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Developing bifunctional catalysts for overall water splitting with high activity and durability at high current density remains a challenge. In an attempt to overcome this bottleneck, in this work, unique CoNiFe-layered double hydroxide nanoflowers are in situ grown on nickel-iron (NiFe) foam through a corrosive approach and following a chemical vapor deposition process to generate nitrogen-doped carbon nanotubes at the presence of melamine (CoNiFe@NCNTs). The coupling effects between various metal species act a key role in accelerating the reaction kinetics. Moreover, the in situ formed NCNTs also favor promoting electrocatalytic activity and stability. For oxygen evolution reaction it requires low overpotentials of 330 and 341 mV in 1M KOH and 1M KOH + seawater to drive 500 mA cm−2. Moreover, water electrolysis can be operated with CoNiFe@NCNTs as both anode and cathode with small voltages of 1.95 and 1.93 V to achieve 500 mA cm−2 in 1M KOH and 1M KOH + seawater, respectively. [ABSTRACT FROM AUTHOR]

Extracting uranium from the ocean is considered a promising solution for meeting nuclear fuel consumption. To date, porous adsorbents fabricated with polyamidoxime (PAO), particularly macroporous PAO hydrogels, have demonstrated exceptional potential for uranium capture from natural seawater. Herein, a novel macroporous PAO hydrogel is developed via a well‐designed wax‐casting method. The developed wax‐casted macroporous PAO (WMPAO) hydrogel particles are subsequently encapsulated in alginate‐polyacrylic acid (A‐PAA) beads. The obtained A‐PAA@WMPAO beads exhibit a high qmax of 687.4 mg‐U/g‐Ads. and show a good adsorption capacity of 8.23 mg g−1 toward uranium in simulated seawater. Additionally, A‐PAA@WMPAO shows good reusability with a 31.2% reduction in uranium adsorption capacity after five consecutive adsorption‐desorption cycles. Furthermore, A‐PAA@WMPAO displays satisfactory extraction efficiencies of 95.9–99.5% for U‐spiked coastal seawater after 10 days of adsorption, achieving adsorption capacities ranging from 207.5 to 3963.2 µg g−1. Particularly, with the utilization of 4 mg of A‐PAA@WMPAO beads, a high adsorption capacity of 4.79 mg g−1 for uranium from 10 L of coastal seawater within 15 days is achieved. These obtained results comprehensively demonstrate the significant potential of the fabricated A‐PAA@WMPAO beads for uranium capture from natural seawater. [ABSTRACT FROM AUTHOR]

Direct electrochemical seawater splitting is a renewable, scalable, and potentially economic approach for green hydrogen production in environments where ultra‐pure water is not readily available. However, issues related to low durability caused by complex ions in seawater pose great challenges for its industrialization. In this review, a mechanistic analysis of durability issues of electrolytic seawater splitting is discussed. We critically analyze the development of seawater electrolysis and identify the durability challenges at both the anode and cathode. Particular emphasis is given to elucidating rational strategies for designing electrocatalysts/electrodes/interfaces with long lifetimes in realistic seawater including inducing passivating anion layers, preferential OH−adsorption, employing anti‐corrosion materials, fabricating protective layers, immobilizing Cl− on the surface of electrocatalysts, tailoring Cl− adsorption sites, inhibition of OH− binding to Mg2+ and Ca2+, inhibition of Mg and Ca hydroxide precipitation adherence, and co‐electrosynthesis of nano‐sized Mg hydroxides. Synthesis methods of electrocatalysts/electrodes and innovations in electrolyzer are also discussed. Furthermore, the prospects for developing seawater splitting technologies for clean hydrogen generation are summarized. We found that researchers have rethought the role of Cl− ions, as well as more attention to cathodic reaction and electrolyzers, which is conducive to accelerate the commercialization of seawater electrolysis. [ABSTRACT FROM AUTHOR]

Recent increases in frequency and intensity of warm water anomalies and marine heatwaves have led to shifts in species ranges and assemblages. Genomic tools can be instrumental in detecting such shifts. In the early stages of a project assessing population genetic structure in Pacific Sardine (Sardinops sagax), we detected the presence of Japanese Sardine (Sardinops melanosticta) along the west coast of North America for the first time. We assembled a high quality, chromosome‐scale reference genome of the Pacific Sardine and generated low coverage, whole genome sequence (lcWGS) data for 345 sardine collected in the California Current Large Marine Ecosystem (CCLME) in 2021 and 2022. Fifty individuals sampled in 2022 were identified as Japanese Sardine based on strong differentiation observed in lcWGS SNP and full mitogenome data. Although we detected a single case of mitochondrial introgression, we did not observe evidence for recent hybridization events. These findings change our understanding of Sardinops spp. distribution and dispersal in the Pacific and highlight the importance of long‐term monitoring programs. [ABSTRACT FROM AUTHOR]

Environmental transitions, such as the salinity divide separating marine and fresh waters, shape biodiversity over both shallow and deep timescales, opening up new niches and creating opportunities for accelerated speciation and adaptive radiation. Understanding the genetics of environmental adaptation is central to understanding how organisms colonise and subsequently diversify in new habitats. We used time‐resolved transcriptomics to contrast the hyposalinity stress responses of two diatoms. Skeletonema marinoi has deep marine ancestry but has recently invaded brackish waters. Cyclotella cryptica has deep freshwater ancestry and can withstand a much broader salinity range. Skeletonema marinoi is less adept at mitigating even mild salinity stress compared to Cyclotella cryptica, which has distinct mechanisms for rapid mitigation of hyposaline stress and long‐term growth in low salinity. We show that the cellular mechanisms underlying low salinity tolerance, which has allowed diversification across freshwater habitats worldwide, includes elements that are both conserved and variable across the diatom lineage. The balance between ancestral and lineage‐specific environmental responses in phytoplankton have shaped marine–freshwater transitions on evolutionary timescales and, on contemporary timescales, will affect which lineages survive and adapt to changing ocean conditions. [ABSTRACT FROM AUTHOR]

We conducted a study to investigate the potential effects of nutrients released from a fish farm, which fell within the typical range found in oligotrophic offshore waters of the Aegean Sea, on phytoplankton growth. We designed an in situ bioassay experiment at a fish farm and incubated natural phytoplankton assemblages inside dialysis membrane bags for six days. Changes in phytoplankton growth in samples of ambient seawater collected throughout the experiment served as controls and were considered indicative of the net population change rates. Half of the bags were filled with seawater filtered through a 150-µm mesh, while the other half contained unfiltered seawater. The growth rates, estimated based on chlorophyll a concentrations and phytoplankton cell numbers inside the filtered and unfiltered bags, showed no significant differences. While no detectable net phytoplankton growth occurred in the ambient seawater, there was an exponential increase in chlorophyll a content and cell numbers within the bags. Moreover, the species richness within the bags gradually declined throughout the experiment. The findings of the study confirm that continuous nutrient releases from fish farms can promote high population growth rates in oligotrophic environments, provided that phytoplankton losses due to grazing, advection, and sinking are minimized or eliminated. [ABSTRACT FROM AUTHOR]

It is estimated that at least 25 % of the anthropogenic carbon dioxide (CO 2) emitted to the atmosphere since the start of the industrial revolution has been absorbed and dissolved by the oceans. The uptake of CO 2 by the oceans leads to an increase in the seawater proton concentration ([H+]), and decreases in seawater pH, carbonate ion concentration ([CO 3 2–]), and saturation state (Ω) with respect to calcium carbonate (CaCO 3) minerals; a process commonly referred to as "ocean acidification". Shallow-water (<200 m), high-magnesium, biogenic calcites are expected to be amongst the first to respond to ocean acidification, and it has been proposed that they will dissolve selectively and sequentially according to their solubility in seawater. In this study, we test this competitive dissolution hypothesis by reacting a mixture of biogenic and synthetic carbonates of varying Mg content with acidified, natural seawater to simulate the progressive acidification of surface-ocean waters by anthropogenic CO 2. The results of this study confirm the hypothesis that carbonates will dissolve sequentially according to their respective solubility. They also reveal that the dissolution of high Mg-calcites will proceed incongruently. The originality of this contribution rests with the demonstration that the presence of a single high Mg-calcite will generate, like in a sediment of mixed mineralogy, a continuum of transient states as lower Mg-calcites of greater stability are precipitated and dissolved. Consequently, in a semi-closed or closed system, the pH buffering of the acidified seawater solution will be progressive rather than occur in steps according to changes in the solubility of the individual carbonate phases that compose a sediment. Hence, we expect that, as the oceans take up more anthropogenic CO 2 and further acidify, the average mineralogy and composition (Mg content) of shallow-water carbonate sediments and reef structures will change over the next few centuries as the most soluble carbonate phases (high-Mg calcites) are dissolved and no longer precipitated. [ABSTRACT FROM AUTHOR]

