Microplastic debris ending up at the sea surface has become a known major environmental issue. However, how microplastic particles move and when they sink in the ocean remains largely unknown. Here, we model microplastic subject to biofouling (algal growth on a substrate) to estimate sinking timescales and the time to reach the depth where particles stops sinking. We combine NEMO-MEDUSA 2.0 output, that represents hydrodynamic and biological properties of seawater, with a particle-tracking framework. Different sizes and densities of particles (for different types of plastic) are simulated, showing that the global distribution of sinking timescales is largely size-dependent as opposed to density-dependent. The smallest particles we simulate (0.1 μm) start sinking almost immediately around the globe and their trajectories produce the longest time to reach their first sinking depth (almost 40 days as a global median). In oligotrophic subtropical gyres with low algal concentrations, particles between 1 mm and 10 μm do not sink within the 90-day simulation time. This suggests that in addition to the comparatively well-known physical processes, biological processes might also contribute to the accumulation of floating plastic (of 1 mm to 10 μm) in subtropical gyres. Particles of 1 μm in the gyres start sinking largely due to vertical advection, whereas 0.1 μm particles sink both due to biofouling and advection. The qualitative impacts of seasonality on sinking timescales are small, however, localised sooner sinking due to spring algal blooms is seen. This study maps processes that affect the sinking of virtual microplastic globally, which could ultimately impact the ocean plastic budget.

How to cite: Lobelle, D., Kooi, M., Koelmans, A. A., Laufkotter, C., Jongedijk, C. E., Kehl, C., and van Sebille, E.: Global modeled sinking characteristics of biofouled microplastic, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-280, https://doi.org/10.5194/egusphere-egu21-280, 2021.

The aim of the study was to determine the correlation of metals on floating marine litter and weathered microplastic samples from the pristine area. Sampled were collected from the accumulated material on the natural beach in Mala Stupica Cove (Žirje Island, Croatia) in June 2020. In addition to weathered microplastic, the concentrations of dissolved metals in the seawater, at the same location were determined. According to these measurements, the sampling site can be considered pristine, with Cd and Pb concentrations as background values and Zn and Cu as elements that have no toxic effect, based on the classification proposed by Bakke et al., (2010). The metals of interest due to their high toxicity were Zn, Cd, Pb, and Cu.

After sampling, the collected material was sieved through a metal sieve with a 4 mesh size, resulting in 4 subsamples (>4 mm; 4-2 mm; 2-1 mm; 1-0.250 mm). The type of plastic particles from subsample >4 mm was determined by FTIR spectroscopy performed on Bruker Tensor 27 in the region from 400-4000 cm^-1. On such defined particles and in the seawater sample, trace metal concentrations were determined by the electrochemical method differential pulse anodic stripping voltammetry (DPASV) with standard addition method by Metrohm Autolab modular potentiostat/galvanostat Autolab PGSTAT204. A static mercury drop electrode (SMDE) was used as the working electrode.

Plastic particles were isolated from additional two fractions (2-1 mm and 1-0.250 mm) as bulk samples, but without polystyrene, and the metal concentration was also determined using the same method. Due to the particle size, the type of plastic was not determined. Additional analyzes of metal concentrations on a defined and isolated polystyrene particles (PS) from a subsample (4-2 mm) and (2-1 mm) were also performed.

By analogy with sediment particles, one would expect smaller microplastic particles to have higher metal concentrations due to their larger specific surface area, but this was not observed in this study. The metal concentration varied with the type of plastic, and from the observed results, plastics could be ranked according to their affinity for the analyzed metals, as follows: polystyrene (PS)>Polypropylene (PP)>Low-density polyethylene (LDPE). According to an average concentration of all analyzed samples defined as LDPE, Zn could be single out as an element with around 7-time higher affinity for LDPE than other elements (Cd, Pb, and Cu). For samples defined as PP, the highest affinity is observed for Pb, even 30 times higher than in LDPE, followed by Zn and Cu, while Cd has similar values as in LDPE.  For PS samples affinity of all elements is higher in comparison with the LDPE and PP, as follows: Pb>Cu> Zn>Cd, with a concentration of Pb 2.5 times higher than in PP and even 88 times higher than in LDPE.

 A general conclusion could be drawn, but the observed wide ranges indicate the need for additional research to determine the relationship between the degree and type of weathering with the associated metals.

This work has been fully supported by Croatian Science Foundation under the project lP-2019-04-5832.

How to cite: Fajković, H., Cukrov, N., Kwokal, Ž., Pikelj, K., Huljek, L., Kostanjšek, I., and Cuculić, V.: Correlation of microplastic type and metal association: Croatian coast case study (Žirje Island), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1022, https://doi.org/10.5194/egusphere-egu21-1022, 2021.

Microplastic particles (MPs) are found in marine ice in larger quantities than in seawater, indicating that the ice is an important link in the chain of spreading of this contaminant. Some studies indicate larger MPs abundance near the ice surface, while others did not find any consistent pattern in the vertical distribution of MPs within sea ice cores. We discuss physical mechanisms of incorporation of MPs in the ice and present the results of laboratory tests, underpinning our conclusions.

First, plastic hydrophobicity is shown to cause the effect of pushing the floating MPs further up of the newly-forming ice. This leads to a concentration of MPs at the ice surface in the laboratory, while in the field the particles at the surface may by covered by snow and become a part of the upper ice layer. Under open-air test conditions, the bubbles of foamed polystyrene (density 0.04 g/cm³), initially floating at the water surface, were gone by weak wind when the firm ice was formed.

Second, the difference between freshwater and marine ice is considered. Since fresh water has its temperature of the density maximum (Tmd=3.98 C) well above the freezing point (Tfr=0 C), the freshwater ice is formed when the water column is stably stratified for a relatively long period of cooling from the Tmd down to the Tfr. Under such steady conditions, even just slightly positively/negatively buoyant MPs have enough time to rise to the surface / to settle to the bottom. In contrast, the ice in the ocean freezes when thermal convection is at work, further enhanced by the brine release. Thus, strong convection beneath the forming marine ice keeps slightly positively/negatively buoyant MPs in suspension and maintains the contact between the MPs and the forming ice. Laboratory tests show both the difference between the solid-and-transparent freshwater ice and the layered, filled with brine marine ice, and the difference in the level of their contamination.

