The scale of the challenge is enormous. Marine and coastal systems are increasingly shaped by multiple, interacting pressures arising from human activities and climate change, and these pressures do not respect administrative boundaries or departmental portfolios. Policy initiatives such as the European Green Deal, the Marine Strategy Framework Directive, and the Maritime Spatial Planning Directive have established ambitious goals for ecosystem-based management. Yet, as the editorial notes, their implementation often reveals persistent fragmentation across sectors, scales, and institutions. The seven contributions to the Research Topic suggest that transformative ocean planning depends on interconnected changes in three areas: how knowledge is generated and integrated, how policies and institutions are coordinated, and how stakeholders and diverse knowledge systems are involved in planning and decision-making. Each of these pillars, the editors argue, is necessary but insufficient on its own.

The first pillar concerns the analytical machinery that underpins ecosystem-based maritime spatial planning, often abbreviated as MSP. One of the most technically significant advances comes from work on cumulative effects assessment, a method used to estimate the combined impact of multiple human pressures on marine ecosystems. These assessments have long suffered from methodological limitations that made their outputs difficult to use in real-world decisions. The new research refines the way pressures from maritime activities are quantified and interpreted by incorporating magnitude-weighted relationships between activities and the pressures they generate. It also introduces an unsuitability metric based on ecosystem sensitivities, which helps planners identify areas where particular activities are least compatible with the local environment. Interestingly, these refinements do not fundamentally alter the overall spatial patterns that the assessments reveal, but they significantly improve the interpretability and practical applicability of the results, particularly when applied at finer spatial resolutions.

That last point carries real weight for practitioners. In geographically constrained areas, such as crowded coastal seas where every square kilometer may host competing demands, management decisions demand higher levels of accuracy than broad-brush regional analyses can provide. Aligning analytical precision with the spatial scale of the planning challenge is therefore not a technical nicety but a practical necessity. The lesson emerging from this line of work is that cumulative effects assessment is evolving from a somewhat abstract mapping exercise into a decision-support tool that can genuinely inform where activities should and should not occur. For a field that has struggled to translate ecological science into actionable planning guidance, that shift in usability may prove as important as any conceptual breakthrough.

Yet the editorial is emphatic that technical improvements alone are insufficient without a deeper integration of social and ecological dimensions. A second study tackles this gap by operationalizing social-ecological indicators, embedding them within the DAPSI(W)R(M) framework, a structured approach that links human activities to pressures, state changes, impacts, and responses in marine systems. By explicitly connecting ecosystem changes to human wellbeing, the research exposes just how limited existing indicators are in capturing these interconnections. Most current metrics track environmental conditions or economic outputs in isolation, leaving the feedback loops between nature and society largely invisible to planners. The study identifies pathways for developing compound, digitally ready indicators that could bridge this divide, and this is where the work connects to one of the most exciting technological developments in ocean science: Digital Twin initiatives.

Digital Twin Ocean projects, such as SEADITO referenced in the editorial, aim to build dynamic virtual replicas of marine systems fed by integrated data infrastructures. The promise is transformative: planners could simulate the consequences of different management choices before committing to them, testing scenarios for offshore energy development, fishing pressure, or conservation measures in silico rather than through costly trial and error in the real ocean. But a digital twin is only as good as the indicators and data that populate it. The push toward compound indicators that simultaneously reflect environmental conditions and societal outcomes is therefore a prerequisite for making these tools meaningful for governance. If the digital revolution in ocean science proceeds without social-ecological integration, it risks producing dazzling visualizations of a partial reality, blind to the human dimensions that ultimately determine whether policies succeed or fail.

The second pillar of transformation involves the stubborn gap between policy ambition and on-the-ground implementation. Empirical analyses from the French Mediterranean and the wider Mediterranean basin demonstrate that while European policy frameworks are relatively coherent at higher levels in their environmental objectives, this coherence often dissolves during implementation. Administrative complexity, fragmented governance structures, and limited institutional capacity erode well-intentioned directives as they cascade downward. Local authorities in both studies face overlapping mandates, resource constraints, and insufficient mechanisms for stakeholder engagement, all of which hinder effective policy delivery. Anyone who has followed the implementation history of European environmental legislation will recognize this pattern, but the Mediterranean cases also offer grounds for optimism. They document examples of innovation, including multi-actor governance platforms, specialized institutional arrangements, and territorially grounded restoration strategies that enhance coordination and collaboration among actors who previously operated in isolation.