Prussian blue (PB) is regarded as a promising cathode for sodium‐ion batteries because of its sustainable precursor elements (e.g., Mn, Fe), easy preparation, and unique framework structure. However, the unstable structure and inherent crystal H2O restrain its practical application. For this purpose, a self‐constructed trace Mg2+/K+ co‐doped PB prepared via a sea‐water‐mediated method is proposed to address this problem. The Mg2+/K+ co‐doping in the Na sites of PB is permitted by both thermodynamics and kinetics factors when synthesized in sea water. The results reveal that the introduced Mg2+ and K+ are immovable in the PB lattices and can form stronger K‒N and Mg‒N Coulombic attraction to relieve phase transition and element dissolution. Besides, the Mg2+/K+ co‐doping can reduce defect and H2O contents. As a result, the PB prepared in sea water exhibits an extremely long cycle life (80.1% retention after 2400 cycles) and superior rate capability (90.4% capacity retention at 20 C relative to that at 0.1 C). To address its practical applications, a sodium salts recycling strategy is proposed to greatly reduce the PB production cost. This work provides a self‐constructed Mg2+/K+ co‐doped high‐performance PB at a low preparation cost for sustainable, large‐scale energy storage. [ABSTRACT FROM AUTHOR]

NiFe‐based hydroxides are well‐established as efficient electrocatalysts for the oxygen evolution reaction (OER) in alkaline purified water. However, they usually degrade rapidly in seawater electrolysis because of concentrated Cl− anions in seawater. In this work, a facile approach utilizing an ultrafast dipping method is presented to fabricate durable and scalable NiFe hydroxides, enhanced by interfacial akaganéite FeOOH for seawater splitting. This study reveals significantly improved electrocatalytic stability of NiFe hydroxides at an ampere‐level current density of 1000 mA cm−2 for 100 h in alkaline seawater. It is realized by the formed FeOOH in a specific akaganéite phase whose lattice tunnels are well filled by intrinsic Cl− anions, that serve to electrostatically repel corrosive chlorides in electrolyte. This anionic design also provides superior corrosion protection for other active metal‐based OER electrocatalysts when deployed in alkaline purified water and allows for facile scaling up of the anode, facilitating the practical utilization for seawater electrolysis. [ABSTRACT FROM AUTHOR]

ABSTRACT To evaluate the global seawater corrosivity and ensure the service safety of marine equipment, the methods of seawater corrosivity classification, which contained the standard metal corrosion rates method and the environmental factors evaluation method, are proposed and then applied to the seawater corrosivity classification in typical China seas. By comparing the results from both methods, the feasibility of the environmental factors evaluation method based on the grey relational model is verified. Furthermore, with the collection and processing of typical seawater factors data of global ocean, the corrosivity of global seawater is classified into six grades with the corrosion test data of carbon steel as baseline, and its distribution in different months is visualized by means of ArcGIS technology. The results show that the sea areas with high corrosivity are mainly located at equatorial and tropical sea areas, and for carbon steel, seawater temperature was the main influence on seawater corrosivity. [ABSTRACT FROM AUTHOR]

Aquaculture in exposed and/or distant ocean sites is an emerging industry and field of study that addresses the need to improve food security along with the challenges posed by expansion of urban and coastal stakeholders into nearshore and sheltered marine waters. This move necessitates innovative solutions for this industry to thrive in high-energy environments. Some innovative research has increased understanding of the physics, hydrodynamics, and structural requirements enabling the development of appropriate systems. The blue mussel (Mytilus edulis), the New Zealand green shell or green lipped mussel (Perna canaliculus), and the Pacific Oyster (Magallana gigas), are the primary targets for commercial exposed bivalve aquaculture. Researchers and industry members are actively advancing existing structures and developing new structures and methodologies for these and alternative high-value species suitable for such conditions. For macroalgae (seaweed) cultivation, such as sugar kelp (Saccharina latissimi), oar weed (Laminaria digitata), or kelp sp. (Ecklonia sp.), longline systems are commonly used, but further development is needed to withstand fully exposed environments and improve productivity and efficiency. In marine finfish aquaculture, three primary design categories for open ocean net pens are identified: flexible gravity pens, rigid megastructures, closed pens, and submersible pens. As aquaculture ventures into more demanding environments, a concerted focus on operational efficiency is imperative. This publication considers the commercial and research progress relating to the requirements of aquaculture's expansion into exposed seas, with a particular focus on the cultivation of bivalves, macroalgae, and marine finfish cultivation technologies and structural developments. [ABSTRACT FROM AUTHOR]

Background: Salmon aquaculture involves freshwater and seawater phases. Recently there has been an increase in multifactorial gill health challenges during the seawater phase which has led to an urgent need to understand the gill microbiome. There is a lack of understanding on what drives the composition of the gill microbiome, and the influence the freshwater stage has on its long-term composition. We characterise the gill microbiome from seven cohorts of Atlantic salmon raised in six different freshwater operational systems—recirculating aquaculture system (RAS), flowthrough (FT) and loch-based system, prior to and after transfer to seven seawater farms, over two different input seasons, S0 (2018) and S1 (2019). Results: Using the V1-V2 region of the 16S rRNA gene, we produced amplicon libraries absent of host contamination. We showed that hatchery system influenced the gill microbiome (PERMAOVA R2 = 0.226, p < 0.001). Loch and FT systems were more similar to each other than the three RAS systems, which clustered together. On transfer to sea, the gill microbiomes of all fish changed and became more similar irrespective of the initial hatchery system, seawater farm location or season of input. Even though the gill microbiome among seawater farm locations were different between locations (PERMAOVA R2 = 0.528, p < 0.001), a clustering of the gill microbiomes by hatchery system of origin was still observed 7–25 days after transfer (PERMAOVA R = 0.164, p < 0.001). Core microbiomes at genera level were observed among all fish in addition to freshwater only, and seawater only. At ASV level core microbiomes were observed among FT and loch freshwater systems only and among all seawater salmon. The gill microbiome and surrounding water at each hatchery had more shared ASVs than seawater farms. Conclusion: We showed hatchery system, loch, FT or RAS, significantly impacted the gill microbiome. On transfer to sea, the microbiomes changed and became more similar. After transfer, the individual sites to which the fish were transferred has a significant influence on microbiome composition, but interesting some clustering by hatchery system remained. Future gill disease mitigation methods that target enhancing the gill microbiome may be most effective in the freshwater stage, as there were more shared ASVs between water and gill at hatchery, compared to at sea. [ABSTRACT FROM AUTHOR]

Suffering from their low conductivity, Mn-base oxides are commonly inactive in H–OH activation. Generally, tailoring the coordinate environment of materials could induce variation in the atomic arrangement and further influence their chemical activity. Herein, we propose a feasible strategy to mediate the electronic structure of Mn-based oxides by facile hydrothermal method and thermal reduction route. Compared with MnO 2 sheets, the as-synthesized Ru/MnO–Mn 7 C 3 /N-doped carbon sheets (Ru/MnO–Mn 7 C 3 /NC) exhibit the higher activity for both acidic (73 mV) and alkaline water reduction reaction (44 mV@10 mA/cm2). Benefitting from unique structures, Ru/MnO–Mn 7 C 3 /NC sheets show the better freshwater/seawater oxidation reactivity, exceeding RuO 2. The strong interaction of MnO–Mn 7 C 3 heterostructures, Ru, and N-doped carbon endows Ru/MnO–Mn 7 C 3 /NC with the good freshwater and seawater dissociation performance, outperforming most of the reported Mn-based oxides. Ru/MnO–Mn 7 C 3 /N-doped carbon sheets could considerably catalyze dissociation of freshwater/seawater into H 2 with 1.52/1.65V at 10 mA/cm2. [Display omitted] • Ru/MnO–Mn 7 C 3 /N-doped carbon sheets are rationally fabricated. • Ru, MnO–Mn 7 C 3 heterojunction, and N-doped carbon are observed. • It achieves high acidic and alkaline hydrogen generation efficiency. • It possesses the pronounced freshwater/seawater electrolysis reactivity. [ABSTRACT FROM AUTHOR]