Lastly, it is demonstrated that MPs tend to be incorporated in the ice together with air bubbles and in-between the ice plates (in brine channels). This is most probably due t plastics’ hydrophobicity.

Investigations are supported by the Russian Science Foundation, grant No 19-17-00041.

How to cite: Chubarenko, I.: Physical processes behind interactions of microplastic particles with ice, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1149, https://doi.org/10.5194/egusphere-egu21-1149, 2021.

Marine plastic litter can be a significant vector for ecotoxic trace metals into coastal areas. Eventually, it can be burried in sediment and in accumulated material on the beach with organic and inorganic material on its surface. In order to analyze the trace metal quantities (Cd, Cu, Pb and Zn) on different size particles in an anthropogenically affected environment, microplastics were sampled from the accumulated material on the Mala Martinska natural beach (Šibenik Bay, Croatia) in September 2019. The city of Šibenik and the Šibenik Bay are located in the lower part of the Krka River estuary (middle Adriatic). It is the main Croatian port for the phosphate ore import. Also, it was found earlier that Šibenik Bay was polluted by the ex-ferromanganese industry located in it, and the industrial slag spreading around the factory was the significant supply of trace metals in the Bay. The concentrations of dissolved and total metals in the surface seawater at the same location and at the reference point (coastal surface seawater at Jadrija, ~4 km SE from the sampling site) were determined in February and June 2020.

The collected material was sieved through a metal sieve with a 4 mesh size, resulting in 4 bulk (mixed microplastics) aliquots (> 4mm; 4-2 mm; 2-1 mm; 1-0.250 mm). From each of of the 4 bulk aliquots, subsamples of mixed plastics and polystyrene (PS) particles were isolated, resulting in 8 subsamples in total. The type of plastic particles (> 4mm; 4-2 mm and PS) was determined by FTIR spectroscopy performed on Bruker Tensor 27 in the region from 4000-400 cm^-1. Trace metal concentrations on such defined particles and in seawater samples were determined using differential pulse anodic stripping voltammetry (DPASV) by Metrohm Autolab modular potentiostat/galvanostat Autolab PGSTAT204, connected with a three-electrode system Metrohm 663 VA STAND (Utrecht, The Netherlands). Working electrode used was static mercury drop electrode (SMDE).

In general, the amounts of trace metals associated with the plastic particles (Cd 0.02-0.35 µg/g; Pb 1.1-34.1 µg/g; Cu 1.7-32.9 µg/g and Zn 6-147 µg/g) were in the range of unpolluted and moderately affected sediments in the Adriatic Sea. The mass fractions of all tested trace metals increase with decreasing plastic particle size, probably due to the larger specific surface areas on the smaller particles. That was not the case for the plastic particles larger than 4 mm, both in mixed and PS samples, where the amounts of metal were higher compared to particles of 4-2 mm and 2-1 mm. Furthermore, all metals except cadmium showed a higher affinity for PS in comparison with mixed plastic samples of the same particle sizes (up to order of magnitude higher metal amounts), due to the PS highly developed specific surface area. In order to better understand the mechanism of association of trace metals with microplastics under different environmental conditions, further investigations are needed.

This work has been fully supported by Croatian Science Foundation under the project lP-2019-04-5832.

How to cite: Cuculić, V., Fajković, H., Kwokal, Ž., and Matekalo, R.: Trace metals load on beached microplastics in the anthropogenically influenced estuarine environment - Croatian middle Adriatic, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1171, https://doi.org/10.5194/egusphere-egu21-1171, 2021.

We study the vertical dispersion and distribution of negatively buoyant rigid microplastics within a realistic circulation model of the Mediterranean sea. We first propose an equation describing their idealized dynamics. In that framework, we evaluate the importance of some relevant physical effects: inertia, Coriolis force, small-scale turbulence and variable seawater density, and bound the relative error of simplifying the dynamics to a constant sinking velocity added to a large-scale velocity field. We then calculate the amount and vertical distribution of microplastic particles on the water column of the open ocean if their release from the sea surface is continuous at rates compatible with observations in the Mediterranean. The vertical distribution is found to be almost uniform with depth for the majority of our parameter range. Transient distributions from flash releases reveal a non-Gaussian character of the dispersion and various diffusion laws, both normal and anomalous. The origin of these behaviors is explored in terms of horizontal and vertical flow organization.

How to cite: de la Fuente, R., Drótos, G., Hernández, E., López, C., and van Sebille, E.: Sinking microplastics in the water column: simulations in the Mediterranean Sea, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1203, https://doi.org/10.5194/egusphere-egu21-1203, 2021.

The COVID-19 pandemic caused a massive use of disposable sanitary face masks. Based on data provided by Prata et al. (2020), we estimated that if only 0.1% of those masks are improperly discarded and enter the soil, approximately 361t of polypropylene (PP) will be monthly added to the soil, threatening the ecological balance of terrestrial systems, the health of wild animals and even humans. For a first evaluation of the environmental consequences of the mask littering during COVID-19, we compared the microbial degradability of 10 x 10 mm cuts of the single masks layers and the complete mask blended with topsoil from a Cambisol of the Sierra de Aznalcóllar, Southern Spain with natural soil organic matter (SOM) by measuring the CO₂ release during a three-month decomposition experiment performed with a soil moisture of 75% of its maximal water holding capacity and at 25°C. In order to focus on biodegradation and to avoid abiotic impact of physical and chemical processes, the masks were not pretreated or exposed to UV-irradiation or natural daylight prior to decomposition. In addition, the incubation occurred in the dark. We identified an easily decomposable fraction with a mean residence time (MRT_fast) of 2 to 3 days, releasing approximately 3 to 5% of the total mask carbon as CO₂. Solid-state nuclear magnetic resonance (NMR) spectroscopy confirmed that all three layers of the mask were composed of PP without contributions of more than 2-3% of other additives. Microbial degradation resulted in a cut-off of terminal PP units as a main degradation mechanism. Assuming again that about 0.1% of the masks used during the COVID-19 crises may enter soil systems, we estimated that this fast pool may cause an additional CO₂ emission of 41 to 68 t year^-1. This corresponds to the globally averaged annual CO₂-footprint of 10 to 17 persons (4 t year^-1 person^-1).  The slow turning fraction was mineralized with a rate constant of 0.05 to 0.14 year^-1 corresponding to a MRT_slow between 7 and 18 years. This is two to four times longer than that determined for the SOM pure reference soil but still lies in the range reported for humified SOM derived from other topsoils of the Sierra de Aznalcóllar. Our results allow us to confirm our hypothesis that in soil, microbes exist that can decompose PP, although their nature still has to be revealed in future attempts. Studies investigating the impact of pre-exposure to daylight and moisture on their degradability in soils are in process.

