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Hydrogen has the potential to revolutionize how we power our lives, from transportation to energy production. This study aims to compare the climate change impacts and the main factors affecting them for different categories of hydrogen production, including grey hydrogen (SMR), blue hydrogen (SMR-CCS), turquoise hydrogen (TDM), and green hydrogen (PEM electrolysis). Grey hydrogen, blue hydrogen, and turquoise hydrogen, which are derived from fossil sources, are produced using natural gas and green hydrogen is produced from water and renewable electricity sources. When considering natural gas as a feedstock, it is sourced from the pipeline route connected to Russia and through the liquefied natural gas (LNG) route from the USA. The life cycle assessment (LCA) result showed that grey hydrogen had the highest emissions, with the LNG route showing higher emissions, 13.9 kg CO2 eq. per kg H2, compared to the pipeline route, 12.3 kg CO2 eq. per kg H2. Blue hydrogen had lower emissions due to the implementation of carbon capture technology (7.6 kg CO2 eq. per kg H2 for the pipeline route and 9.3 kg CO2 eq. per kg H2 for the LNG route), while turquoise hydrogen had the lowest emissions (6.1 kg CO2 eq. per kg H2 for the pipeline route and 8.3 kg CO2 eq. per kg H2 for the LNG route). The climate change impact showed a 12–25% increase for GWP20 compared to GWP100 for grey, blue, and turquoise hydrogen. The production of green hydrogen using wind energy resulted in the lowest emissions (0.6 kg CO2 eq. per kg H2), while solar energy resulted in higher emissions (2.5 kg CO2 eq. per kg H2). This article emphasizes the need to consider upstream emissions associated with natural gas and LNG extraction, compression, liquefaction, transmission, and regasification in assessing the sustainability of blue and turquoise hydrogen compared to green hydrogen. [ABSTRACT FROM AUTHOR]

This paper explores the use of Solar Chimney Power Plants (SCPPs) for the production of green hydrogen as a means to store excess electrical energy generated from renewable energy resources (RESs). The proposed structure produces electrical energy and distilled water by heating the air under the SCPP. The electrolyzer is integrated into the seawater pool and installed at the solar chimney's base. The weather conditions at the proposed location of the SCPP including solar radiation, temperature, humidity, and wind speed, are analyzed to assess their impact on the performance of the SCPP. The potential applications and economic feasibility of the SCPP are discussed, considering its contribution to renewable energy generation and the benefits of hydrogen as a clean energy carrier. The results show that solar radiation levels and favorable temperature profiles play an important role in the performance of the SCPP. The SCPP could produce 380,263 kW h of electrical energy and 139,443 tons of distilled water annually. The results also showed that the SCPP could produce 13,000 kg of green hydrogen and 173,224 kg of oxygen annually. The revenue generated from the production of H 2 and O 2 has improved the levelized cost of energy (LCOE) for the SCPP to 0.51 $/kWh and made it compete with other energy production facilities. Monthly variations in electrical energy, H 2 , O 2 , and distilled water production, highlight the dependence of hydrogen production on solar intensity and temperature. Overall, the research demonstrates the potential of SCPPs and hydrogen production as a sustainable and efficient solution for storing and utilizing excess renewable energy. [Display omitted] • Solar-electrolysis system combing solar chimney & electrolysis station is proposed. • The system produces green hydrogen, oxygen, desalinated water, and electricity. • The solar-electrolysis system was modeled using MATLAB mathematical modeling. • The system produced 380 MW h, 13 ton H 2 , 173.3 ton O 2 , and 139,443 ton water per year. [ABSTRACT FROM AUTHOR]

A facile one-pot microwave-assisted synthesis prepared a new noble metal-free heterostructure of In 2 S 3 /In 2 O 3 nanosheets for blue LED-light-induced photocatalytic water splitting. The appropriate InCl 3 concentrations and reaction temperatures can grow the In 2 S 3 /In 2 O 3 nanosheets with higher photocatalytic water splitting for hydrogen production under blue-LED light irradiation. In addition, the optimized In 2 S 3 /In 2 O 3 nanosheets exhibited a higher hydrogen production rate is 618.0 μmolh−1g−1 in seawater without adjusted pH values under blue-LED light irradiation. Furthermore, the reusability of In 2 S 3 /In 2 O 3 nanosheets revealed the gradual increase of photocatalytic hydrogen production efficiency in four cycles. This phenomenon shall be attributed to the reaction of In 2 S 3 /In 2 O 3 nanosheets and seawater to form In 2 S 3 /In 2 O 3 /In(OH) 3 nanosheets, which can improve the recombination of the photogenerated charge carriers and light-harvesting capacity to promote their photocatalytic hydrogen production. [Display omitted] • In 2 S 3 /In 2 O 3 nanosheets were prepared using one-pot microwave-assisted synthesis. • In 2 S 3 /In 2 O 3 nanosheets exhibited higher photocatalytic water or seawater splitting. • In 2 S 3 /In 2 O 3 /In(OH) 3 nanosheets can be synthesized under photocatalytic seawater splitting. • In(OH) 3 can enhance the separation charge carriers and light-harvesting capacity. [ABSTRACT FROM AUTHOR]

The current work aims to construct an Egyptian Atlas for green hydrogen production utilizing water electrolysis powered by the available wind (wind turbines, WTs) and solar (PV panels) energies based on Egypt's climatic conditions. Different maps are constructed, including the power density (kWh/m2), hydrogen density (kg/m2), production cost ($/kg), and CO 2 mitigation (kg CO2 /m2). The weather data (Solar radiation, ambient temperature, and wind speed) of all 27 Egyptian governorates are fed into MATLAB code for one-year analysis. Five scenarios are adopted for power production having the same used land surface: the system is operated by PV only (S1), WTs only (S2), area of PV equal to WTs (S3), area of PV double WTs (S4) and area of PV half WTs area (S5). The results show that S1 has the highest hydrogen production, followed by S4, while S2 has the lowest value. The highest power and hydrogen densities are 378.4 W/m2 and 57.1 kg/m2 in Sohag Governorate, and the lowest values are 7.342 W/m2 and 0.12 kg/m2, respectively, in New Valley Governorate. The lowest LCOH of each configuration is 3.27 $/kg in Sohag for S1 , 1.017 $/kg in Red Sea for S2 , 2.60 $/kg in Red Sea for S3 , 2.91 $/kg in Red Sea for S4 and 2.14 $/kg Red Sea for S5. Finally, the amount of CO 2 mitigation ranges from 1.16 to 57.1 kg CO2 /m2. Egypt is an excellent opportunity for lower-cost investment in green hydrogen production. • An Egyptian Atlas of green hydrogen production from solar/wind energies is studied. • Power and hydrogen yield, LCOH, and CO 2 mitigation are constructed for 5 cases. • Sohag city has the highest power of 378.4 W/m2 and hydrogen density of 57.1 kg/m2,. • The highest and lowest LCOH is 3.3, and 1.02 $/kg for cases 1, and 2 , respectively. • The amount of CO 2 mitigation ranges from 1.16 to 57.1 kg CO2 /m2. [ABSTRACT FROM AUTHOR]

In this paper, wind resource availability was determined by analyzing the meteorological wind energy potential at the hub height of wind turbines. The wind resource potential was identified in specific geographic locations. Technical factors, such as siting requirements and resource availability, were taken into account in the investigation. The economic potential was calculated for each area of Algeria, considering overall losses. Subsequently, the potential for reducing fossil fuel usage was determined through wind to hydrogen estimation. The main components utilized in this work were a Vestas-90 wind turbine (V90–2.0 MW) and an alkaline electrolyzer. The analysis employed a Geographical Information System (GIS) tool. The results demonstrate Algeria's significant potential for wind to hydrogen production, estimated at 1.093 Gt/year without constraints, and reduced to 1.066 Gt/year when considering constraints. The levelized cost of wind to hydrogen production in Algeria varies between 1.51 and 15.37 US $/kg, depending on the chosen wind turbine. The wind to hydrogen production potential identified has the capacity to replace the entire current fossil fuel consumption in the transportation sector, which amounts to 5.28 Mt H 2 /year. The utilization of wind to hydrogen in the transport sector results in a significant reduction of CO 2 emissions, with a calculated avoidance of 45.69 Mt compared to the use of gasoline and diesel. Hydrogen produced from wind energy resources also could be used to support other sectors, including residential, agricultural, and industry in Algeria. • GIS-Based approach is used to evaluate the potential for wind to hydrogen production in Algeria. • The total wind to hydrogen potential in Algeria, when considering constraints, is estimated at 1.066 Gt/year, covering an area of 730,719 km2. • The levelized cost of wind to hydrogen production in Algeria ranges between 1.51 and 15.37 US $/kg, depending on the selected wind turbine (V90–2.0 MW). • The CO 2 emissions avoided in the transport sector are 45.69 Mt compared if the same amount of gasoline and diesel used. [ABSTRACT FROM AUTHOR]

