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As an important underlying visual processing task, underwater image enhancement techniques have received a lot of attention from researchers due to their importance in marine engineering and lake ecosystem optimization. However, various underwater image enhancement algorithms have been proposed to be evaluated mainly with marine water body datasets, and it is not clear whether these algorithms can be performed on datasets collected from inland lakes in the freshwaters. To bridge this gap, for the first time, we construct an underwater image dataset for highland and freshwater-circumstances (HFUI) using 1000 real images to complement the underwater image datasets. In addition, we propose an unsupervised underwater image enhancement algorithm (HUFI-Net) specifically for this dataset to correct the sharpness and color of the images. This algorithm, as well as current advanced underwater image enhancement algorithms, was investigated qualitatively and quantitatively using this dataset to evaluate the effectiveness and limitations of various algorithms and to provide novel ideas for future underwater image enhancement research. We also further validate the generalization and effectiveness of the algorithm on the underwater image datasets of the UIEB and the RUIE. [ABSTRACT FROM AUTHOR]

To investigate the effects of different pore water environments on compressive behaviours of the deep-sea soft soil from South China Sea, four kinds of soil samples including natural sample with sea water or deionized water, remolded sample with sea water or deionized water were prepared, respectively. Then, a series of oedometer tests and scanning electron microscopy tests were performed on the above samples to examine their compressive behaviours and microscopic characteristics, respectively. Additionally, the microscopic pore distribution of natural sample with sea water was observed by mercury intrusion porosimetry tests. The effects of different water environments on macroscopic compressive behaviours and microscopic particle characteristics are analyzed. The deionized water environment increases the compressibility and decreases the consolidation coefficient for natural samples after structural breakage and remolding. The microscopic particle characteristics corresponding to the macroscopic compressibility are also qualitatively analyzed. In deionized water environment, soil particles exhibit higher roundness, more orderly and lower surface roughness than that in seawater environment. In this study, the deionized water environment has no obvious effect on the structural yield stress and secondary consolidation coefficients of deep-sea soft soil. [ABSTRACT FROM AUTHOR]

The grouting method is commonly used to seal rock fissures in subsea tunnels, and therefore the water and mud inrush can be prevented in this way. However, the current understanding of the grout diffusion mechanism inside the rock fissure under seawater conditions is still limited, especially inside the inclined rock fissure. This study first presented a novel rock fissure geometry schematization, which can be simplified to a single fissure with different inclinations. Then, based on the obtained time-varying grout viscosity under seawater conditions, the grout diffusion model of cement and sodium silicate grout (C-S grout) was developed by combining the equilibrium equation, constitutive equation, and continuity equation, which can be used to calculate the key parameters involved in rock fissure grouting, i.e., the grouting pressure and grout diffusion distance. After that, the change of grouting pressure with time was obtained. Furthermore, the numerical simulation of grouting in the inclined rock fissure was performed to verify the suitability of the grout diffusion model, and the comparison between them shows that they match reasonably well with each other. It is hoped that the conclusions could aid in the design of grouting in rock fissures around subsea tunnels with C-S grout in the future. HIGHLIGHTS: A novel rock fissure geometry schematization is presented. The C-S grout diffusion model in the inclined rock fissure under seawater is developed. The effect of time-varying viscosity on grout diffusion under seawater conditions is studied. The relation between the grouting pressure and grout diffusion distance is obtained. The numerical simulation of grouting in the inclined rock fissure is performed. [ABSTRACT FROM AUTHOR]

We analysed the migratory behaviour of adult Northern Gannets (Morus bassanus) breeding at Helgoland in the North Sea, based on data obtained from geolocation devices in the non-breeding season 2016–2017. Birds moved east and south-west to a broad range of wintering sites, ranging from the western Baltic Sea to North-West Africa. Three out of 12 birds spent the winter in Africa, while 9 birds wintered in Europe, with the primary wintering sites in the North Sea. All but one tagged bird spent some time in the Baltic Sea or in the transitional waters between the North Sea and Baltic Sea. We also analysed data from online databases (dofbasen.dk, ornitho.de) and the German Seabirds at Sea database to explore the extent to which Northern Gannets used the western Baltic Sea, as well as the Kattegat and Skagerrak, during the winter months. Records of Northern Gannets in Danish waters have increased substantially over the last 18 winters, with particular increases in the Baltic Sea. There was also a notable increase in sightings of Northern Gannets in German Baltic Sea waters, but this occurred later than in the more northerly Danish waters. Both analyses demonstrated that Northern Gannets explored the western part of the Baltic Sea, as well as the Kattegat and Skagerrak, increasingly intensively. This recent increase in sightings is in accord with the establishment and exponential increase in the nearest breeding colony of Northern Gannets at Helgoland. [ABSTRACT FROM AUTHOR]

A reduced-order model (ROM) of the global oceans is developed by projecting the hydrostatic Boussinesq equations of motion onto a proper orthogonal decomposition (POD) basis. Three-dimensional POD modes are calculated from the ocean fields of an ensemble climate reanalysis dataset. The coefficients in the POD ROM are calculated using a regression approach. The performance of various POD ROM configurations are assessed. Each configuration is derived from an alternate sea-water equation of state, linking the density and temperature fields. POD ROM variants incorporating an equation of state in which density is a quadratic function of temperature, are able to reproduce the statistics of the large-scale structures at a fraction of the computational cost required to numerically simulate this flow. Due to the speed and efficiency of calculation, such reduced-order models of the global geophysical system will enable researchers and policy makers to assess the physical risk for a broader range of potential future climate scenarios. [ABSTRACT FROM AUTHOR]

