There is a need for baseline information about how much plastics are ingested by wildlife and potential negative consequences thereof. We analysed the frequency of occurrence (FO) of plastics >1 mm in the stomachs of five pursuit-diving seabird species collected opportunistically. Atlantic puffins (Fratercula arctica) found emaciated on beaches in SW Norway had the highest FO of plastics (58.8 %), followed by emaciated common guillemots (Uria aalge; 9.1 %) also found beached in either SW or SE Norway. No plastics were detected in razorbills (Alca torda), great cormorants (Phalacrocorax carbo), and European shags (Gulosus aristotelis) taken as bycatch in northern Norway. This is the first study to report on plastic ingestion of these five species in northern Europe, and it highlights both the usefulness and limitations of opportunistic sampling. Small sample sizes, as well as an unbalanced sample design, complicated the interpretation of the results. Alcids Cormorants Pursuit-diving Seabirds Pollution Microplastics | publishedVersion

There is a need for baseline information about how much plastics are ingested by wildlife and potential negative consequences thereof. We analysed the frequency of occurrence (FO) of plastics >1 mm in the stomachs of five pursuit-diving seabird species collected opportunistically. Atlantic puffins (Fratercula arctica) found emaciated on beaches in SW Norway had the highest FO of plastics (58.8 %), followed by emaciated common guillemots (Uria aalge; 9.1 %) also found beached in either SW or SE Norway. No plastics were detected in razorbills (Alca torda), great cormorants (Phalacrocorax carbo), and European shags (Gulosus aristotelis) taken as bycatch in northern Norway. This is the first study to report on plastic ingestion of these five species in northern Europe, and it highlights both the usefulness and limitations of opportunistic sampling. Small sample sizes, as well as an unbalanced sample design, complicated the interpretation of the results. | publishedVersion

There is a need for baseline information about how much plastics are ingested by wildlife and potential negative consequences thereof. We analysed the frequency of occurrence (FO) of plastics >1 mm in the stomachs of five pursuit-diving seabird species collected opportunistically. Atlantic puffins (Fratercula arctica) found emaciated on beaches in SW Norway had the highest FO of plastics (58.8 %), followed by emaciated common guillemots (Uria aalge; 9.1 %) also found beached in either SW or SE Norway. No plastics were detected in razorbills (Alca torda), great cormorants (Phalacrocorax carbo), and European shags (Gulosus aristotelis) taken as bycatch in northern Norway. This is the first study to report on plastic ingestion of these five species in northern Europe, and it highlights both the usefulness and limitations of opportunistic sampling. Small sample sizes, as well as an unbalanced sample design, complicated the interpretation of the results. Alcids Cormorants Pursuit-diving Seabirds Pollution Microplastics

There is a need for baseline information about how much plastics are ingested by wildlife and potential negative consequences thereof. We analysed the frequency of occurrence (FO) of plastics >1 mm in the stomachs of five pursuit-diving seabird species collected opportunistically. Atlantic puffins (Fratercula arctica) found emaciated on beaches in SW Norway had the highest FO of plastics (58.8 %), followed by emaciated common guillemots (Uria aalge; 9.1 %) also found beached in either SW or SE Norway. No plastics were detected in razorbills (Alca torda), great cormorants (Phalacrocorax carbo), and European shags (Gulosus aristotelis) taken as bycatch in northern Norway. This is the first study to report on plastic ingestion of these five species in northern Europe, and it highlights both the usefulness and limitations of opportunistic sampling. Small sample sizes, as well as an unbalanced sample design, complicated the interpretation of the results.

