Marine Mineral Research Articles

Extraction of various valuable elements from oceanic manganese nodules using coal gasification slag via reduction roasting-acid leaching process

In line with the concept of coal gasification slag treatment and marine mineral exploitation, this research proposed a residual carbon roasting-acid leaching process to extract various valuable metals from oceanic manganese nodules. The residual carbon obtained from coal gasification coarse slag was enriched via gravity separation without chemical treatment, and this carbon-high product served as an inexpensive reducing agent. The feasibility of carbon-high reduction of oceanic manganese nodules was explored using a thermogravimetric-mass spectrometric coupling system and thermodynamic analysis. The influence of mass ratio, roasting time, and roasting temperature on the reduction effect of oceanic manganese nodules was examined, and optimal conditions were determined through orthogonal tests. The results demonstrated that under the optimized conditions, the leaching rate of Mn exceeded 98%, and that of Cu, Co, and Ni exceeded 96%. The reduction and leaching processes were elucidated at the crystal scale through various ways. Finally, a comprehensive process flow diagram was summarized for the extraction of various valuable metals from oceanic manganese nodules using the residual carbon roasting-acid leaching process. This research will pave the way for the design of cost-effective and sustainable roasting reductants and reduction roasting processes for manganese oxide ores, contributing to economic and environmental benefits.

An initial spatial conflict analysis for potential deep-sea mining of marine minerals in U.S. Federal Waters

Demand for critical minerals is projected to double or even triple by 2030 as the global energy and transportation sectors transition away from fossil fuels toward renewable energy. This anticipated demand raises interest in new critical mineral resources, including marine minerals, to supplement future supplies. While the environmental benefits of transitioning to green energy are many, there are inherent environmental costs. In this study, we compiled broad-scale datasets of prominent environmental features and human uses within four deep ocean regions of the U.S. Exclusive Economic Zone where marine minerals are predicted to occur, called prospective regions: they are the Blake Plateau, the Hawaiian Islands, Offshore California, and the Gulf of Alaska. We generated a normalized metric to score regions based on the co-occurrence of either environmental or human use variables within hexagonal grid cells, allowing us to assess the occurrence intensity and spatial patterns of environmental and/or human use variables within each region. Driven by the presence of threatened species and total species richness, the Blake Plateau and the Hawaiian Islands have the highest environmental occurrence scores, followed by Offshore California and the Gulf of Alaska. Offshore California is the busiest shipping region, followed by the Blake Plateau, the Gulf of Alaska and Hawaiian Islands, and subsea cables are densest in Offshore California, followed by Gulf of Alaska and Hawaiian Islands. The Gulf of Alaska has the largest reported fisheries landings. The sensitivities of biota and human uses to mining are highest for benthic or sessile species and infrastructure on or near ferromanganese crusts or manganese nodules that would be directly and physically altered through crust extraction or nodule removal. This study illustrates the usefulness of comprehensive, spatially explicit risk assessments to inform deep sea mining management and minimize ecological harm and human use conflicts. We assert that the relatively straightforward GIS-based methodology tested here can be applied and iterated upon elsewhere.

Control of marine biodegradation of an aliphatic polyester using endospores

Currently, commercially available biodegradable plastics are not well controlled in terms of the rate and timing of biodegradation. To overcome these challenges, several methods have been proposed. Herein, we propose a new system for controlling the onset and degradation rate of plastic biodegradation by encapsulating endospores of degrading microorganisms into plastics with typically slow biodegradation rates. Endospores of bacterial strain YKCMOAS1 germinated and initiated biodegradation when triggered by surface wear of an aliphatic biodegradable polyester, poly(ethylene succinate) (PESu). The weight loss rate of endospore-containing PESu film immersed in seawater was approximately 7-fold faster than that of PESu film without endospores. The YKCMOAS1 strain used in this study grew in seawater and showed PESu film-degrading activity in a marine mineral medium. Based on the weight loss rate of the endospore-containing PESu films, they were estimated to have completely degraded into water-soluble compounds within approximately 400 d Meanwhile, the biochemical oxygen demand degradation test revealed that the water-soluble products from PESu, which were produced by the vegetative cells were completely biodegraded within 10 d Taken together, these results indicate that material hydrolysis by bacterial strain YKCMOAS1 was triggered by material wear, followed by rapid biodegradation. This is the first report of the application of bioaugmentation to the stable expression of environmental degradation of biodegradable plastics. These results might provide insight into the design concept of novel biodegradable plastics that not only exhibit environmentally independent biodegradation, but also allow control of the onset time.