Estuaries are nutrient-rich environments characterized by a gradient in salinity due to the mixing of freshwater and seawater. These bodies of water play vital functions in nature and provide a wide variety of essential ecosystem services. In general, many natural and/or man-made activities have strongly stressed the Egyptian Nile estuarine habitats, as has the water shortage that was expected after the construction of the Grand Ethiopian Renaissance Dam. In recent decades, the Nile Delta has been considered to be one of the most important productive oil-producing petroleum regions due to onshore and offshore gas discoveries alongside gasoline and base oil generation. Up-to-date systematic reviews of the Egyptian estuarine habitats (Rosetta and Damietta) are missing, and the review reported here was undertaken to fill this gap. In this review, we consider the physical, chemical, geological, pollution, and biological parameters of Egyptian Nile estuaries. In this context, our aim is to contribute to a broader understanding of the Egyptian estuarine habitat; moreover, we provide potential warning signals that may aid in estuarine environmental protection. We found that most of the previous studies had focused on the two branches of the Nile or on the marine waters adjacent to these branches, and that only a few studies focused on the estuarine habitats themselves. In most of these previous studies, the salinity gradient of water was reported to be a significant factor in the distribution of the different measured parameters while, in contrast, more recent investigations confirm the importance of potential effluent sources in affecting the distribution of these parameters. We highly recommend that the data reported here be updated in future studies on different environmental aspects. [ABSTRACT FROM AUTHOR]

The article presents the results of experimental studies of the sorption and desorption of rare-earth metal (REM) cations by the Co-bearing ferromanganese crusts of the Govorov Guyot. It has been established that the REM cations are sorbed on the CFC ore minerals (Fe-vernadite, vernadite, Mn-feroxyhite, and goethite. The crusts are characterized by high exchange capacity (1.78–3.57 mg-equiv/g, which increases in the following series: (Dy < Gd < Lu < Sm < Nd < Y, La < Eu) Ce. The REM cation sorption proceeds by the irreversible ion-exchange equivalent mechanism. The exchange complex of ore minerals consists of Na+, K+, Ca2+, and Mg2+ cations, which contribute 97‒98% to their total capacity. The crusts are characterized by the group sorption of REM cations from multicomponent water solutions of metal salts. The selectivity of manganese and ferruginous minerals of crusts to REM cations is significantly higher than to the main cations of ocean water. Experimental data on the desorption of sorbed REM cations with the NaCl solution suggest their irreversible sorption by ore minerals and strengthening of the chemical bond of sorbed REM cations with the main structural elements of these minerals over time. An important property of ore minerals, primarily manganese minerals, is their chemical and structural stability in aqueous electrolyte solutions, suggesting the repeated use of FMC as sorbents of REM cations. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) and nanoplastics (NaPs) in coastal regions, particularly in sediments, have gained increasing attention. However, in Türkiye, research on sediment pollution by MPs and NaPs is still limited. To fill this knowledge gap, the distribution, composition, and ecological impact of MPs and NaPs were investigated for the first time in the literature over a one-year period at three sampling stations on the south coast of Istanbul. The average total particle concentration was 1364.17 ± 600.51 particles.kg−1 dw sediment. Most of the MPs detected in the sediments were in the form of fibers with a size of 100–250 µm and were black and transparent. The study found that NaPs accounted for only 17%, 13.8% and 11.8% of the particles collected at stations S1, S2 and S3, respectively. According to the FTIR results, polyethylene and polyethylene terephthalate were the most abundant compared to polypropylene, polyamide and other polymers. The hazard index was classified as level V with a value of 17,261. This classification emphasizes the urgent need for further comprehensive studies on the risk assessment of MPs and NaPs. Scanning electron microscopy results showed microorganisms on the particle surface, indicating the MP-associated passing-through mechanism. Moreover, energy dispersive spectroscopy detected several unexpected elements such as Nb, Sr, Mo, Bi, Ta and Rn on MP and NaP surfaces. The results indicate that MP and NaP pollution in Istanbul’s coastal sediments may pose a major risk to the environment through the leaching of inherent/adsorbed elements and therefore requires future investigation. [ABSTRACT FROM AUTHOR]

Makassar coastal area has experienced rapid development and has shown various negative impacts from groundwater overexploitation, such as seawater intrusion. This study aimed to assess seawater intrusion based on geochemical and isotopic data in the Makassar coastal area. The research was carried out by field measurement and taking the groundwater samples to the laboratory for geochemical and isotope tests. Geochemical analysis of seawater intrusion was based on TDS, EC, Cl-, Simpson ratio, Ca enrichment, BEX, Na/Cl ratio, and the piper trilinear diagram typer of water. Isotope analysis of seawater intrusion is based on comparing oxygen (d18O) and deuterium (dD) isotopic data from groundwater samples with seawater, river, and rainwater. The results showed that some areas near the sea indicated seawater intrusion in both the semi-unconfined and unconfined aquifers. The indicated seawater intrusion spread in the north Tallo, Mamajang, and Tamalate subdistricts. [ABSTRACT FROM AUTHOR]

Copyright of South China Fisheries Science is the property of South China Fisheries Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Iodate reductase (Idr) gene cluster (idrABP1P2) is involved in bacterial iodate (IO3-) respiration under anaerobic conditions. Putative idr gene clusters are present in both anaerobic and aerobic bacteria; however, the specific physiological roles of idr genes in aerobic bacteria remain unclear. Therefore, in this study, three marine aerobic bacteria with putative idr gene clusters (Roseovarius azorensis, Notoacmeibacter marinus, and Aliiroseovarius sediminilitoris) were grown in the presence of iodate to determine whether they can reduce iodate to iodide (I-). All tested bacteria almost completely reduced 2 mM iodate under static conditions but only reduced 0.1-0.5 mM iodate under shaking conditions. Moreover, the washed cell suspension of R. azorensis reduced iodate only when the cells were pre-grown statically in the presence of iodate. Transcriptional analysis revealed that the expression levels of idrA, idrB, idrP1, and idrP2 genes were upregulated in R. azorensis when the cells were grown statically in the presence of iodate. Specifically, idrA expression was induced by 0.1 μM iodate and was up to 14-fold higher compared to that of the non-iodate control. These results suggest that marine aerobic bacteria reduce iodate under oxygen-limited conditions, and that this capacity is induced by environmentally relevant levels of iodate in seawater. Our results suggest that marine aerobic bacteria contribute to iodide production in marine surface waters, thereby affecting the global iodine cycling and ozone budget. [ABSTRACT FROM AUTHOR]

