To what extent can decommissioning options for marine artificial structures move us toward environmental targets?

Switching from fossil fuels to renewable energy is key to international energy transition efforts and the move toward net zero. For many nations, this requires decommissioning of hundreds of oil and gas infrastructure in the marine environment. Current international, regional and national legislation largely dictates that structures must be completely removed at end-of-life although, increasingly, alternative decommissioning options are being promoted and implemented. Yet, a paucity of real-world case studies describing the impacts of decommissioning on the environment make decision-making with respect to which option(s) might be optimal for meeting international and regional strategic environmental targets challenging. To address this gap, we draw together international expertise and judgment from marine environmental scientists on marine artificial structures as an alternative source of evidence that explores how different decommissioning options might ameliorate pressures that drive environmental status toward (or away) from environmental objectives. Synthesis reveals that for 37 United Nations and Oslo-Paris Commissions (OSPAR) global and regional environmental targets, experts consider repurposing or abandoning individual structures, or abandoning multiple structures across a region, as the options that would most strongly contribute toward targets. This collective view suggests complete removal may not be best for the environment or society. However, different decommissioning options act in different ways and make variable contributions toward environmental targets, such that policy makers and managers would likely need to prioritise some targets over others considering political, social, economic, and ecological contexts. Current policy may not result in optimal outcomes for the environment or society.

Heterogeneity of values for coastal flood risk management with nature-based solutions.

The purpose of this study was to understand preferences for different coastal flood protection measures and the factors that influence such preferences, to inform management and policy. The Discrete Choice Experiment applied to Wales residents revealed that there is willingness-to-pay for coastal flood protection, especially through Nature-based Solutions (NbS) including expanding saltmarsh area and increasing saltmarsh with high vegetation. The preference for NbS provides evidence for including specific coastal area targets in financial schemes initially aimed at other benefits from natural habitats, such as habitat creation for biodiversity. This joint action will maximise the benefits from NbS and ensure integrated and concerted efforts across, often disjointed, sectors. There were also high levels of heterogeneity for preferences in different groups of people. For instance, results support that direct flood experience and damage severity can give rise to behavioural intentions that support mitigation and adaptation measures. Findings also highlight how crucial environmental education and direct contact with the object of study are for securing support and buy-in for flood protection measures. This work is original in that it considers the different types of management for a habitat as NbS and the heterogeneity of preferences within a population. Results are significant in providing a basis for future NbS developments and in supporting flood risk policy and management.

Bright spots as climate-smart marine spatial planning tools for conservation and blue growth.

Marine spatial planning that addresses ocean climate-driven change ('climate-smart MSP') is a global aspiration to support economic growth, food security and ecosystem sustainability. Ocean climate change ('CC') modelling may become a key decision-support tool for MSP, but traditional modelling analysis and communication challenges prevent their broad uptake. We employed MSP-specific ocean climate modelling analyses to inform a real-life MSP process; addressing how nature conservation and fisheries could be adapted to CC. We found that the currently planned distribution of these activities may become unsustainable during the policy's implementation due to CC, leading to a shortfall in its sustainability and blue growth targets. Significant, climate-driven ecosystem-level shifts in ocean components underpinning designated sites and fishing activity were estimated, reflecting different magnitudes of shifts in benthic versus pelagic, and inshore versus offshore habitats. Supporting adaptation, we then identified: CC refugia (areas where the ecosystem remains within the boundaries of its present state); CC hotspots (where climate drives the ecosystem towards a new state, inconsistent with each sectors' present use distribution); and for the first time, identified bright spots (areas where oceanographic processes drive range expansion opportunities that may support sustainable growth in the medium term). We thus create the means to: identify where sector-relevant ecosystem change is attributable to CC; incorporate resilient delivery of conservation and sustainable ecosystem management aims into MSP; and to harness opportunities for blue growth where they exist. Capturing CC bright spots alongside refugia within protected areas may present important opportunities to meet sustainability targets while helping support the fishing sector in a changing climate. By capitalizing on the natural distribution of climate resilience within ocean ecosystems, such climate-adaptive spatial management strategies could be seen as nature-based solutions to limit the impact of CC on ocean ecosystems and dependent blue economy sectors, paving the way for climate-smart MSP.

Using ecosystem-services assessments to determine trade-offs in ecosystem-based management of marine mammals.