In Katell Quillévéré's Réparer les vivants (2016), based on Maylis de Kerangal's best-selling novel, a fatal road accident after a surfing trip leaves Simon Limbres (Gabin Verdet) braindead. His vital organs will be donated, and his heart transplanted into Claire Méjean (Anne Dorval). These grave events shape the film's narrative arc, with the heart connecting Simon's death to Claire's rebirth. Yet this heart transplant film is indebted to a more archaic, elemental connectivity between the heart and the sea, blood and seawater, recognised variously from Galen to René Quinton and beyond. A fusion of the elements of air and water with breath positions the film distinctively in relation to scholarship on the elements and on breathing in film and media studies, inviting its watery bonds to be theorised anew. Engaging with such research before drawing upon Gilles Deleuze's writings on the fold and film scholarship indebted to his work, this article explores how the film's narrative is enfolded into tight formal bonds with the elements, air and water in particular. The lifeblood of this film and its affective heart emerge through myriad folds of foaming, curving waves. [ABSTRACT FROM AUTHOR]

Understanding fate and transport processes for per‐ and poly‐fluoroalkyl substances (PFAS) is critical for managing impacted sites. "PFAS Salting Out" in groundwater, defined herein, is an understudied process where PFAS in fresh groundwater mixes with saline groundwater near marine shorelines, which increases sorption of PFAS to aquifer solids. While sorption reduces PFAS mass discharge to marine surface water, the fraction that sorbs to beach sediments may be mobilized under future salinity changes. The objective of this study was to conceptually explore the potential for PFAS Salting Out in sandy beach environments and to perform a preliminary broad‐scale characterization of sandy shoreline areas in the continental U.S. While no site‐specific PFAS data were collected, our conceptual approach involved developing a multivariate regression model that assessed how tidal amplitude and freshwater submarine groundwater discharge affect the mixing of fresh and saline groundwater in sandy coastal aquifers. We then applied this model to 143 U.S. shoreline areas with sandy beaches (21% of total beaches in the USA), indirectly mapping potential salinity increases in shallow freshwater PFAS plumes as low (<10 ppt), medium (10–20 ppt), or high (>20 ppt) along groundwater flow paths before reaching the ocean. Higher potential salinity increases were observed in West Coast bays and the North Atlantic coastline, due to the combination of moderate to large tides and large fresh groundwater discharge rates, while lower increases occurred along the Gulf of Mexico and the southern Florida Atlantic coast. The salinity increases were used to estimate potential perfluorooctane sulfonic acid (PFOS) sorption in groundwater due to salting out processes. Low‐category shorelines may see a 1‐ to 2.5‐fold increase in sorption of PFOS, medium‐category a 2.0‐ to 6.4‐fold increase, and high‐category a 3.8‐ to 25‐fold increase in PFOS sorption. The analysis presented provides a first critical step in developing a large‐scale approach to classify the PFAS Salting Out potential along shorelines and the limitations of the approach adopted highlights important areas for further research. [ABSTRACT FROM AUTHOR]

The pressure infiltration of fresh and salty bentonite slurries against a medium-fine sand has been investigated in a laboratory setup. In the tests, two series of salty bentonite slurries were used: non-pre-hydrated salty slurry, for exploring what will happen if directly salty water is used to make bentonite slurry, and pre-hydrated salty slurry, for identifying the consequence of pre-hydrated fresh bentonite slurry mixing with the salty water in the soil pores. The salty water employed was a mixture of different percentages of freshwater and seawater. Experimental results show that the test with non-pre-hydrated salty slurry exhibited a significantly faster and shorter (time) mud spurt, or even no mud spurt at all, compared to the test with fresh or pre-hydrated salty slurry. The influence of salty water on the pre-hydrated fresh bentonite is less than on the non-pre-hydrated slurry and depends on the seawater content in the salty water. Compared with the test with fresh bentonite slurry, a slower and shorter (time) mud spurt could be seen in the test with the pre-hydrated salty slurry when the seawater content was not more than 20%. As seawater content exceeded 20%, a faster mud spurt showed up; however, the timespan of the mud spurt may be shorter or longer, mainly depending on the viscosity and sedimentation behavior of the bentonite. A model to estimate the slurry infiltration distance during mud spurt is introduced, which agrees well with the experimental results using the measured input parameters. After the mud spurt, a filter cake would form in each test. The permeability of the filter cake increased with the increase in seawater content. Directly mixing salty water remarkably increased the permeability of the filter cake, while the pre-hydration of bentonite could reduce this increase. For instance, with the salty water containing 10% seawater, the permeabilities of the filter cakes formed by fresh bentonite slurry, non-pre-hydrated salty slurry, and pre-hydrated salty slurry with the 50 g/L bentonite concentration were 1.69 × 10−9 m/s, 2.26 × 10−8 m/s, and 3.23 × 10−9 m/s, respectively. [ABSTRACT FROM AUTHOR]

Seawater chlorination has three main industrial uses: disinfection of water and installations, control of biofouling, and preventing the transport of aquatic invasive species. Once in contact with seawater, chlorine reacts rapidly with water constituents (e.g. bromide ions, ammonia, and nitrogen-containing compounds) to form a range of oxidative species (e.g. bromine and N-haloamines), termed "chlorine-produced oxidants" (CPOs) or "total residual oxidants" (TRO). The chemical nature of CPOs and their concentration are a function of two categories of parameters related to treatment modality (e.g. chlorine dose) and water quality (e.g. temperature, pH, ammonia concentration, and organic constituents). The chlorination process may result in continuous or intermittent releases of CPOs in seawater. The reactivity and potential ecotoxicity of CPO species largely depend on their physical and chemical properties. Therefore, evaluation of the biocidal effectiveness of chlorination and its potential impacts requires not only determining the sum of CPOs (via a bulk parameter), but also their chemical speciation. The aim of this article – which is the first of a trilogy dedicated to the chemical speciation of CPOs in seawater – is to provide an overview of current knowledge about chlorine chemistry in seawater and to discuss the biocidal efficacy and the environmental fate of resulting CPOs. The 2nd and 3rd articles delineate a comprehensive and critical review of analytical methods and approaches for the determination of CPOs in seawater. [ABSTRACT FROM AUTHOR]

Chlorination of seawater forms a range of secondary oxidative species, collectively termed "chlorine-produced oxidants" (CPOs). These compounds do not have the same biocidal efficacy, the same fate and behavior in the marine environment, the same potential formation of chlorination by-products (CBPs), nor the same effects on marine organisms. Their chemical speciation is an important step toward an accurate assessment of the effectiveness of chlorination and the potential impacts of its releases, among others. The aim of this paper - which is the second of a trilogy dedicated to the chemical speciation of CPOs in seawater - is to cover all aspects related to CPOs analysis in seawater, from sampling to instrumental determination. First, it discusses the procedures involved in synthesis, storage, and standardization of analytical standards. Second, it deals with sampling and sample preparation, addressing all relevant issues related to these two key steps. Third, it provides a comprehensive and up-to-date overview of the colorimetric, titrimetric, and electrochemical methods used for CPOs determination and thoroughly discusses their advantages and limitations. Finally, this review ends with some recommendations for progress in the field of CPO analysis with the three aforementioned approaches. Chromatographic and mass spectrometric-based methods will be covered in the third and final article (Part III). [ABSTRACT FROM AUTHOR]

The determination of rare earth elements (REEs) in seawater, especially marine sediment porewater and open-ocean seawater, is challenging because of their ultra-trace concentrations (ng L−1 to pg L−1) and the high salinity of the matrix (approximately 35‰ NaCl), which limits their application in marine science. Herein, we developed an online method for accurate analysis of ultra-trace REEs in seawater using a traditional Q-ICP-MS. The key aspects were: (i) high sensitivity detection in standard mode with no collision/reaction cell functioned, (ii) online automated matrix removal and preconcentration using a commercially available seaFAST system, (iii) use of membrane desolvation to enhance the sensitivity and limit the interferences of LREE oxides on HREEs, and (iv) monitoring and correction of variations in REE signal intensities caused by instrument drift using standard–samples–standard bracketing and an indium internal standard for normalization. The detection limits (0.1–8.0 pg L−1) and procedural blank values (<3 pg L−1 except for La, Ce, and Nd) of this method were low enough for accurate determination of REEs in seawater, even for REE concentrations at tens of picograms per liter level. The good accuracy and long-term precision (30 h, average: 3.5%, 1σ RSD, n = 10) were achieved for all the REEs as verified using certified seawater reference standards NASS-7 and CASS-6, and a 10 ng L−1 artificial seawater standard, respectively. Each run required only approximately 8 mL of sample and 12 min for the measurement, which are suitable values for practical application. The developed method was used to analyze various natural seawater samples, which demonstrated its effectiveness for exploring subtle changes in REE concentrations, fractionation patterns and anomalies in different marine environments. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to investigate how cathodic polarization behavior significantly affects the selection of cathodic protection parameters and the effectiveness of protecting underwater metal structures. Factors such as water depth and operating conditions impact seawater temperature, making it crucial to understand the effects of temperature on cathodic protection parameters for underwater pipelines. Design/methodology/approach: In this paper, potentiostatic polarization was carried out by three-electrode method, and morphology, X-ray diffraction and electrochemical analysis. Findings: It was determined that the stable current densities at the minimum negative potential (−0.8 VSSC) for pipeline steel varied at different temperatures: 7°C, room temperature and 60°C. The cathodic protection potential corresponding to the lowest stable current density was observed to be −1.0 VSSC at 7°C and −0.95 VSSC at room temperature and 60°C. Originality/value: This study elucidates the mechanisms by which different temperatures affect the protective performance of calcareous deposits and current densities. [ABSTRACT FROM AUTHOR]