Freshwater resources have faced serious threats in recent decades, primarily due to rapid population growth and climate change. Seawater desalination has emerged as an essential process to ensure a sustainable supply of freshwater to meet the global demand for freshwater. However, this approach has some shortcomings, such as the disposal of brines containing high levels of contaminants creating environmental problems, and the energy-intensive nature of desalination, primarily powered by fossil fuels, which contribute to greenhouse gas emissions. Consequently, as a solution, the zero liquid discharge approach has been identified by the body of research to be one of the viable methods to solve these problems. Over 90% of freshwater and reusable salts could be recovered through this approach. Adopting renewable energy-powered systems could make zero-liquid discharge desalination plants operate in an entirely environmentally friendly and sustainable manner. This review explores the integration of renewable energy-powered systems for the optimisation of seawater desalination treatment processes for zero-waste and improved productivity. The review also examines technologies and strategies that improve the efficiency and sustainability of desalination systems. By analysing recent research, we provide insights into the advancements, challenges, and prospects for optimizing renewable energy-powered seawater desalination processes aimed at achieving zero waste. [ABSTRACT FROM AUTHOR]

The use of seawater in cement-based concrete is debateable because it may increase the hydration rate but significantly decreases the durability. Alternately, seawater can be used as an alkaline activator solution in geopolymer however, very little is currently known about its effects. This study investigated the effect of seawater as alkaline activator mix solution and curing media on the compressive strength of geopolymer paste. The mixtures varied based on the molarity of alkaline activator solution. Alkaline activators were prepared with two solutions: diluted water and seawater. A day after casting, steam curing method was conducted at 65 °C for 2 hours and then immersed in seawater or normal water for 28 days. This study revealed that seawater in alkaline activator reduced the compressive strength by up to 25%. Applying temperature resulted the early age strength nearly comparable to the later age strength. Immersion the paste in seawater increased the strength up to 15%. The X-Ray diffraction analysis shown the presence of chloride on the surface, consequently preserving the compressive strength without any reduction at 28 days of immersion. The Scanning Electron Microscopy analysis inside the geopolymer paste prepared with seawater shown the microstructure of quartz, mullite, hematite, and the presence of chloride spread around resulting the disruption of polymerization. The results indicated that seawater has the potential as an alkaline activator mix solution and curing media, compensated by requirement of higher molarity of NaOH. [ABSTRACT FROM AUTHOR]

The design of patrol boats, especially in Indonesian waters with extreme sea conditions, requires good stability capabilities and self-righting moments. These conditions require patrol boats to have anti-capsized capabilities where, with these capabilities, the patrol boat can return to an upright position at extreme heeling angles. This study investigates how changing the center of gravity (CoG) due to the deckhouse height factor improves self-righting moment capabilities. Four different deckhouse heights are examined to find the optimal self-righting roll moment, with a deckhouse height in the 2.01–2.31 m range. In addition, the presence of the self-righting roll moment is also validated by the computational fluid dynamics (CFD) method using three different mesh sizes. The height of the deckhouse can significantly influence the ship's stability. The initial investigation shows ships with minimum deckhouse heights of 2.06 m have positive righting lever arms at 170° and are classified as anti-capsized ships. It has been discovered that buoyancy and the center of gravity are crucial variables in obtaining the self-righting moment. The deckhouse's height increases the stability of the ship's righting arm by enhancing the metacenter point. The findings demonstrate that more excellent stability is achieved with a larger deckhouse height. [ABSTRACT FROM AUTHOR]

Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study employs the MIKE 3 Flow Model, incorporating forcing conditions such as inflow from 18 major rivers along the Bohai coast, wind, precipitation, evaporation, and solar radiation, to develop a hydrodynamic and temperature-salinity model for the Bohai Sea, using a finer mesh for more detailed simulation in Laizhou Bay. The residual current in the surface layer primarily flowed eastward, exhibiting coastal transport characteristics in the southern region, leading to the formation of a large low-salinity region. The bottom salinity distribution closely mirrored that of the surface, with the isohaline shifting shoreward due to the high-salinity Bohai Sea water transported by the residual current. By grouping major runoff sources according to river outlet locations and residual current patterns, the study analyzed the impact of freshwater plumes formed by runoff from different directions on the salinity distribution in Laizhou Bay. The results indicate that the influence of freshwater inputs on both the mean salinity and the area of low-salinity zones in Laizhou Bay, ranked from greatest to least, is as follows: the Yellow River, the southwest, and the southeast. The variation in the area of low-salinity regions is closely related to factors such as runoff volume, residual currents, and the selection of boundaries for the low-salinity regions. [ABSTRACT FROM AUTHOR]

The Programmable Hyperspectral Seawater Scanner (PHySS) represents a significant breakthrough in monitoring harmful algal blooms (HABs), specifically targeting the "Florida red tide" caused by Karenia brevis. By utilizing a Fourth-Derivative Spectral Similarity Index (SI), this study establishes a strong positive correlation between the SI and phytoplankton counts, underscoring the PHySS's potential for early detection and effective management of HABs. Our findings suggest that the PHySS could act as a predictive tool, offering crucial lead time to mitigate the ecological and economic repercussions of blooms. However, this study also identifies certain limitations of the PHySS technology, such as its inability to differentiate among various phytoplankton species without additional physical verification of cell counts. This limitation highlights the need for a multifaceted approach to HAB management. Our research suggests that adopting a multi-modal monitoring strategy could lead to more sophisticated and effective methods for combating HABs, fostering an optimistic outlook for future advancements in this area. [ABSTRACT FROM AUTHOR]