publishedVersion

Plastic pollution, including micro- and nanoplastics, is a growing concern. Tyre-wear particles (TWPs) are the second largest source of microplastics in the ocean following abrasion of synthetic fibres. In addition to the particles themselves, TWPs contain many harmful chemicals, including 6PPD. This chemical reacts with atmospheric ozone and forms the toxic compound 6PPD-quinone (6PPDq), which poses a danger to aquatic life. There is a knowledge gap in understanding risks associated with the combined toxicity of nanoplastics (NPs) and 6PPDq. The present study aimed to investigate the toxicity of NPs and 6PPDq on adult zebrafish using phenotypic (behaviour, histology) and transcriptomic endpoints. Zebrafish were exposed to four treatments: control (contaminant-free), 50 μg/L 6PPDq, 3 mg/L polystyrene (PS)-NPs, and a combination of 50 μg/L 6PPDq and 3 mg/L PS-NPs. We did not observe locomotory dysregulation in zebrafish exposed to NPs. However, we found significant hyperlocomotion in zebrafish exposed to 6PPDq and this effect was even more substantial after co-exposure with PS-NPs. This study explores the molecular mechanisms behind these effects, identifying genes associated with neurotransmitters and fatty acid metabolism that were dysregulated by the co-exposure. Transcriptomic analysis further showed that both 6PPDq and PS-NPs impacted cellular processes associated with sterol biosynthesis, cholesterol metabolism, and muscle tissue development. The effects on these mechanisms were stronger in co-exposed zebrafish, indicating a heightened risk to cellular integrity and mitochondrial dysfunction. These results highlight the significance of mixture toxicity when studying the effects of NPs and associated chemicals like 6PPDq. | publishedVersion

Gillnets are among the most common fishing gears worldwide. They are often made of thin twine, which is prone to wear and tear, limiting the lifespan of the gillnet. This increases gillnet turnover, and consequently increased risk of gear discarding, gear loss, ghost fishing and marine pollution. This might be mitigated by increasing twine thickness, and thereby breaking strength. However, the tolerable increase in thickness for gillnet durability without compromising the catch efficiency is unknown. Therefore, this study conducted gillnet fishing trials under commercial conditions in the Northeast-Arctic cod gillnet fishery analysing and comparing ways of capture and efficiency between gillnets with two different twine thicknesses for two different mesh sizes. The results demonstrated that a 30 % increase in breaking strength and twine stiffness did not affect catch performance. Therefore, thicker gillnet twine can potentially reduce marine litter by plastic debris from damaged and lost gears without compromising catch performance. | publishedVersion

Gillnets are among the most common fishing gears worldwide. They are often made of thin twine, which is prone to wear and tear, limiting the lifespan of the gillnet. This increases gillnet turnover, and consequently increased risk of gear discarding, gear loss, ghost fishing and marine pollution. This might be mitigated by increasing twine thickness, and thereby breaking strength. However, the tolerable increase in thickness for gillnet durability without compromising the catch efficiency is unknown. Therefore, this study conducted gillnet fishing trials under commercial conditions in the Northeast-Arctic cod gillnet fishery analysing and comparing ways of capture and efficiency between gillnets with two different twine thicknesses for two different mesh sizes. The results demonstrated that a 30 % increase in breaking strength and twine stiffness did not affect catch performance. Therefore, thicker gillnet twine can potentially reduce marine litter by plastic debris from damaged and lost gears without compromising catch performance.

Numerical models point to the south-east Bay of Biscay as a convergence area for floating particles, including plastics. The few existing studies on plastic abundance in the area mainly focus on open waters and yet information on the coastal area is limited. To fill this gap, neustonic samples were taken along the coastal waters of the south-east Bay of Biscay (2017-2020) to define the spatial distribution of plastic abundances and composition. Results show an average plastic abundance of 739,395 +/- 2,625,271 items/km(2) (998 +/- 4338 g/km(2)). French waters were more affected, with five times higher plastic abundances than Spanish coasts. Microplastics represented 93 % of the total abundance of plastic items (28 % in weight), mesoplastics 7 % (26 %) and macroplastics 1 % (46 %). This study demonstrates that this area is a hotspot for plastic with levels in coastal waters similar to those in the Mediterranean Sea or other litter aggregation areas.

Numerical models point to the south-east Bay of Biscay as a convergence area for floating particles, including plastics. The few existing studies on plastic abundance in the area mainly focus on open waters and yet information on the coastal area is limited. To fill this gap, neustonic samples were taken along the coastal waters of the south-east Bay of Biscay (2017–2020) to define the spatial distribution of plastic abundances and composition. Results show an average plastic abundance of 739,395 ± 2,625,271 items/km² (998 ± 4338 g/km²). French waters were more affected, with five times higher plastic abundances than Spanish coasts. Microplastics represented 93 % of the total abundance of plastic items (28 % in weight), mesoplastics 7 % (26 %) and macroplastics 1 % (46 %). This study demonstrates that this area is a hotspot for plastic with levels in coastal waters similar to those in the Mediterranean Sea or other litter aggregation areas.

