Stranded pellets in Fildes Peninsula (King George Island, Antarctica): New evidence of Southern Ocean connectivity

Microplastic pollution in the marine environment: Distribution factors and mitigation strategies in different oceans

As the COVID-19 pandemic began in 2020, plastic usage spiked, and microplastic (MP) generation has increased dramatically. It is documented that MP can transfer from the source to the ocean environment where they accumulate as the destination. Therefore, it is essential to understand their transferring pathways and effective environmental factors to determine the distribution of MPs in the marine environment. This article reviews the environmental factors that affect MP distribution in the oceans including abiotic such as ocean currents and wind direction, physical/chemical and biological reactions of MPs, natural sinking, particle size and settling velocity, and biotic including biofouling, and incorporation in fecal material. It was found that velocity and physical shearing are the most important parameters for MP accumulation in the deep ocean. Besides, this review proposes different research-based, national-level, and global-level strategies for the mitigation of MPs after the pandemic. Based on the findings, the level of MP pollution in the oceans is directly correlated to coastal areas with high populations, particularly in African and Asian countries. Future studies should focus on establishing predictive models based on the movement and distribution of MPs to mitigate the levels of pollution.

Bottom-Feeders Eat Their Fiber: Ingestion of Anthropogenic Microdebris by Antarctic Deep-Sea Invertebrates Depends on Feeding Ecology

Anthropogenic debris has been documented in Antarctica for the past 40 years. Upon breakdown, large pieces become microdebris, which reaches the seafloor through a variety of physical and biological processes. The Antarctic benthos, deeply reliant on sinking organic particles, is thus vulnerable to ingesting microdebris. By using benthic specimens sampled between 1986 and 2016 and deposited in biological collections, we provide the first record of microdebris in Southern Ocean deep-sea invertebrates. Specimens from 15 species (n = 169 organisms) had their gut content examined, with 13 species yielding microdebris in the shape of fibers (n = 85 fibers). The highest ingestion percentages were recorded in the sea cucumbers Heterocucumis steineni (100%), Molpadia violacea (83%) and Scotoplanes globosa (75%), and in the brittle star Amphioplus peregrinator (53%). Deposit- and suspension-feeding were the strategies which yielded the most fibers, accounting for 83.53% of particles. Seven fibers were identified as microplastics, composed of polyamide, polycarbonate, polyester, polyethylene terephthalate, polyisoprene and polysulfone. We also provide the earliest record of a microplastic in Antarctica, a polysulfone fiber ingested by a Boreomysis sp. mysid caught in 1986. The occurrence of fibers in the world's most remote continental margin renews concerns of pollution in seemingly isolated regions.

Assessment of plastic debris and biofouling in a specially protected area of the Antarctic Peninsula region

The aim of this paper is to characterize the plastic and to study a potential relationship between plastic debris characteristics and the presence of fouling biota in an Antarctic Specially Protected Area Robert Island, on the Antarctic peninsula region. A combination of lab-based sorting, advanced spectral analysis and general linear modelling was used to assess the abundance and type of plastic debris washed up on the shore. Observations recorded 730 debris items, with 85 % being plastic. Polystyrene (PS) and Polyethylene terephthalate (PET) were the dominant plastics (61 %). Biofouling was observed on 25 % of plastic debris, with debris complexity and degradation significantly increasing the likelihood of fouling occurring. There was no correlation found between biofouling type and plastic polymer type. Findings raise concerns that even with the highest level of environmental protection, an external marine-based source of pollution can intrude the coastal habitat, with uncertain consequences to local flora and fauna.

Do Antarctic bivalves present microdebris? The case of Livingston Island

Marine microdebris (MD) seem to be widespread in benthic invertebrates, even in the most remote areas of the planet such as Antarctica, although the information available is still very scarce. Here we provide a detailed quantification and characterization of the MD found on three common bivalve species (Aequiyoldia eightsii, Thracia cf. meridionalis, and Cyclocardia astartoides) inhabiting shallow areas in Johnsons' Bay, Livingston Island (South Shetland Islands, Antarctica) as a snapshot of the MD present. On average, these bivalves contained 0.71 ± 0.89 items per individual and 1.49 ± 2.35 items per gram, being comparable to the few previous existing studies in other Antarctic areas. Nearly half of the organisms analysed here (45.6 %), contained at least one item. No significant differences were found in the three bivalve species. As far as we know, this is the first study to analyse and compare MD in three bivalve species in the Antarctic Peninsula. Although our results indicate bivalves are as not as polluted as in other areas of the planet, this is remarkable since this is considered one of the last pristine areas of the world. Our results point to local activities as the main source of MD pollution in Livingston Island, although global pollution cannot be discarded. We believe this research provides a useful baseline for future studies and will contribute to develop policies and strategies to preserve Antarctic marine ecosystems from MD pollution.