This study investigates the potential of natural gas-based plants designed to produce blue hydrogen and decarbonized electric power, conceived to operate flexibly depending on the electricity price. This paper considers plants based on fired-tubular reforming (FTR) and auto-thermal reforming (ATR) technologies, with MDEA-based pre-combustion CO 2 capture process and partial electrification of the reformer, designed to achieve CO 2 capture efficiency higher than 95 %. Heat and mass balances for the chemical and power island are evaluated at both full and part load to define the corresponding operating maps. With pre-combustion CO 2 capture only, FTR plants can achieve CO 2 capture rates higher than 90 %, H 2 production efficiency of 73–74 % and power generation efficiency of around 47 %. Reformer electrification allows increasing overall capture efficiency to 95 %. Plants based on ATR can approach 95 % capture efficiency without electrification and achieve H 2 efficiency similar to FTR but higher electric efficiency, close to 51 %. An economic analysis is performed to assess profitability of the plants under electricity price scenarios with different penetration of renewables. The economic analysis shows that flexible plants may be profitable in future scenarios with high penetration of renewables and high price variance, resulting in IRR around 10–17 % for hydrogen selling prices of 2.0–2.5 €/kg, natural gas price of 9 €/GJ and carbon tax of 100 €/t CO2. [Display omitted] • Techno-economic study of low-emission H 2 & power plants with CO 2 capture. • Fired tubular reformers and autothermal reformers compared. • Reformer electrification increases capture rate and gives operational flexibility. • 71.3–75.2 % hydrogen production efficiency and 47.4–50.9 % electric efficiency estimated. • IRR 10–17 % in future high wind electricity market with hydrogen prices of 2.0–2.5 €/kg. [ABSTRACT FROM AUTHOR]

Green Hydrogen (GH) is increasingly recognized as a viable solution in the United States (US) for meeting energy demands, achieving net zero emissions by 2050, and mitigating the intermittent nature of renewable sources such as wind and solar. This review paper identifies and examines three crucial research areas concerning GH. Despite significant federal, state, and business investment in the development of hydrogen technology, numerous questions have remained unanswered including economic viability, social acceptance, and policies and regulations. In comparison to the US, Europe, and Asia have taken a lead role in studying the social and regulatory aspects of GH. The study shows limited focus on social acceptance, and the absence of dedicated policies and regulations for hydrogen. The US lacks coordinated policies for GH and is blended with natural gas. The literature shows that the relationship between economics, social sciences, and policies and regulations are intrinsic. The success of GH in the US will require massive investments, public and private collaboration, research on social sciences, and regulatory support. Hence, the GH rollout will bridge the energy transition, and climate and development targets which guide future industrial, government and public decisions. • Knowledge and experience play a major role in the acceptance of green hydrogen. • Green hydrogen technology lacks a value chain. • Lack of green hydrogen-specific regulatory agencies and standards in the US. • Economic, social, and regulatory challenges interlinked for green hydrogen. [ABSTRACT FROM AUTHOR]

Herein, we report the one-step hydrothermal synthesis of bifunctional Cr–Cu 2 S Nanoflakes supported on Cu-foam (Cr–Cu 2 S@CF) for alkaline water electrolyzer for H 2 production at an industrial scale. Vertically oriented Cr–Cu 2 S Nanoflakes, forming a hierarchical network is capable of efficient electrocatalytic activity owing to the high surface area, effective ions channels, and abundant redox sites. Owing to advanced morphological features, Cr–Cu 2 S@CF demonstrates the binder-free electrocatalytic hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at an industrial scale high current density of 500 mA/cm2. Exploiting the synergistic features, the optimized chemical composition of Cr–Cu 2 S delivers the geometric current density of 100 mA/cm2 at overpotential of −407 mV and −350 mV for HER and OER activity, respectively. Alloying Cr in Cu 2 S networks enhances oxygen desorption at the anode by decreasing the energy of adsorption of *OH intermediates, apart from enhanced HER activity due to enhanced electron density at Cu-sites. Moreover, two a two-electrode electrolyzer assembled using Cr–Cu 2 S@CF as an electrocatalyst at both electrodes gives current densities of 10 and 100 mA/cm2 at potentials of 1.75 V and 2.07 V, respectively. • Cr–Cu 2 S@CF Nanoflakes featured a vertically oriented hexagon morphology. • Cr–Cu 2 S@CF electrocatalysts exhibit a wide range of pH values in HER activity. • Cr-doped Cu 2 S can optimize energy barriers of H 2 O dissociation and H adsorption. • Cr–Cu 2 S@CF shows excellent HER activity with overpotential of −305mV vs RHE at 1000 mA/cm2 in acidic media. [ABSTRACT FROM AUTHOR]

Pyrite is widely distributed in the Earth's crust and oceanic systems, and it generally occurs as pentagonal dodecahedra, cubic, octahedral, idiomorphic crystals, or dense, massive, granular, and nodular aggregates. In this study, representative pyrite samples from Hunan, Fujian, Jiangxi, Anhui in China and from Peru were collected. By utilizing a range of analytical techniques, including petrography, X-ray diffraction, infrared spectrum, Raman spectrum, major and trace element analysis, as well as sulfur stable isotope analysis, we comprehensively depict the mineralogical and spectroscopic characteristics of pyrite, and the evolution processes of the physical and chemical conditions of mineralization can be qualitatively constrained. The spectroscopic results indicate all samples show a relatively narrow absorption band with weak to moderate intensity in the vicinity of 343 cm−1, which represents the bending vibration of the Fe-[S2]2− molecular bond. The Co content of pyrite exhibits the characteristics of a positive correlation with temperature and a negative correlation with oxygen fugacity, respectively. The δ34S isotopic compositions of colloidal pyrite are in the range of 0.03 to 0.67, which are close to meteoric sulfur and mantle sulfur compositions, while the δ34S values of nodular pyrite fall within the range of granite, indicating the characteristics of mixtures of sulfur sources are mainly related to magmatic activity. Our results provide insight into the formation mechanisms of pyrite in different environments, its mineralization, and the ore genesis of deposits. Moreover, the integrated analytical methods for pyrite are provided, which can define theoretical guidance for the exploration and development of mineral resources. [ABSTRACT FROM AUTHOR]

[Display omitted] The rapid recombination of interfacial charges is considered to be the main obstacle limiting the photocatalytic CO 2 reduction. Thus, it is a challenge to research an accurate and stable charge transfer control strategy. MIL-53 (Al)-S/Cd 0.3 Zn 0.7 S (MAS/CZS-0.3) photocatalysts with chemically bonded interfaces were constructed by in-situ electrostatic assembly of sulfur defect Cd 0.3 Zn 0.7 S (CZS-0.3) on the surface of MIL-53 (Al) (MAW), which enhanced interfacial coupling and accelerated electron transfer efficiency. An adjustable proportion of syngas (H 2 /CO) was prepared by photothermal catalytic CO 2 reduction at micro-interface. and the optimal yield of CO (66.10 μmol∙g−1∙h−1) and H 2 (71.0 μmol∙g−1∙h−1) was realized by the MAS/CZS-0.3 photocatalyst. The improved activity was due to the photogenerated electrons migrated from CZS-0.3 to the adsorption active sites of MAS, which strengthened the adsorption and activation of CO 2 on MAS. The photothermal catalytic CO 2 reduction to CO follows the pathway of CO 2 →*COOH → CO and CO 2 →*HCO 3 –→CO. This work provided a reference for the research, characterization, and application of in-situ anchoring of metal organic frameworks in photothermal catalytic CO 2 reduction, and provided a green path for the supply of Syngas in industry. [ABSTRACT FROM AUTHOR]

[Display omitted] • The ultrathin MgB 2 nanosheets were prepared by ultrasonic-assisted exfoliation technology. • MgB 2 @PP as separator contributes to the adsorption and catalytic conversion of polysulfides and inhibits the shuttle effect. • MgB 2 @PP as separator significantly improves the sulfur utilization, high specific capacity and cycle stability in Li-S batteries. The separator is an important component in lithium-sulfur (Li-S) batteries. However, the conventional polypropylene (PP) separators have the problem of easy shuttling of lithium polysulfide (LiPSs). Herein, ultrathin magnesium boride (MgB 2) nanosheets were prepared by ultrasonic-assisted exfoliation technology, and were suction-filtered onto a separator to serve as a separator modification layer. The introduction of a microporous structure into MgB 2 nanosheets after ultrasonic peeling increases the specific surface area and pore volume, with more adsorption sites, which can fully utilize the surface adsorption/catalytic performance of MgB 2 for LiPSs and accommodate the volume expansion of lithium sulfide (Li 2 S). Therefore, MgB 2 @PP as a separator significantly improves the sulfur utilization and cycle stability in Li-S batteries. When the MgB 2 @PP separator is used, the reversible specific capacity of the assembled Li-S battery at 0.1 C (current rate) is 1184 mAh/g, and the specific capacity at 2 C is 732 mAh/g. After 500 cycles at 2 C, it remains at 497 mAh/g. [ABSTRACT FROM AUTHOR]