The use of glass fiber‒reinforced polymer (GFRP) bars in seawater–sea sand geopolymer mortars (SSGMs) for coastal engineering has gained significant traction because of the potential to enhance the utilization of noncorrosive GFRP reinforcements and natural resources. However, the durability of GFRP bars under the combined impact of prestressing and SSGM cover in seawater environments must be further investigated. In this study, the tensile strength (TS), interlaminar shear strength, and transverse shear strength degradation of GFRP bars were evaluated through hydrothermal seawater aging tests with immersion temperatures including room temperature, 40°C, and 60°C for 83, 180, 270, and 365 days. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses were performed to investigate the degradation mechanisms of the GFRP bars after conditioning. The test findings indicated that the effect of increasing the thickness of the SSGM cover on GFRP durability was insignificant. However, without the SSGM cover, GFRP bars demonstrated superior strength retention than SSGM-covered bars after 365 days of seawater immersion because of the absence of alkali ion attack. With the application of prestressing, a greater reduction in strength retention was observed due to increased microcrack formation and penetration of OH− ions and water molecules into glass fibers. In addition, the test results were compared with the bars embedded with seawater–sea sand cement-based mortars, while the SSGM-covered GFRP bars exhibited higher TS retention under identical hydrothermal aging conditions. The high addition of ground granulated blast furnace slag in SSGM contributes to a more compact microstructure, resulting in reduced water diffusion from the outer part of the SSGM. Additionally, the strong alkali-binding capacity of the gel led to a decrease in the pH of the pore solution. [ABSTRACT FROM AUTHOR]

This experimental investigation is the first of its kind to evaluate the effects of a combination of long-term loading and marine exposure on the structural response of carbon fiber–reinforced polymer (CFRP) and glass fiber–reinforced polymer (GFRP) tubular composites infilled with seawater and sea sand-based ultrahigh-performance concrete (UHP-SWSSC). The specimens were conditioned under natural seawater exposure at 40°C, 3,000 h of sustained loading, and a combination of the two. Long-term strains indicate that the composite tubes (especially GFRP) experienced swelling due to marine exposure, even under sustained load, suggesting gradual detachment of the tubes from the ultrahigh-performance concrete (UHPC) core. Considerable hoop strength and stiffness of the confining fiber-reinforced polymer (FRP) were necessary to restrain the dilation of UHPC, which was mechanically improved by sustained loading and seawater exposure. Lateral confining pressure and stiffness of FRP correlated with improved confined UHPC properties. The FRP tubes utilized their full material capacity only at a sufficiently high level of confinement to efficiently restrain the UHPC core. Despite the increase in compressive strength, marine exposure reduced the ductility of the FRP–UHPC composites, particularly in those containing GFRP. The gradual stress redistribution from the inner concrete to the outer FRP tubes facilitated better utilization of FRP confinements after creep (with or without seawater exposure). [ABSTRACT FROM AUTHOR]

The deep western boundary current (DWBC) of the Southwest Pacific Basin (SWPB) is the main pathway through which the deep and bottom waters formed around Antarctica are transported northward and distributed throughout the Pacific Ocean. However, historical observations of this current are sparse. Here, we used an unprecedented number of deep‐ocean observations collected by Deep Argo floats since 2016 to examine temperature, salinity, and velocity in the DWBC of the SWPB. Deep Argo trajectory velocities were fastest along the western side of the Kermadec Trench, with an average velocity of 0.057±0.012 $0.057\pm 0.012$ m s−1. Trajectories confirmed the existence of a tight recirculation on the eastern side of the Kermadec Trench (−0.021±0.008 ${-}0.021\pm 0.008$ m s−1). This recirculation was likewise seen in an independent eddy‐resolving ocean reanalysis. For the DWBC within the northern Kermadec Trench (26–30°S), Deep Argo profiles and the ocean reanalysis demonstrated seasonal isopycnal heaving of the deep‐ocean that was likely driven by local Ekman pumping and may influence seasonal DWBC transport. At the northern end of the Kermadec Trench, the deep‐ocean salinity maximum was eroded as the DWBC exited the trench to the north through the Louisville Seamount Chain collision zone, thus revealing a previously unidentified region of enhanced deep‐ocean mixing. Although Deep Argo observations accurately estimated vertical turbulent diffusivity in the Samoan Passage (6.1 × ${\times} $ 10−3 to 1.57 × ${\times} $ 10−2 m2 s−1), mixing within the Louisville Seamount Chain collision zone was not due solely to vertical turbulent diffusivity. A global Deep Argo array could reveal wind‐driven seasonal heaving and unexplored deep‐ocean mixing hotspots in other DWBCs. Plain Language Summary: The cold and dense seawater that fills the ocean interior is formed near the surface in polar regions. This seawater sinks and is transported away from the poles and throughout the ocean by deep western boundary currents. We used data collected by Deep Argo floats (freely drifting robots that measure temperature and salinity between the sea surface and seafloor) to examine the northward‐flowing deep western boundary current in the Southwest Pacific Ocean, north–east of New Zealand. The pathway and speed of the current was identified using the horizontal movements of these floats. A clockwise circulation was evident over a deep‐ocean trench (the Kermadec Trench), with some of the current's northward‐flow returning southward. At the northern end of the Kermadec Trench, temperature and salinity demonstrated seasonal changes that extended at least 4,000‐m deep. These seasonal changes were likely caused by seasonal changes in surface winds, and may influence seasonal transport of water in the deep western boundary current. Saltier waters observed over the Kermadec Trench were not observed north of the trench, identifying the exit of the Kermadec Trench as a region of enhanced deep‐ocean mixing. Implementing Deep Argo globally could reveal other unidentified regions of enhanced deep‐ocean mixing. Key Points: Deep Argo trajectories trace the deep western boundary current (DWBC) pathway, including recirculation over the Kermadec TrenchThe deep salinity maximum is eroded as the DWBC exits the Kermadec Trench to the north through the Louisville Seamount Chain collision zoneSeasonal heaving in the northern Kermadec Trench is predominantly driven by local Ekman pumping at the surface [ABSTRACT FROM AUTHOR]

