Abstract Coastal ‘blue carbon’ ecosystems (mangroves, seagrasses and saltmarshes) are critical for climate regulation and biodiversity, yet significant funding gaps persist in marine conservation. While blue carbon credits are increasingly used to bridge these gaps, concerns remain regarding their efficacy in delivering socio‐economic benefits. Based on lessons from terrestrial carbon markets, failing to prioritise local community needs can lead to inequitable outcomes and externally mandated constraints, which undermine the legitimacy of nature‐based solutions. This research seeks to add to the centralised understanding of the social dimension of blue carbon by delivering a comprehensive review of 77 publicly listed projects from global and regional carbon registries. We employed a thematic domain analysis to categorise intended socio‐economic activities and used the Sustainable Development Goal (SDG) framework to evaluate their alignment with international sustainability targets. We found that blue carbon project proponents, that is the organisations responsible for developing and implementing these projects, target a diverse array of SDGs far beyond ‘Life Below Water’ (SDG 14). We identified a shift towards integrating broader international development activities, such as infrastructure improvement, cultural heritage preservation and water, sanitation and hygiene (WASH) services. Quantitative mapping demonstrates that these non‐carbon activities relate most strongly to SDG 8 (Decent Work and Economic Growth), SDG 2 (Zero Hunger) and SDG 5 (Gender Equality). However, the study identifies a systemic lack of transparency regarding how activities are selected, the role of community co‐design and the mechanisms for long‐term monitoring and evaluation. We provide a baseline analysis of how blue carbon project proponents embed sustainable development principles. Addressing these procedural, distributive and evaluative gaps is essential to ensure that blue carbon markets are developed equitably, fostering social and ecological co‐benefits while supporting international sustainability targets. To ensure blue carbon markets are developed equitably, practitioners and policymakers must move beyond participatory gestures towards robust procedural equity and enhancing project accountability. By integrating clear socio‐economic baselines and measurable social impact criteria, blue carbon project proponents can transition projects from simply carbon‐offsetting tools into trusted, holistic investments that foster resilient coastal communities and secure the long‐term integrity of global marine ecosystems. Read the free Plain Language Summary for this article on the Journal blog.

Plankton monitoring datasets help inform indicators for marine biodiversity assessments under the European Union Marine Strategy Framework Directive and United Kingdom Marine Strategy. These indicators are used to assess long-term changes in the state of the pelagic habitats of the Northeast Atlantic which then guide policy formation and implementation to achieve Good Environmental Status. Across all ecosystems, environmental change has the potential to impact upon human wellbeing by changing the quantity and quality of ecosystem services. Here, we develop a socio-ecological assessment model that can describe how variations in pelagic habitat state, evidenced by plankton indicators, can impact human wellbeing. We show that pelagic habitat state can influence human wellbeing through changing the availability of 'goods and benefits' (as made available via ecosystem services), such as the contribution of phytoplankton to climate regulation, but also through mediating the risks of 'ecosystem hazards'. Importantly, changes to pelagic ecosystem state will also drive changes to ecosystem services and ecosystem hazards in the wider marine food web, supported by ecosystem processes associated with plankton, such as the rate of primary production. Applying the proposed assessment model to plankton monitoring data highlights the potential for a greater depth of understanding of the human wellbeing impacts driven by state changes in pelagic habitats. Alongside making best use of the available plankton monitoring data, quantifying the human wellbeing impacts arising from changes to pelagic habitat state increases the evidence base for decision makers.