Another Look at Marine Minerals

Abstract Deep-sea mining is taking another step closer to reality. Early leases for exploration in the central Pacific manganese nodule fields and elsewhere in the oceans are coming to an end, and contractors are faced with a choice—extend the licenses to continue exploration or apply to mine the deposits they have found. The first 15-year licenses were originally signed into effect by the International Seabed Authority (ISA) in 2001 and began to expire in 2016. With no operations in a position to commence mining and, more importantly, no regulations in place to allow it, most exploration licenses were simply renewed. Eight of the original licenses were extended for five more years, some twice, and new licenses have been granted. Today, there are 31 contracts for exploration: 19 for manganese nodules, 7 for sea-floor massive sulfides, and 5 for Co-rich crusts. The first contract for massive sulfide exploration expires in 2026; the first for Co-rich crusts expires in 2029. Meanwhile, there is strong interest from a number of countries in the mineral resource potential of their exclusive economic zones (EEZs), particularly Japan and Norway. Against this backdrop of rapidly shifting exploration activity, it may be time to take another look at marine minerals as a resource for the future. In a report entitled “The Future of the Ocean Economy by 2030,” the Organization for Economic Cooperation and Development (OECD) asked, “What new developments could result in a complete revision of offshore mineral potential?” For most parts of the oceans, the answer to this question is plagued by inadequate mapping and a lack of geologic knowledge as a basis for assessing the resources. However, new approaches to exploration are emerging, and recent discoveries, such as on the continental shelf and beneath the cover of sediment, are changing our view of the resource potential.

Marine Power System Thrust Distribution Based on Grey Wolf Optimization Algorithm

The ocean is rich in Marine minerals and other resources. To make effective use of these resources, it is indispensable to have good resource exploration and mining equipment, and more attention is paid to ship control methods. A dynamic positioning system can control the position and head of the ship. Thrust distribution is an important part of the DP system, and its performance will have a significant influence on the reliability and accuracy of the system. To settle this matter, a ship thrust distribution method based on the grey Wolf optimization algorithm is offered. Aiming at the research of thrust distribution of ship DP system, a dynamic positioning simulation model is established, which is combined with the grey Wolf optimization algorithm. The results show that the control effect is good.

An underwater near-infrared spectral continuum robot as a tool for in situ detection and classification

Near-infrared spectral data can be used as a critical indicator for the quantitative analysis of sample molecules. However, water can strongly absorb infrared radiation, and the infrared spectrum of underwater targets cannot be directly obtained. In this study, we propose an underwater in situ near-infrared spectroscopy (875 nm–2350 nm) detection system that utilizes the structure of an optical fiber probe housed in a manipulator to perform approaching observation for underwater samples and uses compressed air to blow away the water between the probe and the target. To demonstrate the system validity, we built a set of optical fiber spectrometers embedded in the robotic arm of the traction lines tendon that can provide an air-blowing function to detect the reflection spectra of 15 minerals underwater and constructed the corresponding spectral database. Based on the above spectral database, an automated spectral identification algorithm was used to classify substances, and the SVM classification accuracy could reach 97 %. The experimental results confirm that our system is stable and can be used for infrared spectral detection of underwater mineral reflection. The relevant spectral data can be used to realize high-precision automatic mineral identification. Due to the compact structure of the system, the system will be able to carry out marine mineral detection in the future.

