Search Results (13)

In the field of ocean observation, we often face the challenge of the contradiction between the vast ocean environment and limited ocean sensor observations, resulting in significant sparsity in the acquired ocean sensor data. This sparse ocean sensor data typically exhibits characteristics such as discrete spatial distribution, discontinuous observation time, and vertical stratification with water depth variations. Current methods primarily employ rule-based quality control, time series modeling, or traditional graph neural networks for processing. This paper addresses the characteristics of sparse ocean sensor data, building upon these methods by further utilizing topological correlation and hierarchical feature modeling on a topological basis. It proposes a depth-aware heterogeneous spatiotemporal graph neural network (DAHSGNN) to achieve efficient anomaly detection and data correction for this type of data. DAHSGNN integrates discrete observation data along the depth axis using a local graph construction method. It employs hierarchical feature engineering to characterize the vertical stratification of the ocean. A Gaussian Hidden Markov Model is used to segment the water layers, and intra- and inter-layer trend features are extracted using a water layer probability-guided Transformer encoder. Then, a bidirectional long short-term memory deep sequence encoder captures the local dynamic context, thereby achieving fine-grained modeling of the ocean’s vertical stratification features. Finally, a heterogeneous graph autoencoder is used to reconstruct the site-level data distribution. Experiments were conducted using multiple environmental variables from the International Seabed Authority (ISA) DeepData database. Results show that DAHSGNN exhibits good cross-variable generalization ability, achieves higher reconstruction accuracy than baseline methods, and significantly improves anomaly detection performance. Full article

Marine fish populations have suffered the consequences of overfishing for a long time, leading to a loss in biodiversity. Traditional methods have been historically used to survey fish diversity but are limited to commercial species, particularly on the high seas. Environmental DNA (eDNA) has been successfully used to monitor biodiversity in aquatic environments. In this study, we monitored fish diversity in the Clarion–Clipperton Zone (CCZ) of the Eastern Pacific Ocean using eDNA metabarcoding. Our results identified 2 classes, 35 orders, 64 families, and 87 genera. The genera Mugil, Scomberomorus, and Scomber had high relative abundance in the mesopelagic and demersal zone. Fish diversity varied with sampling sites, and the greatest number of species was found at a depth of 2500 m. Environmental changes drove fish aggregation, and our results indicated that Chla was negatively correlated with fish communities, while DO was positively correlated with fish communities. This study released the fish diversity pattern and the effects of the environment in the CCZ, which would provide useful information for biodiversity management and an environmental baseline for the International Seabed Authority. Full article

The deep seabed mining regime is composed of international legislation and domestic counterparts. International legislation emanates from the International Seabed Authority (ISA) under the mandate of UNCLOS, which is currently in the accelerated process of being drafted for exploitation activities to meet a deadline of July 2023. In contrast, the development of domestic law in ISA Member States has been relatively slow, and this risks failure to fulfill their obligation of “responsibility to ensure” concluded in the advisory opinion in 2011. This possible failure is partly due to States’ different understanding of their obligation to impose more stringent environmental conditions on contractors in their domestic laws than those specified in the Mining Code adopted by ISA. This paper argues that Annex III, article 21(3) of the UNCLOS requires States to adopt a two-tier approach in their national legislation—minimal and optimal levels. The minimal level requires a sponsoring State to comply with the Mining Code’s fundamental requirements while reaching the optimal level means that the sponsoring State tries its best to establish more stringent standards than the Mining Code. Adopting more stringent requirements may be realized by adopting higher or stricter standards or inserting more details in the national legislation. Moreover, all ISA Member States are, including developing States, obliged to meet the minimum line and encouraged to move towards the optimal one Full article