Organic carbon burial in ancient lacustrine settings is a crucial source of petroleum resources. Unlike the marine environment, the dynamics of organic carbon burial in the terrestrial realm are more complex due to the interplay of global and regional climate-tectonic factors. There appears to be a potential linkage between seawater incursion events (SWIEs) and the generation of lacustrine source rocks. However, reliable proxies to reconstruct the frequency and extent of SWIEs are currently lacking. Here, we explore the potential of rhenium-platinum group elements (Re-PGE) system as a novel proxy for determining SWIEs in the Nenjiang Formation of the lacustrine Songliao Basin in China that is noted for its high-quality source rock. By comparing marine and non-marine intervals, we validate the utility of Re-PGE fractionation patterns and osmium (Os) isotope compositions. Moreover, the Re/Ir ratios demonstrate two main episodes of quantitative seawater-lake water exchange. The comparison of variable indicators shows that the Re-PGE system is more sensitive to the changes in water sources, thus providing detailed information of frequency and exchange amount. The inverse variation between seawater contribution and total organic carbon content further implies that the massive sulfate influx from SWIEs facilitated bacterial sulfate reduction in the sediment pile, which had the effect of recycling nutrients (e.g., phosphorous) back into the water column. The SWIEs-triggered eutrophication induced a positive feedback loop between productivity and hypoxia, creating ideal conditions for the preservation of organic carbon. Our data reveals the detailed mechanism of SWIEs-triggered organic carbon burial and emphasizes the significant role of SWIEs in generating economically important hydrocarbon reservoirs. [ABSTRACT FROM AUTHOR]

The Urucum iron- and manganese formation (IF-MnF) in the Santa Cruz Formation, Brazil, was deposited in a glacially influenced, late Neoproterozoic depositional environment. It has proven to be a reliable and robust archive for the late Neoproterozoic, allowing unique insights into the composition of seawater during an interval that is characterized by dramatic changes in the Earth's litho-, hydros-, atmo-, and biosphere, including several episodes of low-latitude glaciations. Here we present highly siderophile element data of the Urucum IF-MnF to evaluate elemental sources that affected the Neoproterozoic seawater from which the Urucum IF-MnF precipitated. High uncertainties associated with current dating attempts of this formation overlapped with the Marinoan glaciation (∼650–635 Ma) as well as the Gaskiers glaciation event (∼580 Ma). A Re-Os regression line defined by iron-, manganese-, and chert-rich samples of the Urucum formation is interpreted as an isochron, yielding a refined age estimate of 577 ± 38 Ma and an initial 187Os/188Os ratio of 0.122 ± 0.003. The proposed depositional age overlaps with previous published age data of the Urucum IF-MnF, but relates the Urucum IF-MnF to the Ediacaran Gaskiers glaciation and overlaps with the age of the Shuram CIE (∼567 Ma). An initial 187Os/188Os ratio of 0.122 ± 0.003 is interpreted to represent pristine Neoproterozoic seawater and supports strong hydrothermal input, probably related to rifting, that promoted ferruginous conditions in the Urucum seawater. In an alternative scenario, Re-Os isotope data for the Urucum IF-MnF could also be interpreted in a multi-component mixing scenario, defined by hydrothermally influenced water masses that sourced most metals within the Urucum basin and a crustal component that entered the Urucum seawater either as detrital admixture or via riverine loads. Although none of the scenarios can be ruled out, we consider the isochron scenario as more plausible. [ABSTRACT FROM AUTHOR]

Rapid development of electronic and grid storage technologies based on lithium-ion batteries are leading to tight supply of lithium resources in the future. Extracting lithium from seawater can completely solve the problem of lithium resource shortage. An electro-deposition method based on a lithium superionic conductive solid-state electrolyte, Li1.5Al0.5Ge1.5(PO4)3 (LAGP), has been reported to obtain metallic lithium from seawater. However, expensive LAGP increases the cost of lithium extraction, while Li1.3Al0.3Ti1.7(PO4)3 (LATP) with relatively lower prices cannot meet the stable requirements. Herein, a low-cost, stable glass–ceramics, Li1.5Al0.3Ti1.7Si0.2P2.8O12 (LATSP), has been prepared for lithium extraction from seawater. The LATSP glass–ceramics show good selectivity towards Li+ and exhibit a high ionic conductivity of 3.98 × 10−4 S cm−1 at 22 °C. After soaking in simulated seawater, LATSP showed much better stability than LATP, comparable to LAGP. The resultant LATSP glass–ceramics was successfully employed in a seawater lithium extraction device, with a high lithium extraction Coulombic efficiency of 94.0%. Moreover, the LATSP exhibits an ionic conductivity of 2.80 × 10−4 S cm−1 and maintains a complete structure after 45 h of lithium extraction. This work presents an effective and practical Li-ion conducting membrane for lithium extraction from seawater. [ABSTRACT FROM AUTHOR]

Long-term preservation of gametes has been identified as a tool to improve broodstock management and increase the number of juveniles produced by artificial fertilization. Paralichthys orbignyanus is an important commercial and recreational species distributed in marine and estuarine waters from Rio de Janeiro (Brazil) to the San Matías Gulf (Argentina). This work focused on studying the seminal quality of tank-reared P. orbignyanus , demonstrating that males are fluent year-round, with the highest yields at the early reproductive season. Fresh sperm exhibited good forward swimming, and samples could be refrigerated up to 48 h while retaining their motility after activation. The optimal conditions for P. orbignyanus sperm motility activation were established as 950 mOsmol/Kg and pH values between 7 and 7.9. Additionally, a well-defined protocol for semen vitrification was developed to assess the cryotolerance of this species' sperm. We successfully produced high-quality sperm samples, using two vitrification formulations containing trehalose and both z-1000 and x-1000 polymers, that can be used in a near-future in vitro embryo production program. • Captive Paralichthys orbignyanus males yield year-round semen quality. • Semen retains good motility when refrigerated up to 48 h. • Optimal conditions for sperm activation were set at 950 mOsmol and pH 7–7.9. • A novel protocol for P. orbignyanus semen vitrification is reported. • The best extender formulations showed good fertilization rates vs fresh samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • NiFe-LDH/FeNi 2 S 4 heterostructured nanoarrays are facily fabricated. • The resultant electrode exhibits excellent SOR and HER activity in alkaline seawater medium. • The chlorine-free hydrogen production is realized in SOR-hybrid seawater electrolysis. • The energy-saving hydrogen production in seawater is demonstrated by the ultralow electricity. Electrochemical seawater splitting is a sustainable pathway towards hydrogen production independent of scarce freshwater resources. However, the high energy consumption and harmful chlorine-chemistry interference still pose major technological challenges. Herein, thermodynamically more favorable sulfion oxidation reaction (SOR) is explored to replace energy-intensive oxygen evolution reaction (OER), enabling the dramatically reduced energy consumption and the avoidance of corrosive chlorine species in electrocatalytic systems of NiFe layered double hydroxide (LDH)/FeNi 2 S 4 grown on iron foam (IF) substrate. The resulting NiFe-LDH/FeNi 2 S 4 /IF with superwettable surfaces and favorable heterointerfaces can effectively catalyze SOR and hydrogen evolution reaction (HER), which greatly reduces the operational voltage by 1.05 V at 50 mA cm−2 compared to pure seawater splitting and achieves impressively low electricity consumption of 2.33 kW h per cubic meter of H 2 at 100 mA cm−2. Significantly, benefitting from the repulsive effect of surface sulfate anions to Cl−, the NiFe-LDH/FeNi 2 S 4 /IF exhibits outstanding long-term stability for SOR-coupled chlorine-free hydrogen production with sulfion upcycling into elemental sulfur. The present study uncovers the "killing two birds with one stone" effect of SOR for energy-efficient hydrogen generation and value-added elemental sulfur recovery in seawater electrolysis without detrimental chlorine chemistry. [ABSTRACT FROM AUTHOR]