The Mazraeh Cu skarn deposit, NW Iran, is situated at the lithological contact between an Oligo--Miocene granodiorite and Cretaceous limestones. The causative granodiorite has I-type medium- to high-K calc-alkaline composition that formed in a subduction arc setting. Metasomatism generated exoskarn and endoskarn characterized by a temporal and spatial mineral-chemistry zonation with massive garnet and garnet-pyroxene proximal and epidote-amphibole skarn at the distal zones of the exoskarn. Our data reveal a multi-stage evolution of the hydrothermal system. Accordingly, the prograde stage was formed by barren, oxidized, high-temperature and hypersaline magmatic fluids, which suggests that the parental magma was emplaced at low lithostatic pressure conditions (~1.5 km depth). By contrast, during the retrograde stage the regime changed from lithostatic to hydrostatic conditions, resulting in a significant decrease in pressure and oxygen fugacity, boiling, cooling, and mixing, respectively. Dilution by meteoric fluids led to additional cooling and lower salinity of the ore fluids. Sulfur isotope compositions (δ34S = -2.8‰-1.3‰) of sulfides indicate a unique magmatic source of the sulfur. The δ18Ofluid and δDfluid values of the prograde stage fluid also indicate a magmatic origin, while their gradual depletions from the prograde to retrograde stage imply increased mixing with meteoric water. We propose that the fluid mixing scenario continued over the entire life cycle of the mineral system in an open hydrostatic regime as reflected in the oxygen isotope values. It is suggested that boiling and fluid mixing played a significant role in the formation of this giant Cu skarn deposit. [ABSTRACT FROM AUTHOR]

The Steptoean Positive Carbon Isotope Excursion (SPICE) event at ca. 497-494 Ma was a major carbon-cycle perturbation of the late Cambrian that coincided with rapid diversity changes among trilobites. Several scenarios (e.g., climatic/oceanic cooling and seawater anoxia) have been proposed to account for an extinction of trilobites at the onset of SPICE, but the exact mechanism remains unclear. Here, we present a chemostratigraphic study of carbonate carbon and carbonate-associated sulfate sulfur isotopes (δ13Ccarb and δ34SCAS) and elemental redox proxies (UEF, MoEF, and Corg/P), augmented by secular trilobite diversity data, from both upper slope (Wangcun) and lower slope (Duibian) successions from the Jiangnan Slope, South China, spanning the Drumian to lower Jiangshanian. Redox data indicate locally/regionally well-oxygenated conditions throughout the SPICE event in both study sections except for low-oxygen (hypoxic) conditions within the rising limb of the SPICE (early-middle Paibian) at Duibian. As in coeval sections globally, the reported δ13Ccarb and δ34SCAS profiles exhibit first-order coupling throughout the SPICE event, reflecting co-burial of organic matter and pyrite controlled by globally integrated marine productivity, organic preservation rates, and shelf hypoxia. Increasing δ34SCAS in the "Early SPICE" interval (late Guzhangian) suggests that significant environmental change (e.g., global-oceanic hypoxia) was under way before the global carbon cycle was markedly affected. Assessment of trilobite range data within a high-resolution biostratigraphic framework for the middle-late Cambrian facilitated reevaluation of the relationship of the SPICE to contemporaneous biodiversity changes. Trilobite diversity in South China declined during the Early SPICE (corresponding to the End-Marjuman Biomere Extinction, or EMBE, of Laurentia) and at the termination of the SPICE (corresponding to the End-Steptoean Biomere Extinction, or ESBE, of Laurentia), consistent with biotic patterns from other cratons. We infer that oxygen minimum zone and/or shelf hypoxia expanded as a result of locally enhanced productivity due to intensified upwelling following climatic cooling, and that expanded hypoxia played a major role in the EMBE at the onset of SPICE. During the SPICE event, global-ocean ventilation promoted marine biotic recovery, but termination of SPICE-related cooling in the late Paibian may have reduced global-ocean circulation, triggering further redox changes that precipitated the ESBE. Major changes in both marine environmental conditions and trilobite diversity during the late Guzhangian demonstrate that the SPICE event began earlier than the Guzhangian-Paibian boundary, as previously proposed. [ABSTRACT FROM AUTHOR]

The inflow of warm and nutrient‐rich Pacific Water (PW) through the Bering Strait into the Arctic Ocean is likely to have far‐reaching consequences for the ecosystem and biogenic sulfur cycle in the Earth's sensitive subarctic–arctic region of the Pacific sector, even impacting climate change under global warming scenarios. We performed a detailed biogeochemical study of summer biogenic sulfur cycling from cold (2012) to warm (2014) years in the Bering Strait and the Chukchi Sea, so as to highlight the importance of enhanced Pacific inflow in driving dimethylsulfide (DMS) variability. In the Bering Strait, the enhanced Pacific inflow led to the vertical expansion of the eastern high‐DMS regions due to the vertical extension of Alaska Coastal Water, and the horizontal expansion of the western surface high‐DMS regions due to the westward intrusion of Bering Shelf Water. The enhanced extension of PW potentially stimulated seawater warming, the northward retreat of the ice edge, and the enlargement of sea ice‐free areas in the Chukchi Sea. The northern ice melting zone at 71°N with a bloom of phytoplankton was an area of locally high dimethylsulfoniopropionate concentrations and slow DMS consumption in 2012. A hotspot for dimethylated sulfur compound concentrations and DMS sea–air flux occurred in the convergence region near 67.7°N during 2014, due to enhanced mixing caused by increased Bering Sea Water. Owing to the increased advection of PW during 2012–2014, surface DMS and its emission to the atmosphere increased sharply by threefold in the Chukchi Sea. [ABSTRACT FROM AUTHOR]

Hydrothermal fluids in ultramafic‐hosted hydrothermal systems associated with oceanic detachment faults can be more oxidizing compared to mafic‐hosted vent sites. These fluids form a mineral assemblage of pyrite, magnetite and hematite. At 13°30′N on the Mid‐Atlantic Ridge, chlorite‐quartz breccias recovered from an exposed fault scarp contain pyrite, with abundant magnetite and hematite, indicating that the redox of the fluids was variable. In primary micron‐scale zonations in pyrite, Ni, Co, and Se have a decoupled relationship, recording fluctuations in the chemical composition and temperature of hydrothermal fluid as the grains grew. Secondary zonations that erase and overprint primary zonations are limited to the grain margin and permeable regions within the grain core. Secondary zonations formed via two processes: (a) grain dissolution followed by overgrowth, and (b) remobilization of metals during oxidizing fluid flow events. In both instances, Ni and Co have been mobilized and concentrated, and are not lost to the hydrothermal fluid. Superimposed on these features is evidence of grain scale deformation related to periods of fault movement along the detachment surface. Sulfur isotope ratios (δ34S) in pyrite systematically decrease from the grain margin to the grain core, indicating that increased amounts of sulfur were derived from thermochemical sulfate reduction of seawater. Thus, pyrite records the evolution of fluid flow and deformation events during exhumation along the detachment surface from ∼1 to 2 km below the seafloor at the base of the lava pile, with temporal fluctuations in fluid redox identified as an important process in controlling Ni and Co enrichment in pyrite. Plain Language Summary: Detachment faults are long lived faults that can expose ultramafic rocks at the seafloor. We aim to investigate the links between hydrothermal activity and detachment fault formation. To do this we use pyrite as a tape recorder for past fluid flow events. Across individual mineral grains, distinct zonations in metal content and sulfur isotope ratios show that the incursion of seawater occurred periodically during pyrite growth, increasing during fault movement events that lead to changes in the temperature and pH of the fluids in the fault zone. These changes concentrated metals toward the center of individual mineral grains. Zonations were then overprinted by later deformation‐related events, providing evidence that the samples formed at deeper crustal levels below the seafloor and were progressively exhumed at the seafloor over time. Key Points: Microtextural, geochemical, and isotopic variations in subseafloor pyrite record the history of sample exhumation along a detachment faultNickel and Co are remobilized and concentrated in pyrite across individual mineral grains in response to fluctuating fluid redox conditionsEvidence of pyrite deformation and alteration mineralogy of samples indicates sample exhumation from a depth of 1–2 km [ABSTRACT FROM AUTHOR]

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Birds exhibit extraordinary mobility and remarkable navigational skills, obtaining guidance cues from the Earth’s magnetic field for orientation and long-distance movement. Bird species also show tremendous diversity in navigation strategies, with considerable differences even within the same taxa and among individuals from the same population. The highly conserved iron and iron-sulfur cluster binding magnetoreceptor (MagR) protein is suggested to enable animals, including birds, to detect the geomagnetic field and navigate accordingly. Notably, MagR is also implicated in other functions, such as electron transfer and biogenesis of iron-sulfur clusters, raising the question of whether variability exists in its biochemical and biophysical features among species, particularly birds. In the current study, we conducted a comparative analysis of MagR from two different bird species, including the migratory European robin and the homing pigeon. Sequence alignment revealed an extremely high degree of similarity between the MagRs of these species, with only three sequence variations. Nevertheless, two of these variations underpinned significant differences in metal binding capacity, oligomeric state, and magnetic properties. These findings offer compelling evidence for the marked differences in MagR between the two avian species, potentially explaining how a highly conserved protein can mediate such diverse functions. [ABSTRACT FROM AUTHOR]