Although commercial deep seabed mining could provide the international community with new sources of metals and minerals, it can potentially cause adverse effects on the marine environment and biodiversity of the Area. To date, insufficient scientific knowledge has been obtained about the complex deep seabed ecosystems and the detailed impacts of deep seabed mining. The International Seabed Authority has begun to make provisions for exploiting mineral resources and related environmental protection requirements. The draft exploitation regulations take precautionary approaches such as stipulating rules, including environmental standards and guidelines, environment impact assessment, environmental management and monitoring plan, and regional environmental management plan. However, there are still apparent differences and controversies about these rules between States. This article elaborates on the evolution and content of drafted rules and explores the manifested specific divergences and interest conflicts in formulating these rules. Implementing precautionary approaches requires balancing potential serious environmental risks, available scientific evidence, and cost-effectiveness. This article also explores the essential requirements of taking precautionary approaches for governing commercial deep seabed mining. The ISA, sponsoring States, Contractors, scientists, experts, and public all play roles in the governance of imminent commercial deep seabed mining. Strengthening multi-subject participation in the ISA’s law-making process for deep seabed environmental protection can be conducive to promoting consensus on taking precautionary approaches to govern commercial deep seabed mining. Full article

It is now scientifically proven that specific categories of submarine raw materials, especially deep seas such as Mn and Fe oxides, polymetallic nodules, polymetallic sulfides (SMS) and some deep-sea sediment categories, can have significant potential for some critical metals for future use. One characteristic of these deposits is that although they often have lower Rare Earth Elements (REE) contents than the well-known land deposits, their sizes are very extensive, much higher than the land-based deposits. Therefore, the future use of these submarine formations as a source of REEs can be an important alternative to the exponentially growing demand for these strategic metals. These formations have significant potential to be a source of REEs in the markets when they are extracted as byproducts of the most critical metals such as copper, nickel, cobalt and manganese, from Mn nodules. To prove how realistic, the extraction of REE from those deposits is in market terms, we studied the economotechnical dimension and the potential or REEs compared to those of the well-known on-land REE deposits. Two studies are presented concerning the existing exploration pre-feasibility cases for REEs originated from two existing licences granted by the International Seabed Authority (ISA) in the Clarion Clipperton Zone (CCZ). The examination of these two cases has clearly shown that compared to the corresponding deposits of REE inland, the total basket prices of these submarine deposits are higher due to the higher contents of heavy REE such as Nd, Pr and Dy and Sm, Eu, Gd, Tb and Y in these marine deposits. Considering that the prices in the international markets for most of the REE oxides between 2019 and 2021 were very high, they gave these deposits even greater economic value. The significant advantage of the mining and metallurgical treatment of these manganese nodules and cobalt-rich manganese crusts is also related to the fact that REEs are not part of the crystal lattice of the minerals that host them, in contrast to what happens with land-based deposits. This makes their metallurgical processing more manageable and cheaper. This fact makes mining and metallurgical treatment economically favourable. On the other hand, the very low Th and U concentrations in these deep-sea deposits do not pose environmental risks in many well-known land-based REE deposits. Full article

In the global maritime industry, ship grounding represents about one-third of commercial groundings. Grounding is a type of accident where the hull of a ship strikes the seabed, causing damage to the hull. This type of accident can lead to damage to the hull and water penetration, but also to the pollution of the marine environment by the spillage of ship fuel or some liquid cargo carried by the ship. This paper presents a chronological overview of the contribution of ship grounding frequency, where one of the first ideas of grounding probability was presented by Macduff (1974) and Fuji (1974) in their models. Their ideas, such as grounding candidates and causing probability, laid the foundation for the development of future models. After their models, years later, other models continued to be developed; e.g., analytically (Macduff, Fujii, Amrowitcz, etc.) and statistically (Pedersen, Simonsen, etc.). To find the probability of grounding in an area of interest or in a scenario, it is necessary to have the number of grounding candidates and the causing probability. There are different internal and external factors that affect both probabilities, and in this paper, we analyze how various authors approach their grounding models and have tried to show the actual event as faithfully as possible and thus contribute to greater safety in maritime transport. The number of grounding frequency models significantly complicates their selection in practice; accordingly, the review of models in this paper should facilitate this, but also it should facilitate future research on this topic. Full article