The goal of ecosystem-based management (EBM) is to support a sustainable and holistic multisectored management approach, and is recognized in a number of international policy frameworks. However, it remains unknown how these goals should be linked to assessments and management plans for marine fauna, such as mammals and fish stocks. It appears particularly challenging to carry out trade-off analyses of various ocean uses without a framework that integrates knowledge of environmental, social, and economic benefits derived from nonstationary marine fauna. We argue this gap can be filled by applying a version of the ecosystem-service approach at the population level of marine fauna. To advance this idea, we used marine mammals as a case study to demonstrate what indicators could operationalize relevant assessments and deliver an evidence base for the presence of ecosystem services and disservices derived from marine mammals. We found indicators covering common ecosystem service categories feasible to apply; examples of indicator data are already available in the literature for several populations. We encourage further exploration of this approach for application to marina fauna and biodiversity management, with the caveat that conceptual tensions related to the use of the ecosystem service concept itself needs to be addressed to ensure acceptance by relevant stakeholders.

Uso de Evaluaciones de Servicios Ambientales para Determinar las Compensaciones en el Manejo de Mamíferos Marinos Basado en Ecosistemas Resumen El objetivo del manejo basado en ecosistemas (EBM) es respaldar una estrategia de manejo multisectorial sustentable y holística, objetivo que es reconocido dentro de varias políticas de marcos de trabajo internacional. Sin embargo, todavía desconocemos cómo deben vincularse este objetivo con las evaluaciones y los planes de manejo de la fauna marina, como los mamíferos y las poblaciones ícticas. Actualmente, parece un reto realizar los análisis de las compensaciones de varios usos oceánicos sin un marco de trabajo que integre el conocimiento sobre los beneficios ambientales, sociales y económicos derivados de la fauna marina no estacionaria. Discutimos que este vacío puede completarse con la aplicación de una versión de la estrategia de servicio ambiental a nivel poblacional para la fauna marina. Para impulsar esta idea usamos mamíferos marinos como estudio de caso para demostrar cuáles indicadores podrían poner en práctica evaluaciones relevantes y entregar una base de evidencias para la presencia de servicios y perjuicios ambientales derivados de los mamíferos marinos. Descubrimos indicadores que cubren las categorías de servicios ambientales comunes cuya aplicación es factible; los ejemplos de datos indicadores ya se encuentran disponibles en la literatura para varias de las poblaciones. Alentamos una exploración más profunda de esta estrategia para su aplicación en la fauna marina y el manejo de biodiversidad, bajo advertencia de que las tensiones conceptuales relacionadas con el uso del concepto de servicio ambiental necesitan ser tratadas para asegurar la aceptación por parte de los actores relevantes.

Bioavailability of Microplastics to Marine Zooplankton: Effect of Shape and Infochemicals.

The underlying mechanisms that influence microplastic ingestion in marine zooplankton remain poorly understood. Here, we investigate how microplastics of a variety of shapes (bead, fiber, and fragment), in combination with the algal-derived infochemicals dimethyl sulfide (DMS) and dimethylsulfoniopropionate (DMSP), affect the ingestion rate of microplastics in three species of zooplankton, the copepods Calanus helgolandicus and Acartia tonsa and larvae of the European lobster Homarus gammarus. We show that shape affects microplastic bioavailability to different species of zooplankton, with each species ingesting significantly more of a certain shape: C. helgolandicus-fragments (P < 0.05); A. tonsa-fibers (P < 0.01); H. gammarus larvae-beads (P < 0.05). Thus, different feeding strategies between species may affect shape selectivity. Our results also showed significantly increased ingestion rates by C. helgolandicus on all microplastics that were infused with DMS (P < 0.01) and by H. gammarus larvae and A. tonsa on DMS-infused fibers and fragments (P < 0.05). By using a range of more environmentally relevant microplastics, our findings highlight how the feeding strategies of different zooplankton species may influence their susceptibility to microplastic ingestion. Furthermore, our novel study suggests that species reliant on chemosensory cues to locate their prey may be at an increased risk of ingesting aged microplastics in the marine environment.

High voltage hybrid organic photovoltaics using a zinc oxide acceptor and a subphthalocyanine donor.

We demonstrate hybrid organic photovoltaic (HOPV) bilayer devices with very high open circuit voltages (VOC) of 1.18 V based on a sol-gel processed zinc oxide (ZnO) acceptor and a vacuum deposited boron subphthalocyanine chloride (SubPc) donor layer. X-ray photoelectron spectroscopy (XPS) and Kelvin Probe (KP) measurements of the ZnO/SubPc interface show that the ZnO preparation conditions have a significant impact on the film composition and the electronic properties of the interface, in particular the work function and interface gap energy. Low temperature processing at 120 °C resulted in a ZnO work function of 3.20 eV and the highest VOC of 1.18 V, a consequence of the increased interface gap energy.

Insights from international environmental legislation and protocols for the global plastic treaty.