Formation and dissociation of CO2 hydrates in porous media in the presence of clay suspensions

CO2 storage in marine sediments in the form of solid hydrates with high storage capacity and stability is a promising approach for the control of greenhouse gas pollution. Specifically, clay is much abundant in marine minerals, and multiple forces exist between fine clay particles suspended in seawater, significantly affecting the hydrate formation and dissociation behavior. This study investigates the phase transition performance of CO2 hydrates with or without montmorillonite and illite particles using low-field nuclear magnetic resonance. According to the DLVO theory, the total interaction potential between the montmorillonite particles reached 358 kbT, with that between illite particles being only 43 kbT. It was found that water in large pores was preferentially consumed during hydrate formation, with clay particles significantly promoting the conversion of water into hydrate. In seawater-montmorillonite and seawater-illite solutions, a higher number of water molecules was detected in the small and medium pores, respectively. Notably, the initial pore structure changed upon hydrate dissociation, with more medium pores formed. This effect was enhanced in the seawater-montmorillonite solutions and weakened in seawater-illite solutions. The findings could further clarify the formation and dissociation kinetics of CO2 hydrates in the presence of clay particles, as well as the geological structure evolution and safety of CO2 hydrate storage under the seafloor.

Influences of digitalization on sustaining marine minerals: A path toward sustainable blue economy

This study's target is to experimentally discover the influence of the digital revolution, both for the public and private industries, on the sustainable development of marine mineral resources. As part of this initiative, it aims to demonstrate its influence on the development of a sustainable blue economy. Several measures are used to measure the blue economy sustainability of European countries. These measures include value added at the factor costs of crude oil extraction; gas extraction; activities related to oil and gas production; crushed stone or rock mining, clay or kaolin mining; salt extraction; as well as supporting activities engaged in the mining and quarry operations. We also use various indicators to capture digitalization performance in both the private and public sectors. During the 2009–2020 period, the European region will benefit from digital transformation in terms of improving marine minerals sustainability. Nevertheless, this effect is likely to be more apparent over the long term. Particularly, over a longer period, some aspects of digitalization in public services do have an empirically measurable effect on any components of marine minerals.

A review on theory, modeling, inversion, and application of self-potential in marine mineral exploration

The self-potential (SP) method is one of the passive geophysical exploration techniques, which employs measurements of naturally occurring electric potential differences on the ground surface and in boreholes or (sea-)water due to causative sources from electrochemical, electrokinetic, and thermoelectric mechanisms. SP signals are directly related to groundwater flow and (electro-)chemical gradient. There has been increasing interest in the application of SP measurements in mineral exploration, environmental surveys, and hydrogeophysical problems. This review focuses primarily on the theory concerning the causative source mechanism, numerical modeling, and inversion and interpretation of SP signals related to ore bodies and applications in mineral exploration. Three field examples focusing on seafloor sulfide deposits exploration are summarized to show the application effect of SP measurements in marine mineral exploration. This study would be helpful to investigating the use of SP surveys in ore prospecting, especially in marine environments.

Biodiversity, biogeography, and connectivity of polychaetes in the world's largest marine minerals exploration frontier

AbstractAimThe abyssal Clarion‐Clipperton Zone (CCZ), Pacific Ocean, is an area of commercial importance owing to the growing interest in mining high‐grade polymetallic nodules at the seafloor for battery metals. Research into the spatial patterns of faunal diversity, composition, and population connectivity is needed to better understand the ecological impacts of potential resource extraction. Here, a DNA taxonomy approach is used to investigate regional‐scale patterns of taxonomic and phylogenetic alpha and beta diversity, and genetic connectivity, of the dominant macrofaunal group (annelids) across a 6 million km2 region of the abyssal seafloor.LocationThe abyssal seafloor (3932–5055 m depth) of the Clarion‐Clipperton Zone, equatorial Pacific Ocean.MethodsWe used a combination of new and published barcode data to study 1866 polychaete specimens using molecular species delimitation. Both phylogenetic and taxonomic alpha and beta diversity metrics were used to analyse spatial patterns of biodiversity. Connectivity analyses were based on haplotype distributions for a subset of the studied taxa.ResultsDNA taxonomy identified 291–314 polychaete species from the COI and 16S datasets respectively. Taxonomic and phylogenetic beta diversity between sites were relatively high and mostly explained by lineage turnover. Over half of pairwise comparisons were more phylogenetically distinct than expected based on their taxonomic diversity. Connectivity analyses in abundant, broadly distributed taxa suggest an absence of genetic structuring driven by geographical location.Main ConclusionsSpecies diversity in abyssal Pacific polychaetes is high relative to other deep‐sea regions. Results suggest that environmental filtering, where the environment selects against certain species, may play a significant role in regulating spatial patterns of biodiversity in the CCZ. A core group of widespread species have diverse haplotypes but are well connected over broad distances. Our data suggest that the high environmental and faunal heterogeneity of the CCZ should be considered in future policy decisions.