Multiphase oxidation of methane sulfinic acid (MSIA) by ozone (O3) in deliquesced aerosol particles is an important but poorly constrained reaction in the marine boundary layer, hindering the accurate prediction of radiative forcing of natural aerosols. Large uncertainties arise from the unmeasured reaction rate constant for the aerosol multiphase reaction between O3 and methanesulfinate (MSI−), the dominant MSIA species in sea salt aerosols. Here, we directly measured kMSI−+O3 ${\mathrm{k}}_{{\text{MSI}}^{-}+{\mathrm{O}}_{3}}$ by performing flow cell experiments coupled with a Raman spectroscopy to investigate the kinetics of multiphase oxidation of MSI− by O3 in pH‐buffered deliquesced aerosol particles relevant to marine atmospheric conditions. kMSI−+O3 ${\mathrm{k}}_{{\text{MSI}}^{-}+{\mathrm{O}}_{3}}$ for aerosol particles was determined to be (2.2 ± 0.5) × 107 M−1 s−1, 10 times the value in dilute solutions. This higher rate constant would increase the yield of methane sulfonic acid from multiphase oxidation of MSIA and has important implications for accurate modeling of sulfur species. Plain Language Summary: Atmospheric oxidation of dimethyl sulfide (DMS) in the marine atmosphere ultimately forms methane sulfonic acid and sulfate aerosols, directly contributing to the global radiative forcing. They can also modify the properties of clouds and indirectly impact the climate. The poor understanding of the kinetics and mechanisms of atmospheric oxidation of DMS and its oxidation products in the marine atmosphere gives rise to large uncertainties in predicting the global radiative forcing. One of the key reactions is the multiphase oxidation of methane sulfinic acid (MSIA) and its deprotonated form methanesulfinate (MSI−) in deliquesced aerosol particles by ozone (O3). However, the reaction rate constant for MSI− and O3 in aerosol particles has never been experimentally determined. In this study, we conducted well‐controlled experiments and show that the reaction rate constant for MSI− and O3 in aerosol particles is 10 times that used in atmospheric models. The new kinetic data provides a better constraint on the product distributions from the multiphase oxidation of MSIA and should be incorporated into atmospheric models to improve the prediction of the radiative forcing of natural aerosols and clouds in the marine atmosphere. Key Points: The kinetics of multiphase oxidation of MSI− by O3 was investigated in pH‐buffered aerosol droplets coupling with Raman characterizationThe rate constant of MSI− and O3 in deliquesced aerosol particles was determined to be 10 times that used in chemical transport modelsThe reaction between MSI− and O3 would dominate the aqueous oxidation of MSIA species by O3 in the marine atmosphere [ABSTRACT FROM AUTHOR]

The importance of energy storage is increased with the intermittent nature of renewable energy resources (RERs). Green hydrogen is increasingly being employed to address its shortcomings. Furthermore, lowering carbon emissions has accelerated the quest for green alternatives instead of fossil-based fuels. This research focuses on Egypt's capacity to generate green hydrogen using natural renewable resources to serve islanded electrical and hydrogen loads. To obtain the lowest net present cost (NPC), cost of hydrogen (COH), and levelized cost of energy (LCOE), the state-of-the-art prices of the system elements are investigated and optimized using the HOMER professional software. Three situations with solar photovoltaic (PV), wind, and hybrid RERs are evaluated in three separate Egyptian cities. A sensitivity analysis is investigated based on the influence of the system's reliability and hydrogen load variance on the cost. The results of the three locations are compared to indicate the best site for green hydrogen production. The results obtained with the wind scenario located on the coast of the Suez Gulf provided the lowest LCOE, ranged from 0.308 $/kWh to 0.353 $/kWh, and the COH ranged from 3.73 $/kg to 4.13 $/kg. • Proposing a complete islanded green hydrogen production scheme. • Testing the model in three different climatic condition locations in Egypt. • Obtaining the optimal sizing of the system components to minimize LCOE, NPC, and COH. • Investigating the hydrogen load variance effect on the system costs and sizes. • Analyzing the impact of reliability consideration on the system sizes and costs. [ABSTRACT FROM AUTHOR]

Prokaryotic communities play important roles in sewer sediment ecosystems, but the community composition, functional potential, and assembly mechanisms of sewer sediment prokaryotic communities are still poorly understood. Here, we studied the sediment prokaryotic communities in different urban functional areas (multifunctional, commercial, and residential areas) through 16S rRNA gene amplicon sequencing. Our results suggested that the compositions of prokaryotic communities varied significantly among functional areas. Desulfomicrobium, Desulfovibrio, and Desulfobacter involved in the sulfur cycle and some hydrolytic fermentation bacteria were enriched in multifunctional area, while Methanospirillum and Methanoregulaceae, which were related to methane metabolism were significantly discriminant taxa in the commercial area. Physicochemical properties were closely related to overall community changes (p < 0.001), especially the nutrient levels of sediments (i.e., total nitrogen and total phosphorus) and sediment pH. Network analysis revealed that the prokaryotic community network of the residential area sediment was more complex than the other functional areas, suggesting higher stability of the prokaryotic community in the residential area. Stochastic processes dominated the construction of the prokaryotic community. These results expand our understanding of the characteristics of prokaryotic communities in sewer sediment, providing a new perspective for studying sewer sediment prokaryotic community structure. [ABSTRACT FROM AUTHOR]

Nowadays, with the need for clean and sustainable energy at its historical peak, new equipment, strategies, and methods have to be developed to reduce environmental pollution. Drastic steps and measures have already been taken on a global scale. Renewable energy sources (RESs) are being installed with a growing rhythm in the power grids. Such installations and operations in power systems must also be economically viable over time to attract more investors, thus creating a cycle where green energy, e.g., green hydrogen production will be both environmentally friendly and economically beneficial. This work presents a management method for assessing wind–solar–hydrogen (H2) energy systems. To optimize component sizing and calculate the cost of the produced H2, the basic procedure of the whole management method includes chronological simulations and economic calculations. The proposed system consists of a wind turbine (WT), a photovoltaic (PV) unit, an electrolyzer, a compressor, a storage tank, a fuel cell (FC), and various power converters. The paper presents a case study of green hydrogen production on Sifnos Island in Greece through RES, together with a scenario where hydrogen vehicle consumption and RES production are higher during the summer months. Hydrogen stations represent H2 demand. The proposed system is connected to the main power grid of the island to cover the load demand if the RES cannot do this. This study also includes a cost analysis due to the high investment costs. The levelized cost of energy (LCOE) and the cost of the produced H2 are calculated, and some future simulations correlated with the main costs of the components of the proposed system are pointed out. The MATLAB language is used for all simulations. [ABSTRACT FROM AUTHOR]

Marine sediments can be used to reconstruct the evolution of seawater [SO 42- ] and δ34 S over time, two key parameters that contribute to refine our understanding of the sulfur cycle and thus of Earth's redox state. δ34 S evolution can be measured from carbonates, barites and sulfate evaporites. [SO 42- ] variations can be reconstructed using fluid inclusions in halites, a method that only allows a low-resolution record. Reconstruction of the past sulfur cycle could be improved if carbonates allowed the tracking of both seawater δ34 S and [SO 42- ] variations in a sole, continuous sedimentary repository. However, most primary carbonates formed in the ocean are biogenic, and organisms tend to overprint the geochemical signatures of their carbonates through a combination of processes often collectively referred to as vital effects. Hence, calibrations are needed to allow seawater δ34 S and [SO 42- ] reconstructions based on biogenic carbonates. Because foraminifera are important marine calcifiers, we opted to focus on calcite synthesized by individuals of rosalinid benthic foraminifera cultured in the laboratory under controlled conditions, with varying seawater [SO 42- ] (ranging from 0 to 180 mM). Our experimental design allowed us to obtain foraminiferal asexual reproduction over several generations. We measured bulk carbonate-associated sulfate (CAS) content and sulfur isotopic composition (δ34 S CAS) on samples of tens to hundreds of specimens from a selection of culture media, where [SO 42- ] varied from 5 to 60 mM. Increasing or decreasing [SO 42- ] with respect to modern-day seawater concentration (28 mM) impacted foraminiferal population size dynamics and the total amount of bioprecipitated carbonate. Foraminiferal CAS concentration increased proportionally with [SO 42- ] concentration from 5 mM up to 28 mM and then showed a plateau from 28 to 60 mM. The existence of a threshold at 28 mM is interpreted as the result of a control on the precipitation fluid chemistry that foraminifera exert on the carbonate precipitation loci. However, at high seawater sulfate concentrations (> 40 mM) the formation of sulfate complexes with other cations may partially contribute to the non-linearity of the CAS concentration in foraminiferal tests at high increases in [SO 42- ]. Yet, despite the significant effect of seawater [SO 42- ] on foraminiferal reproduction and on CAS incorporation, the isotopic fractionation between CAS and seawater remains stable through varying seawater [SO 42- ]. Altogether, these results illustrate that CAS in biogenic calcite could constitute a good proxy for both seawater [SO 42- ] and δ34 S and suggests that sulfate likely plays a role in foraminiferal biomineralization and biological activity. [ABSTRACT FROM AUTHOR]

