Benthic megafauna communities in the Arctic Ocean play a vital role in deep-sea ecosystem functioning by influencing the local biogeochemistry and the global carbon cycle. Their community structure is largely driven by phytodetrital fluxes from the surface ocean, increasing their susceptibility to environmental change. This study assessed short-term variability in benthic megafauna community composition, taxonomically and functionally, across three stations (N3, HG-IV, S3) situated within the lower bathyal zone (similar to 2500 m) at the LTER HAUSGARTEN site, in relation to environmental parameters such as biogenic sediment components and habitat features. The analysis was based on image data and sediment samples collected in consecutive years from 2016 to 2021. Additionally, long-term changes in the density of four selected taxa were examined by comparing two periods: 2002/2004-2015 (literature-based) and 2016-2021 (this study). Over the six-year period, the community structure showed considerable temporal variability, primarily driven by changes in the density of the opportunistic sea cucumber Elpidia heckeri. Environmental parameters explained spatial variation across stations more effectively than temporal variation across years. Long-term analyses revealed a general decline in density of the selected taxa, with average density decreases ranging from 28% for a crinoid to 93% for a soft coral. These findings highlight the dynamic nature of Arctic benthic megafauna communities and their complex responses to local environmental change. The pronounced temporal fluctuations and substantial population declines underscore the urgent need to extend time-series studies both temporally and spatially to enable accurate predictions of the future state of Arctic deep-sea ecosystems.

The stalled multinational effort to protect environmental and human health from plastic pollution is salvageable, with a revamped negotiation process. The stalled multinational effort to protect environmental and human health from plastic pollution is salvageable, with a revamped negotiation process.

The Arctic is undergoing rapid warming, resulting in retreating sea ice and glaciers1, yet how cryospheric changes propagate into the deep ocean remains poorly understood2. Here we identify a climate-driven mechanism linking accelerating glacier disintegration to an increase in deep-sea hard-bottom habitats far beyond calving fronts. Seafloor observations in Fram Strait show a localized increase in the density and patchiness of dropstones delivered by debris-laden icebergs. At the same time, four decades of shipboard records show that the occurrence of icebergs increased abruptly in the early 2000s. Backtracking links these icebergs to the main outlet glaciers in northeast Greenland and the Russian High Arctic. In northeast Greenland, the timing of glacier destabilization coincides with this rise, whereas sparse satellite coverage in the Russian sector limits temporal attribution despite indications of enhanced glacier activity. A model sensitivity study shows that, apart from intensified calving, a more dynamic sea ice cover enhances downstream transport of glacial ice. Along these pathways, increased iceberg activity could reshape deep-sea habitats through enhanced melt and associated lithogenic input, and elevate navigational hazards as maritime traffic expands in the Arctic. Although modest compared with the iceberg discharges of Pleistocene Heinrich events, this mechanism provides a modern analogue of long-range cryospheric influence on the seafloor in a warming climate.

Plastic credits are marketed as an innovative solution to plastic pollution, yet they mirror the well-documented shortcomings of carbon credits and overlook the unique material complexities of plastics. Effective plastics governance must avoid fragmented, loophole-prone, and inequitable approaches to plastic pollution.

A major challenge in ecology is understanding whether observed changes are the result of short-term cycles or long-term environmental changes. This study leverages data collected over a 20 yr period from the Long-Term Ecological Research observatory HAUSGARTEN (Stn HG-I; 79 degrees N, 6 degrees E, 1300 m deep) to disentangle dynamics in epibenthic megafauna. We compared community composition to environmental factors using linear models and redundancy analyses. In all cases, combinations of factors associated with cycles and long-term changes were included in best-fit models. Faunal density and species richness increased and then decreased over the study period. Community structure made a partial return to the 2002 state in 2022, suggesting cyclicality. There was turnover in species composition over the study period, likely reflecting long-term environmental change. The North Atlantic seastar Pontaster tenuispinus was first observed in 2018, and the Arctic eelpout fish Lycodonus flagellicauda was not observed after 2012. Our study demonstrates that complex interactions of environmental factors influence community structure in the Arctic deep sea. The 20 yr study period was not sufficient to capture a full cycle in epibenthic megafauna community composition, which may have a period of >20 yr. Overlaid on this pattern are the long-term impacts of rising ocean temperatures and a changing food supply regime. Continued monitoring will likely show further non-linear responses to environmental change.