Nano-mineralogy and growth environment of Fe-Mn polymetallic crusts and nodules from the South China Sea

Fe-Mn polymetallic crusts and nodules from the South China Sea (SCS) consist of submarine ferromanganese (Fe-Mn) oxide precipitates, and represent important marine mineral resource with substantial economic and scientific research value. Previous studies on the SCS polymetallic crusts and nodules were mainly focused on their bulk mineralogy and geochemistry, whilst research on their nanomineralogy is still lacking. In this study, transmission electron microscopy (TEM), Raman spectroscopic mapping, and in-situ micro X-ray diffraction (XRD) analysis were conducted on the nano-mineralogy of the SCS polymetallic crusts and nodules. It is found that the SCS polymetallic crusts and nodules consist mainly of layered/columnar/mottled nano-phase Fe-Mn minerals and detritus such as quartz, feldspar, and clays. Also, an independent Ti mineral phase has been documented, and the mineralogical analysis reveals the transformation from vernadite to birnessite and todorokite. Titanium forms colloidal minerals in seawater and precipitates into the crusts and nodules with other colloids, such as FeOOH and Si-Al. Vernadite and birnessite can be transformed to todorokite with stable structure under sub-oxic conditions. Therefore, the SCS polymetallic crusts and nodules were formed in a short period of sub-oxic environment and diagenetic process, and the transformation can influence the enrichment of Ni and other metals during the crust/nodule growth.

MINDeSEA: exploring seabed mineral deposits in European seas, metallogeny and geological potential for strategic and critical raw materials

Abstract This study summarizes a compilation of studies and cartographical work on seabed mineral deposit types in pan-European seas developed under the GeoERA-MINDeSEA project. In total, 692 occurrences and 1194 individual mineral samples of volcanogenic massive sulfides and hydrothermal mineralization, ferromanganese crusts, phosphorites, marine placer deposits, polymetallic nodules, and their associated strategic and critical raw material (CRM) elements have been characterized. The GeoERA-MINDeSEA project has been built based on extensive studies carried out previously, which include geophysical surveys, sampling stations, underwater photography and remotely operated vehicle (ROV) surveys, and mineralogical, geochemical and isotopic studies. This study develops pan-European and national databases, and expands strategic and CRM knowledge through a compilation of mineral potential and metallogenic studies of CRM resources in European seas. For the first time, the GeoERA-MINDeSEA portal publishes harmonized marine mineral resource information, case studies and maps, and identifies potential areas for responsible resource exploration and extraction, strategic management, and marine spatial planning. This study also provides recommendations for future target areas, studies and standards to be used across Europe as part of this project.

Scientific potential of ukraine in marine research areas

The study of the national scientific potential in the marine field was carried out on the basis of the analysis of the data of the R&D registration database and dissertations of UkrISTEI for the period 2017–2021, the state of training of specialists in the Higher Education and Research Institute of the Ministry of Education and Science in the fields of marine research in six areas of marine research (1. Ecology of rivers, seas, oceans, coastal areas, ecological consequences of human activity, 2. Fisheries, 3. Infrastructure of water management, 4. Geology and development of marine mineral and energy resources, 5. Production of machines, equipment, means, 6. Logistics) by indicators: quantitative assessment of R&D and dissertations in general in all spheres, as well as in the cross-section of spheres and thematic directions, organizations – performers of R&D (grouped according to the spheres of management to which they belong); dynamics of the number of research and development projects and dissertations, growth rates of the total number of research and development projects and dissertations in thematic areas of marine research; quantitative assessment of the specialties for which scientific and engineering personnel are trained on marine issues. The article provides not only a general analysis of the state of scientific research, dissertation activity of scientists and training of qualified specialists in the field of marine research, but also emphasizes the main, above-mentioned, areas related to water and maritime complexes. According to the results of the analysis of R&D and dissertations, the most relevant thematic directions of marine research were determined, which include: 1.1. Ecosystem of rivers, seas, oceans, 2.3. Aquaculture, 3.2. Hydrotechnical and hydromelioration facilities, 4.2. Development of marine mineral resources, 6.2. Shipbuilding.