Prata, J.C., Silva, A.L.P., Walker, T.R., Duarte, A.C., Rocha-Santos, T., 2020. COVID-19 Pandemic Repercussions on the Use and Management of Plastics. Environ. Sci. Technol. 54, 7760–7765. https://doi.org/10.1021/acs.est.0c02178

How to cite: Knicker, H. and Velasco-Molina, M.: Biodegradability of single-use polypropylene-based face masks, littered during the COVID-19 pandemic – a first approach , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1293, https://doi.org/10.5194/egusphere-egu21-1293, 2021.

Initiation of motion, resuspension, transport, and accumulation of microplastic particles (MPs) at the sea bottom are prescribed by their physical properties – density, size, and shape, as it is known for natural sediment grains. However, from sedimentological approaches, not much can be said about the behavior of non-spherical particles at the bottom covered by another type of material. Thus, experimental disclosure of general features of the MPs transport and accumulation pattern should aid a lot further theoretical description of such a complex process.

Laboratory experiments on the MPs transport by the open-channel flow and their accumulation in regions with various bottom roughness were carried out in 10 m long and 0.33 m wide hydrodynamic flume. The bottom had 4 sections (ca. 2 m long each) with the roughness increasing downstream: smooth-bottom section, followed by the sections covered by natural calibrated coarse sand (particle diameter 1-1.5 mm), marine granules (3-4 mm), and small pebbles (1-2 cm). The upper sediment surface was carefully horizontally leveled. The set of MPs included 1d (flexible and rigid), 2d (square/round/elongated; flexible/rigid), and 3d (round/cubic) particles made of polystyrene, polyester, polyamide (nylon), and polyethylene terephthalat (material density ranging from 1.05 to 1.41 g/cm³). Principal sizes of MPs ranged from 0.5 mm (smaller than the smallest sediment grain) to 5 cm (larger than the largest sediment grain). At the beginning of the experiment, MPs were placed on the smooth bottom. Thereafter, the flow rate was increased step-by-step by small increments. At each step, after at least 5 min since the last particle movement, the coordinates of the particles in their (new) stationary positions were registered.

Although we did not aim to achieve a similarity between a laboratory experiment and natural conditions, the results of the present study can be useful for a qualitative interpretation of field observations and further theoretical efforts. The results show, that the initiation of motion of particular MPs is dependent both on MPs size and the sediment characteristics. The cumulative curve, integrating coordinates of all the kinds of MPs in their stationary locations at all the flow steps, indicates the potential for the existence of MP accumulation zones in the regions right after the change in the bottom roughness, at the side of coarser sediment.

Investigations are supported by the Russian Science Foundation, grant No 19-17-00041.

How to cite: Isachenko, I. and Chubarenko, I.: Different microplastics versus different bottom sediments: transport and accumulation pattern in the open-channel flow experiments, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1791, https://doi.org/10.5194/egusphere-egu21-1791, 2021.

                The quality of the Black Sea ecosystem is partly but importantly dependent on the survival and sustainability of the top predator populations. It is difficult to foresee all consequences for the regional biodiversity if cetaceans disappear as it had happened with the Mediterranean monk seals in the past. During 7 days, between 30 September and 7 October, 2019, a joint oceanographical survey was made with a multipurpose R/V Mare Nigrum in offshore as well as deep sea locations, within the Romanian (RO), Bulgarian (BG) and western Turkish (TK) national waters of the Black Sea in the frame of ANEMONE project. The total track line was around 700 nautical miles and the sampled area covered 9754,58 km². Observations were made of cetaceans and floating litter, following line transect sampling method, with a single platform (2 observers, on the left and right of the vessel bridge) over 380.44 km of transects. A total of 54 cetacean sightings and 81 floating litter items were recorded. All the three species, short-beaked common dolphin (Delphinus delphis ssp. ponticus), Black Sea bottlenose dolphin (Tursiops truncatus ssp. ponticus), and Black Sea harbour porpoise (Phocoena phocoena ssp. relicta), were registered with a similar density (individuals/km²), 0.012 for RO sector and 0.013 for BG-TK sector. The number of debris varied between 1 and 24 items, reaching 5.26± 5.93 items on average. Among the transects, 53% contained less than 5 items and only 13% were with more than 10 items. Based on these results, the average density of floating macro-litter in BG waters was found 2.43 ± 2.4 items/km², 1.73 ± 1.24 items/km² in the RO waters and 2.43±2.17 items/km² in TR waters. This study was the first to make a joint and continuous survey effort for both cetaceans and litter simultaneously in the Black Sea.

Key words:  Black Sea, cetaceans, marine litter, joint cruise, ANEMONE project.

How to cite: Paiu, R.-M., Tonay, A. M., Timofte, C., Paiu, A., Mirea Candea, M., Gheorghe, A.-M., Slabakova, V., Amaha Ozturk, A., and Murariu, D.: Using line transect sampling to detect cetaceans and floating litter during vessel survey in western Black Sea, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2361, https://doi.org/10.5194/egusphere-egu21-2361, 2021.