Plastics are deeply embedded in contemporary life, and their production and pollution contribute to irreversible harm across ecological and social systems. Recognized as a “novel entity” in the Planetary Boundaries framework, plastics challenge traditional governance models due to their chemical complexity and diversity, cross-sectoral impacts, and pushback from powerful political and economic actors. This study addresses urgent science-policy gaps through a structured expert elicitation, conducted during the ongoing negotiations on the global plastics treaty. We present the Experts Multi-Issue Knowledge Elicitation (EMIKE) method - a flexible, co-productive approach that addresses social-ecological dimensions of plastics pollution. Through a three-phase process involving 21 interdisciplinary experts, we identified 21 critical issue areas spanning toxic chemical use, social inequality, overconsumption, climate impacts, and financing and policy incoherence, among others. The EMIKE process generated a matrix of interrelated indicators across plastics’ life cycle to inform adaptive, more comprehensive, just, and evidence-based policymaking. EMIKE offers a methodology for surfacing often neglected issues in natural science driven studies, fostering interdisciplinary dialogue, and advancing policy-relevant knowledge. It enables structured elicitation - attuned to power, uncertainty, and evolving political contexts - to better integrate diverse science inputs into global governance. This approach is essential not only for plastics governance, but also for any multifaceted sustainability issue requiring intersectional, systems-based solutions. Key findings highlight the inseparability of ecological and social concerns, the limits of technocratic quantification, and the need to democratize science-policy interfaces. Experts emphasized the importance of precautionary action, transparency, and justice-based governance to counteract corporate influence and systemic inertia. Our study also illustrates how scientific frameworks can support policy development by adequately considering the complexity of global sustainability challenges.

Following a number of meetings devoted to knowledge sharing, identification of key issues, and discussing the best ways to move forward, a wide international expert community is now able to provide recommendations regarding the monitoring of seafloor macrolitter through observation and imaging. As the seafloor constitutes a major sink for marine litter including plastics, it is important to acquire robust and extensive data on litter distribution, abundance, types and size ranges across marine habitats. This should be done through widely agreed, harmonised, and non-destructive methods encompassing advanced technologies. Training and capacity building are essential elements in this endeavour. Both new and legacy imagery are needed to establish baseline assessments and trends. Informing policy-making is indispensable for effective action through upstream and targeted measures, with seafloor macrolitter (and megalitter) being a vital part of the evidence base for global mitigation measures.

Hard-bottom habitats, including dropstones and rocky reefs, increase habitat heterogeneity and host unique communities in the Fram Strait. This manuscript synthesizes research on the composition and dynamics of hardbottom communities over HAUSGARTEN's 25 years, combining known patterns with previously unpublished data. Our research reveals that hard-bottom communities have high biodiversity, including taxa that have not yet been identified or described. Research on reproduction in hard-bottom taxa has been limited. For the most common hard-bottom species, which include sponges, soft corals, and anemones, larvae tend to settle near their parents. Hydroids have much broader-range dispersal and serve as pioneer species in the deep Fram Strait. Results from two novel recruitment experiments (2015-2024, 2019-2024), combined with results from two previous studies, show the process of succession in hard-bottom communities. Initial recruitment of hydroids was followed by tube worms, sponges, and cnidarians, leading to a strong increase in rarefied species richness and differences in species composition over time. Tracking of the hard-bottom fauna on marked stones showed negligible growth and 0-23 % mortality over 5 years (2019-2024). In summary, our research indicates that hardbottom taxa in the deep Fram Strait have short-range larval dispersal, low recruitment, and slow growth. These characteristics suggest that hard-bottom communities have limited resilience to anthropogenic disturbance.