Understanding long-term carbon storage in temperate seagrass habitats is crucial for assessing their role as a "nature-based" climate solution. However, many studies often use shallow cores, low-resolution analyses, and inconsistent methodologies, limiting the ability to infer large-scale carbon storage potential. This study presents the first high-resolution carbon analysis of temperate seagrass sediments to 3 m depth and provides first estimates of sediment and carbon accumulation rates for UK subtidal meadows. Three sediment vibrocores were collected from a subtidal Zostera marina meadow at Drakes Island, Plymouth Sound, UK. High-resolution sampling at 1 cm intervals in the upper meter, and every 5 cm thereafter, enabled detailed analysis of organic carbon (%OC), calcium carbonate, and particle size, with microscope observations recorded. Several methods for %OC analysis were compared, and 210Pb dating was used to determine accumulation rates. OC content varied widely (0.24%-27.55%), yielding variable mean OC stocks of 302.34 +/- 197.44 Mg C ha-1 over the upper meter. Exceptionally high OC peaks were attributed to coal layers in the sediment. Estimated sediment and carbon accumulation rates ranged from 0.19 to 0.27 g cm-2 yr-1 and 0.32 to 0.45 Mg C ha-1 yr-1, indicating potential core ages up to 1,300 years. Findings highlight the importance of high-resolution, multi-proxy analysis to assess long-term carbon storage and provided valuable historical insights. This study shows how methodological inconsistencies can lead to inaccurate stock estimates, emphasizing the need for standardization. Addressing these issues aids the advancement of accurate carbon storage quantification, provides valuable storage rate data for management, and strengthens future seagrass carbon research.

Functional trait-based approaches have enriched our understanding of key ecological processes such as species assembly and biodiversity loss. This focus on traits, rather than taxonomy, promotes comparability across spatial and organisational scales, further enabling the application of trait-based methodologies to systems where species identity is difficult to recognise. Among other issues, however, the lack of standardisation is preventing trait-based approaches from unlocking their true potential. Here, 407 published articles (peer-reviewed and grey literature) are reviewed alongside the Biological Traits Information Catalogue (BIOTIC) to document inconsistencies in the understanding and use of trait terminology in the context of marine benthic ecosystems. Firstly, discrepancies in the operationalisation of key concepts are noted, each associated with six to ten separate definitions. Secondly, three distinct trait classification frameworks are identified, of which one presents considerable internal variation; within-framework trait classification also emerges as inconsistent. Lastly, a total of 290 synonyms and associated modalities are noted with respect to 18 traits commonly implemented in benthic research, amounting to an average of 16 synonyms per trait. Researchers should be aware of such inconsistencies; to overcome them, we propose a set of guidelines aimed at standardising the reporting and classification of traits in benthic research for policy and management applications. As other standards may exist, we further present a 'translation' table intended for use by trait ecologists when reviewing existing literature that adheres to different trait classification frameworks than the ones we recommend. Standardising the reporting and storage of trait data will help align our understanding of the function of benthic assemblages, their role in delivering ecosystem services, and the impact of human activities on ecosystem function.

Degradation of the natural world and associated ecosystem services is attributed to a historical failure to include its ‘value’ in decision-making. Uncertainty in the quantification of the relationship between natural capital ‘assets’ that give rise to critical societal benefits and people is one reason for the omission of these values from natural resource management. As this uncertainty increases in marine systems and further still with distance from the coast, the connection between society and natural capital assets is less likely to be included adequately in decision-making. Natural capital assets of Areas Beyond National Jurisdiction (ABNJ), including those of the deep sea, are distant but are known to generate many benefits for society, from the diffuse and broad-scale benefits of climate regulation to the provision of wild fish for food. While our understanding of the precise relationships (the status of asset stocks, ecosystem functions and processes) that control the availability of ecosystem services and the flows of benefits is limited, this does not preclude opening a discourse on how these natural capital assets could best be managed to continue to benefit society. Here we apply a natural capital approach to the South East Atlantic ABNJ, one of the least scientifically understood regions of the planet, and develop a framework for risk assessment. We do this by describing the benefit flows from the natural capital assets of the region, appraising how activities are creating pressures on these flows and whether the controls for these pressures protect them. Our risk register highlights how governance currently favours the protection of direct (extractive) benefit flows from natural capital assets of the region, which are primarily targeted for financial benefit. Without a systems-based framework that can account for the cumulative pressures on natural capital assets their status, associated ecosystem services and benefits are at risk. Such an approach is essential to capture and protect the foundational and often diffuse connections between marine natural capital and global society.