Global trends analysis of science development in the areas of marine research

The world ocean plays an extremely important role in the life of mankind, has crucial importance for the accelerated development of the world economy, and is an important factor in geopolitics. Despite the huge potential of self-regulation, its condition is rapidly deteriorating today, mostly with the participation of humans. The problem of a more complete understanding of the role of the ocean in the functioning of the Earth system, the interaction of human and the ocean acquires special importance in these conditions, which requires appropriate research in many fields of science. One of the ways to identify gaps in knowledge about the world ocean can be a comprehensive analysis of the global array of scientific works in the areas of marine research. The global trends analysis of science development in the areas of marine research was carried out on the basis of data from the international platforms Web of Science and Research4Life. The analysis was carried out according to six conventional areas of marine research: (1. Ecology of rivers, seas, oceans, coastal areas, ecological consequences of human activity; 2. Fishing and aquaculture, water use activities; 3. Marine infrastructure; 4. Geology and development of marine mineral and energy resources; 5. Production of machines and equipment; 6. Management of water (sea, ocean, river) resources by indicators of publication number, citation number, growth rates of these indicators. According to the results of the scientometric publication analysis, the most relevant areas of marine research were determined, which include: “microplastics”, “biodiversity”, “aquatic biological resources”, “marine species”, “aquaculture”, “artificial intelligence”, “Internet of Things”, “green” and “smart” ports, “offshore wind farms”, “corrosion protection”, “blue economy”, which is confirmed by the results of the analysis. The world experience deserves special attention, including Ukraine’s scientific developments on protecting the ocean from plastic. The scientists’ list of technologies currently in use or being developed to prevent or collect plastic pollution includes 52 technologies.

First record of sponge-associated deep-sea polychaete (Polynoidae: Bathymoorea) on the ultraslow-spreading Southwest Indian Ridge

We identified a rarely found deep-sea polynoid polychaete Bathymoorea, in association with a hexactinellid sponge (Dictyaulus sp.) during our marine mineral exploration expedition in the Southwest Indian Ridge (SWIR). The genus Bathymoorea appears to be restricted to the deep sea and currently includes two valid species described from the northeast Pacific region. The polychaete specimen was part of the megabenthos sample collected in a benthic sledge associated with a sponge from a water depth of 2358 m. The sponge-associated Bathymoorea is described and illustrated based on a single specimen and is the first occurrence of the genus Bathymoorea in the Southwest Indian Ocean. The morphological characteristics and phylogenetic analysis of Bathymoorea using Cytochrome C Oxidase subunit 1 (COI), 16S, and 18S gene sequences confirmed the monophyly clade for the SWIR specimen. Our finding extends the known geographical distribution of the genus Bathymoorea to the Indian Ocean.

Application of multi-criteria decision making to sustainable deep-sea mining vertical transport plans

Ever since the concept of deep-sea mining was first described, the prospect of deep-sea mining testing and monitoring has proved to be a subject of great interest. Despite the considerable research and commercial attention given to developing deep-sea mining strategies, no previous study has looked explicitly at the sustainability of deep-sea mining transport plans. The objective of this paper, therefore, is to evaluate the sustainability of deep-sea mining vertical transport plans, using the methodology of fuzzy analytic network process. Major criteria for evaluating deep-sea mining vertical transport plans can be divided into technological, economic, environmental, and social components, each containing both qualitative and quantitative attributes. Weights for each criterion are determined through a questionnaire survey, completed by experts in the fields of environmental impact, policy making, marine mining, project sustainability consultancy and project economic profitability research. The research presented in this paper could be used directly in the sustainability assessment of upcoming deep-sea mining projects, furtherly contributing to the industrialization of the entire deep-sea mining industry.

