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Hydrothermal ecosystems face threats from planned deep‐seabed mining activities, despite the fact that patterns of realized connectivity among vent‐associated populations and communities are still poorly understood. Since populations of vent endemic species depend on larval dispersal to maintain connectivity and resilience to habitat changes, effective conservation strategies for hydrothermal ecosystems should include assessments of metapopulation dynamics. In this study, we combined population genetic methods with biophysical models to assess strength and direction of gene flow within four species of the genus Alviniconcha (A. boucheti, A. kojimai, A. strummeri and A. hessleri) that are ecologically dominant taxa at Western Pacific hydrothermal vents. In contrast to predictions from dispersal models, among‐basin migration in A. boucheti occurred predominantly in an eastward direction, while populations within the North Fiji Basin were clearly structured despite the absence of oceanographic barriers. Dispersal models and genetic data were largely in agreement for the other Alviniconcha species, suggesting limited between‐basin migration for A. kojimai, lack of genetic structure in A. strummeri within the Lau Basin and restricted gene flow between northern and southern A. hessleri populations in the Mariana back‐arc as a result of oceanic current conditions. Our findings show that gene flow patterns in ecologically similar congeneric species can be remarkably different and surprisingly limited depending on environmental and evolutionary contexts. These results are relevant to regional conservation planning and to considerations of similar integrated analyses for any vent metapopulations under threat from seabed mining.

Ocean mining activities have been ongoing for nearly 70 years, making great contributions to industrialization. Given the increasing demand for energy, along with the restructuring of the energy supply catalyzed by efforts to achieve a low-carbon economy, deep seabed mining will play an important role in addressing energy- and resource-related problems in the future. However, deep seabed mining remains in the exploratory stage, with many challenges presented by the high-pressure, low-temperature, and complex geologic and hydrodynamic environments in deep-sea mining areas, which are inaccessible to human activities. Thus, considerable efforts are required to ensure sustainable, economic, reliable, and safe deep seabed mining. This study reviews the latest advances in marine engineering geology and the environment related to deep-sea mining activities, presents a bibliometric analysis of the development of ocean mineral resources since the 1950s, summarizes the development, theory, and issues related to techniques for the three stages of ocean mining (i.e., exploration, extraction, and closure), and discusses the engineering geology environment, geological disasters, in-situ monitoring techniques, environmental protection requirements, and environmental effects in detail. Finally, this paper gives some key conclusions and future perspectives to provide insights for subsequent studies and commercial mining operations.

This study presents in situ, high-resolution optical measurements of particle size distributions (PSD) within sediment plumes generated by a pre-prototype deep seabed nodule collector vehicle operating in the abyssal Pacific Ocean. These measurements were obtained using a cutting-edge instrument, the LISST-RTSSV sensor. The data collected in situ reveal marked differences compared to previously reported laboratory-based, ex situ measurements. The grain size and other key particle shape characteristics are found to be dependent on multiple factors, including the collector vehicle maneuvers, the time elapsed following sediment discharge, and the complex hydrodynamic processes that generate the sediment in suspension. Significantly, the PSD from a highly complex succession of straight-line maneuvers converges to that of the canonical case of a simple straight-line driving maneuver within a timescale of ten minutes. Our results underscore the importance of parameterizing sediment plume transport models based on well-informed, comprehensive PSDs of detrained suspended sediment measured in situ at adequate timescales and in regions no longer strongly influenced by active and complex hydrodynamic processes.

As land-based mining industries face increasing complexities, e.g., diminishing return on investments, environmental degradation, and geopolitical tensions, governments are searching for alternatives. Following decades of anticipation, technological innovation, and exploration, deep seabed mining (DSM) in the oceans has, according to the mining industry and other proponents, moved closer to implementation. The DSM industry is currently waiting for international regulations that will guide future exploitation. This paper aims to provide an overview of the current status of DSM and structure ongoing key discussions and tensions prevalent in scientific literature. A narrative review method is applied, and the analysis inductively structures four narratives in the results section: (1) a green economy in a blue world, (2) the sharing of DSM profits, (3) the depths of the unknown, and (4) let the minerals be. The paper concludes that some narratives are conflicting, but the policy path that currently dominates has a preponderance towards Narrative 1—encouraging industrial mining in the near future based on current knowledge—and does not reflect current wider discussions in the literature. The paper suggests that the regulatory process and discussions should be opened up and more perspectives, such as if DSM is morally appropriate (Narrative 4), should be taken into consideration.