Urban park management generally prioritises green spaces and activities within park boundaries, rather than landscape interactions. Understanding how people experience and connect with broader landscapes is essential for improving societal environmental, economic and wellbeing outcomes. A geospatial and discourse analysis of three urban parks was conducted in Plymouth, UK. The predominant landscape gaze at each park revealed strong social ties to blue spaces - namely the coast and sea - indicating an interconnectedness between parks and coastal spaces beyond park boundaries. Textual analysis emphasised the beauty of nature, the expanse of the ocean, and the health and wellbeing benefits of blue and green spaces. These findings suggest that where there is a geographical intersection, experiences cannot be separated. Consideration should therefore be given to the ways that blue and green space combine to shape the landscape gaze and the significance both within, and beyond, the boundaries of urban parks.

With ecosystem services (ES) vital for human wellbeing1, the protection of nature is a human rights matter. We outline how recent advances in international human rights law should inform a revamp of how precaution is applied within environmental decision-making. Critically, precautionary decision-making must evolve to make use of best-available evidence, including novel ES research approaches, to assess ‘foreseeable’ harms to all aspects of human wellbeing that are protected as human rights.

AbstractMarine protected areas (MPAs) can protect and restore marine biodiversity and fisheries, but there are concerns that they may also benefit invasive species. The spatial and temporal colonization of invasive lionfish (Pterois miles) in the eastern Mediterranean was compared across zones with varying fishing restrictions (no fishing, recreational and commercial fishing, and commercial fishing only), and stations where targeted removal events were conducted by volunteer SCUBA divers. Lionfish density in no fishing areas was nearly double that of areas with commercial fishing only, and over four times greater than in areas where both commercial and recreational fishing were allowed. Lionfish density increased with depth, possibly due to easier human exploitation in shallow waters (0–10 m) that are accessible to recreational spearfishers. Targeted removals by volunteer divers decreased lionfish densities by over 60%, while areas without removals had a 200%–400% increase. Along with management actions, natural and ecological processes might drive lionfish densities within MPAs, and the speed with which lionfish colonized fishery‐restricted zones, emphasized the need for a more sophisticated MPA management strategy that considers invasive species impacts and dynamics in an ecosystem‐based approach.

Seagrass is an important marine habitat that provides benefits to society in the form of ecosystem services. Services include the provision of food via fisheries, the regulation of water quality and the ability to sequester and store carbon. In the UK, seagrass beds are in decline, increasing the risk of ecosystem service loss. Current efforts to protect, restore and create seagrass habitat, beyond spatial management measures, rely on grant funding and donations. Emerging carbon, biodiversity and wider ecosystem service markets offering potential revenue sources could facilitate the enhancement of seagrass habitat at scale. Participation in ecosystem service markets, requires that projects deliver on the ecosystem service benefits defined. As the benefits will have been paid for, there are risks associated with not delivering on ecosystem service benefits. It is important that the risk is clearly defined. In this study we further the marine natural capital and risk register approach and apply the method to a case study area to support the development of sustainable funding options for seagrass habitat enhancement in Plymouth Sound, UK. Habitat Suitability modelling is also used to map potential areas for seagrass habitat enhancement. We find that, in the Plymouth Sound area, the risk of loss of ecosystem services for subtidal seagrass habitats is, at present, high. This is primarily linked to the declining extent and condition of subtidal seagrass assets. Under current governance, all of Plymouth Sound’s subtidal seagrass are within a Marine Protected Area, though this conservation designation does not guarantee that the seagrass bed is protected from damaging activity. Under current environmental conditions there is opportunity for widespread seagrass restoration and creation. Risk to seagrass beds and any future private funding could be reduced by governance actions that enable effective direct protection of the seagrass assets and mitigate harmful pressures (e.g., reduction of water pollution). Emerging financial ‘products’ from seagrass ecosystem services that can support restoration and creation, require a high degree of integrity. The natural capital asset and risk register framework can provide information to underpin product development. With the development of revenue streams from ecosystem services there is a need for more intentional governance and site-based monitoring of these habitats as natural capital assets. Further research is needed to define any social or economic outcomes. Synthesis and Application By assessing the risk to the status of seagrass assets through this approach, it is possible to determine the complementary governance actions needed to underpin investment in seagrass habitat enhancement. The methods are transferable to other locations where data exists to define the asset status. These specific findings are relevant nationally where similar vectors of risk (pressures) are identified.