Observational and modeling studies have suggested that Indonesia among the top plastic polluting countries globally. Data on the presence of plastic pollution are crucial to designing effective plastic reduction and mitigation strategies. Research quantifying plastic pollution in Indonesia has increased in recent years. However, most plastic research to date has been done with different goals, methods, and data formats. In this study, we present a meta-analysis of 85 studies published on plastic pollution in Indonesia to uncover gaps and biases in current research, and to use these insights to suggest ways to improve future research to fill these gaps. Research gaps and biases identified include a clear preference for marine research, and a bias towards certain environmental compartments within the marine, riverine, and terrestrial ecosystems, which are compartments that are easier to quantify such as riverbanks and beaches. Moreover, we identify polypropylene (PP) and polyethylene variants (HDPE, LDPE, PE) to be among the most frequently found polymers in both macro- and microplastic pollution, though polymer identification is lacking in most studies. Plastic research is mostly done on Java (57%). We recommend a shift in ecosystem focus of research towards the riverine and terrestrial environments, and a shift of focus of environmental compartments analyzed within these ecosystems. Moreover, we recommend an increase in spatial coverage across Indonesia of research, a larger focus on polymer characterization, and lastly, the harmonization of methods used to quantify plastic. With these changes, we envision future research that can aid with the design of effective reduction and mitigation strategies.

How to cite: Vriend, P., Hidayat, H., Cordova, R., Purba, N. P., Lohr, A., Ningsih, N., Agustina, K., Husrin, S., Suryono, D. D., Hantoro, I., Widianarko, B., van Leeuwen, J., Vermeulen, B., and van Emmerik, T.: Plastic pollution research in Indonesia: State of science and future research directions., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2418, https://doi.org/10.5194/egusphere-egu21-2418, 2021.

The distribution of plastic in the ocean is poorly constrained, with the mass of floating plastic at the ocean surface being orders of magnitude smaller than estimated plastic inputs. Coastlines likely contain significant amounts of plastic, but inconsistent methodologies between beached plastic observations prevent determining the mass and distribution of globally beached plastic. We present Lagrangian model sensitivity experiments to estimate the beached fraction of marine plastic and to investigate the global distribution of beached plastic on coastlines.

We perform simulations where particles, representing masses of floating plastic, are inserted at the ocean coasts. The particles are then advected by surface currents (HYCOM/NCODA global reanalysis and surface Stokes drift from the WaveWatch III global reanalysis) for 5 years. Beaching is parametrized stochastically using exponentional probability. Here, we test the sensitivity to e-folding time scales between 1 and 100 days, applied when plastic is within the coastal zone, within 10km of the nearest coastline. Resuspension of beached plastic is parameterised exponentially with an e-folding timescale between 69 and 273 days. No other loss processes are implemented.

Between 39-95% of floating plastic mass is beached after 5 years, with the beached fraction depending on the ratio between the beaching and resuspension timescales. In all simulations, at least 77% of floating plastic mass is found either beached or within the coastal zone, indicating coastal regions are a significant reservoir of mismanaged terrestrial plastic. However, plastic entering the ocean from islands or near energetic boundary currents is more likely to reach the open ocean. The distribution of beached plastic is closely related to the input distribution, with the highest concentrations found in Southeast Asia and the Mediterranean.

Our results highlight coastlines and coastal waters as important reservoirs of marine plastic debris and indicate a need for greater understanding of plastic transport near and at the coastlines. Furthermore, improved representation of plastic beaching can help study marine plastic fragmentation, as mechanical stress during the transitions between coastlines and coastal waters and the increased UV exposure of beached plastic likely contribute to the fragmentation.

How to cite: Onink, V., Jongedijk, C., Hoffman, M., van Sebille, E., and Laufkötter, C.: Global modelling of plastic beaching indicates coastlines and coastal waters as significant plastic reservoirs, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4092, https://doi.org/10.5194/egusphere-egu21-4092, 2021.

Field studies have shown that plastic fragments make up the majority of plastic pollution in the oceans in terms of abundance. How quickly environmental plastics fragment is not well understood, however. Here, we study this process by considering a model which captures continuous fragmentation of particles over time in a cascading fashion. With this cascading fragmentation model, we simulate particle size distributions (PSDs), specifying the abundance or mass of particles for different size classes.

The fragmentation model is coupled to an environmental box model, simulating the distributions of plastic particles in the ocean, coastal waters, and on the beach. Transport in the box model is based on a previous study regarding a previous study regarding sources and sinks of marine plastics in the Mediterranean Sea. We compare the modelled PSDs to available observations, and use the results to illustrate the effect of size-selective processes such as vertical mixing in the water column and resuspension of particles from the beach into coastal waters.

Using the coupled fragmentation and environmental box model, we quantify the role of fragmentation on the marine plastic mass budget. While fragmentation is a major source of (secondary) plastic particles in terms of abundance, it seems to have a minor effect on the total mass of particles larger than 0.1 mm. Future comparison to observed PSD data should allow us to understand size-selective plastic transport in the environment, and potentially inform us on plastic longevity.

How to cite: Kaandorp, M., Dijkstra, H., and van Sebille, E.: Modelling size distributions of marine plastics under the influence of continuous cascading fragmentation, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4342, https://doi.org/10.5194/egusphere-egu21-4342, 2021.

The large difference between the estimates of global plastic input in mass in the oceans (Jambeck et al., Science 347, 2015) and current global predictions from numerical models (van Sebille et al., Environ. Res. Lett. 10, 2015) or observations (Cózar et al., P. Natl. Acad. Sci., 111, 2014) is one of the most important issue regarding oceanic plastic litter. Yet, global predictions are based on observations, and uncertainties on the latter are rarely considered to provide error bounds on the former.

We discuss here the sources of uncertainties on plastic concentrations estimates (in number and mass), based on a recent model presented in (Poulain et al., Environ. Sci. Technol. 53, 2019). The two main sources of error are the plastic rise velocity and the model for the turbulent diffusivity, although they do not have the same importance. We validated the model with controlled laboratory experiments. Applying this model to global predictions provides us with more realistic encompassing values for the mass of plastic at sea, with a more important correction concerning small microplastics (with characteristic dimensions smaller than ~1mm).

How to cite: Mercier, M., Poulain-Zarcos, M., ter Halle, A., Saint-Martin, M., and Simatos, F.: Uncertainties on plastic concentration estimates at sea, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-5026, https://doi.org/10.5194/egusphere-egu21-5026, 2021.