Plastic pollution has emerged as a global challenge necessitating collective efforts to mitigate its adverse environmental consequences. International negotiations are currently underway to establish a global plastic treaty. Emphasizing the need for solution-orientated research, rather than focusing on further defining the problems of widespread environmental occurrence and ecological impacts, this paper extracts insights and draws key patterns that are relevant for these international negotiations. The analysis reveals that (i) environmental rather than human health concerns have been the predominant driving force behind previous regulations targeting pollutants, and (ii) the decision to ban or discontinue the use of harmful pollutants is primarily affected by the availability of viable substitutes. These two key findings are relevant to the discussions of the ongoing Intergovernmental Negotiating Committee (INC) on the global plastic treaty and underscore the recognition of environmental consequences associated with plastic pollution while emphasizing the need to enhance the knowledge base of potential human health risks. Leveraging the availability of substitutes can significantly contribute to the development and implementation of effective strategies aimed at reducing plastic usage and corresponding pollution.

Identifying potential high-risk zones for land-derived plastic litter to marine megafauna and key habitats within the North Atlantic.

The pervasive use of plastic in modern society has led to plastic litter becoming ubiquitous within the ocean. Land-based sources of plastic litter are thought to account for the majority of plastic pollution in the marine environment, with plastic bags, bottles, wrappers, food containers and cutlery among the most common items found. In the marine environment, plastic is a transboundary pollutant, with the potential to cause damage far beyond the political borders from where it originated, making the management of this global pollutant particularly complex. In this study, the risks of land-derived plastic litter (LDPL) to major groups of marine megafauna - seabirds, cetaceans, pinnipeds, elasmobranchs, turtles, sirenians, tuna and billfish - and a selection of productive and biodiverse biogenic habitats - coral reefs, mangroves, seagrass, saltmarsh and kelp beds - were analysed using a Spatial Risk Assessment approach. The approach combines metrics for vulnerability (mechanism of harm for megafauna group or habitat), hazard (plastic abundance) and exposure (distribution of group or habitat). Several potential high-risk zones (HRZs) across the North Atlantic were highlighted, including the Azores, the UK, the French and US Atlantic coasts, and the US Gulf of Mexico. Whilst much of the modelled LDPL driving risk in the UK originated from domestic sources, in other HRZs, such as the Azores archipelago and the US Gulf of Mexico, plastic originated almost exclusively from external (non-domestic) sources. LDPL from Caribbean islands - some of the largest generators of marine plastic pollution in the dataset of river plastic emissions used in the study - was noted as a significant input to HRZs across both sides of the Atlantic. These findings highlight the potential of Spatial Risk Assessment analyses to determine the location of HRZs and understand where plastic debris monitoring and management should be prioritised, enabling more efficient deployment of interventions and mitigation measures.

Top ten priorities for global saltmarsh restoration, conservation and ecosystem service research.

Coastal saltmarshes provide globally important ecosystem services including 'blue carbon' sequestration, flood protection, pollutant remediation, habitat provision and cultural value. Large portions of marshes have been lost or fragmented as a result of land reclamation, embankment construction, and pollution. Sea level rise threatens marsh survival by blocking landward migration where coastlines have been developed. Research-informed saltmarsh conservation and restoration efforts are helping to prevent further loss, yet significant knowledge gaps remain. Using a mixed methods approach, this paper identifies ten research priorities through an online questionnaire and a residential workshop attended by an international, multi-disciplinary network of 35 saltmarsh experts spanning natural, physical and social sciences across research, policy, and practitioner sectors. Priorities have been grouped under four thematic areas of research: Saltmarsh Area Extent, Change and Restoration Potential (including past, present, global variation), Spatio-social contexts of Ecosystem Service delivery (e.g. influences of environmental context, climate change, and stakeholder groups on service provisioning), Patterns and Processes in saltmarsh functioning (global drivers of saltmarsh ecosystem structure/function) and Management and Policy Needs (how management varies contextually; challenges/opportunities for management). Although not intended to be exhaustive, the challenges, opportunities, and strategies for addressing each research priority examined here, providing a blueprint of the work that needs to be done to protect saltmarshes for future generations.

Inclusion of condition in natural capital assessments is critical to the implementation of marine nature-based solutions.