Plastic litter affected by heat or pressure: A review of current research on remoulded plastic litter

Pyroplastic, plastiglomerates, anthropogenic rocks, plasticrusts, pebble clasts, plastitar, plastisoil and anthropoquinas are examples of terms that have been used to describe the secondary products of plastic litter that have been melted, moulded, pressed, or cemented together with other plastic litter and/or minerogenic sediments or organic matter, either naturally or anthropogenically. Such processes may also favor the formation of new geological features containing plastics, such as coastal landforms or sedimentary rocks. Further research and classification of this secondary plastic litter is critical for understanding the implications of this emerging contaminant as well as to create well-targeted measures to reduce it. The literature review as presented includes 32 peer-reviewed articles published between 1997 and June 2023, all of which describe various burnt or otherwise remoulded plastic litter from around the world. Based on our review we propose a new umbrella term for the different forms of secondary plastic litter that have been modified by heat or pressure: Remoulded Plastic Litter (RPL). If accepted by the research community, important steps for future research and policy will be to implement RPL into the OSPAR protocol for monitoring and assessment of marine litter and thereby fill knowledge gaps of the geographic distribution of RPLs and their potential toxicities to nature and humans. It is clear that the distribution of RPL research spans the globe, however, studies in Africa, Oceania, large tracts of the polar regions, and terrestrial areas in general, are scarce to absent, as are ecotoxicological studies and recommendations for policy development.

Assessing the current state of plastic pollution research in Antarctica: Knowledge gaps and recommendations

Antarctica stands as one of the most isolated and pristine regions on our planet. Regardless, recent studies have evidenced the presence of plastic pollution in Antarctic environments and biota. While these findings are alarming and put into perspective the reach of plastic pollution, it is necessary to assess the current knowledge of plastic pollution in Antarctica. In the present review, an updated literature review of plastic pollution in multiple Antarctic environmental compartments and biota was conducted. Studies were cataloged based on environmental compartments (e.g., sediments, seawater, soil, atmosphere) and biota from different ecological niches. A detailed analysis of the main findings, as well as the flaws and shortcomings across studies, was conducted. In general terms, several studies have shown a lack of adequate sampling and analytical procedures for plastic research (particularly in the case of microplastics) and standard procedures; thus, compromising the reliability of the data reported and comparability across studies. Aiming to guide future studies and highlight research needs, a list of knowledge gaps and recommendations were provided based on the analysis and discussion of the literature and following standardized procedures.

Monitoring plastic pellet pollution in coastal environments through handheld Raman spectroscopy: Data from the Mediterranean coasts (Southern Italy)

This paper examines the distribution and chemical properties of beached plastic pellets along the Ionian and Tyrrhenian coasts of Southern Italy. Three locations have been sampled: Agnone Bagni (SR) and Paradiso (ME) on the Ionian coast of Sicily, Baia del Tono in Milazzo (ME) on the Sicilian Tyrrhenian coast, and Pizzo Calabro (VV) in Calabria on the Tyrrhenian coast. Variations in shape, size, compactness, color, and other physical features, correlated with residence times and transport, has been highlighted. Raman spectroscopy, used in a portable configuration, enabled rapid identification of polymer types, demonstrating its utility for on-site plastic pollutant monitoring. Polyethylene and polypropylene were the predominant polymers. Principal component analysis of the spectra determined the optimal chemometric classification of pellets by composition, avoiding interference or distortion. In conclusion, the study provided preliminary insights into pellet abundance, composition, weathering extent, and distribution across these shorelines, underscoring the importance of regular beach monitoring.

Comparison of three digestion methods for microplastic extraction from aquaculture feeds

Microplastics (MPs) are ubiquitous pollutants found in aquaculture animals that may threaten human health through the food chain. However, there is a lack of effective methods for extracting MPs from aquaculture feeds containing complex components such as organic matter and fish bones. Therefore, in the present study, the extraction efficiency of three digestion methods using 30 % H2O2, Fenton reagent, and 30 % H2O2 + HNO3 for different particle sizes and types of MPs in aquaculture feeds was investigated and compared. The total digestion efficiency of the aquaculture feeds by 30 % H2O2 was 97.3 ± 0.1 %, while the recovery efficiency of MPs was 91.3 ± 1.1 % -103.1 ± 0.9 %. However, there was a large deviation in the extraction efficiency of MPs from aquaculture feeds by the Fenton reagent and 30 % H2O2 + HNO3. Notably, the surface morphology, particle size distribution, and oxidation degree of MPs hardly changed after 30 % H2O2 digestion. More importantly, the changes in the spectral features and carbonyl index of MPs after 30 % H2O2 digestion were smaller than those of the Fenton reagent and 30 % H2O2 + HNO3, which did not affect the identification of MPs. Overall, 30 % H2O2 was more efficient in extracting MPs from aquaculture feeds, and no significant effect on the characteristics of MPs was observed. This work provides novel insights into the effect of chemical pretreatment on the extraction of MPs in aquaculture feeds and provides an optimal protocol for the detection of MPs in aquaculture feeds.