Currently, all natural environments, including the Arctic seas, are contaminated by microplastics (MP, plastic fragments less than 5 mm). Biogeochemical processes significantly affect the physical properties of MP, primarily its density due to biofouling.
The aim of this work is to develop a numerical model for assessing the fate of MP in the marine environment under the influence of natural biogeochemical cycles in the Arctic seas on the example of Oslofjord.
The biogeochemical model OxyDep (E. V. Yakushev et al., 2011) was used to reproduce the temporal variability of the phyto- and zooplankton, dissolved and particulate organic matter. The two-dimensional 2D benthic-pelagic transport model (2DBP), which considers the processes in the water column and bottom sediments together, is used as a hydrophysical model.
The separate module which describes the transformation of the MP under biogeochemical processes was developed. The biogeochemical and MP modules were coupled with the transport model using the Framework for Aquatic Biogeochemical Modeling (FABM) (Bruggeman & Bolding, 2014).
The results show, that there would be a decrease in the MP content in the surface layer in summer period due to the ingestion by zooplankton and its transfer to the sediments. Based on the obtained patterns, it is possible to predict zones of accumulation of MP for a specific water area, depending on the local ecosystem.

Funding: The reported study was funded by RFBR, project number 20-35-90056. This work was partly funded by the Norwegian Ministry of Climate and Environment project RUS-19/0001 “Establish regional capacity to measure and model the distribution and input of microplastics to the Barents Sea from rivers and currents (ESCIMO)” and the Russian Foundation for Basic Research, research project 19-55-80004.

How to cite: Berezina, A., Yakushev, E., and Ivanov, B.: Modeling the influence of biogeochemical and ecosystem processes on microplastic transport in the Arctic seas on the example of Oslofjord, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-6531, https://doi.org/10.5194/egusphere-egu21-6531, 2021.

One of the main sources of plastic pollution in agricultural fields is the plastic mulch used by farmers to improve crop production. The plastic mulch is often not removed completely from the fields after harvest. Over time, the plastic mulch that is left of the fields is broken down into smaller particles which are dispersed by the wind or runoff. In the Region of Murcia in Spain, plastic mulch is heavily used for intensive vegetable farming. After harvest, sheep are released into the fields to graze on the vegetable residues. The objective of the study was to assess the plastic contamination in agricultural soil in Spain and the ingestion of plastic by sheep. Therefore, three research questions were established: i) What is the plastic content in agricultural soils where plastic mulch is commonly used? ii) Do livestock ingest the microplastics found in the soil? iii) How much plastic could be transported by the livestock? To answer these questions, we sampled top soils (0–10 cm) from 6 vegetable fields and collected sheep faeces from 5 different herds. The microplastic content was measured using density separation and visual identification. We found ~2 × 10³ particles∙kg⁻¹ in the soil and ~10³ particles∙kg⁻¹ in the faeces. The data show that plastic particles were present in the soil and that livestock ingested them. After ingesting plastic from one field, the sheep can become a source of microplastic contamination as they graze on other farms or grasslands. The potential transport of microplastics due to a herd of 1000 sheep was estimated to be ~10⁶ particles∙ha⁻¹∙y⁻¹. Further studies should focus on: assessing how much of the plastic found in faeces comes directly from plastic mulching, estimating the plastic degradation in the guts of sheep and understanding the potential effects of these plastic residues on the health of livestock.

How to cite: Beriot, N., Peek, J., Zornoza, R., Geissen, V., and Huerta Lwanga, E.: Low density-microplastics detected in sheep faeces and soil: A case study from the intensive vegetable farming in Southeast Spain, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-7376, https://doi.org/10.5194/egusphere-egu21-7376, 2021.

Microplastics have been recognised as persistent marine contaminants and mounting evidence supports their designation as anthropogenic stressors to marine organisms. Despite the remoteness of Antarctica, microplastics contamination has been reported in every marine environment investigated in this area to date. Due to ocean currents and frontal systems, microplastics may become entrapped within polar regions and increase bioavailibilty to inhabiting fauna. Antarctic marine benthic invertebrates represent a research priority due to their sensitivity to change as well as contribution to ecological functioning and food webs. The current study investigated microplastics ingestion by the epifaunal, carnivorous polychaete Barrukia cristata and the infaunal, filter-feeding bivalve, Laternula elliptica. Animals were collected by SCUBA adjacent to Rothera research station, Adelaide Island. After digestion in 10 % potassium hydroxide (KOH) followed by filtration, microplastics ingested by individual animals were separated. Microplastics were then counted and characterised by shape, colour, size and polymer type by Micro-Fourier transform Infrared spectroscopy. Polyethylene terephthalate (PET) was the most abundant polymer type, followed by polyacrylonitrile (PAN) and ethylene-vinyl acetate (EVA). Congruent to earlier reports, fibres were found to be the most abundant source of microplastics contamination. However, it must be highlighted that fragments were also recovered from the animals analysed. Results determined the current level of microplastics ingestion by two benthic marine invertebrates of different feeding strategies in coastal environments of the Antarctic Peninsula. These findings indicated the bioavailability of microplastics and highlighted the potential of trophic transfer throughout the Antarctic marine food web.

How to cite: Hurley, J., Hardege, J., Wollenberg Valero, K. C., and Morley, S.: In situ microplastics ingestion by Antarctic marine benthic invertebrates, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-10252, https://doi.org/10.5194/egusphere-egu21-10252, 2021.

Microplastics are ubiquitous in the global ocean and have even been found in remote polar environments, including in Arctic snowfall and Antarctic subtidal sediments. Levels in some areas of the Southern Ocean have been shown to be 100,000 times higher than predictions.

This is the first comprehensive survey of microplastic in the nearshore waters of South Georgia, a sub-Antarctic South Atlantic island noted for its biodiversity. Microplastic has been previously documented in resident populations of higher predators. This is likely to originate from their food, but the degree to which their prey is exposed to microplastics from background environments has yet to be examined.

Surface water samples were collected from 12 sites at 1km intervals around the accessible shoreline of the Thatcher Peninsula, South Georgia, including adjacent to the outflow pipes of the research station, King Edward Point (KEP). Additionally, samples were taken directly from: (i) outflow pipes at KEP and Grytviken (a nearby whaling station, occupied in summer), in order to determine the level of local input from anthropogenic wastewater systems; (ii) Gull Lake, a freshwater system isolated from oceanographic influence; and (iii) directly from falling snow to evaluate the potential risk of atmospheric transfer of microplastics via precipitation. Preliminary results using FT-IR spectroscopy have confirmed over 24,000 suspected anthropogenic particles/fibres as being microplastic. Microplastics were present in every sample, from every site and range in size from 0.05-3mm.