Current approaches to measure ecosystem services (ES) within natural capital (NC) and nature-based solutions (NbS) assessments are generally coarse, often using a single figure for ecosystem services (e.g., nutrient remediation or blue carbon sequestration) applied to the local or national habitat stock, which fails to take account of local ecosystem conditions and regional variability. As such, there is a need for improved understanding of the link between habitat condition and ES provision, using comparable indicators in order to take more informed management decisions. Here the UK, Solent Marine Sites (SEMS) is used as a case study system to demonstrate how Water Framework Directive (WFD) 'ecological status' and other indicators of ecosystem condition (state or quality) can be coupled with habitat extent information to deliver a more precise locally-tailored NC approach for active coastal and marine habitat restoration. Habitat extent and condition data are collected for seven NbS relevant coastal habitats (littoral sediment, mat-forming green macroalgae, subtidal sediment, saltmarsh, seagrass, reedbeds and native oyster beds). The workflow includes: 1) biophysical assessment of regulatory ES; 2) monetary valuation; and 3) compilation of future scenarios of habitat restoration and creation. The results indicate that incorporating classifications by condition indices into local NC extent accounts improved ES benefits by 11-67%. This suggests that omitting condition from NC assessments could lead to undervaluation of ES benefits. Future scenarios of restoration in the SEMS also show that the additional regulatory benefits of reaching 'Good' ecological status are £376 million annually, but could be as much as £1.218 billion if 'High'status and all habitat creation targets were met. This evidence of the potential value of restoration and importance of including condition indices in assessments is highly relevant to consider when investing in water ecosystems conservation and restoration as called for by the UN Decade on Ecosystem Restoration (2021-2030), and more generally in global nutrient neutrality and blue carbon policy strategies.

Priorities to inform research on marine plastic pollution in Southeast Asia.

Southeast Asia is considered to have some of the highest levels of marine plastic pollution in the world. It is therefore vitally important to increase our understanding of the impacts and risks of plastic pollution to marine ecosystems and the essential services they provide to support the development of mitigation measures in the region. An interdisciplinary, international network of experts (Australia, Indonesia, Ireland, Malaysia, the Philippines, Singapore, Thailand, the United Kingdom, and Vietnam) set a research agenda for marine plastic pollution in the region, synthesizing current knowledge and highlighting areas for further research in Southeast Asia. Using an inductive method, 21 research questions emerged under five non-predefined key themes, grouping them according to which: (1) characterise marine plastic pollution in Southeast Asia; (2) explore its movement and fate across the region; (3) describe the biological and chemical modifications marine plastic pollution undergoes; (4) detail its environmental, social, and economic impacts; and, finally, (5) target regional policies and possible solutions. Questions relating to these research priority areas highlight the importance of better understanding the fate of marine plastic pollution, its degradation, and the impacts and risks it can generate across communities and different ecosystem services. Knowledge of these aspects will help support actions which currently suffer from transboundary problems, lack of responsibility, and inaction to tackle the issue from its point source in the region. Being profoundly affected by marine plastic pollution, Southeast Asian countries provide an opportunity to test the effectiveness of innovative and socially inclusive changes in marine plastic governance, as well as both high and low-tech solutions, which can offer insights and actionable models to the rest of the world.

Assessing the natural capital value of water quality and climate regulation in temperate marine systems using a EUNIS biotope classification approach.

Using a natural capital framework to inform improvements to water quality and mitigation of climate change requires robust and spatially explicit ecosystem service data. Yet, for coastal habitats this approach is often constrained by a) sufficient and relevant habitat extent data and b) significant variability in baseline assessments used to quantify and value regulatory habitat services. Here, the European Nature Information System (EUNIS) habitat classification scheme is used to map seven key temperate coastal biotopes (littoral sediment, mat-forming green macroalgae, subtidal sediment, saltmarsh, seagrass, reedbeds and native oyster reefs) within the UK's Solent European Marine Site (SEMS). We then estimate the capacity of these biotopes to remove nitrogen (N) and phosphorus (P) and carbon (C), alongside monetary values associated with the resulting benefits. Littoral and sublittoral sediments (including those combined with macroalgae) were the largest contributors to total N, P and C removal, reflecting their large biotope area. However, our results also show considerable differences in relative biotope contributions to nutrient removal depending on how they are analysed and delineated over large spatial scales. When considered at a regional catchment level seagrass meadows, saltmarshes and reedbeds all had considerable N, P and C removal potential. Overall, we estimate that SEMS biotopes provide nutrient reductions and avoided climate damages equivalent to UK £1.1 billion, although this could be nearly £10 billion if water-treatment infrastructure costs and high carbon trading prices are utilised. Despite the variability in the final natural capital evaluations, the substantial regulatory value of N, P and C ecosystem services support a strong rational for restoring temperate coastal biotopes.

Developing conceptual models that link multiple ecosystem services to ecological research to aid management and policy, the UK marine example.

