Habitat heterogeneity and species diversity are often linked. On the deep seafloor, sediment variability and hard-substrate availability influence geographic patterns of species richness and turnover. The assumption of a generally homogeneous, sedimented abyssal seafloor is at odds with the fact that the faunal diversity in some abyssal regions exceeds that of shallow-water environments. Here we show, using a ground-truthed analysis of multibeam sonar data, that the deep seafloor may be much rockier than previously assumed. A combination of bathymetry data, ruggedness, and backscatter from a trans-Atlantic corridor along the Vema Fracture Zone, covering crustal ages from 0 to 100 Ma, show rock exposures occurring at all crustal ages. Extrapolating to the whole Atlantic, over 260,000 km2 of rock habitats potentially occur along Atlantic fracture zones alone, significantly increasing our knowledge about abyssal habitat heterogeneity. This implies that sampling campaigns need to be considerably more sophisticated than at present to capture the full deep-sea habitat heterogeneity and biodiversity.
Extractive activities in the ocean are expanding into the vast, poorly studied deep sea, with the consequence that environmental management decisions must be made for data-poor seafloor regions. Habitat classification can support marine spatial planning and inform decision-making processes in such areas. We present a regional, top–down, broad-scale, seafloor-habitat classification for the Clarion-Clipperton Fracture Zone (CCZ), an area targeted for future polymetallic nodule mining in abyssal waters in the equatorial Pacific Ocean. Our classification uses non-hierarchical, k-medoids clustering to combine environmental correlates of faunal distributions in the region. The classification uses topographic variables, particulate organic carbon flux to the seafloor, and is the first to use nodule abundance as a habitat variable. Twenty-four habitat classes are identified, with large expanses of abyssal plain and smaller classes with varying topography, food supply, and substrata. We then assess habitat representativity of the current network of protected areas (called Areas of Particular Environmental Interest) in the CCZ. Several habitat classes with high nodule abundance are common in mining exploration claims, but currently receive little to no protection in APEIs. There are several large unmanaged areas containing high nodule abundance on the periphery of the CCZ, as well as smaller unmanaged areas within the central CCZ, that could be considered for protection from mining to improve habitat representativity and safeguard regional biodiversity.
This paper proposes institutional innovations to advance a transparent monitoring system for the environmental impacts from mineral development on the deep seabed beyond national jurisdictions managed by the International Seabed Authority (ISA). Using a literature review, ISA’s regulations, and five cases of other environmental monitoring of the deep sea, this study observes that ISA’s environmental monitoring system for exploration and exploitation currently lacks critical elements to facilitate transparency. Insufficient compliance reporting and review systems, as well as limited access to information by stakeholders, lower the system’s effectiveness. ISA has not developed adequate mechanisms to support effective multinational collaboration in monitoring. The ISA monitoring system without these characteristics may not be sufficiently adaptive to allow detection and management of environmental changes in the deep seabed. This study suggests 15 institutional recommendations to ISA in order to enhance transparency for monitoring nodule mining in the Central Pacific deep seabed. Principal recommendations include establishing compliance review committees independent of ISA governing bodies, implementing collective monitoring and reporting by adjacent contractors, and reconsidering the centralized decision-making authority by the Secretary-General to improve confidentiality.
The potential for imminent abyssal polymetallic nodule exploitation has raised considerable scientific attention. The interface between the targeted nodule resource and sediment in this unusual mosaic habitat promotes the development of some of the most biologically diverse communities in the abyss. However, the ecology of these remote ecosystems is still poorly understood, so it is unclear to what extent and timescale these ecosystems will be affected by, and could recover from, mining disturbance. Using data inferred from seafloor photo-mosaics, we show that the effects of simulated mining impacts, induced during the “DISturbance and reCOLonization experiment” (DISCOL) conducted in 1989, were still evident in the megabenthos of the Peru Basin after 26 years. Suspension-feeder presence remained significantly reduced in disturbed areas, while deposit-feeders showed no diminished presence in disturbed areas, for the first time since the experiment began. Nevertheless, we found significantly lower heterogeneity diversity in disturbed areas and markedly distinct faunal compositions along different disturbance levels. If the results of this experiment at DISCOL can be extrapolated to the Clarion-Clipperton Zone, the impacts of polymetallic nodule mining there may be greater than expected, and could potentially lead to an irreversible loss of some ecosystem functions, especially in directly disturbed areas.
Manganese nodules contain economically valuable metals which may be mined in the future to supply metals to a growing world population. Thus far, environmental research has focused mainly on impacts occurring at the seafloor or in the water column but largely neglected any impacts caused above the sea surface. Emissions of greenhouse gases and other air pollutants contribute to, inter alia, global warming, acidification and photochemical ozone formation, which all negatively affect ecosystems and humans. We quantify the annual fuel consumption and emissions associated with a potential nodule mining operation in the Clarion-Clipperton Zone with an annual production of 3 million dry tons. We base the assessment on publicly-accessible energy demand estimates from three different studies and complement this with a calculation of the fuel demand and emissions of nodule transport scenarios to three different destinations. The global warming, acidification and photochemical ozone formation potentials range between 82,600–482,000 t CO2-equivalent (-eq.), 1,880–11,197 t SO2-eq., and 1,390–8,734 t NOx-eq., respectively, depending on factors including the engine loads, specific fuel oil consumption and transport speeds. We then discuss the regulatory dimension surrounding the topic. As three separate regimes (climate change, deep-sea mining and shipping) are applicable, we analyze the applicable framework and provide an outlook for the future regulation of DSM-related GHG emissions.