Here we present the following results:

• 1) the amount of microplastic in the background environment to which local biodiversity is exposed and;
• 2) the similarity between the microplastic profiles of an anthropogenic point source and the local environment.

How to cite: Buckingham, J., Waller, C., Waluda, C., and Manno, C.:  Microplastic in marine, nearshore waters of South Georgia: a study of background environmental levels of microplastic contamination, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-11667, https://doi.org/10.5194/egusphere-egu21-11667, 2021.

Plastic production has soared since the 1950s, with the last decade seeing an  increase of 43% from 250Mt (million tonnes) in 2009 to 368Mt in 2019. Plastics and their associated chemical congeners (variants of chemical structures) which enter the environment further exacerbate pollution within already contaminated ecosystems. In this study, we investigated the effect of plastic leachate on the common littoral marine hermit crab Pagurus bernhardus,  a species  at great risk from potential adverse effects of microplastics. The effects of  plastic additives released into the environment via microplastic leaching, and of contaminants adsorbed and accumulated onto the surface of microplastics on marine organisms is understudied. This study sought to (I) investigate whether plastic leachate has an effect on the respiration rate of hermit crabs and, (II) investigate whether plastic leachate has an effect on the foraging behaviour of hermit crabs. We found that within repeated measures design hermit crabs exposed to plastic leachate had different levels of oxygen consumption when compared to their control; with there being an increase or decrease dependent on the leachate type. This is potentially problematic due to high concentrations of microplastics along coastlines which may lead to impaired filtration within crustaceans resulting in lethality and reduced food intake.

How to cite: Scott, V. F., Hardege, J. D., and Wollenberg Valero, K. C.: The effect of plastic leachates on respiration and foraging behaviour in hermit crabs, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-12313, https://doi.org/10.5194/egusphere-egu21-12313, 2021.

Microplastic pollution in oceans is among the global environmental concerns of our time. Emerging research on ocean environments indicates that microfibers, such as those originating from textiles, are some of the most commonly occurring type of microplastic contaminants. While Fourier-transform infrared spectroscopy (FTIR) is commonly used to identify and characterize pollutant samples obtained from the environment, this identification is challenging because infrared spectra of materials can be modified by exposure to the ocean, air, UV light, and other ambient conditions, in a process referred to as “weathering”. We report preliminary efforts in improving FTIR characterization of microplastics by building a library of infrared spectra of common textile fibers weathered under a selection of ambient conditions. Consumer textile materials including polyester, nylon, cotton, and other, were exposed to a selection of ambient conditions: ocean, air, and wastewater treatment stages, in a controlled weathering experiment. Infrared spectra were monitored for up to 52 weeks, with the resulting data illuminating on the environmental fate and longevity of synthetic and natural fibers. Spectral changes caused by weathering were found to depend strongly on both the composition of the material and the specific ambient conditions. This library of weathered material spectra is useful not only in easier identification of environmental microfibers, but also in helping us estimate the duration and manner of weathering that a given environmental microfiber may have experienced.

How to cite: Patankar, S., Vassilenko, E., Watkins, M., Posacka, A., and Ross, P.: Fourier-Transform Infrared Spectroscopy of Environmentally Weathered Textile Fabrics for Enhanced Microplastic Identification, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13702, https://doi.org/10.5194/egusphere-egu21-13702, 2021.

With a coastal population of nearly 150 million inhabitants, the influx of freshwater from densely populated river catchments and a contribution to 30% of the global shipping activity, the Mediterranean Sea has been recognized as one of the world most affected areas by marine litter. Moreover, the countries surrounding the region yearly attract about one third of the world tourism. Taken together, these pressures make this semi-enclosed sea an accumulation zone for marine litter. This high contamination goes hand to hand with a stream of adverse effects to marine ecosystems, public health or socio-economic costs. The beaches are one of the main land-based sources for litter to enter the oceans. The Mediterranean Sea is not an exception as during the summer, the beaches are a hotspot for leisure. This is particularly true for the Mediterranean islands, which due to their attractiveness will host a far greater population during the summer. In this study we evaluate the seasonal variation of marine litter as an effect of tourism on sandy beaches of Mediterranean islands and we assess the effectiveness of pilot actions in order to reduce the amount of marine litter.

147 surveys were conducted in 2017 during both the low and high touristic season. For each of the eight participating islands (Mallorca, Sicily, Rab, Malta, Crete, Mykonos, Rhodes and Cyprus), three different beaches were selected: a touristic beach, a beach mainly used by locals and a remote beach. For each beach, a periodic monitoring was performed on the same fixed 100m portion. Here, any item found was collected, characterized and properly disposed of. We included the mesoplastics (0.5 – 2.5cm), large microplastics (0.1 – 0.5cm) and pellets (raw plastic material). In 2019, a monitoring of 11 of the selected beaches was conducted following the implementation of pilot actions (mainly awareness campaigns). To test their effectiveness, the results are compared to those of 2017.

Our results show that tourism in Mediterranean island beaches is a main driver of marine litter generation. Popular beaches (touristic and locals) are clearly the most impacted sites. Every day, during the high touristic season peak (July-August), visitors will leave (i.e.: cigarette butts, drink can, etc.) or generate (i.e.: MePs and MPs) 950 – 1190 items on every 100m of beach. This amount falls to 60 items for the remote beaches. At the region scale, we estimated that during July-August, visitors could be responsible for the accumulation of about 47.5 10⁶ ± 13.5 10⁶ items/day on the beaches of the Mediterranean islands.

The awareness campaigns is an efficient tool to reduce the amount of litter generated by visitors on the beaches. We observed an average decrease of 52.5% of the accumulation of the items abandoned by the visitors after the implementation of the pilot actions. These encouraging results probably benefit from the growing attention of the public to the plastic pollution issue. However, this reduction has a price: the average cost of the pilot actions for the whole high season would be of 111.6 k€ per km of beach.

How to cite: Grelaud, M. and Ziveri, P.: The generation of marine litter in Mediterranean island beaches as an effect of tourism and its mitigation, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14421, https://doi.org/10.5194/egusphere-egu21-14421, 2021.