Complementing these case studies, another contribution identifies archetypal patterns of barriers and enablers that recur across governance contexts, providing a broader structural diagnosis of policy incoherence. Fragmented governance roles, weak coordination across the land-sea interface, and insufficient integration across policy domains emerge as recurrent obstacles. On the enabling side, harmonized data systems, knowledge-sharing platforms, and inclusive stakeholder engagement are highlighted as key factors that allow governance systems to function. These findings reinforce the need for governance that is not only better aligned in design but also more adaptive and interconnected in practice, capable of responding to the complexity and dynamic nature of marine socio-ecological systems. The land-sea interface deserves particular attention, since many of the most damaging pressures on coastal waters originate in terrestrial activities, from agricultural runoff to coastal development, yet land-use planning and marine planning typically proceed through entirely separate institutional channels.

The alignment of maritime spatial planning with overarching sustainability agendas forms a third strand of the collection. Researchers developed an operational framework to assess the extent to which existing Maritime Spatial Plans contribute to the European Green Deal, and applied it across several EU countries. The results reveal both progress and remaining gaps. Climate change mitigation is widely reflected in current plans, largely through the expansion of offshore renewable energy, which has become the dominant driver of marine spatial reorganization in European waters. However, other Green Deal priorities, such as ecosystem restoration, the circular economy, and zero pollution, remain less consistently operationalized. This uneven integration highlights the need to move beyond declarative commitments toward concrete, measurable actions, supported by frameworks that enable systematic assessment, comparison, and iterative improvement of planning outcomes over time. Without such feedback mechanisms, plans risk becoming aspirational documents rather than instruments of change.

The third and perhaps most socially resonant pillar concerns who gets a say in ocean governance. A case study from the United States Virgin Islands demonstrates how community-based coral and mangrove restoration workshops can function as powerful sites for co-producing knowledge, integrating local ecological understanding, and fostering culturally responsive restoration strategies. Participants prioritized ecological function, local livelihoods, and intergenerational engagement, a value set that challenges conventional top-down models of decision-making and points toward more relational and community-driven forms of governance. The editorial draws a pointed conclusion from this work: participation is not merely a procedural requirement to be checked off, but a transformative component of effective and legitimate marine management. Taken together, the seven studies identify key enabling conditions and practical pathways for change, including stronger social-ecological knowledge integration, more coherent and implementable policies, greater coordination across sectors and scales, strengthened local capacity, and more inclusive and adaptive planning processes. For a planet whose blue half is changing faster than the institutions meant to steward it, these insights remain pivotal to the continued evolution of ecosystem-based and transformative ocean planning in Europe and beyond.

Subject of Research: Transformative approaches in marine governance and maritime spatial planning

Article Title: Editorial: Navigating change: Transformative approaches in ocean planning

Article References: Depellegrin, D., Li, S., & Kyriazi, Z. (2026). Editorial: Navigating change: Transformative approaches in ocean planning. Frontiers in Ocean Sustainability, 4, Article 1988794. https://doi.org/10.3389/focsu.2026.1988794

Image Credits: AI Generated

DOI: 10.3389/focsu.2026.1988794

Keywords: ocean governance, maritime spatial planning, cumulative effects assessment, Digital Twin Ocean, European Green Deal, policy coherence, social-ecological indicators, participatory approaches, Mediterranean Sea, ecosystem-based management, marine restoration, coastal management

The scale of the problem facing oyster reefs provides the backdrop for the new valuation. Worldwide, an estimated 85 percent of oyster reefs have been lost over the past century, with the steepest declines concentrated in estuaries and river deltas, the very environments where these reef-building bivalves thrive. Like all coastal ecosystems, oyster reefs are under growing stress from overexploitation, pollution, and climate change. The United Nations’ Sustainable Development Goal on life below water calls for the conservation and sustainable use of coastal and marine resources to safeguard human wellbeing, yet the habitats that could deliver many of those benefits continue to disappear. The new study was designed to quantify exactly what is being lost, and what could be regained, if restoration were pursued at scale.

To build their global picture, the researchers, led by corresponding author Dr Matteo Convertino, an associate professor at Tsinghua University, began by assessing where suitable habitat for oyster reefs exists today and where reefs could spontaneously form given the right protection and restoration interventions. They imported thousands of geotagged records of oyster reefs from two public databases and then applied a well-established machine learning algorithm to predict geographic distributions and habitat suitability around the world, flagging potential new locations where reefs might be established. The suitability model weighed a suite of environmental variables, including local water temperature, salinity, light availability, nutrient richness, and oxygenation. Any location scoring 65 percent or greater on habitat suitability was classified as suitable for reef formation.

The team then went a step further, combining each area’s suitability score with a measure of the ecosystem services a reef there could provide to calculate what they call the ecopotential of every location. The higher the ecopotential, the greater the potential benefit of restoring or protecting a reef at that site. This portfolio of services extends far beyond oysters for human consumption. Oyster reefs filter enormous volumes of water, protect shorelines from erosion and storm damage, recycle nutrients through the food web, and sequester carbon. They also provide food, shelter, and nursery grounds for a plethora of fish and invertebrates, functioning as foundational habitat that supports entire coastal food webs. Capturing the full value of this portfolio is what pushes the estimated GEP into the trillions.