Microplastic (MP) pollution has reached the remotest areas of the globe, including the polar regions. In the Arctic Ocean, MPs have been detected in ice, snow, water, sediment, and biota, but their temporal dynamics remain poorly understood. To better understand the transport pathways and drivers of MP pollution in this fragile environment, this study aims to assess MPs (≥ 11 μm) in sediment trap samples collected at the HAUSGARTEN observatory (Fram Strait) from September 2019 to July 2021. MP fluxes determined by μ-Fourier transform infrared (FTIR) imaging ranged from 0 to 2.9 MP m-2 d-1, peaking in April 2020 and April 2021, with all detected MPs being <300 μm in size. There was no strong correlation between MPs and any of the recorded biogeochemical and physical variables, as each MP flux event was associated with different variables such as biogenic matter, sea ice concentration, or origin. By providing time series data over 21 months, this study provides a baseline for future MP flux assessments in Fram Strait, Arctic.

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The ongoing international negotiations on a global plastics treaty will have pivotal implications for future efforts to transform the plastic economy. This is essential since the current use of plastic in the economy impacts the environment beyond the planetary carrying capacity. To ensure that the forthcoming Treaty can provide the foundation for this transition, the best available science must be made available in the negotiations, but with no formal scientific mechanism to inform the negotiations process, this is not ensured. The Scientists’ Coalition for an Effective Plastic Treaty serves as an example of how the global scientific community has self-organized and come together to address this task, working with five different categories of science-policy communication. The Scientists’ Coalition’s work is made transparent here with the hope that it can inspire organization of scientific input into other future policy areas.

Plastic pollution is a planetary level threat which affects Earth's environment and ecosystems.From the poles to deep ocean basins,the growth of plastic waste has already exceeded its limits.The projected increase of plastic production and waste generation over the coming years makes the situation even more daunting.Even after stagnation in 2020 due to the COVID-19 pandemic,the global plastic production has also increased from 335 to 391 million met-ric tons(Mt)between 2016 and 2021(Fig.S1 online);yet currently post-consumer recycled and bio-based/attributed plastics only accounts～9％of the world's plastic production[1].

Plastic production and plastic waste have increased to such an extent that it has become globally ubiquitous. Several studies already have investigated the meso- and microplastic pollution along the German Baltic and North Sea coasts, but were all limited to a few locations. To obtain representative bulk samples from sandy beaches along the entire German coast, we initiated a citizen-science project entitled “Microplastic Detectives.” Here, we describe in detail 1) how we recruited, instructed, and engaged citizen scientists, 2) why we chose bulk sampling over reduced-volume sampling, and 3) the laboratory methods we used. The citizen scientists collected 1,139 samples from 71 locations along the German coast, totalling 2.2 tons of sand. After drying, sieving with a 1 mm sieve, and visual inspection of the retained fraction under a binocular microscope, all putative plastic particles ≥1 mm were analysed by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. 177 out of 1,139 samples (15.5%) contained a total of 260 plastic particles, with a large right-skewed variation among locations. Most of the particles were fragments, foils, foams, fibres, and pellets (96.2% in total), and 89.6% of the particles were made of polyethylene, polypropylene, polyester, and polystyrene. The unweighted mean pollution densities were 4.12 particles m−2, 0.17 particles kg−1 and 0.27 particles L−1, and the weighted mean pollution densities were 3.77 particles m−2, 0.11 particles kg−1 and 0.18 particles L−1. These densities are lower than in other similar studies, but previous studies had important methodological differences. We discuss how these differences could have influenced the results and make recommendations for improving future studies. Two important recommendations are 1) to use random or stratified random sampling and 2) to run transects perpendicular (rather than parallel) to the waterline. Our study highlights that large-scale, scientifically rigorous monitoring of meso- and microplastic pollution is possible at the national level, and possibly even at much larger spatial and temporal scales. With the help of local authorities, such a monitoring program could be established.