Understanding and predicting the transport and fate of microplastics (MPs) in aquatic systems is a complex research challenge due to the simultaneous effect of different physical processes and the large variability in MPs dynamical properties. The dynamical behavior of MPs is further complicated by the development of biofilms and weathering processes. However, the effect of these processes on the dynamical properties of MPs is not fully understood. This study aims to evaluate the effect of the particle properties and biofilm on the settling velocity of microplastic sheets and fibers under laboratory conditions. The experiments focus on two types of particles (polyethylene sheets and polyester fibers), of nine sizes (between 1 and 5 mm), two degrees of biological colonization (new and aged during 3 months in the ocean) and three replicas of each type of particles. Density, size, and shape indices were first quantified. The settling velocity was then estimated by image analysis in a sedimentation column with salt- and freshwater. The dynamical behavior of the two types of particles was very different. Interestingly, the settling velocity of sheets increased with size up to a threshold in both salt- and freshwater, from which particle swinging and drag force increased, and settling velocity decreased. The effect of biofilm was also complex, increasing or decreasing the settling velocity of sheets as a result of the combined effect of the enhanced density and the biofilm distribution that influences the particle swinging. The settling velocity of fibers was independent of their length. Biofilms increased densities but their impact on settling velocity increase is less evident due to the high variability of this property for the same type of fiber. The relevance of theoretical drag models to predict the settling velocity of pristine and biofouled particles in salt- and freshwater will be also evaluated.

How to cite: Jalon-Rojas, I., Romero-Ramirez, A., Fauquembergue, K., Rossignol, L., Morin, B., and Cachot, J.: Experimental assessment of settling velocity of pristine and biofouled microplastics , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15053, https://doi.org/10.5194/egusphere-egu21-15053, 2021.

Plastics and microplastics are regularly found in the marine environment around the world. Currently, the spatial and temporal dynamics of microplastics in remote areas, including polar regions, are poorly assessed and only limited long-term data is available on occurrence. Long-term data series are required to address changes in abundances of microplastics including variations in spatial and temporal distribution as well as to understand the influence of, for example, different seasons, changing weather or hydrological conditions. But there is very little data from remote regions of the world⁽¹⁾ including the Arctic and Antarctic.

One approach is to use ships of opportunity (www.norsoop.com) to collect data over replicated transects: these include research vessels as well as commercial vessels and expedition cruise ships. Advances in technology enable assessment of microplastic abundance at large spatial scale using existing infrastructure in addition to the collection of oceanographic meta-data. As part of the Hurtigruten – NIVA collaboration, a microplastic sampling module and a marine monitoring system (Ferry Box) was fitted on Hurtigruten’s Expedition vessel MS Roald Amundsen. The science center in this expedition ship, where single use plastic has been removed from all areas, provides a lab facility for preliminary plastic analysis and also a place for interaction with the passengers and engagement in citizen science. During the first year of operation, NIVA and Hurtigruten have collected microplastic samples in the Arctic and the Antarctic for long time periods. In addition, as part of a citizen science project, data and samples have been collected during beach clean-ups in remote areas and analysed on board using a handheld NIR smartphone scanner directly linked to a NIVA cloud database.

Average levels of microplastic within the Arctic (1.8-10 n/m³) and Antarctic (1.8-4.6) are still relatively low and consist mostly of fibres. The levels found in the Arctic study were comparable with the results from Lusher et al. 2015 and recent work in the Russian Arctic. Cellulose and cotton-based fibres dominate in the Antarctic samples and polyester is the dominant polymeric fibre. A citizen science project involving a beach clean-up and the subsequent analysis of the samples collected was performed on board MS Roald Amundsen in the Falkland/Malvinas Islands. The results showed large amounts of fishery related material including several polymer-based ropes and net pieces but also plastic utensils, food wrapping and plastic bottles.

 (1)        GESAMP (2016). Sources, fate and effects of microplastics in the marine environment: part two of a global assessment (Kershaw, P.J., and Rochman, C.M., eds). Rep. Stud. GESAMP No. 93, 220 p.

(2)         Lusher, A. L., Tirelli, V., O’Connor, I., and Officer, R. (2015). Microplastics in Arctic polar waters: the first reported values of particles in surface and sub-surface samples. Nature-scientific reports. 9 p.

(3)         Yakushev E., Gebruk A., Osadchiev A., Pakhomova S., Lusher A., Berezina A., van Bavel B., Vorozheikina E., Chernykh D., Kolbasova G., Razgon I., Semiletov I. Microplastics distribution in the Eurasian Arctic is affected by Atlantic waters and Siberian rivers. Communications Earth & Environment in press. DOI: 10.1038/s43247-021-00091-0

How to cite: Meraldi, V., Morgan, T., Sørensen, K., and van Bavel, B.: The use of expedition cruise ships and citizen science to bridge the gaps in plastic marine litter knowledge in remote areas. , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15307, https://doi.org/10.5194/egusphere-egu21-15307, 2021.

The Indonesian archipelago is rated globally the second contributor to marine plastic litter pollution. This has driven the government in recent years to step up its efforts to combat plastic pollution, on land, in rivers and in the ocean. Indeed, although most of the plastic is disposed on land, lack of a systematic collection and processing network means that it often ends up rivers and ultimately into the seas. Heavy precipitation events during the Monsoon season exacerbate the problem by transporting massive amounts of plastic into rivers and hence into the coastal seas. Amongst the more recent initiative to combat the plastic litter issue, and with funding from the World Bank, the government of Indonesia has set up a program to track the movement of plastic through a hybrid observation & model approach and to determine the location of accumulation areas if any. The project deployed and tracked number of 20 Argos drifters over a year and set up a series of drift model simulation. As the project focuses on macro plastic, several types of macro-waste drifts have been modelized depending on their buoyancy by varying wind coefficient. Three river mouths were studied, located downstream from major populated areas. Results show that the dispersion and trajectory of particles vary depending on the source river, time of the year and meteoceanic conditions. For each river, accumulation areas were identified, concentring 38% to 90% of particles and all located on shore.  

How to cite: Fauny, O., Lucas, M., Dufau, C., and Voisin, J.-B.: Marine Litter in Indonesia –  Tracking macro-plastic from river mouths with Argos buoys and modelling, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15416, https://doi.org/10.5194/egusphere-egu21-15416, 2021.