As the Arctic warms at an increased rate compared to the rest of the globe, freshwater runoff has been shown to be increasing into the Arctic Ocean. The effects of this contemporary increase in riverine freshwater into the Arctic Ocean are estimated from ocean model simulations, using two runoff data sets. One runoff data set is based on older climatological data, which has no inter‐annual variability after 2007 and as such does not represent the observed increases in river runoff into the Arctic. The other data set comes from a hydrological model developed for the Arctic drainage basin, which includes contemporary changes in the climate. At the Pan‐Arctic scale this new data set represents an approximately 11% increase in runoff, compared with the older climatological data. Comparing two ocean model runs forced with the different runoff data sets, overall changes in different freshwater markers across the basin were found to be between 5% and 10%, depending on the regions. The strongest increases were seen from the Siberian rivers, which in turn caused the strongest freshening in the Eastern Arctic. As the surface waters of the Arctic Ocean are sensitive to runoff, incorporating hydrological model data can help to better understand current changes and potential future impacts from increased runoff with climate change. Plain Language Summary: Climate change increases freshwater supply to the Arctic. This study looks at understanding the impacts of this increased riverine water into the Arctic Ocean using a state of the art regional ocean model. Two runoff forcing data sets are used, one data set which only extends to 2007 and thus does not include the recently observed runoff increases due to climate change, and a newer data set which extends up to present day and as such represents contemporary increases in the river runoff into the Arctic. Comparing two simulations forced by the two runoff datasets highlights the effects of river runoff changes on the Arctic Ocean. We find the Arctic surface waters freshen by 5%–10% over 2007–2018, depending on the metric and region considered. Much of this increased freshwater found is driven by the major Siberian rivers. This primarily affects the Eastern Arctic. Our work shows that recently observed increases in Arctic river runoff are likely impacting surface Arctic waters as well as waters transported to lower latitudes. Key Points: Pan‐Arctic river runoff increased by 11% over 2002–2019 according to hydrological model outputIn ocean model simulations this dataset gave a subsequent surface freshening of 5%–10%, as compared with classical runoff climatologySiberian rivers dominate runoff and are the main source of differences, enhancing export through Fram and Davis Straits, as observed [ABSTRACT FROM AUTHOR]

The Southern Ocean (SO) is central to the global overturning circulation. South of the Antarctic Polar Front, Antarctic Winter Water (WW) forms in the wintertime mixed layer (ML) and becomes a subsurface layer following summertime restratification of the ML, overlaying upwelled deep waters. Model simulations show that WW acts as a conduit to seasonally transform upwelled deep waters into intermediate waters. Yet, there remains little observational evidence of the distribution and seasonal characteristics of WW. Using 18 years of in situ observations, we show seasonal climatologies of WW thickness, depth, core temperature, and salinity, revealing a distinct regionality and seasonality of WW. The seasonal cycle of WW characteristics is tied to the annual sea ice evolution, whereas the spatial distribution is impacted by the main topographic features in the SO driving an equatorward flux of WW. Through the identification of these localized northward export regions of WW, this study provides further evidence suggesting an alternative view from the conventional "zonal mean" perspective of the overturning circulation. We show that specific overturning pathways connecting the subpolar ocean to the global ocean can be explained by ocean‐topography interactions. Plain Language Summary: The Southern Ocean (SO) around Antarctica is central to the global ocean circulation system. The cold wintertime atmosphere drives ocean cooling and sea ice formation, which causes surface waters to become denser, mixing with deep waters that rise to the surface from the deep ocean. As the ocean surface layer warms in summer, there remains a cold layer below the surface known as Antarctic Winter Water (WW). This layer warms throughout the summer, thinning the WW layer. However, the properties of WW (temperature, salinity, thickness, and depth) vary in space and in erosion rate around the SO. By compiling 18 years of ocean observations, we investigate the physical dynamics that determine how WW changes in space and over the average annual cycle. We find that there are localized regions across the SO where WW properties are transported northward as part of the ocean circulation system, which typically aligns with large topographic features and acts to connect SO water masses to the global ocean. Key Points: Seasonal climatologies of Antarctic Winter Water (WW) and its properties are mapped using 18 years of in situ observationsObservations reveal the distinct seasonal and regional characteristics of WW and their potential link to processes such as sea ice formationLocalized redistribution of WW properties equatorward is steered by large topographic features [ABSTRACT FROM AUTHOR]