Our understanding of ecological processes that lead to ecosystem services is still evolving but ecological research aims to understand the linkages between the ecosystem and services. These linkages can affect trade-offs between different ecosystem services. Understanding these linkages, by considering multiple ecosystem services simultaneously supports management of the environment and sustainable use of resources. The UK marine environment is relatively data rich, yet the links between ecosystem and several ecosystem services and linkages between services are poorly described. A workshop with 35 marine scientists was used to create a conceptual model that links ecosystem components and key processes to four services they provide and to highlight trade-offs between them. The model was subsequently further developed to include pressures and mitigating management measures. The models are discussed in terms of their application to marine data to facilitate evidence-based marine management and their usefulness to communicate management measures with managers and stakeholders.

Bioavailability and effects of microplastics on marine zooplankton: A review.

Microplastics are abundant and widespread in the marine environment. They are a contaminant of global environmental and economic concern. Due to their small size a wide range of marine species, including zooplankton can ingest them. Research has shown that microplastics are readily ingested by several zooplankton taxa, with associated negative impacts on biological processes. Zooplankton is a crucial food source for many secondary consumers, consequently this represents a route whereby microplastic could enter the food web and transfer up the trophic levels. In this review we aim to: 1) evaluate the current knowledge base regarding microplastic ingestion by zooplankton in both the laboratory and the field; and 2) summarise the factors which contribute to the bioavailability of microplastics to zooplankton. Current literature shows that microplastic ingestion has been recorded in 39 zooplankton species from 28 taxonomic orders including holo- and meroplanktonic species. The majority of studies occurred under laboratory conditions and negative effects were reported in ten studies (45%) demonstrating effects on feeding behaviour, growth, development, reproduction and lifespan. In contrast, three studies (14%) reported no negative effects from microplastic ingestion. Several physical and biological factors can influence the bioavailability of microplastics to zooplankton, such as size, shape, age and abundance. We identified that microplastics used in experiments are often different to those quantified in the marine environment, particularly in terms of concentration, shape, type and age. We therefore suggest that future research should include microplastics that are more representative of those found in the marine environment at relevant concentrations. Additionally, investigating the effects of microplastic ingestion on a broader range of zooplankton species and life stages, will help to answer key knowledge gaps regarding the effect of microplastic on recruitment, species populations and ultimately broader economic consequences such as impacts on shell- and finfish stocks.

Global ecological, social and economic impacts of marine plastic.

This research takes a holistic approach to considering the consequences of marine plastic pollution. A semi-systematic literature review of 1191 data points provides the basis to determine the global ecological, social and economic impacts. An ecosystem impact analysis demonstrates that there is global evidence of impact with medium to high frequency on all subjects, with a medium to high degree of irreversibility. A novel translation of these ecological impacts into ecosystem service impacts provides evidence that all ecosystem services are impacted to some extent by the presence of marine plastic, with a reduction in provision predicted for all except one. This reduction in ecosystem service provision is evidenced to have implications for human health and wellbeing, linked particularly to fisheries, heritage and charismatic species, and recreation.

The future of Blue Carbon science.

The term Blue Carbon (BC) was first coined a decade ago to describe the disproportionately large contribution of coastal vegetated ecosystems to global carbon sequestration. The role of BC in climate change mitigation and adaptation has now reached international prominence. To help prioritise future research, we assembled leading experts in the field to agree upon the top-ten pending questions in BC science. Understanding how climate change affects carbon accumulation in mature BC ecosystems and during their restoration was a high priority. Controversial questions included the role of carbonate and macroalgae in BC cycling, and the degree to which greenhouse gases are released following disturbance of BC ecosystems. Scientists seek improved precision of the extent of BC ecosystems; techniques to determine BC provenance; understanding of the factors that influence sequestration in BC ecosystems, with the corresponding value of BC; and the management actions that are effective in enhancing this value. Overall this overview provides a comprehensive road map for the coming decades on future research in BC science.

Author Correction: The future of Blue Carbon science.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Bioremediation of waste under ocean acidification: Reviewing the role of Mytilus edulis.

Waste bioremediation is a key regulating ecosystem service, removing wastes from ecosystems through storage, burial and recycling. The bivalve Mytilus edulis is an important contributor to this service, and is used in managing eutrophic waters. Studies show that they are affected by changes in pH due to ocean acidification, reducing their growth. This is forecasted to lead to reductions in M. edulis biomass of up to 50% by 2100. Growth reduction will negatively affect the filtering capacity of each individual, potentially leading to a decrease in bioremediation of waste. This paper critically reviews the current state of knowledge of bioremediation of waste carried out by M. edulis, and the current knowledge of the resultant effect of ocean acidification on this key service. We show that the effects of ocean acidification on waste bioremediation could be a major issue and pave the way for empirical studies of the topic.