Cobalt Crusts Research Articles

Blue Light-Dependent Pre-mRNA Splicing Controls Pigment Biosynthesis in the Mushroom Terana caerulea.

ABSTRACTLight induces the production of ink-blue pentacyclic natural products, the corticin pigments, in the cobalt crust mushroom Terana caerulea. Here, we describe the genetic locus for corticin biosynthesis and provide evidence for a light-dependent dual transcriptional/cotranscriptional regulatory mechanism. Light selectively induces the expression of the corA gene encoding the gateway enzyme, the first described mushroom polyporic acid synthetase CorA, while other biosynthetic genes for modifying enzymes necessary to complete corticin assembly are induced only at lower levels. The strongest corA induction was observed following exposure to blue and UV light. A second layer of regulation is provided by the light-dependent splicing of the three introns in the pre-mRNA of corA. Our results provide insight into the fundamental organization of how mushrooms regulate natural product biosynthesis.IMPORTANCE The regulation of natural product biosyntheses in mushrooms in response to environmental cues is poorly understood. We addressed this knowledge gap and chose the cobalt crust mushroom Terana caerulea as our model. Our work discovered a dual-level regulatory mechanism that connects light as an abiotic stimulus with a physiological response, i.e., the production of dark-blue pigments. Exposure to blue light elicits strongly increased transcription of the gene encoding the gateway enzyme, the polyporic acid synthetase CorA, that catalyzes the formation of the pigment core structure. Additionally, light is a prerequisite for the full splicing of corA pre-mRNA and, thus, its proper maturation. Dual transcriptional/cotranscriptional light-dependent control of fungal natural product biosynthesis has previously been unknown. As it allows the tight control of a key metabolic step, it may be a much more prevalent mechanism among these organisms.

Cobalt crust recognition based on kernel Fisher discriminant analysis and genetic algorithm in reverberation environment

Recognition of substrates in cobalt crust mining areas can improve mining efficiency. Aiming at the problem of unsatisfactory performance of using single feature to recognize the seabed material of the cobalt crust mining area, a method based on multiple-feature sets is proposed. Features of the target echoes are extracted by linear prediction method and wavelet analysis methods, and the linear prediction coefficient and linear prediction cepstrum coefficient are also extracted. Meanwhile, the characteristic matrices of modulus maxima, sub-band energy and multi-resolution singular spectrum entropy are obtained, respectively. The resulting features are subsequently compressed by kernel Fisher discriminant analysis (KFDA), the output features are selected using genetic algorithm (GA) to obtain optimal feature subsets, and recognition results of classifier are chosen as genetic fitness function. The advantages of this method are that it can describe the signal features more comprehensively and select the favorable features and remove the redundant features to the greatest extent. The experimental results show the better performance of the proposed method in comparison with only using KFDA or GA.

Report of the workshop Evaluating the nature of midwater mining plumes and their potential effects on midwater ecosystems

Report of the workshop Evaluating the nature of midwater mining plumes and their potential effects on midwater ecosystems

Cytotoxic Terphenyl Neolignans from Fungus Terana coerulea: New Natural Corticins D and E, and Revised Structure for Corticin A

The cobalt crust fungus Terana coerulea (Phanerochaetaceae family) was selected for a bio-guided study after an ethnobotanical survey at the Irati's Forest (Navarra, Spain) for its local use as antibiotic. Six extracts of increasing polarity, from hexane to hot water, were obtained from powdered dry fungi and tested for cytotoxicity against four human tumour cell lines and one non-tumour primary cell culture. From the most cytotoxic, EtOAc extract, we isolated and identified three terphenyl neolignans: two of them new natural products, named corticins D and E, and one previously described as corticin A, whose earlier structure has been revised. Their structural elucidation and biological evaluation as cytotoxic agents are described.

Geochemical characteristics and metal element enrichment in crusts from seamounts of the Western Pacific