The North Adriatic Dense Water (NAddW)—the densest Mediterranean water generated by extreme cooling during wintertime hurricane‐strength winds—drives the thermohaline circulation, ventilates the deep layers, and changes the biogeochemical properties of the Adriatic Sea. However, modeling the dynamical properties of such dense water at the climate scale has been a challenge for decades due to the complex coastal geomorphology of the Adriatic basin not properly reproduced by existing climate models. To overcome these deficiencies, a 31‐year‐long simulation (1987–2017) of the Adriatic Sea and Coast (AdriSC) kilometer‐scale atmosphere‐ocean model is used to analyze the main NAddW dynamical phases (i.e., generation, spreading and accumulation). The study highlights four key results. First, during winter, the NAddW densities are higher in the shallow northern Adriatic shelf than in the deeper Kvarner Bay—where 25%–35% of the overall NAddW are found to be generated—due to a median bottom temperature difference of 2°C between the two generation sites. Second, the NAddW mass transported across most of the Adriatic peaks between February and May, except along the western side of the Otranto Strait. Third, for the accumulation sites, the bottom layer of the Kvarner Bay is found to be renewed annually while the renewal occurs every 1–3 years in the Jabuka Pit and every 5–10 years in the deep Southern Adriatic Pit. Fourth, the NAddW cascading and accumulation is more pronounced during basin‐wide high‐salinity conditions driven by circulation changes in the northern Ionian Sea. Plain Language Summary: The densest water in the Mediterranean Sea known as the North Adriatic Dense Water (NAddW) forms during severe winter wind events in the northern Adriatic. This phenomenon which brings oxygen‐rich waters to the sea bottom, plays a vital role in sustaining life in the Adriatic Sea. However, due to the complex geography of the Adriatic, accurate representation of NAddW is very challenging and requires fine‐resolution atmosphere‐ocean models such as the Adriatic Sea and Coast (AdriSC) model. Here, the AdriSC historical simulation is used to study NAddW generation, spreading and accumulation. The findings reveal that about a third of NAddW is produced in the Kvarner Bay which is a deeper and warmer than the Northern Adriatic shelf. Further, it is found that NAddW spreads over most of the Adriatic between February and May bringing dense waters to the bottom of the accumulation sites, which are renewed annually in the northern Adriatic, up to every 3 years in the middle Adriatic pit, and up to every decade in the Southern Adriatic Pit. Lastly, the study highlights that NAddW spreading and accumulation are significantly enhanced during periods of higher salinity across the Adriatic, a phenomenon driven by water exchanges with the Ionian Sea. Key Points: The kilometer‐scale dense water generation, spreading and accumulation is quantified in the Adriatic Sea during the 1987–2017 periodAbout a third of the dense water is generated within the Kvarner Bay which is deeper and warmer than the well‐studied main generation siteThe bottom layer renewal of the accumulation sites is annual in the Kvaner Bay and up to decadal in the deepest Adriatic pits [ABSTRACT FROM AUTHOR]

Downstream of Cape Hatteras, the vigorously meandering Gulf Stream forms anticyclonic warm core rings (WCRs) that carry warm Gulf Stream and Sargasso Sea waters into the cooler, fresher Slope Sea, and forms cyclonic cold core rings (CCRs) that carry Slope Sea waters into the Sargasso Sea. The Northwest Atlantic shelf and open ocean off the U.S. East Coast have experienced dramatic changes in ocean circulation and water properties in recent years, with significant consequences for marine ecosystems and coastal communities. Some of these changes may be related to a reported regime shift in the number of WCRs formed annually, with a doubling of WCRs shed after 2000. Since the regime shift was detected using a regional eddy‐tracking product, primarily based on sea surface temperatures and relies on analyst skill, we examine three global eddy‐tracking products as an automated and potentially more objective way to detect changes in Gulf Stream rings. Currently, global products rely on altimeter‐measured sea surface height (SSH), with WCRs registering as sea surface highs and CCRs as lows. To identify eddies, these products use either SSH contours or a Lagrangian approach, with particles seeded in satellite‐based surface geostrophic velocity fields. This study confirms the three global products are not well suited for statistical analysis of Gulf Stream rings and suggests that automated WCR identification and tracking comes at the price of accurate identification and tracking. Furthermore, a shift to a higher energy state is detected in the Northwest Atlantic, which coincides with the regime shift in WCRs. Plain Language Summary: In the Northwest Atlantic Ocean, a specific type of eddy, known as a ring, is formed by the Gulf Stream, a strong ocean current that closely follows the U.S. East Coast between Florida and Cape Hatteras. Northeast of Cape Hatteras, the Gulf Stream separates from the continental shelf and starts to meander. Sometimes, these meanders grow into oxbow‐like structures that pinch off from the Gulf Stream and become rings. Warm core rings (WCRs) are formed north of the Gulf Stream, with warm centers that create sea surface hills. In contrast, cold core rings (CCRs) form south of the stream, with cold centers and sea surface valleys. Since 1980 an analyst, who studies the Gulf Stream, has used primarily sea surface temperature to identify WCRs. A regional Ring Census based on this work found a doubling in WCR formations after 2000. Other eddy data sets are based on satellite data, such as sea surface height (SSH), and are created by automated tracking algorithms. This study compares global eddy data sets with the Ring Census. Our findings suggest global data sets using SSH alone cannot replicate the results of the Ring Census. Additionally, we find the Northwest Atlantic region has become more energetic since 2000. Key Points: Global altimetry‐based products evaluated to study Gulf Stream rings differ from regional data products based on sea surface temperatureGlobal products do not detect an observed regime shift in the number of Warm Core Ring formations and do not reflect the known seasonalityA shift to a higher energy state in the Northwest Atlantic around 2000 is detected via satellite altimetry‐based geostrophic velocities [ABSTRACT FROM AUTHOR]