Renewable hydrogen production has an important role in global decarbonization. However, when coupled with intermittent and variable sources, such as wind or PV, electrolyzers are subjected to part-load and dynamic operation. This can lead to low utilization factors and faster degradation of the electrolyzers and affect the specific hydrogen cost. The design and sizing of such electrolysis systems are fundamental to minimize costs. In this study, several configurations of an electrolysis system producing green hydrogen from a 39 MW-wind farm are compared. The effects of both the size of the plant and the number of separated groups into which it is divided are investigated. Dividing the plant into two separated groups resulted to be enough to increase hydrogen production; a further increase in the number of groups didn't produce significant differences. The most profitable configurations resulted that with one or two groups, depending on the hydrogen selling price. • Effects of overall size and number of separated electrolysis groups are investigated. • Stack degradation included in the electrolyzer model. • Higher production in 2-group configurations compared to equivalent single-group ones. • Minimum hydrogen selling price between 4.5 and 6.5 €/kg required for profitability. • Dividing the electrolysis plant into more than 2 groups didn't result profitable. [ABSTRACT FROM AUTHOR]

The presence of seagrasses facilitates numerous microbial-mediated biogeochemical cycles, with sulfur- and nitrogen-cycling microorganisms playing crucial roles as regulators. Despite efforts to comprehend the diversity of microbes in seagrass ecosystems, the metabolic functions of these benthic microorganisms in seagrass sediments remain largely unknown. Using metagenomics, we provide insights into the sulfur- and nitrogen-cycling pathways and key metabolic capacities of microorganisms in both Z. japonica-colonized and unvegetated sediments over a seasonal period. Taxonomic analysis of N and S cycling genes revealed that δ- and γ- proteobacteria dominated the benthic sulfate-reducing bacteria, while α- and γ-proteobacteria played a significant role in the sulfur-oxidation processes. The proteobacterial lineages were also major contributors to the benthic nitrogen cycling. However, at a finer taxonomic resolution, microbial participants in different processes were observed to be highly diverse and mainly driven by environmental factors such as temperature and salinity. The gene pools of sulfur and nitrogen cycles in the seagrass sediments were dominated by genes involved in sulfide oxidation (fccA) and hydroxylamine oxidation (hao), respectively. Seagrass colonization elevated the relative abundance of genes responsible for sulfite production (phsC), hydroxylamine oxidation (hao), and nitrogen fixation (nifK), but suppressed sulfur oxidation (soxXYZ) and denitrification (nosZ and nirS). The prevalence of proteobacterial lineages functioned with versatile capabilities in both sulfur and nitrogen cycles in seagrass ecosystems, highlighting tight couplings between these processes, which was further supported by the recovery of 83 metagenome-assembled genomes (MAGs). These findings broaden our understanding of the biogeochemical processes that are mediated by microorganisms in seagrass ecosystems. [ABSTRACT FROM AUTHOR]

The origin of Earth's volatile elements is highly debated. Comparing the chalcogen isotope ratios in the bulk silicate Earth (BSE) to those of its possible building blocks, chondritic meteorites, allows constraints on the origin of Earth's volatiles; however, these comparisons are complicated by potential isotopic fractionation during protoplanetary differentiation, which largely remains poorly understood. Using first-principles calculations, we find that core-mantle differentiation does not notably fractionate selenium and tellurium isotopes, while equilibrium evaporation from early planetesimals would enrich selenium and tellurium in heavy isotopes in the BSE. The sulfur, selenium, and tellurium isotopic signatures of the BSE reveal that protoplanetary differentiation plays a key role in establishing most of Earth's volatile elements, and a late veneer does not substantially contribute to the BSE's volatile inventory. [ABSTRACT FROM AUTHOR]

The shortage of freshwater resources in the world today has limited the development of water splitting, and our eyes have turned to the abundant seawater. The development of relatively low-toxicity and high-efficiency catalysts is the most important area in seawater electrolysis. In this paper, the preparation of NiS2@Co4S3@FeS via a hydrothermal method on nickel foam has been studied for the first time. In the process of vulcanization, Fe will first generate FeS by virtue of its high affinity for vulcanization. Once Fe is vulcanized, the residual sulfur will be used to generate NiS2, while the vulcanization of Co requires a higher sulfur concentration and reaction temperature; thus, Co4S3 will be generated last. NiS2@Co4S3@FeS is confirmed to have excellent hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) catalytic properties in alkaline seawater. Its unique structure allows it to expose more reaction centres, and the synergies between the multiple metals optimize the charge distribution of the material and accelerate the OER and HER kinetics. NiS2@Co4S3@FeS requires overpotentials of only 122 mV and 68 mV for the OER and HER when reaching 10 mA cm−2, which is superior to most catalysts reported to date for seawater electrolysis, and the material displays acceptable stability. In an electrolytic cell composed of both positive and negative electrodes, when the current density is 10 mA cm−2, the NiS2@Co4S3@FeS material displays a low overpotential of only 357 mV for seawater splitting. Density functional theory shows that the FeS electrode has the optimum Gibbs free energy of H to accelerate reaction kinetics, and the synergistic catalysis of the NiS2, Co4S3 and FeS materials promotes the hydrogen production activity of the NiS2@Co4S3@FeS electrode. This work proposes a novel idea for designing environmentally friendly seawater splitting catalysts. [ABSTRACT FROM AUTHOR]

Coccolithophores are the most abundant calcifying organisms in modern oceans and are important primary producers in many marine ecosystems. Their ability to generate a cellular covering of calcium carbonate plates (coccoliths) plays a major role in marine biogeochemistry and the global carbon cycle. Coccolithophores also play an important role in sulfur cycling through the production of the climate‐active gas dimethyl sulfide. The primary model organism for coccolithophore research is Emiliania huxleyi, now named Gephyrocapsa huxleyi. G. huxleyi has a cosmopolitan distribution, occupying coastal and oceanic environments across the globe, and is the most abundant coccolithophore in modern oceans. Research in G. huxleyi has identified many aspects of coccolithophore biology, from cell biology to ecological interactions. In this perspective, we summarize the key advances made using G. huxleyi and examine the emerging tools for research in this model organism. We discuss the key steps that need to be taken by the research community to advance G. huxleyi as a model organism and the suitability of other species as models for specific aspects of coccolithophore biology. [ABSTRACT FROM AUTHOR]

The development of low‐temperature lithium–sulfur batteries (LSB) has been suppressed by rather poor sulfur utilization and cycle performance, caused by planar Li2S growth, hindered lithium polysulfides (LiPSs) transformation, and poor stability of the anode. Recently, low‐concentration electrolytes (LCE) have been employed as promising solutions to solve the above issues. However, aggregation and deposition behavior of polysulfides have been rarely studied. In this work, by comparing the performance of 0.1 and 1 m LiFSI electrolytes, LCEs are proven beneficial for low‐temperature LSBs via new fundamental insights. According to growth pattern analyses by both morphology observation and theoretical models, Li2S nucleation in LCEs switch into progressive mode with less initial nuclei, which favors the vertical growth of Li2S, resulting in a more complete lithium–sulfur conversion reaction under cold conditions. Through visual experiments, computational simulation, and progressive electrochemical impedance spectroscopy, the ability of LCEs to suppress LiPSs clustering is supported and this anti‐clustering ability effectively enhances the Li–S conversion reaction kinetics. Moreover, in LCEs a protective SEI with LiF and Li2S/Li2S2 is likely to form on and stabilize the anode. As a whole, the boosting effect and the mechanism of LCEs enlighten future designs on low‐temperature electrolytes for high‐performance cryogenic LSBs. [ABSTRACT FROM AUTHOR]

Formation of the Kanda Bay resulted from construction of a railway dam (1916) and subsequent isolation of the sea lagoon from the main basin of the Kandalaksha Gulf, White Sea. Decreased action of tidal flows, which mix the water column of the lagoon, altered the hydrological regime of the basin. Decreased water exchange resulted in formation of oxygen-depleted near-bottom water and to sulfide contamination. A freshwater lake was, however, preserved in the southern part of the Kanda Bay. The composition of microbial communities was studied for the near-bottom water horizons at different sides of the Kanda Bay. The oxygen regime in this layer was found to change, with increasing concentrations of sulfide and methane and active processes of sulfate reduction and methane oxidation. The composition of the microbial community changed noticeably, with lower abundance of true marine and freshwater microorganisms and development of bacteria and archaea predominant in microbial communities of anoxic water in meromictic basins. Among the microbial diversity, indicator species with increased abundance were revealed. These are archaea of the genera Methanoregula and Methanosaeta (phylum Halobacterota). The sulfur cycle microorganisms, which were the indicators of stagnant marine water, included anoxygenic phototrophic bacteria of the class Chlorobia, (Chlorobium phaeovibrioides, Pelodictyon phaeoclathratiforme), Chloroflexi of the genus Chloronema, nonsulfur purple bacteria related to the genus Rhodoferax, colorless sulfur bacteria of the family Beggiatoaceae, and sulfur oxidizers of the genus Thiobacillus. Archaea of the genus Nitrosopumilus (phylum Crenarchaeota) and bacteria of the genus Woeseia may be considered opposites to the indicator microorganisms, since they were found only in the open sea water. In our opinion, stable water exchange through the dam will result in the stable composition of the Kanda Bay microbial community, with only seasonal variations and year-to-year fluctuations. The negative scenario supports prediction of conversion of the Kanda Bay into a stratified basin with anoxic near-bottom water and the microbial community similar to that found in meromictic lakes. [ABSTRACT FROM AUTHOR]