Draft commercial exploitation regulations have been on the agenda of the ISA since several 15-year exploration contracts expired a few years ago. Given the ineffective implementation in practice and the ignored chapter in several mining regulations on the transfer of mining technology, the future Enterprise and developing countries may take a more positive approach to the transfer of mining technology by striking a delicate balance between the provisions on the protection of intellectual property and those on capacity building under the framework of UNCLOS and the 1994 Agreement, through reciprocal and mutual beneficial means such as direct technology purchasing and investment cooperation. The International Seabed Authority, as the competent inter-governmental organization, has the duty to foster favorable conditions for such transfer. Full article

In 2006, the BGR signed a contract with the International Seabed Authority (ISA) for the exploration of polymetallic nodules in the Clarion-Clipperton Zone of the northeast Pacific. During nine expeditions, in particular, “Area E1”, the eastern part of the contract area, with a size of ~60,000 km², was explored in detail. Here, we outline BGR’s exploration methods and provide resource estimates for Area E1 and three sub-areas. The resource assessment is predominantly based on statistical analyses of data obtained by 12-kHz multibeam bathymetry and backscatter mapping, box core sampling and geochemical analysis of nodules. The main parameter for the assessment is the nodule abundance (kg/m²), as its coefficient of variation (CoV) over the entire eastern contract area is relatively high at 36%. In contrast, the metal contents of nodules show only minor variation, with a CoV of 8% for manganese and 8% for the sum of copper, nickel and cobalt. To estimate mineral resources for the entire Area E1, we used an artificial neural network approach with a multivariate statistical correlation between nodule abundance derived from box cores and hydro-acoustic data. The total estimated resources are 540 ± 189 million tonnes (Mt) of dry nodules, and the total estimated metal contents are 168 Mt of manganese, 7.5 Mt of nickel, 6.3 Mt of copper, 0.9 Mt of cobalt, 0.4 Mt of rare-earth elements and 0.3 Mt of molybdenum. A geostatistical resource estimate of three economically prospective areas with a total size of 4498 km², intensively sampled by box cores, was carried out using ordinary kriging of nodule abundance and metal grades. Within these three nodule fields, 7.14 Mt of dry nodules are classified as measured mineral resources covering an area of 489 km². Indicated mineral resources amount to 11.2 Mt, covering an area of 825 km², and inferred mineral resources of 35.5 Mt of dry nodules were estimated for an area of 3184 km². In total, the metal contents of the three prospective areas amount to 16.8 Mt of manganese, 0.74 Mt of nickel, 0.63 Mt of copper and 0.09 Mt of cobalt. Full article

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. Full article

The international seabed area (i.e., the “Area”) is rich in mineral resources. According to the United Nations Convention on the Law of the Sea (UNCLOS) and the relevant implemented agreements, in 2012, the International Seabed Authority (ISA) began to develop the regulations for the exploitation of mineral resources in the Area. The most important part of the regulations involves determining the distribution of benefits from the exploitation of mineral resources in the Area between the ISA and the contractors. The establishment of a financial model to evaluate the economic benefits and compare the distribution scheme was the basic method relied on in the current study of payment mechanism. According to the characteristics of the exploitation project of mineral resources in the Area, the discounted cash flow method was selected to construct the financial model. Taking China’s deep-sea mineral resources development project in the Area as the background, the main parameters of the model were determined. A comparative study of similar financial models with Massachusetts Institute of Technology (MIT) and other foreign countries was carried out, in addition to a sensitivity analysis of parameters. On the basis of the assurance that the contractor’s internal rate of return was not lower than the level of the land mining enterprise, the financial model was used to calculate the internal rate of return and the revenue of royalty under different payment mechanisms and rates. The advantages and disadvantages of different payment mechanisms in the exploitation of mineral resources in the area were analyzed. Lastly, the possible impacts of deep-sea polymetallic nodule mining on Terrestrial metal markets were highlighted. Full article