The formation of dense Brine‐enriched Shelf Water (BSW) in Storfjorden is analyzed during Winter 2016–2017 from mooring observations, a polynya model nudged to satellite observations, and an original BSW production model. The ice season was two months shorter than average, yet 44.2 km3 ${\text{km}}^{3}$ of sea ice were formed, in line with estimates for the period preceding the atlantification of the Barents Sea in the mid‐2000s: A thinner, more fragile ice may favor polynya openings and frazil ice production. A saline specimen of BSW was produced in large volumes, corresponding to an annual mean transport of 0.042 Sv, larger than previous estimates. The important production is due to the preconditioning of the polynya with a more saline source water, exceeding the pre‐2005 values by 0.37. The BSW overflow was observed on the West Spitsbergen shelf slope from hydrographic sections down to 750 m, thus entering the Norwegian Sea Deep Water layer. Its core temperature was about 1° $1{}^{\circ}$C warmer than the pre‐2005 values owing to the entrainment of a warmer water in Storfjordrenna, suggesting that a part of the excess surface heat of the Barents Sea could be exported into the deep ocean. Overall our results suggest that dense water formation in the Storfjorden polynya may not, at least for now, be hampered by the atlantification of the Barents Sea, and perhaps even temporarily favored by the more saline source water. Anomalous atmospheric warming during the Winter‐Spring may however disrupt the production, as was observed 1 year before. Plain Language Summary: Sea‐ice extent has strongly declined in the Barents Sea since the mid‐2000s. The sea has also become warmer and saltier, a phenomenon referred to as atlantification. This raises concerns regarding the future of dense water production in coastal polynyas, an essential cog in the climate machine. Polynyas work as ice factories, releasing large quantities of salt in the ocean, which can lead surface waters to cascade into the deep ocean when dense enough. We analyze dense water production in Winter 2016–2017 in the Storfjorden polynya (Svalbard) from a time series of hydrographic observations and an ice production model. Despite a shorter freezing season, the ice production and salt release remained average, while preconditioning with a more saline source water permitted the production of a particularly saline dense water in large volumes. The dense bottom plume was observed to sink into the deep ocean. It was warmer than in the past, suggesting that part of the excess surface heat could be stored at depth. Overall our results suggest that dense water production may not, at least for now, be hampered by the atlantification of the Barents Sea, unless strongly anomalous winter atmospheric warming disrupts ice production, as observed 1 year before. Key Points: A simple model to estimate the production of dense water from hydrographic time series and salt forcing is developedPreconditioning of the polynya with saltier source water promoted the production of dense Brine‐enriched Shelf Water (BSW) in 2017 despite an average ice productionThe BSW overflow was observed to sink down to the Deep Water layer: It was warmer than in observations prior to the atlantification [ABSTRACT FROM AUTHOR]

Dissolved strontium (Sr) concentrations from Southern Ocean water samples and Sr export fluxes from sediment trap moorings at 1,000 m were used to assess particulate organic carbon (POC) export associated with Acantharia for 2010, 2018, and 2020. The dissolved Sr data revealed a prominent vertical gradient with lower surface Sr concentrations depleted up to 1.5% relative to deep waters. A strong latitudinal surface gradient was observed, ranging from 86.8 μmol kg−1 near the northern end to 88.0 μmol kg−1 near the southern end of a transect through the Australian sector of the Southern Ocean. The vertical and latitudinal gradients are associated with celestite (SrSO4) precipitation by Acantharia and subsequent export to depth. Seasonal variability in Sr export fluxes can be large, particularly during intense events in summer, and reaches a maximum of 11.7 mmol Sr m−2 yr−1, contributing up to 7% of the POC export flux. The coincidence of Sr flux with the second peak of POC export flux implies an association of Acantharia biomass with summertime productivity. Plain Language Summary: Acantharia are tiny marine organisms found worldwide. Their skeletons, composed of a heavy mineral called strontium sulfate (SrSO4, or celestite), make Acantharia important in the oceanic strontium cycling. They also form cysts by resorbing their skeletons and main cellular components, allowing them to sink quickly to depths for reproduction. Despite their dense skeletons and cysts, which could act as effective ballasts, Acantharia were previously thought to have little impact on carbon export in the deeper ocean layers due to their high solubility in seawater. Our study focused on understanding how Acantharia influence strontium cycling and contribute to carbon export in the Southern Ocean. We discovered that Acantharia efficiently remove strontium from the ocean's surface and release it at intermediate depths. These organisms exhibit seasonal variations and are particularly abundant in summer, contributing up to 7% to POC export during the summer productive season. This is significant for the Southern Ocean as a major region for carbon sequestration and global climate buffering. Key Points: Strong vertical and latitudinal gradients of dissolved Sr observed in the Southern Ocean were driven by AcanthariaSr export fluxes exhibited seasonal variations with peaks occurring annually in summer, contributing up to 7% to particulate organic carbon fluxElevated Acantharia biomass is possibly associated with summertime productivity [ABSTRACT FROM AUTHOR]

Glaciers are a source of fine‐ground rock flour to proglacial and coastal marine environments. In these environments, suspended rock flour may affect light and (micro)nutrient availability to primary producers. Due to high loads of glacier rock flour, the particulate metal load of glacier runoff typically exceeds the dissolved metal load. As glacier rock flour is deposited in downstream environments, short‐term exchange between particulate and dissolved metal phases may have a moderating influence on dissolved metal concentrations. Here we compare the behavior of iron (Fe), manganese (Mn), cobalt (Co) and silica (Si) following the addition of different glacier‐derived sediments into seawater under conditions of varying sediment load (20–500 mg L−1), time (0.5 hr–21 days), temperature (4–11°C) and light exposure (dark/2,500 Lux). Despite a moderately high labile Fe content across all particle types (0.28–3.50 mg Fe g−1 of dry sediment), only 0.27–7.13 μg Fe g−1 was released into seawater, with less efficient release as sediment load increased. Conversely, Si, Mn, and Co exhibited a more constant rate of release, which was less sensitive to sediment load. Dissolved Si release was equivalent to 17% ± 22% of particulate amorphous Si after 1–2 weeks. Dissolved Mn concentrations in most incubations exceeded dissolved Fe concentrations within 1 hr despite labile Mn content being 12‐fold lower than labile Fe content. Our results show the potential for glacier‐derived particles to be a large source of Mn and Co to marine waters and add to the growing evidence that Mn may be the bio‐essential metal most affected by glacier‐associated sources. Plain Language Summary: Glacier runoff is associated with high sediment loads derived from glacier weathering. Particle surfaces can, depending on ambient conditions, act as a source or sink for dissolved metals in solution. With increasing glacier discharge and ongoing glacier retreat around the Arctic, shifts in the seasonal timing and magnitude of sediment delivery to the coastline are expected. However, the net effect of glacier‐derived particles on marine metal and nutrient availability is not clear, especially for elements other than Fe, which are less well studied. Here we used sediment‐seawater incubations with different glacier and iceberg sediment samples from Greenland and Svalbard to quantify the change in Fe, Mn, Co, and Si concentrations when particles were suspended in Atlantic seawater. Our results and a comparison with in situ concentrations reveal the significance of particle dissolution on elemental cycles, particularly for Mn. Key Points: Changing light and temperature had no effect on the net release of Fe, Mn, Co, or Si from glacier rock flour in seawaterA small fraction of labile particulate Fe was soluble in seawater, although this was partially reversible over short (<24 hr) timescalesMn and Co showed a consistent gradual dissolution behavior with Mn present at dissolved concentrations ∼8× higher than Fe within 24 hr [ABSTRACT FROM AUTHOR]