The pollution of the marine environment with plastic debris is expected to increase, where ocean currents and winds cause their accumulation in convergence zones like the North Pacific Subtropical Gyre (NPSG). Surface-floating plastic (>330 mu m) was collected in the North Pacific Ocean between Vancouver (Canada) and Singapore using a neuston catamaran and identified by Fourier-transform infrared spectroscopy (FT-IR). Baseline concentrations of 41,600-102,700 items km(-2) were found, dominated by polyethylene and polypropylene. Higher concentrations (factors 4-10) of plastic items occurred not only in the NPSG (452,800 items km(-2)) but also in a second area, the Papahanaumokuakea Marine National Monument (PMNM, 285,200 items km(-2)). This second maximum was neither reported previously nor predicted by the applied ocean current model. Visual observations of floating debris (>5 cm; 8-2565 items km(-2) and 34-4941 items km(-2) including smaller "white bits") yielded similar patterns of baseline pollution (34-3265 items km(-2)) and elevated concentrations of plastic debris in the NPSG (67-4941 items km(-2)) and the PMNM (295-3748 items km(-2)). These findings suggest that ocean currents are not the only factor provoking plastic debris accumulation in the ocean. Visual observations may be useful to increase our knowledge of large-scale (micro)plastic pollution in the global oceans.

Plastic debris is ubiquitous in all ecosystems and has even reached locations that humans will hardly reach such as the deep ocean floor and the atmosphere. Research has highlighted that plastic debris is now pervasive even in remote Arctic regions. While modeling projections indicated local sources and long-distance transport as causes, empirical data about its origin and sources are scarce. Data collected by citizen scientists can increase the scale of observations, especially in such remote regions. Here, we report abundance and composition data of marine debris collected by citizen scientists on 14 remote Arctic beaches on the Spitsbergen archipelago. In addition, citizen scientists collected three large, industrial sized canvas bags (hereafter: big packs), filled with beached debris, of which composition, sources and origin were determined. A total debris mass of 1,620 kg was collected on about 38,000 m2 (total mean = 41.83 g m-2, SEM = ± 31.62). In terms of abundance, 23,000 pieces of debris were collected on 25,500 m2 (total mean = 0.37 items of debris m-2, SEM = ± 0.17). Although most items were plastic in both abundance and mass, fisheries waste, such as nets, rope, and large containers, dominated in mass (87%), and general plastics, such as packaging and plastic articles, dominated in abundance (80%). Fisheries-related debris points to local sea-based sources from vessels operating in the Arctic and nearby. General plastics could point to both land- and ship based sources, as household items are also used on ships and debris can be transported to the north via the oceans current. Overall, 1% of the items (206 out of 14,707 pieces) collected in two big packs (2017 and 2021), bore imprints or labels allowing an analysis of their origin. If the categories ‘global’ and ‘English language’ were excluded, most of identifiable items originated from Arctic states (65%), especially from Russia (32%) and Norway (16%). But almost a third of the items (30%) was of European provenance, especially from Germany (8%). Five percent originated from more distant sources (e.g. USA, China, Korea, Brazil). Global measures such as an efficient and legally binding plastic treaty with improved upstream measures and waste management are urgently needed, to lower the amount of plastic entering our environments and in turn lifting the pressure on the Arctic region and its sensitive biota.

Abstract Plastic pollution is of growing concern, especially regarding plausible microplastic exposure with relevance to vulnerable communities’ well-being. A microplastic potential exposure index (MPEI) was developed by mapping microplastic concentration in the ocean followed by calculating the potential exposure through food consumption with implications for Indigenous coastal Peoples that are heavily reliant on seafood. The countries that comprise communities with high maximum values of MPEI are Kiribati, Greenland, the USA, Canada, and Cape Verde. This approach provides a powerful tool for decision-makers tasked with establishing precautionary public ocean policies and allocating equitable interventions for plastic waste management and pollution mitigation in exposed coastal communities.