Descriptions and patterns in opportunistic marine debris collected near Palmer Station, Antarctica

Observations of marine debris in Antarctica have been increasing; however, impacts, distributions, sources, and transport pathways of debris remain poorly understood. Here, we describe the spatial distribution, types, and potential origins of marine debris in 2022/2023 near Palmer Station, Antarctica. We opportunistically collected 135 pieces of marine debris with the majority of items found along shorelines (90 %), some found in/near seabird nests/colonies (7 %) and few on inland rocky terrain (3 %). Plastic and abandoned, lost, or discarded fishing gear dominated observed debris. Results suggest that wind and the Antarctic Coastal Current may be a major pathway for debris. This study is the first assessment of marine debris in this region and suggests that oceanography, weather patterns, and shoreline geomorphology could play a role in determining where debris will accumulate. Continued tracking of debris and development of structured surveys is important for understanding the impacts of human activities in a biological hotspot.

Characterization of three plastic forms: Plasticoncrete, plastimetal and plastisessiles

Plastic forms, including plastiglomerate, pyroplastic, plasticrusts, anthropoquinas, plastistone and plastitar, were recorded worldwide. These plastic forms derive from geochemical or geophysical interactions such as heat-induced plastic fusion with rock in campfires, incomplete plastic combustion, water motion-driven plastic abrasion in the rocky intertidal zone, plastic deposition in hardened sediments and plastic bonding with tar. Thereby, these interactions can profoundly influence the fate of plastics in the environment. This study characterized three novel plastic forms (plasticoncrete, plastimetal and plastisessiles) discovered on Helgoland island (North Sea). Plasticoncrete consisted of common polyethylene (PE) and polypropylene (PP) fibers hardened in concrete. Plastimetal included PE fibers rusted with metal. Plastisessiles consisted of PE fibers attached to benthic substrates by sessile invertebrates (oysters and polychaetes). Plasticoncrete and plastimetal are the first plastic forms composed of two man-made materials. Plastisessiles show that plastic forms not only result from human- or environment-mediated interactions but also from biological interactions between invertebrates and plastic. All plastic forms (bulk density ≥ 1.4 g/cm3) sunk during floating tests and hardly changed their positions during a 13-day field experiment and 153- to 306-day field monitorings, indicating their local formation, limited mobility and longevity. Still, experimentally detached plastic fibers floated, confirming that the formation of these plastic forms influences the fate of plastic fibers in the environment. Furthermore, the experiment showed that plasticoncrete got deposited in beach sand under wavy and windy conditions, indicating that coastal waves and onshore winds drive plasticoncrete deposition in coastal sediments. We also provide first records of plasticoncrete on Mallorca island (Mediterranean Sea) and plastimetal on Hikoshima island (Sea of Japan), respectively, which show that these plastic forms are no local phenomena. Thereby, our study contributes to the growing fundamental knowledge of plastic forms that is essential to understand the role and fate of these pollutants in coastal habitats worldwide.

Quantification and distribution of marine microdebris in the surface waters of Livingston Island (South Shetland Islands, Antarctica)

Microdebris are ubiquitous and the Southern Ocean is no exception. Despite the recent increment in Antarctic studies assessing this threat, there is still scarce information available. Here, we quantified the microdebris in surface water, and their distribution within two bays of Livingston Island (South Shetlands, Antarctica). The two studied bays included one with human presence and one pristine, barely visited. Microdebris pollution was found in all samples with a mean concentration of 0.264 ± 0.185 items/m3. Fibres (82.19 %) were the main item, with polyester (61.67 %) as the main plastic polymer, followed by nylon (29.54 %). No differences in the distribution pattern were observed, with microdebris being homogeneously distributed along the two bays. Our results suggest that nearshore waters of Livingston Island are prone to the accumulation and retention of microdebris. The composition of the microdebris also points to Antarctic local activities as principal contamination contributors.