In this study, porous activated carbon was produced from coffee waste and used as an effective adsorbent for the removal of humic acid (HA) from seawater and methyl orange (MO) dye from aqueous solutions. Phosphoric acid H3PO4 was used as an activating agent for the chemical activation of these agricultural wastes. The characterization of the activated carbon obtained using a scanning electron microscope (SEM), Fourier-transform infrared (FTIR) spectroscopy analysis, X-ray diffraction (XRD) and the Brunauer–Emmett–Teller (BET) method revealed that the activated carbon products exhibited high porosity and the formation of various functional groups. The effects of different parameters were examined using batch adsorption experiments, such as the adsorbent masses, pH, initial pollutant concentration and contact time. The results show that the performance increased with an increased adsorbent mass (up to 0.25 g/L) and decreased initial concentration of the adsorbent tested. On the other hand, this study clearly showed that the adsorption efficiency of the MO on the raw spent coffee grounds (SCGs) waste was around 43%, while no removal was observed for the humic acid. The experiments demonstrated that the activated carbon synthesized from the used coffee grounds (the efficiency was compared with commercial activated carbon (CAC) with a difference of 13%) was a promising alternative to commercially available adsorbents for the removal of humic acid from seawater. To understand and elucidate the adsorption mechanism, various isothermal and kinetic models were studied. The adsorption capacity was analyzed by fitting experimental data to these models. The experimental data for methyl orange dyes were analyzed using Langmuir and Freundlich isothermal models. The Freundlich isotherm model provided a superior fit to the equilibrium data, as indicated by a higher correlation coefficient (R2) than that of the Langmuir model. The maximum adsorption was observed at pH 3. The Freundlich adsorption capacity was found to be 333 mg/g adsorbent. The PAC showed a high adsorption capacity for the MO and HA. The PAC showed the highest adsorption capacities for the HA and MO compared with the other adsorbents used (SCGs and CAC) and would be a good material to increase the adsorption efficiency for humic acid removal in the seawater pretreatment process. In addition, the prepared AC BET surface area was 520.40 m2/g, suggesting a high adsorption capacity. This makes the material potentially suitable for various applications that require a high surface area. These results indicate that high-quality sustainable activated carbon can be efficiently produced from coffee waste, making it suitable for a wide range of adsorbent applications targeting various pollutants. [ABSTRACT FROM AUTHOR]

As a new type of liquid discharged into the sea, concentrated brine exhibits complex mixing and stratification patterns due to changes in its density and hydrodynamic properties. This complexity impacts salinity transmission and can result in brine intrusion disasters, directly affecting both ecosystem and human life. This research adopted brine discharge into Dingzi Bay, Shandong Peninsula, a typical estuarine bay, as a case study. 3D convective diffusion numerical simulation techniques were applied to investigate the pathways, salinity rise, impact range, and overall effects on brine dispersal in marine water environments under the combined influence of river flow and tides. The results indicated the followings: (1) Significant spatial variations were observed in flow velocities within Dingzi Bay, with higher velocities near Xiang Island (where river flow turned into the bay) and at bay mouth; (2) The brine discharge point is influenced by complex hydrographic terrain and the combined effects of river flow and tidal movements, resulting in the formation of a high salinity area at the base of the discharge point, where salinity increases by more than 4 PSU within a 100-meter radius.; (3) During high tides, high-concentration brine was clearly transported upstream along the tidal channel, with a salinity increase of =3psu covering an area of 5.72×104 m2, extending up to 270 m upstream and 180 m downstream. Brine discharge led to significant mixing of concentrated seawater with seawater within the bay, altering the spatial and temporal distributions of salinity in Dingzi Bay and consequently affecting local sensitive marine species and water environment safety. This study systematically investigated the process of brine discharge into the ocean and its impact range. It was found that discharging brine in areas with higher currents promotes the mixing and dispersion of brine. Additionally, a seasonal discharge plan should be established to avoid discharges during periods of low runoff (such as winter) to minimize negative impacts on aquatic ecosystems and promote the health and diversity of marine ecosystems. [ABSTRACT FROM AUTHOR]

This work presents a spatial and temporal distribution of tributyltin (TBT) and TBT pollution assessment of the Croatian Adriatic coast in the period 2016 - 2023. The monitoring of TBT pollution was carried out within the Water Framework Directive (2000/60/EC) and the Marine Strategy Framework Directive (2008/56/EC). TBT concentrations were measured at 63 sites in coastal and transitional waters in three compartments - water, sediments and mussels. The ranges of TBT concentrations were <0.06 - 6.40 ng(TBT)/L in the water column, <1 - 2546 ng (TBT)/g(d.w.) in sediments, and <1 - 655 ng(TBT)/g(d.w.) in mussels, while transitional waters were in general more polluted than coastal waters. Monitoring of TBT concentrations in water showed that 30% of monitored sites were continuously polluted with TBT with average annual concentrations exceeding AA-EQS [0.2 ng (TBT)/L], while 20% of the sites had concentrations in sediments above the proposed EQS for sediments [1.6 ng(TBT)/g(d.w.)]. In mussels, TBT was detected at 70% of the sites with more than 60% of the sites exceeding the OSPAR criteria [12.6 ng(TBT)/g (d.w.)], indicating that the occurrence of imposex in gastropods at these sites is very likely. Only a slight decrease in TBT levels was observed over the investigated period, but concentrations at most contaminated sites did not fall below the EQS. This study shows that, despite the ban of TBT-based antifouling paints more than 15 years ago (except for public and military vessels), contamination of the Croatian Adriatic coast with TBT still exists and regular monitoring is essential. The TBT distribution was primarily determined by the vicinity of the pollution source, i.e. shipping traffic, but the role of physicochemical parameters, such as dissolved organic carbon (DOC) and transparency of the water column, should not be disregarded as well as the influence of hydrodynamics in the transitional waters. Although monitoring of TBT concentrations in water is an established approach to assess recent pollution, this long-term study has shown that mussels can be the most reliable indicator of pollution in a given area over the last several months. [ABSTRACT FROM AUTHOR]

This study utilizes recycled sand and shell sand to replace sea-sand in seawater sea-sand recycled aggregate concrete (SSRAC) and explores their dynamic compressive properties. A total of 28 sets of specimens were designed, and their stress-strain curves under different strain rates were analyzed. The findings indicated that the dynamic increasing factor (DIF) of peak stress in SSRAC reached its peak at a 50% replacement ratio of recycled sand, exhibiting a 3.9% to 7.7% increase compared to a 0% replacement ratio. Conversely, there was an overall decreasing trend in the DIF when the replacement ratio of shell sand increased. Using recycled sand resulted in an average reduction of approximately 45% in the elastic modulus of the interfacial transition zone (ITZ), while the introduction of shell sand slightly increased that of it. Finally, considering strain rate effects, a dynamic compressive prediction model for SSRAC with different types of fine aggregates was established. [ABSTRACT FROM AUTHOR]

Sea squirts (Tunicata) are chordates and develop a swimming larva with a small and defined number of individually identifiable cells. This offers the prospect of connecting specific stimuli to behavioral output and characterizing the neural activity that links these together. Here, we describe the development of a microfluidic chip that allows live larvae of the sea squirt Ciona intestinalis to be immobilized and recorded. By generating transgenic larvae expressing GCaAMP6m in defined cells, we show that calcium ion levels can be recorded from immobilized larvae, while microfluidic control allows larvae to be exposed to specific waterborne stimuli. We trial this on sea water carrying increased levels of carbon dioxide, providing evidence that larvae can sense this gas. Research Highlights: Development of a microfluidic chip in which Ciona larvae can be immobilized, exposed to controlled stimuli, and recorded.A transgenic construct was designed to drive expression of the live cell calcium ion reporter GCaMP in Ciona palp cells and other sensory cells.Exposure of Ciona larvae to carbon dioxide‐enriched sea water leads to detectable changes in GCaMP activity. [ABSTRACT FROM AUTHOR]

Enhancing oil recovery (EOR) through water flooding methods, including smart water injection, low salinity water injection, polymer injection, and surfactant injection has become a pivotal strategy for enhancing productivity. Despite their promising outcomes, these methods often encounter challenges such as scaling formation and deposition, impacting reservoir permeability and production rates. A comprehensive understanding of scaling formation is crucial for effective implementation of these methods. This article explores various scaling types prevalent in the field, examining key parameters (temperature, pressure, and pH) that influence scaling formation. Additionally, it presents a diverse range of inhibitors employing both chemical and mechanical methods to mitigate and prevent scaling, thus safeguarding reservoir performance. The efficiency of inhibitors is scrutinized concerning chemical composition and performance maintenance under different temperature and pressure conditions. This study serves as a valuable resource for researchers, engineers, and industry experts involved in the oil industry and reservoir management. By elucidating scaling mechanisms, delineating consequences, and offering extensive solutions, it enhances comprehension and provides a foundation for improving oil recovery strategies. The findings of this study contribute to a better understanding of scaling mechanisms, providing insights that can be applied to optimize oil recovery processes, mitigate reservoir challenges, and improve overall reservoir management strategies. [ABSTRACT FROM AUTHOR]