Agroecological management is emerging as a promising alternative to current agricultural management, which is associated with deterioration of environmental quality and soil fertility. Therefore, the aim of this study was to evaluate the conversion from conventional to agroecological management by analysing soil chemical and microbiological properties. This study was carried out in the Barrow Experimental Farm of the National Institute of Agricultural Technology (INTA), Buenos Aires, Argentina, where two treatments were evaluated: agroecological (AE) and conventional (CV) management. Samples were taken at 0 - 10 cm depth, and several soil chemical and microbiological parameters were determined. The AE management resulted in an apparent restoration of soil fertility, with increases in soil organic carbon (SOC), total nitrogen (TN) and pH of 21%, 16% and 3%, respectively. AE management also led to an increase in the activities of enzymes involved in the carbon cycle: cellobiohydrolase (CBH) and ß-glucosidase (BG), nitrogen cycle: N-acetyl-β-glucosamine (NAG) and sulfur cycle: arylsulfatase (SUL), as well as an increase in the microbial biomass carbon and in the diversity and richness of the bacterial community (p<0.05). Bacterial and fungal communities differed between treatments (PERMANOVA, bacteria p<0.017 r²=0.1074; fungi p<0.001, r²=0.1973). The bacterial and fungal communities of the AE management were the only ones that correlated positively and significantly with the measured properties, confirming their key role in this system. The bacterial community correlated with the parameters SOC, TN, BG and SUL, while the fungal community correlated with SOC and BG. These results confirm the importance of improving above and belowground biodiversity to maintain or restore soil fertility. [ABSTRACT FROM AUTHOR]

The Tethyan domain hosts the world's most abundant hydrocarbon and Mississippi Valley-type (MVT) Pb-Zn resources. The relations among organic matter-rich sediments, MVT Pb-Zn mineralization, and the Tethyan tectonic evolution history are an important scientific issue. The data of paleogeographic reconstruction indicate that the Proto-, Paleo-, and Neo-Tethys oceans mainly lay in low latitude areas between 30°N and 45°S. The high temperature and precipitation and the lack of sea water overturning in stagnant basins resulted in high marine biological productivity and good preservation conditions for organic matter-rich sediments. Consequently, abundant organic matter-rich sediments were developed and preserved in the Tethyan domain and thus created abundant hydrocarbon resources. Mineralization age data demonstrate that MVT deposits mainly formed during the continent-continent convergence in the late stage of the Tethyan tectonic evolution. Deposits are located in the fold-and-thrust belts and forelands of the continent-continent convergence orogen, and spatially associated with hydrocarbon basins. Organic matter-rich sediments are well developed in MVT ore districts, where hydrocarbon activity appeared earlier than or nearly simultaneous with the Pb-Zn mineralization event. Hydrocarbon activity generally began earlier than the Pb-Zn mineralization in individual deposits. Organic matter-rich sediments and hydrocarbons mainly play the role of reducing agents in the MVT Pb-Zn mineralization process. Through bacterial or thermal reduction, dissolved sulfates from sedimentary strata were reduced to generate reduced sulfur for Pb-Zn sulfide mineralization. In summary, the Tethyan oceans have long been in low latitude areas near the equator, making the Tethyan domain develop abundant organic matter-rich sediments and associated hydrocarbon resources which reduce sulfates to provide sufficient reduced sulfur for MVT Pb-Zn mineralization in the region. [ABSTRACT FROM AUTHOR]

Circulating fluids within Earth's mid-ocean ridge system cool and alter the oceanic crust, contribute distinct chemistry to the ocean, and generate economically and geologically important metal-sulfide deposits at the seafloor. Yet, we have few constraints on the characteristics of these fluids at peak subseafloor pressure and temperature conditions or how the primary variable, seafloor spreading, affects these fluids' delivery of metals and sulfur to seawater. Here, we develop a new, robust technique for estimating the peak endowment of heat and dissolved sulfur, iron, and copper in subseafloor hydrothermal fluids and determining their fate as these superheated fluids rise to the seafloor. Calculations using this technique indicate that >20%-70% of sulfur, iron, and copper dissolved at peak subseafloor conditions are lost during upflow due to cooling and concomitant decreases in sulfide mineral solubility. The interpretation of these estimates within the geologic context of vent fields allows us to demonstrate a strong inverse relationship between seafloor spreading rate and peak pressure-temperature conditions, subseafloor heat loss, and the magnitude of subseafloor sulfide mineralization. Our results demonstrate the extent to which the secular variation of Earth's mid-ocean ridge system over geologic time has impacted sulfide deposition rates and hydrothermal fluxes of sulfur and metals to the ocean. [ABSTRACT FROM AUTHOR]

Organic sulfur plays a crucial role in the biogeochemistry of aquatic sediments, especially in low sulfate (< 500 μM) environments like freshwater lakes and the Earth's early oceans. To better understand organic sulfur cycling in these systems, we followed organic sulfur in the sulfate‐poor (< 40 μM) iron‐rich (30–80 μM) sediments of Lake Superior from source to sink. We identified microbial populations with shotgun metagenomic sequencing and characterized geochemical species in porewater and solid phases. In anoxic sediments, we found an active sulfur cycle fueled primarily by oxidized organic sulfur. Sediment incubations indicated a microbial capacity to hydrolyze sulfonates, sulfate esters, and sulfonic acids to sulfate. Gene abundances for dissimilatory sulfate reduction (dsrAB) increased with depth and coincided with sulfide maxima. Despite these indicators of sulfide formation, sulfide concentrations remain low (< 40 nM) due to both pyritization and organic matter sulfurization. Immediately below the oxycline, pyrite accounted for 13% of total sedimentary sulfur. Both free and intact lipids in this same interval accumulated disulfides, indicating rapid sulfurization even at low concentrations of sulfide. Our investigation revealed a new model of sulfur cycling in a low‐sulfate environment that likely extends to other modern lakes and possibly the ancient ocean, with organic sulfur both fueling sulfate reduction and consuming the resultant sulfide. [ABSTRACT FROM AUTHOR]

The Goshgarchay Cu‐Au deposit is located in the central part of the northwest flank of the Murovdagh region in the Lesser Caucasus. The Goshgarchay Cu‐Au deposit is associated with Middle Jurassic volcanic and Late Jurassic–Early Cretaceous high‐K calc‐alkaline intrusive rocks. The Cu‐Au mineralization is commonly related to quartz‐sericite‐chlorite alteration dominantly composed of chalcopyrite, gold, sphalerite, pyrite, bornite, hematite, covellite, chalcocite, malachite, and azurite. The Goshgarchay copper‐gold deposit, which is 600 m wide and approximately 1.2 km long, is seen as a fault‐controlled and vein‐, stockwork– and disseminated type deposit. The Goshgarchay Cu‐Au deposit predominantly comprises Cu (max. 64500 ppm) and Au (max. 11.3 ppm), while it comprises relatively less amounts Zn (max. 437 ppm), Mo (max. 47.5 ppm), Pb (max. 134 ppm), and Ag (max. 21 ppm). The homogenization temperatures and salinities of fluid inclusions in quartz for stage I range from 380°C to 327°C, and 6.9 wt% to 2.6 wt% NaCl eq., respectively. Th and salinities in quartz for stage II range from 304°C to 253°C, and 7.6 wt% to 3.2 wt% NaCl eq., respectively. The calculated δ34Sh2s values (–1.5‰ to 5.5‰) of sulfides and especially the narrow range of δ34Sh2s values of chalcopyrite and bornite (between –0.07‰ and +0.7‰) indicate that the source of the Goshgarchay Cu‐Au mineralization is magmatic. Based on the mineralogical, geochemical, fluid inclusion, and sulfur isotopic data, the Goshgarchay Cu‐Au deposit represents a late stage peripheral magmatic‐hydrothermal mineralization probably underlain by a concealed porphyry deposit. [ABSTRACT FROM AUTHOR]