Recent trends on microplastics abundance and risk assessment in coastal Antarctica: Regional meta-analysis

We investigated sources, abundance and risk of microplastics (MPs) in water, sediments and biota around Antarctica. The concentration of MPs in Southern Ocean (SO) ranged from 0 to 0.56 items/m³ (mean = 0.01 items/m³) and 0-1.96 items/m³ (mean = 0.13 items/m³) in surface and sub-surface water. The distribution of fibers in water was 50%, sediments were 61%, and biota had 43%, which were followed by fragments in the water (42%), sediments (26%), and biota (28%). Shapes of film had lowest concentrations in water (2%), sediments 13%), and biota (3%). Ship traffic, drift of MPs by currents, and untreated waste water discharge contributed to the variety of MPs. The degree of pollution in all matrices was evaluated using the pollution load index (PLI), polymer hazard index (PHI), and potential ecological risk index (PERI). PLI at about 90.3% of locations were at category I followed by 5.9% at category II, 1.6% at category III, and 2.2% at category IV. Average PLI for water (3.14), sediments (6.6), and biota (2.72) had low pollution load (<10). Mean PHI for water, sediments, and biota showed hazards level V with a higher percentage of 84.6% (>1000) and 63.9% (PHI:0-1) in sediments and water, respectively. PERI for water showed 63.9% minor risk, and 36.1% extreme risk. Around 84.6% of sediments were at extreme risk, 7.7% faced minor risk, and 7.7% were at high risk. While 20% of marine organisms living in cold environments experienced minor risk, 20% were in high risk, and 60% were in extreme risk. Highest PERI was found in the water, sediments, and biota in Ross Sea, due to high hazardous polymer composition of polyvinylchloride (PVC) in the water and sediments due to human activity, particularly use of personnel care products and waste water discharge from research stations.

Diet and debris ingestion of skuas on Fildes Peninsula, King George Island, Antarctica

Using pellet analysis, we characterized the diet and plastic and non-plastic debris ingestion of skuas (Catharacta spp.) during 2017-2020 summer seasons along the coastal sector of Fildes Peninsula (King George Island, Antarctica). In addition, we conducted the same analysis during the 2020 breeding season on reproductive territories of south polar (Catharacta maccormicki) and brown (Catharacta antarctica lonnbergi) skua. Our results confirm the generalist and opportunistic habits of both skua species. Additionally, it has been proposed that brown skua displaces south polar skua from penguin breeding colonies given its higher competitive abilities, and our results suggest this might not have happened during the study period. Along with evidence from other studies, this work underlines the idea that potential local anthropogenic sources of plastic and non-plastic debris at Fildes Peninsula need to be further addressed to improve current mitigation efforts.

Frequent observations of novel plastic forms in the Ariho River estuary, Honshu, Japan

Pyroplastic and plastiglomerate are novel plastic forms that are currently being reported from coastal beaches worldwide. Pyroplastic is burned plastic with a rock-like appearance. Plastiglomerate is a solid bond consisting of either melted plastic attached to rock (in-situ plastiglomerate) or a melted plastic matrix containing (in)organic material (clastic plastiglomerate). Both plastic forms have been related to the (un)intentional burning of plastic. Yet, information on pyroplastic and plastiglomerate from estuarine habitats is limited to a pilot study (for this study) and knowledge of pyroplastic and plastiglomerate dynamics as well as the underlying drivers is missing. To address these knowledge gaps, we frequently surveyed stranded pyroplastics and plastiglomerates in the Ariho River estuary (Honshu, Japan) over seven months and studied the collected samples at the lab. In total, 37 pyroplastics (consisting of polyethylene, polypropylene, polystyrene, alkyd resin, polyacrylate styrene and polyvinyl chloride) and seven plastiglomerates (consisting of polyethylene and polypropylene) occurred. While pyroplastics occurred frequently, plastiglomerates occurred occasionally which indicates that both forms are common. Pyroplastic (but not plastiglomerate) occurrence and density (items/m²) were related to intertidal elevation. Strandline pyroplastic density, that contributed heavily to the pyroplastic and plastiglomerate entirety, increased under prevailing onshore winds which shows that such winds are environmental drivers of pyroplastic density. Floating tests revealed that clastic plastiglomerate can float. Macro-, micro- and spectroscopic examinations indicated only slight pyroplastic and plastiglomerate weathering which suggests the regional and/or recent formation of both plastic forms. Additionally, we detected the first plastiglomerate with clastic and in-situ features (a plastic matrix containing (in)organic material firmly melted to a rock) which constituted a novel plastiglomerate subtype that we termed "clastic/in-situ plastiglomerate". Overall, our study initiates the development of the fundamental understandings of pyroplastic and plastiglomerate dynamics and the underlying drivers in estuaries.