The iron (Fe)-oxide deposits of the Lahn-Dill-type are composed of haematite-quartz and rare siderite-haematite ores. These ores formed as marine chemical sediments on top of volcaniclastic rocks near the Middle to Late Devonian boundary (∼ 380 Ma). As such, their trace element fractionation patterns provide key information on venting style, ocean chemistry, particle-solution interaction, and depositional environment at the time of ore formation. This study combines WDXRF and ICP-MS/OES whole-rock geochemistry with complementary in-situ LA-ICP-MS analysis, and TEM element mapping of ore samples from the Fortuna Mine (Rhenish Massif, Germany). In-situ measurments were conducted on quartz-haematite, haematite, and siderite-haematite microdomains. Bulk major element contents of the ores indicate (volcani)clastic contamination and post-depositional hydrothermal alteration. Microdomain trace element distributions reveal four different trace element signatures, which are related to: (1) syngenetic apatite formation due to sorption of P and REY from seawater; (2) Fe-(oxyhydr)oxide-specific trace element scavenging and fractionation within the seawater column; (3) diagenetic Fe(III) reduction and trace element mobilisation in pore water; and (4) simultaneous deposition of (volcani)clastic material and Fe-(oxyhydr)oxides. These results show that Lahn-Dill-type iron ore formation resulted from mixing of a low-temperature vent fluid with ambient seawater at high seawater to vent fluid ratios. This likely was related to an environment in which diffuse venting dominated over focused venting, and in which quick Fe-particle precipitation led to formation of haematite-quartz ores. Local diagenetic Fe(III) reduction resulted in post-depositional siderite-haematite ore formation during which trace elements were partially remobilised in pore water. [ABSTRACT FROM AUTHOR]

Dimethylsulfide (DMS) is a climatically active volatile sulfur compound found in Earth's oceans and atmosphere that plays an important role in cloud formation. DMS originates from its precursor dimethylsulfoniopropionate (DMSP), which is produced by several classes of phytoplankton. Concentrations of DMS and DMSP in Antarctic sea ice, snow and underlying seawater are not well documented and there is currently no dataset available to find the existing data. The purpose of this project was to compile historical measurements into a publicly available dataset. A total of 220 samples collected since 1992 were compiled using the Antarctic Sea ice Processes and Climate program template, in accordance with the existing datasets for chlorophyll-a, macronutrients, and dissolved iron. Analyses performed on the completed DMS dataset showed that the spatial and temporal coverages are limited; there are barely any measurements in autumn and winter, nor in the Amundsen or Ross seas. These findings provide a basis for future sampling efforts in the Antarctic region. [ABSTRACT FROM AUTHOR]

Although several studies have shown that sea spray aerosol (SSA) has the potential to act as ice nucleating particles (INP) impacting cloud formation, there is a lack of marine INP studies in tropical latitudes. This is partly due to the unavailability of local oceanographic cruises that perform aerosol-cloud interaction studies in the tropics, as well as the scarcity of appropriate aerosol and cloud microphysics instrumentation. The present study shows the development of the UNAM-MARine Aerosol Tank (UNAM-MARAT), a device that simulates wave breaking to generate SSA particles with the main purpose to characterize their physicochemical properties including their ice nucleating abilities. The UNAM-MARAT was characterized using Instant Ocean Sea Salt and its potential to study ambient sea waters was evaluated with sea seawater samples collected from the Port of Veracruz (PoV) in the Gulf of Mexico, and from the Bay of Acapulco (BoA) and the Bay of Santiago- Manzanillo (BoSM) in the Mexican Pacific Ocean. The portable and automatic UNAM-MARAT is able to generate aerosol particle concentrations as high as 2000 cm-3 covering a wide range of sizes, from 30 nm to 10 μm, similar to those found in the ambient marine boundary layer. The SSA generated from the three natural seawater samples was found to act as INP via immersion freezing, with INP concentrations as high as 130.7 L-1. The particles generated from the BoA seawater samples were the most efficient INPs, reporting the highest ice active site density (ns) values between -20 and -30 °C. Our results also show the direct relationship between particle size and its composition. Larger particles (> 1 μm) were found to be enriched in sodium chloride. In contrast, the fraction of Ca2+, Mg2+, and NO3- was found to increase with decreasing the particle size from 10 μm to 320 nm. This suggests the presence of dissolved organic material in the submicron particles. [ABSTRACT FROM AUTHOR]

Marine plastic pollution poses a growing environmental threat, with microplastics accumulating in the global oceans. This study profiles the seasonal dynamics and taxonomic composition of the plastisphere, the microplastic ecosystem, in the Eastern Mediterranean Sea. Using long-read 16 S and 18 S metabarcoding, we analyzed offshore microplastic and whole seawater samples across each season over a two-year period. The analysis revealed a higher richness of prokaryotic communities on microplastics compared to seawater, which was predominantly composed of Proteobacteria and Bacteroidota and exhibited notable seasonal variability. Benthic eukaryotes were enriched on microplastics compared to the surrounding seawater. Diatoms (Bacillariophyceae), in particular, showed significant enrichment within the microplastic eukaryotic community with primarily pennate diatoms of Amphora, Navicula, and Nitzschia genera, whereas the seawater included mostly centric diatoms. Seasonal fluctuations were less pronounced in the microplastic communities than in seawater, highlighting the relative stability of this new human-made ecosystem. These findings underscore the unique ecological niche of microplastic-associated communities in marine environments. [ABSTRACT FROM AUTHOR]

During the 2018 Kīlauea eruption, over half the erupted lava was deposited on the seafloor. Lava flows crossing the shoreline generated sounds that were recorded by a network of hydrophones. We show that short‐duration, broadband signals associated with lava‐water interactions occurred throughout the eruption but increased in number when the Ahalanui ocean entry initiated on July 11. These terminated in early August coincident with the eruption's end. We compare hydroacoustic data with transmission loss models and eruption photographs to show that coastal explosive activity was poorly recorded by the hydrophone network. Similarly, strong hydroacoustic signals did not correlate with observed activity. These results suggest that acoustic signals were generated by lava flowing up to 100 s of meters offshore. Offshore lava flows can be hazardous to boaters, but hydrophones provide a means by which these hazards can be detected. Plain Language Summary: During the 2018 eruption of Kīlauea volcano, Hawai'i, lava flowed past the coastline and into the sea where it was deposited on the volcano's submarine flank. In this study we show that the interaction of lava and sea water created noise that was detected by a network of hydrophones (underwater microphones) placed offshore. Lava‐water interactions that occurred very close to the coastline, however, were not well‐recorded by the hydrophones, suggesting that sound was trapped in the shallow water. Other strong sounds were recorded when no obvious activity was visible at the coast. These observations suggest lava was flowing much farther offshore than was observed from the surface, potentially posing a threat to boaters and coastal observers. Key Points: Lava flows entering the ocean during the 2018 Kīlauea eruption generated sounds that were detected by hydrophonesExplosive activity observed near the coastline was only weakly detected by the hydrophonesSignals detected by the hydrophones may have initiated >100 m from the coast, suggesting that lava advanced well offshore [ABSTRACT FROM AUTHOR]

Satellite altimetry water level measurements are valuable in episodic and climate change related hydrodynamic impact studies, despite their sparse temporal distribution over the global ocean. This study presents the spatiotemporal characteristics of the open-ocean satellite derived water level measurements globally for the period 31/12/1992-15/10/2019 and evaluates their efficacy to represent the water level even during intense atmospheric conditions. Water level measurements from 23 different satellite missions are compared with tide gauge records and hydrodynamic simulations. The satellite measurements reproduce the water-level variations with good to excellent skill for ~60% of the areas considered. Additionally, satellite measurements and local atmospheric conditions are utilized in order to examine whether statistical data driven models can contribute to decreasing the temporal sparseness of the water level data over the global ocean. The suitability of this low computational-cost method is demonstrated by deriving a 63-year hindcast of the daily maximum water level for the global ocean, and for a medium-term 15-day ensemble forecast. The publicly available long-term water-level hindcast and the parameters of the datadriven statistical model derived can serve as a tool for designing and facilitating local and global coastal risk-assessment studies. [ABSTRACT FROM AUTHOR]