The modeling results identified ten hotspot nations where predicted ecopotential is greatest: the United States, Australia, Chile, China, Japan, South Korea, Argentina, France, Germany, and Italy. Across these countries, approximately 295,000 square kilometers, or about 6 percent of their coastal zones, were deemed suitable for oyster reefs. Yet reefs are currently known to occupy only 10 percent of that suitable area, mainly in lagoons and bays, estuaries, and river deltas. The gap between what exists and what could exist points to enormous room for expansion. Perhaps more striking is the finding that only 23 percent of the suitable area currently falls under any form of marine protection, meaning the vast majority of remaining and potential reef habitat remains exposed to the pressures that have already erased most of the world’s oyster reefs.

The quantified benefits of full restoration are vivid when expressed in raw ecological terms. If every area with positive ecopotential were occupied by reefs, the authors calculate that these ecosystems could filter prodigious volumes of water: 77.58 quadrillion liters in the United States, 69.92 quadrillion liters in Australia, and 46.58 quadrillion liters in Chile. Water filtration by dense aggregations of filter-feeding oysters improves clarity, removes excess nutrients, and can help suppress harmful algal blooms, cascading through coastal ecosystems in ways that benefit seagrasses, fish populations, and human users alike. The same fully realized reef network could sequester as much as 12.3 million metric tons of carbon per year, adding a meaningful climate mitigation component to the reefs’ portfolio of services.

For a single country, the monetary value of just a subset of these services is already substantial. In the United States alone, the combined potential value of nitrogen removal, carbon sequestration, and water purification by oyster reefs was estimated at 25.1 billion dollars a year. Nitrogen removal matters because coastal eutrophication, driven by agricultural and urban runoff, is one of the most damaging forces in estuarine systems worldwide, and oysters incorporate and process nitrogen as they filter and grow. Carbon sequestration reflects the burial of organic material in reef structures and surrounding sediments. Water purification, meanwhile, underpins fisheries, tourism, and coastal water quality. These three services represent only part of the total portfolio, which is why the global GEP estimate reaches into the trillions when all services and all suitable nations are considered.

The authors are careful to frame these figures as estimates rather than guarantees. The calculations infer ecosystem services from global averages of key parameters, and the actual values could shift with changes in oyster populations over time or with the advancing climate crisis. Significant work on habitat restoration and protection would also be required before any of the potential could be unlocked. We estimated that 90 percent of sites suitable for oyster reefs require restoration, while 80 percent need protection through conservation efforts, Convertino said. In other words, the current oyster situation is very suboptimal, but there is a huge opportunity, considering the benefits. The statement captures the central tension of the study: the ecological and economic potential is enormous, but realizing it demands investment and policy action on a comparable scale.

Climate change adds a further layer of complexity to the outlook. Because global warming generally decreases the habitat quality of oyster reefs, the researchers expect the global GEP to decline from the current potential value of twelve trillion dollars as conditions shift. Yet the picture is not uniformly negative. Some countries may see an expansion of reefs due to more favorable conditions for the growth and dispersal of oysters. The study singles out Australia, Indonesia, South Korea, Japan, and France as places where reef extent could grow under warming conditions, a reminder that the biogeography of coastal ecosystems will be reshuffled rather than simply diminished. For policymakers, the implication is that restoration priorities may need to be dynamic, tracking shifting habitat suitability over decades.

What the study ultimately offers is a new way of seeing an ecosystem that most people encounter only on a dinner plate. By translating the ecological work of oyster reefs into the language of gross ecosystem product, the researchers make a case that resonates in ministries of finance as much as in marine biology laboratories. A reef that filters quadrillions of liters of water, sequesters millions of tons of carbon, buffers shorelines, and nurseries commercial fish stocks is not a luxury but infrastructure, and infrastructure that has been allowed to collapse by 85 percent in a single century. The twelve trillion dollar figure is not a promise but a ceiling, one that depends on restoring nine tenths of suitable sites and protecting four fifths of them. Whether the world’s nations choose to make that investment will determine whether oyster reefs remain a remnant of past coastlines or become a cornerstone of future planetary health.

Subject of Research: Global valuation of the gross ecosystem product of oyster reefs

Article Title: The world’s oyster reefs could add $12 trillion to planetary health each year – if they were better managed

Article References: The world’s oyster reefs could add $12 trillion to planetary health each year – if they were better managed. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: oyster reefs, ecosystem services, gross ecosystem product, marine restoration, coastal ecosystems, water filtration, carbon sequestration, habitat suitability, machine learning, climate change, marine conservation, Frontiers in Marine Science