Elemental geochemistry is an essential part of understanding mineralization mechanisms. In this paper, a data set of 544 cobalt crust samples from seamounts of the Western Pacific are used to study the enrichment characteristics of metal elements. REE normalization is utilized to reveal the origin of the crusts; effects of water depth on Co enrichment and impacts of phosphatization on mineral quality are discussed to obtain the evolution of these marine mineral deposits, which gives support to further resource assessment. Conclusions are reached as follows: 1) Elemental abundances, inter-element relationships, and shale-normalized REE patterns for phosphate-poor crusts from different locations reflect hydrogenetic origin of the crusts. EFs (enrichment coefficients) of REE exhibit exponential increase from surface sediments to phosphorite to polymetallic nodules to crusts, suggesting that the improved degree of hydrogeneous origin induces the enrichment of REE. 2) The crusts in the Western Pacific, formed through hotspot produced guyots trails, have relatively lower REE than those in the Mid-Pacific. The latter could be attributed to the peculiar submarine topography of seamounts formed by intraplate volcanism. 3) The non-phosphatized younger crust layers have 40% higher Co than the phosphatized older layers. This indicates the modification of the elemental composition in these crusts by phosphatization. A general depletion of hydroxide-dominated elements such as Co, Ni, and Mn and enrichment of P, Ca, Ba, and Sr is evident in phosphatized crusts, whereas non-phosphatized younger generation crusts are rich in terrigenous aluminosilicate detrital matter. 4) Co increases above the carbonate compensation depth (CCD) from less than 0.53% to over 0.65% in seamount regions with water depth of less than 2,500 m, suggesting the significance of the dissolution of carbonate in the sea water column to the growth and composition of crusts.

Solar Energy: Review of Potential Green & Clean Energy for Coastal and Offshore Applications

World appetite for energy and mineral resources seems insatiable. The study reveals that the natural reserve of fossil fuels represent 150 years (coal), 58 years (natural gas) and almost 46 years (oil) of consumption at current rates. The Ocean covers approximately 71% of the Earth's surface and full of abundant esoteric resources. This blue economy attracting greater interest for harnessing the ocean wealth. Energy Intensity (EI) for Ocean trades activity e.g. Extraction of Oil & Gas, Shipping, Fisheries, and Ocean Mining for Excavation of massive Sulphides, Manganese Nodules, Cobalt Crust and Methane Hydrates reviewed. Most of the offshore energy requirement is for fuel, cooking, maintaining comfort condition, recreation, preservation of commodity, distillation etc. Use of high grade energy viz. electricity through conversion into low grade energy such as water heating, distillation, cooling is not advantageous when abundant low grade energy is capable to do so efficiently. Solar PV/T technology can cater the offshore energy requirement substantially. However Levelized Cost Of Energy (LCOE) of Solar per kWh is more than that of any other renewable energy, but mobility, portability and feasibility of offshore installations are the key factors which dominate amongst the renewable energy sources. In the present paper various offshore energy applications are explored and potential of solar energy to substitute conventional oil and gas fuels for these applications are explained. Marine pollution on account of use of fossil fuel and its devastating consequences on sea creatures also reviewed.

Chemical Characterization of Cobalt Crust from Afanasy-Nikitin Seamount in the Eastern Indian Ocean by Inductively Coupled Plasma Time-of-Flight Mass Spectrometry

Analytical methodology was developed for the chemical characterization of cobalt crust samples collected from the Afanasy-Nikitin seamount in Eastern Equatorial Indian Ocean by inductively coupled plasma time-of-flight mass spectrometry (ICP-TOF-MS). Concentrations of geochemically significant groups of different trace elements such as large-ion-lithophile elements (e.g., Rb, Cs), high field strength elements (e.g., Ta, Nb, Hf and Zr), rare earth elements in addition to a few major and minor elements were determined in these samples. Samples (~50 mg) were digested in closed digestion vessels for 48 h before the expulsion of Si and the residues were taken in 5 % nitric acid. 103Rh was used as an internal standard. Matrix matching external calibrations were utilized in order to compensate for the spectroscopic and non-spectroscopic interferences. The detection limits obtained for various elements were in the range 1–0.01 ng/ml for majority of the elements analyzed. Accuracy for the determination of different elements is assessed by measuring them in a few cobalt crust samples, ferromanganese nodules and similar marine sediment reference materials. Also, there is a very good agreement between the data sets obtained by ICP-TOF-MS as well as the well established ICP-quadrupole MS on cobalt crust samples. The precisions obtained in this study are <5 % RSD for majority of the elements with comparable accuracy. The results are in agreement with certified and reference values wherever available for comparison. The geochemical characteristics of these rare marine sediments have been described.

Underwater Sediments Echoes Recognition Based on KECCA + PLS

In order to solve the nonlinear feature fusion of underwater sediments echoes, the shortage of Enhanced Canonical Correlation Analysis (ECCA) was analyzed and made ECCA extend to Kernel ECCA (KECCA) in the nuclear space, a multi-feature nonlinear fusion classification model with KECCA combining with Partial Least-Square (PLS ) was put forward。In the process of identifying four types of underwater sediment such as Basalt, Volcanic breccia, Cobalt crusts and Mudstone, the results showed that the recognition accuracy could be further improved for the KECCA + PLS model.