Plastic pollution in the natural environment is causing increasing concern at both the local and global scale. Understanding the dispersion of plastic through the environment is of key importance for the effective implementation of preventive measures and cleanup strategies. Over the past few years, various models have been developed to estimate the transport of plastics in rivers, using limited plastic observations in river systems. However, there is a large discrepancy between the amount of plastic being modelled to leave the river systems, and the amount of plastic that has been found in the seas and oceans. Here, we investigate one of the possible causes of this mismatch by performing an extensive uncertainty analysis of the riverine plastic export estimates. We examine the uncertainty from the homogenisation of observations, model parameter uncertainty, and underlying assumptions in models. To this end, we use the to-date most complete time-series of macro-plastic observations (macroplastics have been found to contain most of the plastic mass transported by rivers), coming from three European rivers. The results show that model structure and parameter uncertainty causes up to four orders of magnitude, while the homogenisation of plastic observations introduces an additional three orders of magnitude uncertainty in the estimates. Additionally, most global models assume that variations in the plastic flux are primarily driven by river discharge. However, we show that correlations between river discharge (and other environmental drivers) and the plastic flux are never above 0.5, and strongly vary between catchments. Overall, we conclude that the yearly plastic load in rivers remains poorly constrained.

Plastic pollution in the natural environment is causing increasing concern at both the local and global scale. Understanding the dispersion of plastic through the environment is of key importance for the effective implementation of preventive measures and cleanup strategies. Over the past few years, various models have been developed to estimate the transport of plastics in rivers, using limited plastic observations in river systems. However, there is a large discrepancy between the amount of plastic being modelled to leave the river systems, and the amount of plastic that has been found in the seas and oceans. Here, we investigate one of the possible causes of this mismatch by performing an extensive uncertainty analysis of the riverine plastic export estimates. We examine the uncertainty from the homogenisation of observations, model parameter uncertainty, and underlying assumptions in models. To this end, we use the to-date most complete time-series of macroplastic observations (macroplastics have been found to contain most of the plastic mass transported by rivers), coming from three European rivers. The results show that model structure and parameter uncertainty causes up to four orders of magnitude, while the homogenisation of plastic observations introduces an additional three orders of magnitude uncertainty in the estimates. Additionally, most global models assume that variations in the plastic flux are primarily driven by river discharge. However, we show that correlations between river discharge (and other environmental drivers) and the plastic flux are never above 0.5, and strongly vary between catchments. Overall, we conclude that the yearly plastic load in rivers remains poorly constrained.

Plastic pollution in the natural environment is causing increasing concern at both the local and global scale. Understanding the dispersion of plastic through the environment is of key importance for the effective implementation of preventive measures and cleanup strategies. Over the past few years, various models have been developed to estimate the transport of plastics in rivers, using limited plastic observations in river systems. However, there is a large discrepancy between the amount of plastic being modelled to leave the river systems, and the amount of plastic that has been found in the seas and oceans. Here, we investigate one of the possible causes of this mismatch by performing an extensive uncertainty analysis of the riverine plastic export estimates. We examine the uncertainty from the homogenisation of observations, model parameter uncertainty, and underlying assumptions in models. To this end, we use the to-date most complete time-series of macroplastic observations (macroplastics have been found to contain most of the plastic mass transported by rivers), coming from three European rivers. The results show that model structure and parameter uncertainty causes up to four orders of magnitude, while the homogenisation of plastic observations introduces an additional three orders of magnitude uncertainty in the estimates. Additionally, most global models assume that variations in the plastic flux are primarily driven by river discharge. However, we show that correlations between river discharge (and other environmental drivers) and the plastic flux are never above 0.5, and strongly vary between catchments. Overall, we conclude that the yearly plastic load in rivers remains poorly constrained.