Plastic pollution has become ubiquitous with very high quantities detected even in ecosystems as remote as Arctic sea ice and deep-sea sediments. Ice algae growing underneath sea ice are released upon melting and can form fast-sinking aggregates. In this pilot study, we sampled and analyzed the ice algaeMelosira arcticaand ambient sea water from three locations in the Fram Strait to assess their microplastic content and potential as a temporary sink and pathway to the deep seafloor. Analysis by μ-Raman and fluorescence microscopy detected microplastics (≥2.2 μm) in all samples at concentrations ranging from 1.3 to 5.7 × 104 microplastics (MP) m-3 in ice algae and from 1.4 to 4.5 × 103 MP m-3 in sea water, indicating magnitude higher concentrations in algae. On average, 94% of the total microplastic particles were identified as 10 μm or smaller in size and comprised 16 polymer types without a clear dominance. The high concentrations of microplastics found in our pilot study suggest thatM. arctica could trap microplastics from melting ice and ambient sea water. The algae appear to be a temporary sink and could act as a key vector to food webs near the sea surface and on the deep seafloor, to which its fast-sinking aggregates could facilitate an important mechanism of transport.

The Arctic Monitoring and Assessment Programme has published a plan and guidelines for the monitoring of litter and microplastics (MP) in the Arctic. Here, we look beyond suggestions for immediate monitoring and discuss challenges, opportunities, and future strategies in the long-term monitoring of litter and MP in the Arctic. Challenges are related to environmental conditions, lack of harmonization and standardization of measurements, and long-term coordinated and harmonized data storage. Furthermore, major knowledge gaps exist with regard to benchmark levels, transport, sources, and effects, which should be considered in future monitoring strategies. Their development could build on the existing infrastructure and networks established in other monitoring initiatives in the Arctic, while taking into account specific requirements for litter and MP monitoring. Knowledge existing in northern and Indigenous communities, as well as their research priorities, should be integrated into collaborative approaches. The monitoring plan for litter and MP in the Arctic allows for an ecosystem-based approach, which will improve the understanding of linkages between environmental media of the Arctic, as well as links to the global problem of litter and MP pollution.

Litter and microplastic assessments are being carried out worldwide. Arctic ecosystems are no exception and plastic pollution is high on the Arctic Council's agenda. Water and sediment have been identified as two of the priority compartments for monitoring plastics under the Arctic Monitoring and Assessment Programme (AMAP). Recommendations for monitoring both compartments are presented in this publication. Alone, such samples can provide information on presence, fate, and potential impacts to ecosystems. Together, the quantification of microplastics in sediment and water from the same region produce a three-dimensional picture of plastics, not only a snapshot of floating or buoyant plastics in the surface water or water column but also a picture of the plastics reaching the shoreline or benthic sediments, in lakes, rivers, and the ocean. Assessment methodologies must be adapted to the ecosystems of interest to generate reliable data. In its current form, published data on plastic pollution in the Arctic is sporadic and collected using a wide spectrum of methods which limits the extent to which data can be compared. A harmonised and coordinated effort is needed to gather data on plastic pollution for the Pan-Arctic. Such information will aid in identifying priority regions and focusing mitigation efforts.

Abstract Plastic pollution is of growing concern, especially regarding plausible microplastic exposure with relevance to vulnerable communities’ well-being. A microplastic potential exposure index (MPEI) was developed by mapping microplastic concentration in the ocean followed by calculating the potential exposure through food consumption with implications for Indigenous coastal Peoples that are heavily reliant on seafood. The countries that comprise communities with high maximum values of MPEI are Kiribati, Greenland, the USA, Canada, and Cape Verde. This approach provides a powerful tool for decision-makers tasked with establishing precautionary public ocean policies and allocating equitable interventions for plastic waste management and pollution mitigation in exposed coastal communities.