Spillovers between cobalt, copper and nickel prices: implications for deep seabed mining

Interaction between prices of nickel, copper and cobalt, the latter a by-product of nickel and copper in laterites and sulphite deposits, are analysed in relation to the price of oil, the US real interest rate and the real effective exchange rate of dollar using an autoregressive distributed lag model, to draw considerations on the profitability in the exploitation of polymetallic manganese nodules and cobalt crust in a mutually exclusive scenario. The results show co-movements between these variables through the presence of three long-run relationships. Focusing mainly on the cobalt/nickel relationship, it is shown that price of cobalt anticipates and exerts a negative effect on nickel while, as expected, the price of oil has a positive impact and the exchange rate a negative one. Conversely, the impact of the real interest rate is not significant. A Monte Carlo simulation is employed to forecast a robust average price of nickel in the long run, finding that under the actual stagnant economic conditions and an average price of cobalt of $40/kg (at 2000 price equivalence), the price of nickel will remain close to the actual, around $18/kg (at 2000 price equivalence). This result, coupled with the literature findings that in a mutually exclusive scenario, the prevalence of cobalt crust over manganese nodules can be shown only if the price of nickel is below $9/kg (at 2000 price equivalence), justifies why increased attention has been re-directed towards polymetallic nodules.

Optimal Design of Cobalt Crust Cutting Head Structure Parameter Based on Genetic Algorithm

With the aim of reducing the energy consumption in the cobalt crust crushing process, the spiral mining head energy consumption is taken as the objective function. And mining head diameter, cutting pick intercept, width of cutting edge and cutting pick installation angle are selected as the optimum design variables. The constraints of each parameter is given. Genetic algorithm is applied to optimize this model. The optimized results suggest that the energy consumption is reduced by 38.3%. And it also improves the performance and economic efficiency of the spiral mining head.

A comparison between manganese nodules and cobalt crust economics in a scenario of mutual exclusivity

The past 20 years have been characterised by limited interest in the economic viability of deep seabed mining with the exception of those mineral ores rich in precious metals such as polymetallic sulphides. This paper goes against the tide. After reviewing the most significant literature, it compares the economic feasibility of mining polymetallic manganese nodules and cobalt-rich ferromanganese crusts in a scenario of mutual exclusivity. It uses a new indicator, the cobalt–nickel price ratio, whose aim is to verify at what metal prices the net present value of the two mining projects equalises. Previous research has shown that the turning margin between manganese nodules and cobalt crusts is a cobalt price of $50/kg. The present paper revises this by showing that the choice between mining crust and nodules depends on fluctuations in the price of nickel. A Monte Carlo simulation proves that cobalt crust mining could be reasonably preferred to manganese nodules at cobalt prices of $40–60/kg if the price of nickel fell below $11/kg. Within this condition, investors would receive the minimum acceptable internal rate of return of 15%, which is at a level of risk closer to the land-based mining. However, when the price of nickel passes the $11/kg threshold, the equilibrium between the two ventures can be reached only at a cobalt price greater than $100/kg, causing cobalt crust to become uncompetitive. Finally, the paper, recognising that prices are not unique drivers, introduces legal, political, technological and environmental concerns to show that the final choice between the two mining ventures cannot be merely driven by economic issues.

Optimal control of cobalt crust seabed mining parameters based on simulated annealing genetic algorithm

Under the condition of the designated collection ratio and the interfused ratio of mullock, to ensure the least energy consumption, the parameters of collecting head (the feed speed, the axes height of collecting head, and the rotate speed) are chosen as the optimized parameters. According to the force on the cutting pick, the collecting size of the cobalt crust and bedrock and the optimized energy consumption of the collecting head, the optimized design model of collecting head is built. Taking two hundred groups seabed microtopography for grand in the range of depth displacement from 4.5 to 5.5 cm, then making use of the improved simulated annealing genetic algorithm (SAGA), the corresponding optimized result can be obtained. At the same time, in order to speed up the controlling of collecting head, the optimization results are analyzed using the regression analysis method, and the conclusion of the second parameter of the seabed microtopography is drawn.