The unilateral authorization of deep seabed mining by states not party to the United Nations Convention on the Law of the Sea (UNCLOS) exposes a critical governance gap. While international law requires all states to cooperate in governing shared resources, the substantive content of cooperative obligation for non-party states in deep seabed mining remains undefined. This article examines the cooperative obligation of non-party states toward the International Seabed Authority (ISA), with particular attention to the unilateral authorization by the United States of deep seabed mining in the Area. Drawing on international jurisprudence, it identifies the boundaries of this obligation and the specific requirements of the cooperative obligation across three dimensions. Environmental cooperation encompasses environmental impact assessment, ongoing monitoring, and pollution control. Resource-related cooperation requires due regard for the interests of other states and equitable consideration of developing states. Scientific and technical cooperation includes data sharing and capacity-building initiatives. It then examines implementation pathways. It demonstrates that UNCLOS dispute settlement mechanisms face jurisdictional obstacles when applied to non-party states, examines the potential of advisory opinions from international judicial bodies to clarify cooperative duties, and discusses complementary enforcement mechanisms, including ISA institutional measures and market-based compliance tools adapted from fisheries governance. The cumulative interaction of these pathways constrains unilateral conduct even without formal treaty ties. The article establishes a conduct-based compliance approach that renders this obligation assessable through benchmarks. It further reveals that traditional positive economic incentives for cooperation fail in deep seabed mining, requiring a shift toward negative incentives based on reputational, institutional, and market costs. More importantly, it identifies an exception to the principle that treaties bind only their parties when applied to global commons governance.

Development of deep seabed mining - legal framework for settlement of disputes - dispute settlement mechanisms from a participant's perspective - perspective of the International Seabed Authority (ISA) - perspective of the sponsoring state - policy advice.

A pivotal point in time has been reached in the ongoing negotiations under the auspices of the International Seabed Authority (ISA) towards the adoption of regulations for the commercial exploitation of mineral resources in the deep seabed beyond national jurisdiction. The ISA has a mandate to ensure that activities in the Area, legally designated as ‘common heritage of humankind’, are carried out for the benefit of humankind as a whole. Yet, there is a growing sense of unease with the potential imminence of the commercial exploitation phase, and concern that the implementation of all components of the common heritage principle, including its environmental and distributive ambitions, will be compromised in the interest of a handful of industry stakeholders. This article dives under the surface of these tensions by asking how the public interest in a global commons can become constructed in a way that conflates diverse and opposing interests in favour of value extraction by the private sector, revealing the ambivalent role of international law in the process. It uses the concept of ‘false necessity’ to question the apparent urgency and inevitability of commercial exploitation, more specifically to the extent it obscures and pre-empts more inclusive conceptions of ‘benefit’ for humankind. By shifting the focus from the much-debated risks of deep seabed mining to the notion of benefit, the article illuminates the inherent contradictions and distributional asymmetries obscured by the conflated yet purportedly universal conception of public interest in exploitation.

The ocean plays a key role in sustaining life on our planet and is inextricably linked to biodiversity, climate, human well-being, and health. However, the governance of the ocean is primarily pursued through sectoral-based legal and institutional frameworks that falls short in ensuring the long-term protection of the marine environment and the sustainability of marine resources. This is especially concerning in areas beyond the limits of national jurisdiction (ABNJ) where human activities continue to expand. The existence of two distinct regimes in ABNJ, namely the High Seas (applicable to the water column, which is a global common) and the Area (applicable to the international seabed and its mineral resources, which are the common heritage of mankind), that have been largely regulated separately, impede the development and implementation of integrated marine environmental governance and biodiversity conservation in ABNJ. On the one hand, the International Seabed Authority (ISA), which is mandated to administer the mineral resources of the Area, is currently discussing a set of regulations to enable future exploitation activities. On the other hand, multilateral negotiations are taking place for the development of an internationally legally binding instrument for the conservation and sustainable use of marine biodiversity in areas beyond national jurisdiction (referred to as the proposed ‘BBNJ’ Instrument). Both processes offer a unique opportunity to foster an ecosystem approach to management (EAM) in ABNJ. In this article, we elaborate on options for stronger governance integration and the development of a coherent and collaborative interplay between these two processes. To this end, we explore the potential of Regional Environmental Management Plans (REMPs) established by the ISA as a case study to contribute to global biodiversity conservation, and the opportunity for the proposed BBNJ Instrument to promote overarching coherence to biodiversity conservation in ABNJ, premised on EAM. We conclude that the proposed BBNJ Instrument could have a pivotal role to streamline multilateral action for the conservation of biodiversity in ABNJ by adopting an ambitious, overarching environmental vision and strategic goals, accompanied by strong implementation and enforcement mechanisms.