The pursuit of carbon‐neutral energy has intensified the interest in green hydrogen production from direct seawater electrolysis, given the scarcity of freshwater resources. While Ni‐based catalysts are known for their robust activity in alkaline water oxidation, their catalytic sites are prone to rapid degradation in the chlorine‐rich environments of seawater, leading to limited operation time. Herein, we report a Ni(OH)2 catalyst interfaced with laser‐ablated LiFePO4 (Ni(OH)2/L‐LFP), derived from spent Li‐ion batteries (LIBs), as an effective and stable electrocatalyst for direct seawater oxidation. Our comprehensive analyses reveal that the PO43− species, formed around L‐LFP, effectively repels Cl− ions during seawater oxidation, mitigating corrosion. Simultaneously, the interface between in situ generated NiOOH and Fe3(PO4)2 enhances OH− adsorption and electron transfer during the oxygen evolution reaction. This synergistic effect leads to a low overpotential of 237 mV to attain a current density of 10 mA cm−2 and remarkable durability, with only a 3.3 % activity loss after 600 h at 100 mA cm−2 in alkaline seawater. Our findings present a viable strategy for repurposing spent LIBs into high‐performance catalysts for sustainable seawater electrolysis, contributing to the advancement of green hydrogen production technologies. [ABSTRACT FROM AUTHOR]

Nitrite is a ubiquitous compound found across aquatic systems and an intermediate in both the oxidative and reductive metabolisms transforming fixed nitrogen in the environment. Yet, the abiotic cycling of nitrite is often overlooked in favor of biologically mediated reactions. Here we quantify the apparent acid dissociation constant (pKa) between nitrous acid and its conjugate base nitrite in both freshwater and seawater systems across a range of environmentally relevant temperatures (5–35°C) using potentiometric‐based titration. In freshwater, we measured a pKa,NBS of 3.14 at 25°C and a pKa,T of 2.87 for seawater at the same temperature. We quantify substantial effects of both salinity and temperature on the pKa, with colder and fresher water manifesting higher values and thus a greater proportion of protonated nitrite at any given pH. Because nitrous acid is unstable and decomposes to nitric oxide, the implications for the nitrous acid dissociation constant on ecosystem function are broad. [ABSTRACT FROM AUTHOR]

The large, metabolically expensive brains of manta and devil rays (Mobula spp.) may act as a thermogenic organ representing a unique mechanistic basis for cranial endothermy among fishes that improves central nervous system function in cold waters. Whereas early hominids in hot terrestrial environments may have experienced a thermal constraint to evolving larger brain size, cetaceans and mobulids in cold marine waters may have experienced a thermal driver for enlargement of a thermogenic brain. The potential for brain enlargement to yield the dual outcomes of cranial endothermy and enhanced cognition in mobulids suggests one may be an evolutionary by‐product of selection for the mechanisms underlying the other, and highlights the need to account for non‐cognitive functions when translating brain size into cognitive capacity. Computational scientific imaging offers promising avenues for addressing the pressing mechanistic and phylogenetic questions needed to assess the theory that cranial endothermy in mobulids is the result of temperature‐driven selection for a brain with augmented thermogenic potential. [ABSTRACT FROM AUTHOR]

In large areas of the Southern Ocean, iron limits phytoplankton production. Although biologically mediated iron recycling has been studied for the higher trophic-level whales and the lower trophic-level krill, less is known of the numerically abundant seabirds foraging in Antarctic waters. In this study, we estimate the magnitude of iron recycled by two Antarctic breeding seabirds, the Adé lie and emperor penguins, across the austral spring and summer in the Prydz Bay region, East Antarctica. Their contribution to iron recycling and associated pathways differs in line with their contrasting life history strategies (summer and winter breeding) and their breeding habitat (land and fast ice). We consider their breeding cycle in relation to their terrestrial activities compared to foraging periods at sea. High iron concentration (~419 mg kg-1) in guano of both penguin species suggests that they are a source of regenerated iron. Breeding emperor penguins supplied an average of 237 mmol iron m-2 day-1 on the fast ice that they breed on that eventually ends in the ocean when the ice melts completely in summer (November-February). During their foraging trips, the adult emperor penguins contribute between 7 × 10-5 and 4 × 10-4 mmol iron m-2 day-1, as their foraging ranges increase over the breeding season. In contrast, breeding Adé lie penguins supplied between 254 and 1,243 mmol iron m-2 day-1 whilst at their colony, with a fraction of guano entering the ocean via meltwater flowing into the ocean. The flux decreases to 2 × 10-3 to 6 × 10-2 mmol iron m-2 d-1, whilst they are foraging. Our study finds that penguins redistribute a large flux of iron onto their colonies, which may enter the adjacent water through sea ice melt and facilitated through katabatic winds. Despite their high abundance in Prydz Bay, the contribution of penguins to iron flux during their foraging periods is minor, due to the enormous foraging range being covered. Further research into the bioavailability of iron by marine organisms coupled with parallel measurements of seawater iron concentration and phytoplankton uptake experiments will be invaluable in refining iron budgets in both this region and other hotspots along the Antarctic coast where higher trophic-level animals are abundant. [ABSTRACT FROM AUTHOR]

Introduction: Archaeal communities play a crucial role in marine ecosystems, yet our understanding of their ecological and functional traits remains incomplete. This study focuses on northern Hangzhou Bay to fill gaps in knowledge regarding the biogeography and functionality of archaeal groups. Methods: We utilized a high-throughput sequencing dataset based on the 16S rRNA gene to characterize the archaeal community, aiming to identify biogeographic patterns and assess the influence of environmental factors on community structure. Results: The predominant phyla identified were Woesearchaeota, Thaumarchaeota, Euryarchaeota, and Crenarchaeota. Archaeal community structure in sediments showed a geographical pattern along the environmental gradient, influenced by factors such as salinity, ammonium, total phosphorus, pH, and total nitrogen content. Network analysis revealed nonrandom cooccurrence patterns, with associations changing along the salinity gradient. Additionally, this study directly proved the existence of dispersal limitation in this strongly connected marine ecological system through null model analyses. Variation in the archaeal community was attributed to both environmental constraints and stochastic processes due to dispersal limitation. Furthermore, our results revealed that the key biogeochemical functions of the archaeal community also exhibited a clear salinity gradient, the functional differences appear to be influenced by salinity, and the critical roles of archaeal diversity were highlighted. [ABSTRACT FROM AUTHOR]

Developing efficient and stable oxygen evolution reaction (OER) electrocatalysts under various alkaline conditions is crucial for commercial hydrogen (H₂) production. This study synthesized superhydrophilic NiFe LDH/NF with a nanosheet structure. The strong electronic interactions between the metals modify the electronic structures of Ni and Fe. In-situ Raman spectroscopy reveals numerous high-valent nickel intermediates with high OER activity during the reaction, significantly improving the catalyst's overall performance. At room temperature, the NiFe LDH/NF catalyst exhibits a current density of 50/100 mA cm−2 with only 217/233 mV required in 1 M KOH. Moreover, the catalyst requires only 180 mV under industrial conditions (60 °C, 6 M KOH), 243 mV in alkaline artificial seawater, and 280 mV in alkaline natural seawater to achieve 100 mA cm−2. The catalyst also exhibits long-term operational durability under these conditions, indicating a wide range of potential applications. [Display omitted] • NiFe LDH was directly grown in situ on a nickel foam surface by a hydrothermal method. • The catalyst's nanosheet structure and superhydrophilicity enhance the exposure of active sites to the electrolyte. • The two metalssynergistically alter the electronic structure,generating numerous high-valent active metals. • The catalysts demonstrate high activity and stability in alkaline media, even under harsh industrial conditions and seawater. [ABSTRACT FROM AUTHOR]

Seawater direct electrolysis (SDE) using renewable energy provides a sustainable pathway to harness abundant oceanic hydrogen resources. However, the side-reaction of the chlorine electro-oxidation reaction (ClOR) severely decreased direct electrolysis efficiency of seawater and gradually corrodes the anode. In this study, a redox-mediated strategy is introduced to suppress the ClOR, and a decoupled seawater direct electrolysis (DSDE) system incorporating a separate O2 evolution reactor is established. Ferricyanide/ferrocyanide ([Fe(CN)6]3−/4−) serves as an electron-mediator between the cell and the reactor, thereby enabling a more dynamically favorable half-reaction to supplant the traditional oxygen evolution reaction (OER). This alteration involves a straightforward, single-electron-transfer anodic reaction without gas precipitation and effectively eliminates the generation of chlorine-containing byproducts. By operating at low voltages (~1.37 V at 10 mA cm−2 and ~1.57 V at 100 mA cm−2) and maintaining stability even in a Cl−-saturated seawater electrolyte, this system has the potential of undergoing decoupled seawater electrolysis with zero chlorine emissions. Further improvements in the high-performance redox-mediators and catalysts can provide enhanced cost-effectiveness and sustainability of the DSDE system. Seawater direct electrolysis using renewable energy provides an appealing pathway to harness abundant oceanic hydrogen resources. Here, authors report a redox-mediated decoupled seawater direct electrolysis strategy to suppress the chlorine electro-oxidation side reaction. [ABSTRACT FROM AUTHOR]