Deep-Sea Cobalt Crusts Water Jet Cutting Ability

Deep-sea cobalt crusts water jet cutting method is proposed to avoid cutter impact load. With simulation calculations and experimental tests, water jet system parameters and its cutting ability were studied. Simula-tion results show that working pressure, ejection range and ejection angle of water jet system are main parameters of its cutting ability. Its important degree is in turn the working pressure, ejection range and ejection angle. Increasing water jet system working pressure is the most effective way to improve its cutting ability. When water jet working pressure is constant, in order to improve its cutting ability, the ejection range should be less than 4mm (four times of nozzle diameter) and the ejection angle should be about 13o. Experimental results show that there is a threshold pressure during water jet cutting cobalt crusts simulation material. With the increase of water jet working pressure, its cutting ability increases dramatically. With the increasing of water jet ejection range, its cutting ability decreases sharply. The optimal ejection angle is about 13o</sup.

黄鉄鉱とのガルバニック反応によるコバルト・リッチ・クラストの浸出について

Cobalt-rich ferromanganese crusts (cobalt crust) contain strategic metals such as copper, nickel and cobalt. In order to recover cobalt, the reduction and dissolution of manganese oxide in crusts is required because cobalt is interlocked in manganese oxide. It is known that galvanic interactions between metal sulfide minerals and manganese nodule cause oxidation-reduction reactions on them. In this study, galvanic leaching of chemical analytical MnO2 and cobalt crust has been examined in the presence of pyrite.The measurement of rest potential indicated that MnO2 was nobler than pyrite. The dissolution of the MnO2 was accelerated in the presence of pyrite because MnO2 could act as cathode to be reduced in the galvanic couple MnO2/FeS2 .The dissolution of manganese and cobalt from the cobalt crust was enhanced in the presence of pyrite, and 84% of cobalt was extracted in three days while about 1% in the absence of pyrite in sulfuric acid solution of pH0.8. The leaching of the cobalt crust has been studied under various experimental parameters such as pH, amount of pyrite and particle size.

Distribution Characteristics of Cobalt‐rich Ferromanganese Crust Resources on Submarine Seamounts in the Western Pacific

AbstractBased on the survey data of five submarine seamount provinces (chains) in the Western Pacific, the distribution characteristics of cobalt‐rich ferromanganese crust resources have been researched in this paper by using the relative reference data and applying the theories of hotspot and seafloor spreading. The main research results obtained are as follows: The Co‐rich crust thickness in the study area is gradually increasing from east to west and from south to north having a negative correlation (r = −0.59) with longitude and a positive correlation (r = 0.48) with latitude. The crust thickness varying along longitude and latitude is influenced by the hotspot and seafloor spreading. The oceanic crusts and seamounts in the northwest part of the study area are older, and the crust resources are superior to those in the southeast part. In the depth of &lt;1500 m, 1500–2000 m, 2000–2500 m in the study area, the cobalt crust thickness is respectively 5.45 cm, 4.34 cm and 3.55 cm, and in the depth of 2500–3000 m and 3000–3500 m, it drops respectively to 2.84 cm and 3.37 cm. The Co‐rich crust resources are mainly concentrated in the seamount summit margins and the upper flanks in the depth of &lt;2500 m. There is a strong negative correlation (r = −0.67) between the cobalt crust abundance and the slope of the seamount, 75 kg/m2 and 50 kg/m2 at the slopes of 0°–20° and 20°–34° respectively. Cobalt crusts are mainly distributed in the parts whose slopes are less than 20°. It is consistent with the fractal result that the slope threshold of cobalt crust distribution is 19°, and slopes over 20° are not conducive to the crust growth. The cobalt crusts of high grade are mainly enriched in the region within 150°E‐140°W and 30°S‐30°N in the Pacific, where there are about 587 seamounts at the depth of 3500–6000 m and over 30 Ma of the oceanic crusts. The perspective area rich in cobalt crust resources is about 41times104 km2 and the resource quantity is approximately 27 billion tons.

Fractal characteristics of resource quantity of cobalt crusts and seamount topography, the West Pacific

This paper presents the fractal distribution of topography of seamounts from the West Pacific and the resource quantity of cobalt crust therein. The cobalt resource quantity has three to four variable fractal dimensions, corresponding to the distinct slopes and water depths of the seamount. The multiple fractal property of resource quantity may have resulted from various factors, such as types and components of cobalt crusts and ages of oceanic crusts hosting the seamounts. Individual seamounts display complex topography and quantity of cobalt crust, both in the same and different regions.