The latest negotiating text from the International Seabed Authority (ISA) on the Environmental Compensation Fund (ECF) system shows significant progress compared to the provisions in the 2019 Draft Exploitation Regulations. First, the formulation of the ECF rules and procedures has been further elaborated. Second, the scope of application of the ECF has been more precisely delineated. Third, the mechanisms for funding the ECF have been improved. Fourth, the “polluter-pays principle” has been introduced for the first time. Fifth, a periodic review mechanism has also been incorporated for the first time. Nevertheless, the 2025 Draft continues to exhibit certain deficiencies. First, the financial foundations of the ECF remain unreliable. Several new or modified sources of funding, such as voluntary contributions from member States, targeted contributions from sponsoring States, and donations from international or non-governmental organizations, are inherently uncertain. Second, the text fails to establish clear and operational criteria for determining eligibility to submit claims to the ECF. Third, the scope of compensation available under the ECF remains inadequately defined. Fourth, transparency for stakeholders with respect to the operation of the ECF is insufficient. This study proposes the following recommendations to deal with the abovementioned deficiencies. First, the principles, mechanisms, and specific measures for the ECF fundraising and management should be optimized. Second, with respect to eligible claimants, a multi-tiered and sequential framework is recommended. Third, the scope of the ECF’s compensatory mandate should be refined, and detailed standards developed to ensure that the ECF is used exclusively to address liability gaps where environmental harm cannot otherwise be remedied. Fourth, stakeholder transparency must be enhanced.

The oceanic bottom mixed layer (BML) is a well mixed, weakly stratified, turbulent boundary layer. Adjacent to the seabed, the BML is of intrinsic importance for studying ocean mixing, energy dissipation, particle cycling and sediment-water interactions. While deep-seabed mining of polymetallic nodules is anticipated to commence in the Clarion-Clipperton Zone (CCZ) of the northeastern tropical Pacific Ocean, knowledge gaps regarding the form of the BML and its potentially key influence on the dispersal of sediment plumes generated by deep-seabed mining activities are yet to be addressed. Here, we report recent field observations from the German mining licence area in the CCZ that characterise the structure and variability of the BML locally. Quasi-uniform profiles of potential temperature extending from the seafloor reveal the presence of a spatially and temporally variable BML with an average local thickness of approximately 250 m. Deep horizontal currents in the region have a mean speed of 3.5 cm s-1 and a maximum speed of 12 cm s-1 at 18.63 ms above bottom over an 11 month record. The near-bottom currents initially have a net southeastward flow, followed by westward and southward flows with the development of complex, anticyclonic flow patterns. Theoretical predictions and historical data show broad consistency with mean BML thickness but cannot explain the observed heterogeneity of local BML thickness. We postulate that deep pressure anomalies induced by passing surface mesoscale eddies and abyssal thermal fronts could affect BML thickness, in addition to local topographic effects. A simplified transport model is then used to study the influence of the BML on the interplay between turbulent diffusion and sediment settling in the transport of deep-seabed mining induced sediment plumes. Over a range of realistic parameter values, the effects of BML on plume evolution can vary significantly, highlighting that resolving the BML will be a crucial step for accurate numerical modelling of plume dispersal.Article HighlightsField observations detail the presence of bottom mixed layer in the abyss of the Clarion-Clipperton Zone in the northeastern tropical PacificMean local thickness of the layer is approximately 250 m, with large spatial and temporal heterogeneity that needs further understandingThe transport of benthic sediment plumes generated by deep-seabed mining can be greatly influenced by bottom mixed layer variability