The sulfur biogeochemical cycle controls the sulfur dynamics in the soil. In contrast to almost all deposited sulfur leaching out in temperate catchments, approximately 80% of the deposited S is retained in the catchments in subtropical regions. However, the mechanisms for sulfur retention were unclear, hindering the understanding of potential threats of legacy sulfur with environmental changes. Here, we demonstrated that sulfate reduction (as sulfide fixed in soil) was a prominent yet overlooked mechanism for sulfur retention in addition to the widely recognized sulfate adsorption in soil, based on a study on soil sulfur storage and stable isotope signatures within entire soil profiles in a typical subtropical catchment in China. Using a dual‐isotopic model, the sulfate reduction flux was further determined to be 30% of the S deposition. Due to a lot of deposited sulfur fixed via sulfate reduction, the release of soil legacy sulfur would be less in response to decreasing sulfur deposition compared to the projections only considering adsorption. However, the remobilization of large amounts of reduced S should be regarded as a threat to the environment under climate change in the future. Plain Language Summary: Sulfur budget in catchments reveals substantial retention of around 80% of deposited sulfur in subtropical soils, mitigating acidification arising from heightened sulfur deposition. The substantial sulfur retention was previously ascribed to sulfate adsorption. However, our study unveils sulfate reduction as a prominent yet overlooked retention mechanism, evidenced by soil sulfur storage estimates and stable isotope signatures across complete soil profiles in a typical subtropical Chinese catchment. Sulfate adsorption displays reversibility with declining atmospheric deposition. However, sulfate reduction exhibits relatively stable except during periods of frequent drought attributed to climate change or the soil excavation induced by land‐use change. Key Points: A dual isotopic mass balance model was built to quantify the transformations of S in the ecosystemsSulfur retention accounted for approximately 80% of deposition based on the sulfur input–output budgets for 17 sites in subtropical ChinaSulfate reduction was a prominent mechanism for sulfur retention in addition to widely recognized sulfate adsorption [ABSTRACT FROM AUTHOR]

Anthropogenic emissions of aerosols and precursor compounds are known to significantly affect the energy balance of the Earth–atmosphere system, alter the formation of clouds and precipitation, and have a substantial impact on human health and the environment. Global models are an essential tool for examining the impacts of these emissions. In this study, we examine the sensitivity of model results to the assumed height of SO 2 injection, seasonality of SO 2 and black carbon (BC) particulate emissions, and the assumed fraction of SO 2 emissions that is injected into the atmosphere as particulate phase sulfate (SO 4) in 11 climate and chemistry models, including both chemical transport models and the atmospheric component of Earth system models. We find large variation in atmospheric lifetime across models for SO 2 , SO 4 , and BC, with a particularly large relative variation for SO 2 , which indicates that fundamental aspects of atmospheric sulfur chemistry remain uncertain. Of the perturbations examined in this study, the assumed height of SO 2 injection had the largest overall impacts, particularly on global mean net radiative flux (maximum difference of - 0.35 W m -2), SO 2 lifetime over Northern Hemisphere land (maximum difference of 0.8 d), surface SO 2 concentration (up to 59 % decrease), and surface sulfate concentration (up to 23 % increase). Emitting SO 2 at height consistently increased SO 2 and SO 4 column burdens and shortwave cooling, with varying magnitudes, but had inconsistent effects across models on the sign of the change in implied cloud forcing. The assumed SO 4 emission fraction also had a significant impact on net radiative flux and surface sulfate concentration. Because these properties are not standardized across models this is a source of inter-model diversity typically neglected in model intercomparisons. These results imply a need to ensure that anthropogenic emission injection height and SO 4 emission fraction are accurately and consistently represented in global models. [ABSTRACT FROM AUTHOR]

Understanding the composition and sources of atmospheric ultrafine particles (UFPs) is essential in evaluating their exposure risks. It requires long-term measurements with high time resolution, which are scarce to date. We performed near-continuous measurements of UFP composition during four seasons in urban Beijing using a thermal desorption chemical ionization mass spectrometer, accompanied by real-time size distribution measurements. We found that UFPs in urban Beijing are dominated by organic components, varying seasonally from 68 % to 81 %. CHO organics (i.e., molecules containing carbon, hydrogen, and oxygen) are the most abundant in summer, while sulfur-containing organics, some nitrogen-containing organics, nitrate, and chloride are the most abundant in winter. With the increase of particle diameter, the contribution of CHO organics decreases, while that of sulfur-containing and nitrogen-containing organics, nitrate, and chloride increases. Source apportionment analysis of the UFP organics indicates contributions from cooking and vehicle sources, photooxidation sources enriched in CHO organics, and aqueous/heterogeneous sources enriched in nitrogen- and sulfur-containing organics. The increased contributions of cooking, vehicle, and photooxidation components are usually accompanied by simultaneous increases in UFP number concentrations related to cooking emission, vehicle emission, and new particle formation, respectively, while the increased contribution of the aqueous/heterogeneous composition is usually accompanied by the growth of UFP mode diameters. The highest UFP number concentrations in winter are due to the strongest new particle formation, the strongest local primary particle number emissions, and the slowest condensational growth of UFPs to larger sizes. This study provides a comprehensive understanding of urban UFP composition and sources and offers valuable datasets for the evaluation of UFP exposure risks. [ABSTRACT FROM AUTHOR]

The Precambrian‐Cambrian (Pc‐C) boundary marks significant biological, atmospheric, and oceanic changes. These changes include extinction of the Ediacaran fauna, initiation of complex lifeforms, and oxygenation of the atmosphere and oceans. In this contribution, elemental and Mo‐S isotopic compositions of organic‐rich shales overlying the Pc‐C boundary from the Tal Formation, Lesser Himalaya, have been investigated. These datasets are used to reconstruct past oceanic redox state and sulfate concentrations. The principal component analysis of the elemental dataset identifies six major factors, with factors associated with organic matter and sulfide phases accounting for about half of the total variance. Iron speciation and Mo/U data suggest that the shales were deposited in anoxic and ferruginous deep water conditions. The δ98Mo data (1.5 ± 0.2‰) and their mass balance calculations indicate that the areal extent of sulfidic waters and pyrite burial rates were about 2–4 times higher during the Pc‐C transition than in the modern ocean. The pyrite‐δ34S values (3.6–8.3‰) for the Tal shales are isotopically heavier compared to modern‐day sedimentary pyrites (∼−21‰). Calculations involving earlier‐reported δ34S values for early Cambrian seawater and our measured pyrite‐δ34S data estimate the seawater sulfate concentration (8 ± 3 mM) during their deposition. This sulfate value for the Tal basin is higher than that reported for the late Neoproterozoic ocean (<5 mM), attributable to increasing oxygen availability and continental supply during this time. The observed basinal conditions and high terrestrial input may have influenced metazoan diversification. Key Points: Chemical and Mo‐S isotopic study of black shales overlying the Pc‐C boundary from the Tal Formation (Lesser Himalaya) was carried outTrace element, Fe‐speciation and Mo isotopic data suggest a stratified basin with anoxic and ferruginous bottom water conditionsHigher seawater sulfate (∼8 mM) during the Pc‐C transition (than Proterozoic) linked to atmospheric oxygenation and enhanced riverine input [ABSTRACT FROM AUTHOR]

Authigenic molybdenum (Moauth) in marine sediments holds great potential to archive the Mo isotopic composition of seawater and biogeochemical processes. However, the factors that control authigenic Mo isotope (δ98Moauth) distribution patterns remain poorly constrained. Here, we report Mo abundances and δ98Mo compositions for bulk‐rock (bulk) and sequentially extracted fractions—including total authigenic (auth; i.e., non‐lithogenic fraction), carbonate (carb), iron and manganese oxyhydroxides, pyrite (py), and organic fractions (OM)—of authigenic carbonates recovered from various hydrocarbon seep sites in the Gulf of Mexico and the South China Sea. Extracted pyrite fractions exhibit Mo contents varying from 0.1 to 23.4 μg/g and generally dominate the Mo budget of seep carbonate rocks. Our data indicate large ranges of δ98Mobulk and δ98Moauth values relative to NIST 3134 (0.25‰), varying from 1.02 to 1.98‰ (n = 4) and from 0.15 to 3.07‰ (n = 34), respectively. The difference in δ98Mo values between carbonate and pyrite fractions of seep carbonate rocks formed under sulfidic conditions increases with higher Moauth contents, suggesting a control of dissolved hydrogen sulfide concentrations on Mo isotope fractionation during carbonate precipitation. Compared with δ98Moauth and δ98Mopy, δ98Mocarb of seep carbonate rocks formed under sulfidic conditions shows a relatively narrow range with an average of 1.98 ± 0.31‰ (1 SD; n = 10), providing constraints on the δ98Mo composition of seawater in the course of Earth history. Overall, our findings show that the δ98Mo composition of sequentially extracted phases of carbonate‐rich sedimentary rocks can provide insights into seawater‐sediment interactions and biogeochemical pathways of Mo during early diagenesis. Plain Language Summary: Sulfate reduction has created widespread euxinic conditions in the water column of ancient oceans and prevalent sulfidic conditions in subseafloor pore‐water environments of the modern ocean. Ancient seawater δ98Mo compositions have been considered to reflect the overall extent of oxic versus euxinic conditions of the global ocean, highlighting the importance of a robust reconstruction of the marine Mo isotope inventory largely unaffected by diagenesis. Under sulfidic conditions, the seawater δ98Mo value can be archived by authigenic Mo in marine carbonate sediments formed during early diagenesis. However, the conditions of capturing the seawater δ98Mo signature remain poorly constrained. Using a sequentially chemical leaching procedure, we investigated Mo contents and isotopic compositions of different fractions of modern seafloor seep carbonate rocks. Our results show that a δ98Mo average value of 1.98 ± 0.31‰ (1 SD; n = 10) of the carbonate mineral phase results from small or no Mo isotope fractionation during near‐quantitative authigenic Mo sequestration under sulfidic conditions, potentially capturing seawater δ98Mo. Our study shows that δ98Mo of sequentially extracted phases of sedimentary carbonate rocks is a robust tool to constrain seawater and pore fluid properties. Key Points: δ98Mo of sequentially extracted phases of carbonates is useful to trace Mo isotope fractionation during early diagenesisDegree of Mo isotope fractionation during carbonate precipitation is controlled by hydrogen sulfide concentrationsAuthigenic Mo sequestration into the carbonate phase under sulfidic conditions generates small Mo isotope fractionation [ABSTRACT FROM AUTHOR]