The world's first deep-sea mining (DSM) project has witnessed the commercial development of plans to extract copper and gold from deposits 1600m deep in the waters of offshore Papua New Guinea (PNG). Viewed as ‘experimental’ and ‘uncertain’ by its critics, it has afforded both controversy and resistance. This paper critically analyses the multifarious strategies that the industry's apologists use in order to respond to environmental concerns and to manufacture consent. It draws upon extensive primary data conducted at the ‘Solwara 1’ DSM project in Papua New Guinea in order to highlight three different ways in which DSM is legitimised by its contractor, Nautilus Minerals. All of these draw upon the spatio-temporal materialities of the deep-sea. In the first instance, the corporation shifts its responsibility away from the ‘social’ realm, instead placing it on a ‘nature’ that is constructed as violent and unruly. Secondly, it emphasises both the relatively short life-span and areal footprint of its mining operations. Finally, Nautilus emphasises the ‘placelessness’ and remoteness of the deep-ocean by claiming that its operations ‘have no human impact’ despite the presence of proximate small island communities. These strategies are part of a corporate understanding that is aware, rather than ignorant, of contemporary geopolitical formations that include geologic and non-human actors and operate dynamically in space and time. Taken together, the paper shows the ways in which resource spatio-temporalities come to matter for the types of CSR practices and narratives that emerge in the context of deep-ocean space and time.
Deep-sea mining (DSM) may become a significant stressor on the marine environment. The DSM industry should demonstrate transparently its commitment to preventing serious harm to the environment by complying with legal requirements, using environmental good practice, and minimizing environmental impacts. Here existing environmental management approaches relevant to DSM that can be used to improve performance are identified and detailed. DSM is still predominantly in the planning stage and will face some unique challenges but there is considerable environmental management experience in existing related industries. International good practice has been suggested for DSM by bodies such as the Pacific Community and the International Marine Minerals Society. The inherent uncertainty in DSM presents challenges, but it can be addressed by collection of environmental information, area-based/spatial management, the precautionary approach and adaptive management. Tools exist for regional and strategic management, which have already begun to be introduced by the International Seabed Authority, for example in the Clarion-Clipperton Zone. Project specific environmental management, through environmental impact assessment, baseline assessment, monitoring, mitigation and environmental management planning, will be critical to identify and reduce potential impacts. In addition, extractive companies’ internal management may be optimised to improve performance by emphasising sustainability at a high level in the company, improving transparency and reporting and introducing environmental management systems. The DSM industry and its regulators have the potential to select and optimize recognised and documented effective practices and adapt them, greatly improving the environmental performance of this new industry.
Environmental Impact Assessment (EIA) is an important process for evaluating the effects of development, and to assist decisions to effectively manage potential deep-sea mining (DSM). However, although EIA is a widely used and accepted approach, there has been considerable debate over its effectiveness. In this paper, we summarise some of the key problems raised by previous EIA reviews, as well as examining several EIAs carried out in recent years for DSM, and highlight issues identified by management agencies. Scientific shortcomings are discussed, and recommendations provided on ways to improve performance. These include inadequate baseline data, insufficient detail of the mining operation, insufficient synthesis of data and the ecosystem approach, poor assessment and consideration of uncertainty, inadequate assessment of indirect impacts, inadequate treatment of cumulative impacts, insufficient risk assessment, and consideration of linkages between EIA and other management plans. The focus of the paper is on scientific limitations, but we also consider some aspects of their application to elements of process and policy.
Mining impacts will affect local populations to different degrees. Impacts range from removal of habitats and possible energy sources to pollution and smaller-scale alterations in local habitats that, depending on the degree of disturbance, can lead to extinction of local communities. While there is a shortage or even lack of studies investigating impacts that resemble those caused by actual mining activity, the information available on the potential long-lasting impacts of seabed mining emphasise the need for effective environmental management plans. These plans should include efforts to mitigate deep-sea mining impact such as avoidance, minimisation and potentially restoration actions, to maintain or encourage reinstatement of a resilient ecosystem. A wide range of mitigation and restoration actions for deep-sea ecosystems at risk were addressed. From an ecological point of view, the designation of set-aside areas (refuges) is of utmost importance as it appears to be the most comprehensive and precautionary approach, both for well-known and lesser studied areas. Other actions range from the deployment of artificial substrates to enhance faunal colonisation and survival to habitat recreation, artificial eutrophication, but also spatial and temporal management of mining operations, as well as optimising mining machine construction to minimise plume size on the sea floor, toxicity of the return plume and sediment compression. No single action will suffice to allow an ecosystem to recover, instead combined mitigation/restoration actions need to be considered, which will depend on the specific characteristics of the different mining habitats and the resources hosted (polymetallic sulphides, polymetallic nodules and cobalt-rich ferromanganese crusts). However, there is a lack of practical experience regarding mitigation and restoration actions following mining impacts, which severely hamper their predictability and estimation of their possible effect and success. We propose an extensive list of actions that could be considered as recommendations for best environmental practice. The list is not restricted and, depending on the characteristics of the site, additional actions can be considered. For all actions presented here, further research is necessary to fully encompass their potential and contribution to possible mitigation or restoration of the ecosystem.
Commercial seabed mining seems imminent, highlighting the urgent need for coherent, effective policy to safeguard the marine environment. Reconciling seabed mining with the United Nations Sustainable Development Goals will be difficult because minerals extraction will have irreversible consequences that could lead to the loss of habitats, species and ecosystems services. A dialog needs to take place around social, cultural, environmental and economic costs and benefits. Governance of human interactions with the seabed is fragmented and lacks transparency, with a heavy focus on facilitating exploitation rather than ensuring protection. In the light of high uncertainties and high stakes, we present a critical review of proposed policy options for the regulation of seabed mining activities, recommend actions to improve seabed governance and outline the alternatives to mining fragile deep-sea ecosystems.