We developed the LabVIEW-based virtual instruments (VIs) to bridge a gap in commercial software and to enable systematic peak-overlapping studies to recognise the concentration levels enabling reliable simultaneous determination of major and minor constituents in samples with wide concentration proportions. The VIs were applied to a case study of the ion chromatographic determination of potassium as minor and sodium as a major ion with an IonPac CS12A column and 50 μL injection loop. Two successive studies based on multilevel two-factorial response surface experimental designs, (1) a model peak-overlapping study based on single-ion injections, and (2) an accuracy and precision study, provided guidelines for real sample analyses. By adjusting sample dilutions so that the sodium mass concentration was set to 340 mg/L, the simultaneous determination of potassium in the presence of sodium was possible in samples with sodium over potassium concentration ratios between 14 and 341. The relative expanded uncertainty associated with potassium ion determination was between 0.52 and 4.4%, and the relative bias was between −3.8 and 1.9%. We analysed Ringer's physiologic solutions, standard sea, trisodium citrate anticoagulant, and buffered citrate anticoagulant solutions. We confirmed that the VI-supported peak-overlapping studies contributed to the quality of results by enabling the evidence-based choices of concentration levels adjusted by a dilution. [ABSTRACT FROM AUTHOR]

China is the largest producer and user of Ordinary Silicate Cement (OPC), and rapid infrastructure development requires more sustainable building materials for concrete structures. Portland cement emits large amounts of CO2 in production. Given proposals for "carbon peaking and carbon neutralization", it is extremely important to study alternative low-carbon cementitious materials to reduce emissions. Alkali-activated slag (AAS) cement, a new green cementitious material, has high application potential. The chemical corrosion resistance of AAS concrete is important for ensuring durability and prolonging service life. This paper reviews the hydration mechanism of AAS concrete and discusses the composition of hydration products on this basis, examines the corrosion mechanism of AAS concrete in acid, sulfate, and seawater environments, and reviews the impact of its performance due to the corrosion of AAS concrete in different solutions. Further in-depth understanding of its impact on the performance of concrete can provide an important theoretical basis for its use in different environments and provides an important theoretical basis for the application of AAS concrete, so that we can have a certain understanding of the durability of AAS concrete. [ABSTRACT FROM AUTHOR]

Freshwater purification from wasted water and seawater is crucial in addressing the global problem of water scarcity. Porous fiber felt with a micro/nanostructure emerges as an efficient approach for water purification; however, its production usually relies on chemical postprocessing to create micro/nano structures on the fiber surface, which might pollute the environment. This study proposed an ecofriendly method to produce micro/nanostructured copper fiber felt without chemical treatment. First, a new transverse-feeding vibration cutting is proposed to fabricate micro/nanostructured fibers with controllable structure characteristics. Through the sintering of the structured fibers without postprocessing, the fiber felt can be produced in an ecofriendly way and exhibit special wettability and excellent photothermal properties. Felt-based freshwater purification, including oil–water separation and solar-driven seawater desalination, can be realized effectively. Results show an oil–water separation efficiency of > 90% and a high evaporation rate of water of > 1.08 kg m−2 h−1 at 73 mW cm−2 are achieved, demonstrating the application prospect of the produced fiber felt. Highlights: A transverse-feeding vibration cutting process is proposed to fabricate micro/nanostructured copper fibers. Micro/nanostructured based felts can achieve special wettability and corresponding wettability transition. Micro/nanostructured fibers can enhance the felts' photothermal conversion ability and reduce heat transfer loss. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel core–shell Co 2 (PS 3)@Co 2 P is designed as a pre-catalyst. • The Co 2 (PS 3)@Co 2 P catalyst with fast surface reconstruction. • The PO 4 3−, SO 3 2− and SO 4 2−-decorated CoOOH as a true catalyst. • The oxyanions can enhance the activity and stability in seawater. • The oxyanions can optimize the intermediates' chemisorption. The design of pre-catalysts and the rational manipulation of corresponding electrochemical reconstruction are vitally important to construct the highly durable and active catalysts for seawater oxidation, but rather challenging. Herein, a novel core–shell catalyst of Co 2 (PS 3)@Co 2 P (labeled as CoPS) by epitaxial growth of amorphous cobalt phosphide (Co 2 P) on crystalline cobalt phosphorous trichalcogenide (Co 2 (PS 3)) is firstly designed as a pre-catalyst for alkaline seawater oxidation. Various characterization techniques are employed to demonstrate that the unique amorphous-crystalline nanowire structure (CoPS) achieves the rapid surface reconstruction into active CoOOH and diversiform oxyanions species (labeled as CoPS-R). Theoretical simulations uncover that the in situ derived oxyanions (PO 4 2−, SO 3 2− and SO 4 2−) on the surface of CoOOH can tune the electron distribution of Co site, thereby optimizing the chemisorption of oxygen evolution reaction (OER) intermediates on CoOOH and reducing the energy barrier of determining step. Consequently, in an alkaline natural seawater solution, the reconstructed CoPS-R catalyst exhibits small overpotentials of 357 and 402 mV for OER at 200 and 500 mA cm−2, respectively, together with an impressive durability over 500 h at a large current density of 500 mA cm−2 benefiting from the strong repulsive effect of the derived PO 4 2−, SO 3 2− and SO 4 2− oxyanions. This work offers a new insight for comprehending the relationship of structure-composition-activity and develops a new approach toward the construction of efficient and robust OER catalysts for seawater electrolysis. [ABSTRACT FROM AUTHOR]

Trap and transport, the capture and subsequent translocation of fish during the freshwater phase of their migration, is becoming more common as a management intervention. Although the technique can be successful, it is costly and can have unintended effects on the fish being transported. This study investigates whether trap and transport can be used to increase the migration success of Atlantic salmon, Salmo salar, smolts in naturally flowing rivers. Seaward‐migrating S. salar (n = 294) from two UK rivers were tracked using acoustic telemetric techniques. Outmigration success and timing were compared between non‐transported (released at the original in‐river capture site) and transported (released ca. 23 km downstream of the capture site) individuals. Downstream translocation increased the proportion of fish that successfully migrated to marine waters, and there was no indication that transport reduced post‐release survival. The post‐release migration speed of transported fish was slower than expected but this was likely a function of their advanced migration timing rather than an inhibition of their capacity to migrate. These results suggest that trap and transport can increase the outmigration success of S. salar smolts, but the earlier river exit dates of transported fish could negatively affect their survival at sea. [ABSTRACT FROM AUTHOR]

Microplastic pollution in the marine environment is of concern, with evidence of harmful effects on marine biota and ecosystems. There is still a knowledge gap of the mass of plastics supplied to the ocean and plastics observed in the ocean, indicating a missing sink. Therefore, baseline and monitoring data are needed to inform policy and regulatory measures. The goal of this study was to collect harmonised data of microplastics from the surface of the ocean using the Neuston Microplastic Catamaran. This study shows that the surface water of the coastal ocean in the North Sea holds/sustains high concentrations of microplastic, which exceed previously recorded measurements from the North-East Atlantic and Scottish Waters, indicating that the total stock of plastics might be much higher than previously determined. Microplastics were detected in all samples with concentrations ranging from 857 to 25,462 items km-2. The majority of microplastics analysed were fragments of polyethylene, polypropylene, and polystyrene in the size range of 1,000-5,000 µm. Mesoplastics (>5,000 µm) mainly in the form of filaments were found with concentrations ranging from 0 to 2,139 items km-2, and macroplastics (>5,000 µm) in the form of fragments and filaments were also found with concentrations ranging from 0 to 1,078 items km-2. These fragments and filaments likely originate from the break-up of common macrolitter items in the environment, such as plastic bags, bottles, and fishing gears, which are commonly comprised of similar polymers to those found in the present study. Our findings demonstrate that litters of all size classes are abundant in surface water, highlighting that it is a key compartment for the transport of marine litter and should be monitored to better our understanding of the fate and danger of plastic contamination in our ocean. [ABSTRACT FROM AUTHOR]