The increase in hard artificial structures in the marine environment is contributing to ocean sprawl. As well as adding hard structure to the seabed, mussel aquaculture adds rope droppers and anchor lines to the water column, where such structure would otherwise be absent. This paper aims to monitor the effects of mussel headlines on the pelagic fish community over time, as well as to investigate whether there is an interaction between the age of cultivated mussels with the number of epibiota species and the abundance of pelagic fishes. Two surveys were carried out: a time series monitoring survey to assess whether the mussel headlines change the surrounding fish species relative to control areas over time, and a fish aggregation device effect survey to investigate whether older and larger mussels support greater abundances of pelagic fishes and epibiota. The most abundant fish species was Atlantic horse mackerel, Trachurus trachurus , with significantly greater numbers recorded around ropes growing older mussels. Results from the surveys show that the physical farm infrastructure has provided a substrate for colonisation by a variety of epibiota: A total of 21 species were recorded growing on the mussel ropes. Furthermore, the older and larger the mussels become, the greater the numbers of epibiota taxa that can colonise, coupled with a greater abundance of pelagic fish recorded around the ropes. The sustainable development of offshore Blue Industries is essential to produce renewable resources. This study brings essential evidence for marine managers and regulators that offshore mussel farming can provide benefits for pelagic and benthic species of both conservation and commercial importance while producing sustainable protein to feed a growing population.

This decade represents a critical period to profoundly rethink human-nature interactions in order to address the interwoven climate and biodiversity crises. Marine Protected Areas (MPAs) demonstrate promise for increasing ecosystem resilience and reversing habitat and population declines, but outcomes vary considerably from context to context. Partially protected areas offer a compromise between ecological recovery and the social needs of local communities, but their success is contingent on an array of factors. This in-depth review summarizes 15 years of marine conservation research and impact in Lyme Bay (southwest UK), to serve as a model for the future adoption of partially protected MPAs. The findings from the UK's longest integrated socioecological monitoring MPA study are presented and supplemented by an evaluation of the whole-site management approach as a core element of Lyme Bay's achievements. The journey from research to improved monitoring and ambitious policy is illustrated within and interspersed with stories of novel discoveries, ongoing challenges, and method developments. What started as a dedicated group of community members has grown into an immense collaboration between fishers, scientists, NGOs, and regulators, and their combined efforts have sent ripple effects of positive change across the globe.

The Agreement on Marine Biodiversity of Areas beyond National Jurisdiction ( BBNJ Agreement) opens a new path in international law towards addressing issues at the ocean-climate nexus, as well as considering implications for the protection of human rights and achieving equity among States in the context of ocean knowledge production and environmental management. Based on an interdisciplinary reflection, the new international obligations on strategic environmental assessments ( SEA s), and new institutional arrangements, are identified as crucial avenues to addressing climate change mitigation and ensuring fair research partnerships, mutual capacity-building and technology co-development between the Global North and South. SEA s can also support integrated implementation of other parts of the BBNJ Agreement and contribute to the broader effectiveness of the general provisions of the United Nations Convention on the Law of the Sea on the protection of the marine environment, within and beyond national jurisdiction.

Although stakeholder engagement is one of the founding principles of marine spatial planning (MSP), meaningful representation of people and their connections to marine resources within marine governance is still lacking. A broad understanding of how concepts surrounding social capital and capacity is translated into MSP practice is missing. With this article, we describe detailed case studies in the United Kingdom, Brazil and South Africa to build a better understanding of the ways in which MSP and other ocean governance initiatives operationalise the concepts of social capital and capacity. Drawing on insights from the cases, we call for a rethinking of capacitation as a two-way process. In particular, trust-building, social learning and efforts to build social capacity should be elaborated without imposing a hierarchy between people 'who know' and people 'who don't'. Innovative approaches to relationship building, knowledge development, and collaboration highlighted in the case studies highlight ways to build social capacity both among stakeholders and planners, as is necessary for more equitable and sustainable MSP development and implementation.