Exploration of seabed polymetallic nodules identifies the Clarion Clipperton Zone and the Indian Ocean Nodule Field to be of economic interest. Mineral resource estimation is important to the owner of the resource (all of mankind; and managed by the International Seabed Authority; ISA) and to developers (commercial and government groups holding contracts with the ISA). The Committee for Mineral Reserves International Reporting Standards was developed for the land-based minerals industry and adapted in 2015 for ISA-managed nodules. Nodules can be sampled in a meaningful manner using mechanical devices, albeit with minor issues of bias. Grade and moisture content are measured using the established methodology for land-based minerals. Tonnage of resource is determined via the abundance of nodules in kilograms per square metre of seabed. This can be estimated from physical samples and, in some cases, from photographs. Contemporary resource reporting for nodules classify the level of confidence in the estimate, by considering deposit geology, sample geostatistics, etc. The reporting of estimates also addresses reasonable prospects for eventual economic extraction, including factors such as mining technology, the marine environment, metallurgical processing, and metals markets. Other requirements are qualified persons responsible for estimation and reporting, site inspection, and sample chain of custody. Full article

The amount and accuracy of nodule resources estimation in the Pacific Ocean are among the main factors conditioning the future exploitation. The estimates are based on the results of classical, direct seafloor sampling. Due to the large distance between sampling sites, the accuracy of assessing nodule resources in small parts of the deposit is low. The accuracy can be increased by using a large number of seafloor photographs taken along the route of the research vessel performing classic sampling. The study conducted for a part of the area administered by Interoceanmetal Joint Organization (IOM) included: (i) determining a model of the relationship between nodule abundance and seafloor nodule coverage using statistical methods, (ii) assessing the accuracy of nodule resources estimation using a geostatistical kriging procedure, (iii) proposing a preliminary classification of resources referring to International Seabed Authority (ISA) classification standards as material for further discussion. It was found that achievement of high accuracy in the estimation of nodule resources (with relative standard error <5%) in blocks planned for annual exploitation based on direct sampling is difficult. While the use of seafloor photographs increases the accuracy of estimating nodule resources, this improvement is not radical due to the unfavorable, preferential arrangement of photographic data. Full article

Recent years have seen increased survey and sampling expeditions to the Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyss, driven by commercial interests from contractors in the potential extraction of polymetallic nodules in the region. Part of the International Seabed Authority (ISA) regulatory requirements are that these contractors undertake environmental research expeditions to their CCZ exploration claims following guidelines approved by the ISA Legal and Technical Commission (ISA, 2010). Section 9 (e) of these guidelines instructs contractors to “…collect data on the sea floor communities specifically relating to megafauna, macrofauna, meiofauna, microfauna, nodule fauna and demersal scavengers”. There are a number of methodological challenges to this, including the water depth (4000–5000 m), extremely warm surface waters (~28 °C) compared to bottom water (~1.5 °C) and great distances to ports requiring a large and long seagoing expedition with only a limited number of scientists. Both scientists and regulators have recently realized that a major gap in our knowledge of the region is the fundamental taxonomy of the animals that live there; this is essential to inform our knowledge of the biogeography, natural history and ultimately our stewardship of the region. Recognising this, the ISA is currently sponsoring a series of taxonomic workshops on the CCZ fauna and to assist in this process we present here a series of methodological pipelines for DNA taxonomy (incorporating both molecular and morphological data) of the macrofauna and megafauna from the CCZ benthic habitat in the recent ABYSSLINE cruise program to the UK-1 exploration claim. A major problem on recent CCZ cruises has been the collection of high-quality samples suitable for both morphology and DNA taxonomy, coupled with a workflow that ensures these data are made available. The DNA sequencing techniques themselves are relatively standard, once good samples have been obtained. The key to quality taxonomic work on macrofaunal animals from the tropical abyss is careful extraction of the animals (in cold, filtered seawater), microscopic observation and preservation of live specimens, from a variety of sampling devices by experienced zoologists at sea. Essential to the long-term iterative building of taxonomic knowledge from the CCZ is an “end-to-end” methodology to the taxonomic science that takes into account careful sampling design, at-sea taxonomic identification and fixation, post-cruise laboratory work with both DNA and morphology and finally a careful sample and data management pipeline that results in specimens and data in accessible open museum collections and online repositories. Full article