Lithium–sulfur (Li-S) batteries are the most attractive candidates for next-generation large-scale energy storage because of their high theoretical energy density and the affordability of sulfur. However, most of the reported research primarily concentrates on low sulfur loading (below 2 mgs cm−2) cathodes using binders and traditional collectors, thus undermining the expected energy density. Herein, a N, O co-doped carbon nanotube (N, O-CNT) decorated wood framework (WF), denoted as WF-CNT, was designed as a free-standing sulfur host, achieving high sulfur loading of 10 mgs cm−2. This unique cathode featured low tortuosity microchannels and a conductive framework, reducing the diffusion paths for both ions and electrons and accommodating the volume changes associated with sulfur. Moreover, the internal CNT forests effectively captured soluble lithium polysulfides (LiPSs) and catalyze their redox kinetic. Consequently, the S@WF-CNT-800 sample exhibited a high initial discharge capacity of 1438.2 mAh g−1 at a high current density of 0.5 A g−1. Furthermore, a reversible capacity of 404.5 mAh g−1 was obtained after 500 cycles with sulfur loading of 5 mgs cm−2 at 0.5 A g−1. This work may support the development of high sulfur loading cathodes utilizing cost-effective and sustainable biomass materials for Li-S batteries. [ABSTRACT FROM AUTHOR]

Pyrite is an important proxy used to reflect the redox state of a sedimentary environment. Currently available studies on pyrite focus on the process of sulfur cycles between an ocean and sediment. However, our understanding of the biogeochemical cycle of sulfur in terrestrial lake basins remains unclear, and the growth patterns of different types of pyrite are poorly understood. In this paper, we used samples from the 34 section of the Qianjiang depression in the Jianghan Basin as direct research objects by combining pyrite and sulfur isotope determination. The one-dimensional diffusion–advection–reaction simulation (1D-DAR) model was applied to simulate the changes in the pyrite content and sulfur isotope values in the sediment. The results show that the sediments in the saline lake basin environment contain a high organic matter content, a high sedimentation rate, and a high H2S diffusion oxidation rate, reflecting the strong reducing background and high productivity of this ancient lake. Sensitivity tests revealed that the organic matter content and H2S diffusion oxidation rate at the sediment–water interface are sensitive to the pyrite content. The sedimentation rate, organic matter content, and sulfate concentration are sensitive to the pyrite’s sulfur isotope values. However, the variation in the active iron content had little effect on the pyrite content or sulfur isotope value.

Reconstructions of coupled carbon, oxygen, and sulfur cycles rely heavily on sedimentary pyrite sulfur isotope compositions (d34Spyr). With a model of sediment diagenesis, paired with global datasets of sedimentary parameters, we show that the wide range of d34Spyr (~100 per mil) in modern marine sediments arises from geographic patterns in the relative rates of diffusion, burial, and microbial reduction of sulfate. By contrast, the microbial sulfur isotope fractionation remains large and relatively uniform. Over Earth history, the effect of increasing seawater sulfate and oxygen concentrations on sulfate and sulfide transport and reaction may explain the corresponding increase observed in the d34S offset between sulfate and pyrite. More subtle variations may be related to changes in depositional environments associated with sea level fluctuations and supercontinent cycles. [ABSTRACT FROM AUTHOR]

Reconstructions of past environmental conditions and biological activity are often based on bulk stable isotope proxies, which are inherently open to multiple interpretations. This is particularly true of the sulfur isotopic composition of sedimentary pyrite (δ34Spyr), which is used to reconstruct ocean-atmosphere oxidation state and track the evolution of several microbial metabolic pathways. We present a microanalytical approach to deconvolving the multiple signals that influence δ34Spyr, yielding both the unambiguous determination of microbial isotopic fractionation (εmic) and new information about depositional conditions. We applied this approach to recent glacial-interglacial sediments, which feature over 70‰ variations in bulk δ34Spyr across these environmental transitions. Despite profound environmental change, εmic remained essentially invariant throughout this interval and the observed range in δ34Spyr was instead driven by climate-induced variations in sedimentation. [ABSTRACT FROM AUTHOR]

Investigations into lithium–sulfur batteries (LSBs) has focused primarily on the initial conversion of lithium polysulfides (LiPSs) to Li2S2. However, the subsequent solid–solid reaction from Li2S2 to Li2S and the Li2S decomposition process should be equally prioritized. Creating a virtuous cycle by balancing all three chemical reaction processes is crucial for realizing practical LSBs. Herein, amorphous Ni3B in synergy with carbon nanotubes (aNi3B@CNTs) is proposed to implement the consecutive catalysis of S8(solid) → LiPSs(liquid) → Li2S(solid) →LiPSs(liquid). Systematic theoretical simulations and experimental analyses reveal that aNi3B@CNTs with an isotropic structure and abundant active sites can ensure rapid LiPSs adsorption‐catalysis as well as uniform Li2S precipitation. The uniform Li2S deposition in synergy with catalysis of aNi3B enables instant/complete oxidation of Li2S to LiPSs. The produced LiPSs are again rapidly and uniformly adsorbed for the next sulfur evolution process, thus creating a virtuous cycle for sulfur species conversion. Accordingly, the aNi3B@CNTs‐based cell presents remarkable rate capability, long‐term cycle life, and superior cyclic stability, even under high sulfur loading and extreme temperature environments. This study proposes the significance of creating a virtuous cycle for sulfur species conversion to realize practical LSBs. [ABSTRACT FROM AUTHOR]

Here we present stable carbon, nitrogen and sulfur isotope ratios of collagen extracted from Rangifer, Equus and Bison bone (n = 128) from different stratigraphic levels at the chronologically well-constrained Middle and Upper Palaeolithic site of Les Cottés, France. Samples were taken from five phases of site use (US08, US06, US04 [upper and lower], and US02; ~ 45.8–35.3 ka cal BP) to explore the dietary and spatial palaeoecology of these ungulate species during MIS 3, and the contemporary climate. Temporal trends in δ15N values of all species broadly align with other climatic indicators at the site and the lowest values in US04 correspond to the Heinrich 4 cooling event, reflecting changes in the composition of soil/plant nitrogen at this time. Rangifer collagen is 13C-enriched compared to the other species throughout, consistent with lichen consumption. However, this isotopic niche partitioning between Rangifer and Equus/Bison is most extensive during US04, indicating plasticity in reindeer feeding behaviour, and potentially overall increased lichen biomass during this cooler/more arid phase. Rangifer δ34S values are consistently lower than Equus and Bison, which could be indicative of their more extensive spatial ranges incorporating greater inland areas. Equus and Bison demonstrate a significant decrease in δ34S values through time, which may be linked to contemporary climatic decline. [ABSTRACT FROM AUTHOR]

The formation of secondary sulfate in the atmosphere remains controversial, and it is urgent to seek for a new method to quantify different sulfate formation pathways. Thus, SO2 and PM2.5 samples were collected from 4 to 22 Dec. 2019 in Nanjing. Sulfur and oxygen isotope compositions were synchronously measured to study the contribution of SO2 homogeneous and heterogeneous oxidation to sulfate. Meanwhile, the correlation of δ18O values between H2O and sulfate from SO2 oxidation by H2O2 and Fe3+/O2 were investigated in the lab. Based on isotope mass equilibrium equations, the ratios of different SO2 oxidation pathways were calculated. The results showed that secondary sulfate constituted higher than 80 % of total sulfate in PM2.5 during the sampling period. Laboratory simulation experiments indicated that δ18O of sulfate was linearly dependent on δ18O of water, and the slopes of linear curves for SO2 oxidation by H2O2 and Fe3+/O2 were 0.43 and 0.65, respectively. The secondary sulfate in PM2.5 was mainly ascribed to SO2 homogeneous oxidation by OH radicals and heterogeneous oxidation by H2O2 and Fe3+/O2. SO2 heterogeneous oxidation was generally dominant during sulfate formation, and the contribution of SO2 heterogeneous oxidation was about 52 %. Especially, SO2 oxidation by H2O2 predominated in SO2 heterogeneous oxidation reactions with an average ratio around 55 %. This study provided an insight into precisely evaluating sulfate formation pathways by combining stable sulfur and oxygen isotopes. [ABSTRACT FROM AUTHOR]