Despite its remoteness, human activity has impacted the deep sea and changes to the structure and function of deep-sea ecosystems are already noticeable. In terrestrial and shallow water marine environments, demonstrating how ecosystems support human well-being has been instrumental in setting policy and management objectives for sustainable resource use. Foundational to this approach is a framework of ecosystem service (ES) classification and a synthesis of the knowledge base, which can then be used to structure decision-support tools such as ecosystem accounts or Environmental Impact Assessments. At present, no such framework exists for the deep sea. There is thus an urgent need to determine and assess the ES provided by deep-sea habitats and species before (potentially irreversible) decisions are made about deep-sea habitat use and governance. As a first step towards the incorporation of ES in such decision-making, we undertake two systematic reviews of the scientific literature based on the principles of the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) systematic process. This was to define a comparative ES framework and synthesise the current evidence base for how deep-sea habitats support ecosystem services. Our framework proposes four supporting services, three regulating services, four provisioning services and three cultural services for which there is an established and growing body of evidence for the role of deep-sea habitats. The ES framework presented here provides a structure for deep-sea ecosystem services. In its next phase of development, this could provide the foundation for the development of habitat-ecosystem service matrices, which are a critical component for truly accounting for ES in decision-making, particularly spatial management. This framework has significant implications for deep-sea management, conservation and policy, as it provides an ecosystem services-based tool that can be used in any deep-sea ecosystems management across the planet, and it also shows how critical these data gaps are for today’s decisions and how seriously they should be considered in decision-making processes.

Marine Protected Areas (MPAs) are advocated as tools to support sustainable fisheries and biodiversity by excluding the most destructive fishing practices. Some MPAs protect the whole-site of habitat mosaics from bottom-towed fishing but most only restrict damaging activities from specific evidenced conservation features. Social and economic factors influence the success of an MPA but the impact of spatial management changes to local fisheries is rarely captured in post MPA designation monitoring. In Jersey, Channel Islands, two offshore MPAs were designated in 2017 that are managed following the whole-site approach. This study provides an insight into the overall economic importance of key fishery species (whelk (Buccinum undatum), brown crab (Cancer pagurus), scallop (Pecten maximus), lobster (Homarus gammarus), and spider crab (Maja brachydactyla) to local fishing fleets and the impact of the MPAs on local, small-scale fishers in Jersey. Total landings (kg and & POUND;) in Jersey pre and post MPA designation were calculated from logbook and primary sales data and a structured interview was developed and tested as a research tool to document the impact (positive and negative) of the MPA designation on local fishers. Specific questions were designed to elicit both quantitative and qualitative data relating to the participants (n = 21) fishing activity; support for the MPAs; income and job satisfaction; subjective well-being and current sales strategies. The results demonstrate that one mobile gear vessel respondent was displaced from traditional fishing grounds as a result of the MPA designation. Fishers also reported an increase in static fishing inside the MPAs, post designation. Generally, there are high levels of support for the MPA from static fleet respondents. In the first year since designation there have been no reported changes to catch (kg, & POUND;). Mobile gear fishers reported a lower subjective wellbeing and satisfaction with their job and income than static gear fishers, despite greater profits. The major concern reported by the mobile fleet that contributed to their stress levels, was not attributed to the MPA designations but related to conflict with French static net fisheries operating outside of the MPAs. Ongoing support for Jersey's fishers and securing a sustainable and fulfilling livelihood will require further spatial management of fisheries outside of the MPAs with a possibility of setting gear or effort limits on static fishereis within the MPAs.

After drawing attention to the crucial role of marine biodiversity, including that of deep-sea ecosystems, in current scientific understanding of the ocean-climate nexus, this article highlights the limited extent to which the international climate change regime has so far addressed the ocean. The focus then shifts to how the international climate change regime could contribute to the protection of marine biodiversity as part of mitigation, adaptation and finance, taking into account human rights impacts and standards, drawing a comparison with REDD +. The article concludes with an original proposal, inspired by the Climate and Clean Air Coalition, to develop urgent, synergistic approaches to ocean- and human rights-based climate action through a multi-actor coalition, including different international treaties and United Nations bodies, to ‘protect and restore the ocean’s contributions to climate regulation, human well-being and planetary health’.

