers and were analysed by GIS. By weight, 75.9% was plastic, metal and glass. Glass and plastics were mainly found close to the coast. A high concentration of metal was observed in some isolated zones of both open and coastal waters. Fishing activity was the source of 29.16% of the macro-marine litter, almost 68.1% of the plastics, and 25.1% of the metal. The source of the other 60.84% could not be directly identified, revealing the high degree of uncertainty regarding its specific origin. Indirectly however, a qualitative analysis of marine traffic shows that the likely sources were merchant ships mainly in open waters and recreational and fishing vessels in coastal waters.
Seasonal sea surface microplastic distribution was recorded at 17 sites along the Israeli Mediterranean coast. Microplastics (0.3-5mm) were found in all samples, with a mean abundance of 7.68±2.38particles/m(3) or 1,518,340particles/km(2). Some areas had higher abundances of microplastics than others, although differences were neither consistent nor statistically significant. In some cases microplastic particles were found floating in large patches. One of these patches contained an extraordinary number of plastic particles; 324particles/m(3) or 64,812,600particles/km(2). Microplastic abundances in Israeli coastal waters are disturbingly high; mean values were 1-2 orders of magnitude higher than abundances reported in other parts of the world. Light-colored (white or transparent) fragments were by far more abundant than all other microplastic colors and types. The results of this study underline the need for action to reduce the flux of plastics to the marine environment.
Plastics are the most common material of marine litter and have become a global pollution concern. They are persistent in the environment where they gradually degrade into increasingly smaller particles–microplastics (MP). Our study presents results of sea-surface monitoring for MP in the Slovenian part of the Trieste Bay in the Northern Adriatic Sea. In 17 trawls conducted over a 20-month period we found a high average concentration of 406 × 10³ MP particles/km². Over 80% of the particles were identified as polyethylene. The significant variability of MP concentrations obtained on different sampling dates is explained by use of surface current maps and a recently developed Markov chain marine litter distribution model for the Adriatic Sea.
We assessed the annual accumulation rates of beach litter on the Tyrrhenian coast of central Italy, providing the characterization of litter following European standardized guidelines. Three different sites of a beach were sampled seasonally from spring 2014 to winter 2015. A total of 31,739 items were removed and classified into 103 categories. Plastic represented the majority (94.4%) of the collected items. We detected temporal and spatial differences in the abundance and composition of litter between seasons and between sites. Furthermore, we found that plastic cotton bud sticks composed > 30% of the total amount of litter and, together with plastic and polystyrene pieces, made up > 70% of the total items. Finally, our results led us to propose that the most effective strategy to reduce litter pollution is to devise specific management procedures focusing on the most abundant items.