해저 열수광상 및 망간각 자원 개발을 위한 국제적 논의에 대한 고찰

In August 1998, during the resumed fourth session of the Authority, the delegation of the Russian Federation reminded the Assembly that, in addition to polymetallic nodules, other mineral resources existed in the Area, including polymetallic sulphides and cobalt crusts, and requested the Authority to adopt rules, regulations and procedures for exploration for such resources. Pursuant to article 162, para. 2(o)(ii), of the 1982 UNCLOS, such rules, regulations and procedures are to be adopted within three years of the date of such a request. This article reviewed the 'Draft Rules and Regulations for the Exploration and Exploitation of Sea-Floor Massive Sulphides and Cobat-rich Ferromanganese Crusts in the Area' by ISA in 2001, and the 'Madang Guideline for Offshore Mineral Policy' written in 1999 in respect of the international trends of polymetallic sulphides and cobalt crusts. Issues for size of mining area and relinquishment, application of the site-banking system, procedure for dealing with overlapping claims and precautionary approach etc. for the establishment of the norm of polymetallic sulphides and cobalt crusts are reviewed as consideration factors.

亜硫酸ガスを用いたコバルトクラストのアンモニア浸出および溶媒抽出特性

Cobalt crusts were leached in an ammoniacal solution using sulfur dioxide gas as a reductant, and the effects of leaching time, leaching temperature and concentration of ammonium carbonate on the leaching of nickel, cobalt, copper, iron and manganese were investigated. The selective leaching of nickel, cobalt and copper from cobalt crusts was attained by using ammonium carbonate solution and sulfur dioxide gas as a reductant. The leaching percentages of metallic elements under the suitable leaching conditions were 90 % for nickel, 97 % for cobalt, 93 % for copper, 1.8 % for iron and 6.0 % for manganese. The separation of nickel, cobalt, copper from ammonium carbonate solution was carried out by solvent extraction. Extraction experiment was done by using LIX84-I as extractant. The extraction percentages of copper and nickel were more than 99 %, while that of cobalt was less than 1.0 %. Extraction of cobalt was masked by sulfite ion. From the organic phase containing nickel and copper, nickel was selectively stripped by dilute sulfuric acid or hydrochloric acid solution at the pH of 1.5. Copper was stripped at the pH of zero.

コバルトクラスト酸性浸出液中に存在する有価金属の抽出と分離

Cobalt crust, one of the mineral resources at the seabed, includes nickel, cobalt, copper, iron and manganese fairly.At the beginning of this study, the dilute sulfuric acid leaching have been occurred on cobalt crust using hydrogen peroxide as a reductant. As a result of the leaching test, almost of all valuable metals in the cobalt crust were leached in the solution.By addition of the calcium carbonate in the leaching solution, iron was removed completely as iron hydroxide. In this time, the other valuable metals were not effected by the calcium carbonate.In the experiment of extraction, 10% LIX-84I kerosene solution was used. The extraction percentage from the leached solution with the 10% LIX 84-I kerosene solution were more than 99% for nickel, cobalt at pH: nearly 7.0 and copper at pH: nearly 2.0.In the stage of extraction, the separation of nickel and cobalt was difficult, because of the same extraction behavior. Therefore, the studies were occurred on separation by stripping. In the stripping from the organic phase containing nickel, cobalt and copper, copper was stripped with the hydrochloric acid solution at pH: nearly O. Nickel was stripped at pH: 1. After this operation, cobalt may be got by hydrogen sulfide.

溶媒抽出における亜硫酸イオンによるコバルトのマスキング効果

After leaching cobalt crusts in an ammoniacal solution using sulfur dioxide gas as a reductant, the extraction of cobalt was held down in the solvent extraction process. The effects of sulfite ion on cobalt were studied by using nitroso R salt which forms a complex with cobalt. As a result, formation of cobalt complex salt was negligible in the solution of ammonium sulfite and sodium sulfite. It is supposed that sulfite ion acts as a masking reagent for cobalt.Solvent extraction of cobalt and nickel was carried out using LIX84-I as an extractant for the solution of ammonium sulfite. The effects of the ammonium sulfite concentration and retention time on the extraction of cobalt were investigated. Cobalt (10 ppm) was not extracted from the ammonium sulfite solution of concentration more than 0.5 M and the pH over 10.5. In the same condition, nickel (10 ppm) was extracted completely. Same studies were carried out by using PC-88A and D2EHPA, but superior separation of cobalt and nickel was not attained.An EDTA titration was carried out by addition of sodium sulfite or ammonium sulfite to the solution including cobalt and nickel. As a result, only nickel was titrated quantitatively inthe mixed solution containing up to 1 mg (20 ppm) of cobalt