Historical and existing environmental and human induced pressures have negatively impacted diadromous species, as well as benefits to humans, derived from the ecosystem services these species contribute to. As species move across national boundaries, successful management is rendered a complex process. Future climate change scenarios are likely to change species distributions, further impacting management and the benefits available to people across each species range. To provide an evidence base on the contribution of eleven diadromous fish populations to ecosystem services, and so gains and losses of ecosystem service benefits in the European Atlantic Area, we completed an evidence review of available literature identified within the search strategy. We also gathered expert opinion of diadromous species contributions to ecosystem services for individual catchments across Europe, to gather the full extent of contributions. Evidence was arranged in a matrix, documenting each species ecosystem service contribution to aid communication of results and application to policy and decision makers. The evidence base provided by the literature review identified that each diadromous species contributed to provision of multiple ecosystem services. Volume of evidence available to compile the matrix was far greater for Atlantic salmon Salmo salar and brown trout Salmo trutta. All species had historically contributed to provisioning ecosystem services. However, in recent decades, declines in certain species populations has reduced opportunity for commercial fisheries, leading to contributions to cultural services such as recreational activities and cultural heritage becoming comparatively greater. Evidence of contribution to regulating ecosystem services is growing in recent years, especially transfer of nutrients from marine to freshwater environments. Inclusion of local expert knowledge enabled verification of evidence from literature, in addition to identification of important contributions of lesser studied species, to culturally important commercial fisheries and cultural heritage in European regions. Collecting expert knowledge also aided communication of ecosystem service approaches.

Kelp forests and seagrasses are important carbon sinks that are declining globally. Rewilding the sea, through restoring these crucial habitats, their related biodiversity and ecosystem contributions, is a movement and concept, gathering pace in the United Kingdom and globally. Yet understanding of the economic costs and benefits for setting areas of the sea aside—and removing some human impacts from them—is not well understood. The potential benefits and distributional impacts on marine users and wider society is critical to make evidence based decisions. Ensuring that areas of the sea recover, and that the impacts (both positive and negative) are understood, requires targeted research to help guide decisions to optimize the opportunity of recovery, while minimizing any negative impacts on sea users and coastal communities. We approach the problem from an ecosystem services perspective, looking at the opportunity of restoring a kelp bed in Sussex by removing fishing activity from areas historically covered in kelp. Development of an ecosystem services valuation model showed restoring kelp to its highest mapped past extent (96% greater, recorded in 1987) would deliver a range of benefits valued at over £ 3.5 million GBP. The application of an ecosystem services approach enabled the full range of benefits from habitat restoration to be assessed. The results and the gaps identified in site specific data and values for this area, have broader implications in fisheries management and natural resource management tools for restoring marine habitats and ecosystems in the United Kingdom.

Fisheries are in decline worldwide, and Marine Protected Areas (MPAs) are being advocated as tools that can not only protect and restore biodiversity but also improve fisheries sustainability and protect fisher livelihoods. To understand the role of Marine Protected Areas (MPAs) in underpinning commercial fisheries, this study demonstrates the economic value of Jersey's benthic substrates (habitats) for five predominant species fished by Jersey and French vessels: Homarus gammarus, Cancer pagurus, Maja brachydactyla, Pecten maximus and Buccinum undatum. Value was apportioned between habitats that support these commercial species across their essential life history stages, and the proportional economic value that was protected from bottom-towed fishing within MPAs was analysed. Multiple habitats across Jersey's territorial waters contributed a total economic value of 14,664,729 pound, with 4,127,999 pound protected within MPAs. Overall, subtidal sediment was the most valuable habitat to both Jersey (2.12 pound million) and French (2.47 pound million) fisheries but was also the least protected habitat from bottom-towed fishing (2.73%). Our findings support an ecosystem-based approach to fisheries management and emphasise the importance of considering species life histories, and their habitat requirements, in management plans.