Worldwide, there is intensive plastic waste accumulation in soil, agricultural fields, and water bodies. Focus has been on oceans and aquatic environments, but recently, plastic accumulation into terrestrial ecosystem is getting attention. In many sub-tropical countries plastic wastes are being buried or disposed in open landfills without proper environmental management. In Rwanda, despite efforts undertaken by the Government to control use of non-degradable plastic bags, plastic wastes dumped into open landfills continue to be redistributed within the landscape through soil erosion processes, which presents a risk of contamination of agricultural fields, water reservoirs and groundwater ecosystems. There is a strong lack of knowledge on possible pathways of (micro-) plastics into the terrestrial environment. This study identified and evaluated the use and source of plastic material in agricultural fields around landfills in three study sites in Rwanda: Kicukiro, Rwamagana, and Muhanga villages through survey  questionnaires. A total of 1,240 households (HHs) were surveyed. The Kicukiro landfill, near the capital, was established before 1994 and closed between 2011-2014, while the landfills of Muhanga and Rwamagana were established between 2006 and 2017. Results revealed that in rural areas (Muhanga and Rwamagana) most respondents do not use plastic bags (Muhanga 63% and Rwamagana 76.9%) compared to urban areas like Kicukiro where a high rate (64.3%) of respondents still use plastic bags, which were easily available from local (super)markets, according to 45.5% of the respondents. Most interviewees in all study sites ignore if the plastic materials that they are using are degradable or not. Results revealed also that the majority of respondents are aware of the impact of using plastic bags (Kicukiro: 77.6%; Muhanga: 60.5%; and Rwamagana: 62%), and they also confirmed that they would not use plastic bags even if the government would not punish people using these (Kicukiro: 78.8%; Muhanga: 74.8%; and Rwamagana: 81.8%).

Principal component analysis (PCA) was used to identify the most influential variables, and results revealed that respondents are aware of the impacts of using plastic bags on the environment with high significance. Furthermore, also a strong correlation was found between the study sites, and plastics wastes eroded during high rainfall events and causing environmental problems in surrounding areas located near the landfill. Results showed that the education level is correlated negatively to the use of plastics bags and the age of respondents. Environmental policies on plastic ban should be reinforced for improving the strategies of controlling plastic bags from neighboring countries to overcome the use of non-degradable plastic bags. There is a high need from the country to teach its population through differnt educational programs so that they can improve their level of knowledge and awareness and risks of using non degradable plastic bags. 

How to cite: Godeberthe, N., Baartman, J., Riksen, M., and Geissen, V.: Sources of macro and micro-plastics contamination of agricultural fields in Rwanda, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15455, https://doi.org/10.5194/egusphere-egu21-15455, 2021.

Contamination of the World Ocean by synthetic non-biodegradable material has become a high profile environmental concern. Standardized sampling methods and methods of plastic identification should be developed so that results can be fed into international monitoring strategies to map plastic distribution worldwide. Here we present results of studies carried out on a transect between Tromsø and Svalbard and from Montevideo to Antarctica performed with the same sampling procedure onboard Norwegian and Russian ships in 08.2019 and 01.2020 respectively. Microplastic sampling was carried out using a filtering system. Water passed through the system and SPM was collected on a metal mesh screens. All potential plastic particles and fibers were checked for polymeric identification using a PerkinElmer Spotlight ATR-FTIR. The level of confirmed microplastics ranged from 0 to 1.9 items/m³ (0.7 items/m³ in average) on a transect Tromsø-Svalbard and from 0 to 2.5 items/m³ (0.4 items/m³ in average) on Montevideo-Antarctica transect. Both data sets were represented by 40% of fragments and 60% of fibers. Polyester was found as the main polymer type for both transects, 46% of microplastics. Other found polymer types were different in the North and South Atlantic Ocean waters. Nylon (polyamide) was the next most common polymer type in South Atlantic which was not found in Northern part. Difference was also observed in higher number of stations without any microplastics in South Atlantic.

This work was partly funded by the Norwegian Ministry of Climate and Environment project RUS-19/0001 “Establish regional capacity to measure and model the distribution and input of microplastics to the Barents Sea from rivers and currents (ESCIMO)” and the Russian Foundation for Basic Research, research projects 19-55-80004.

How to cite: Pakhomova, S. and Yakushev, E.: Microplastics pollution in North and South Atlantic Ocean surface waters , EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15851, https://doi.org/10.5194/egusphere-egu21-15851, 2021.

While the Arctic Ecosystem is already stressed by the effects of the climate crisis, another threat is emerging: plastics. Plastic pollution has become an environmental issue of the highest concern world-wide, and the plastic pollution tide is also rising in the Arctic.

The pristine Arctic environments, far from most of the world’s major industrial areas, are becoming laden with plastic pollution. Microplastics have been found in Arctic snow, sea-ice, seawater, in sediments collected on the ocean floor, and on Arctic beaches. Larger pieces of plastic debris are also making their way into the food webs as whales, fish and birds can ingest them or get entangled in them. Climate change is expected to exacerbate the amount of debris in the Arctic, via melting sea-ice and increasing contributions from human activities.

The Artic Monitoring and Assessment Programme (AMAP) is a Working Group of the Arctic Council. AMAP has a mandate to monitor and assess the status and trends of contaminants in the Arctic. In the Spring of 2019, AMAP decided to step up its efforts on the plastic issue and established an Expert Group on microplastics and litter with experts from Artic Council States and Observer countries.

The Expert Group has developed a comprehensive monitoring plan and technical guidelines for monitoring microplastics and litter in the Arctic. It will be the first time that all parts of the Arctic ecosystem are examined for traces of this type of pollution. The Expert Group aims to:

• Design a program for the monitoring of microplastics and litter in the Arctic environment.
• Develop necessary guidelines supporting the monitoring program.
• Formulate recommendations and identify areas where new research and development is necessary from an Arctic perspective.

How to cite: Larsen, J. R., Provencher, J., and Farmen, E.: Litter and Microplastics: Environmental monitoring in the Arctic, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16515, https://doi.org/10.5194/egusphere-egu21-16515, 2021.