High resolution geomorphological classification of benthic structure on the Western Pacific Seamount

The benthic structure of seamounts is critical for understanding the ecological environment and for assessing the influence of resource exploitation. However, the characteristics of the benthic structure of the seamount, especially for guyot, are still far from being clearly understood. For the first time, we carried out detailed hydroacoustic mapping in conjunction with surficial sediment sampling and underwater video recording to investigate the geomorphical and biological characteristics of Pallada Guyot in the Western Pacific Ocean (WPO). We utilized the Benthic Terrain Modeler (BTM) as an initial step to describe the detailed benthic structures and then classify the textural seabed according to backscatter images and sediment samples. We further discussed the relationship between geomorphology and the occurrence of benthic megafauna from video images. The results revealed that 13 classes of benthic structural zones were differentiated, and the dominant zones were flat abyssal plains, where the number and size of megafauna were smaller than those on the flank and flat-topped areas. The second most notable feature is the flat top, where sea cucumbers, starfish, fish, and shrimp have higher biomass and diversity. In the flank region, which is characterized by complex and extensive current-scoured ridges and depressions, sponges and corals are distributed in high-relief bedrocks. We also found that the maximum water depth where cold-water corals develop is 2,250 m. The sponge grounds appear in a marked bathymetric belt (1,800–2,150 m), which is shallower than that on a tropical seamount (2,500–3,000 m) located in the northeastern Atlantic. The findings of this study contribute to understanding the geomorphological drivers and biogeography of WPO seamounts and provide a reference for identifying priority areas for improved marine mineral planning in WPO areas.

A transient solution on potential equation of diffusion type with time-varying coefficients

Research on hydrothermal sulphide ore of marine mineral resources exploration is hot recently. According to the general solution of first order differential equation, Laplace transform is used to transform the linear homogeneous differential equation of second order variable coefficient into first order differential equation of complex domain. The general solution of the first-order differential equations in complex domain is similarly obtained without regard for the difference between real domains and complex domains. Further more, the general solutions are deduced to the second order linear differential equations with variable coefficients. Then it is used to solve the thermoelectric coupling electric field model in oceanic strike exploration; A closed analytical solution with integral form of elementary functions is obtained to the simplified diffusion electric field potential model. To get an explicit solution, with the help of MAPLE software, the general solution of the linear combination of Kummer functions is obtained. This research has theoretical significance for the engineering implementation of the frequency domain induced dipole drag system.

Vertical Conflict on Sea Sand Mining Activities in Lampung; Law Enforcement and Sociological Approach

The inadequate enforcement of laws related to marine sand mining in Lampung Province leads to significant issues, including high social conflict, damage to environmental ecosystems, and potential ecological disasters. Moreover, the overlap in the allocation of permits complicates the management of coastal areas and small islands. This article aims to analyze law enforcement against marine sand mining activities that conflict with the community in Lampung Province, using a normative empirical approach and qualitative analysis model, with inputs from WALHI’s Irfan Tri Musri and several miners. The research finds that effective law enforcement must encompass law formulation, application, and execution stages and emphasizes the need for robust prevention efforts through optimal use of monitoring and licensing instruments. Additionally, the proper implementation of Lampung Province Regulation Number 1 of 2018, concerning Zoning Plans for Coastal Areas and Small Islands, is vital as it addresses community interests effectively. The most significant barriers to law enforcement are legislative shortcomings and the reluctance of officers to strictly enforce sea sand mining laws.

Volcanically hosted venting with indications of ultramafic influence at Aurora hydrothermal field on Gakkel Ridge

The Aurora hydrothermal system, Arctic Ocean, hosts active submarine venting within an extensive field of relict mineral deposits. Here we show the site is associated with a neovolcanic mound located within the Gakkel Ridge rift-valley floor, but deep-tow camera and sidescan surveys reveal the site to be ≥100 m across—unusually large for a volcanically hosted vent on a slow-spreading ridge and more comparable to tectonically hosted systems that require large time-integrated heat-fluxes to form. The hydrothermal plume emanating from Aurora exhibits much higher dissolved CH4/Mn values than typical basalt-hosted hydrothermal systems and, instead, closely resembles those of high-temperature ultramafic-influenced vents at slow-spreading ridges. We hypothesize that deep-penetrating fluid circulation may have sustained the prolonged venting evident at the Aurora hydrothermal field with a hydrothermal convection cell that can access ultramafic lithologies underlying anomalously thin ocean crust at this ultraslow spreading ridge setting. Our findings have implications for ultra-slow ridge cooling, global marine mineral distributions, and the diversity of geologic settings that can host abiotic organic synthesis - pertinent to the search for life beyond Earth.