Dimethyl sulfide (DMS) contributes to cloud condensation nuclei (CCN) formation in the marine environment. DMS is ventilated from the ocean to the atmosphere, and, in most models, this flux is calculated using seawater DMS concentrations and a sea–air flux parameterization. Here, climatological seawater DMS concentrations from interpolation and parameterization techniques are passed through seven flux parameterizations to estimate the DMS flux. The seasonal means of calculated fluxes are compared to identify differences in absolute values and spatial distributions, which show large differences depending on the flux parameterization used. In situ flux observations were used to validate the estimated fluxes from all seven parameterizations. Even though we see a correlation between the estimated and observation values, all methods underestimate the fluxes in the higher range (>20 µ mol m -2 d -1) and overestimate the fluxes in the lower range (<20 µ mol m -2 d -1). The estimated uncertainty in DMS fluxes is driven by the uncertainty in seawater DMS concentrations in some regions but by the choice of flux parameterization in others. We show that the resultant flux is, hence, highly sensitive to both and suggest that there needs to be an improvement in the estimation methods of global seawater DMS concentration and sea–air fluxes for accurately modeling the effect of DMS on the atmosphere. [ABSTRACT FROM AUTHOR]

Dimethyl sulfide (DMS) is a naturally emitted trace gas that can affect the Earth's radiative budget by changing cloud albedo. Most atmospheric models that represent aerosol processes depend on regional or global distributions of seawater DMS concentrations and sea–air flux parameterizations to estimate its emissions. In this study, we analyse the differences between three estimations of seawater DMS, one of which is an observation-based interpolation method following Hulswar et al. (2022) (hereafter referred to as H22) and two of which are proxy-based parameterization methods following Galí et al. (2018) (hereafter referred to as G18) and Wang et al. (2020a) (hereafter referred to as W20). The interpolation-based method depends on the distribution of observations and the methods used to fill data between observations, while the parameterization-based methods rely on establishing a relationship between DMS and environmental parameters such as chlorophyll a , mixed-layer depth, nutrients, sea surface temperature, etc., which can then be used to predict DMS concentrations. On average, the interpolation-based methods show higher DMS values compared to the parameterization-based methods. Even though the interpolation method shows higher values than the parameterization-based methods, it fails to capture mesoscale variability. The regression-based parameterization method (G18) shows the lowest values compared to other estimations, especially in the Southern Ocean, which is the high-DMS region in austral summer. The parameterization-based methods suggest positive long-term trends in seawater DMS (3.82±0.79 % per decade for G18 and 2.13±0.32 % per decade for W20). Since large differences, often more than 100 %, are observed between the different estimations of seawater DMS, the derived sea–air fluxes and, hence, the impact of DMS on the radiative budget are sensitive to the estimate used. [ABSTRACT FROM AUTHOR]

Advancing membranes with enhanced solute-solute selectivity is essential for expanding membrane technology applications, yet it presents a notable challenge. Drawing inspiration from the unparalleled selectivity of biological systems, which benefit from the sophisticated spatial organization of functionalities, we posit that manipulating the arrangement of the membrane's building blocks, an aspect previously given limited attention, can address this challenge. We demonstrate that optimizing the face-to-face orientation of building blocks during the assembly of covalent-organic-framework (COF) membranes improves ion-p interactions with multivalent ions. This optimization leads to extraordinary selectivity in differentiating between monovalent cations and anions from their multivalent counterparts, achieving selectivity factors of 214 for K+/Al3+ and 451 for NO3-/PO4 3-. Leveraging this attribute, the COF membrane facilitates the direct extraction of NaCl from seawater with a purity of 99.57%. These findings offer an alternative approach for designing highly selective membrane materials, offering promising prospects for advancing membrane-based technologies. [ABSTRACT FROM AUTHOR]

Hitherto unreported whale fall fauna has been found from the Lower Miocene of Khari Nadi Formation of Kutch, India.This vertebrate-invertebrate assemblage comprises jumbled up bone fragments of different parts of the whale along with molluscs and echinoids. Some representatives in this assemblage are characteristic whale fall fauna and some are characteristic shallow marine fauna. The molluscs belong to the families Buccinidae, Provannidae, Naticidae, Turritellidae, Borsoniidae, Volutidae, Haminoeidae, Cypraeidae, Strombidae, Rostelleriidae, Cassidae, Osteridae, Veneridae, Astartidae and the echinoids to family Spatangidae and Schizasteridae. The present study reveals that the deposition of this entire assemblage was in a shallow marine environment and also sheds some light on the molluscan association related to a whale fall from the western Indian sea waters in the Lower Miocene. [ABSTRACT FROM AUTHOR]

Several of the icy moons in the Jupiter and Saturn systems appear to possess internal liquid water oceans. Our knowledge of the Uranian moons is more limited but a future tour of the system has the potential to detect subsurface oceans. Planning for this requires an understanding of how the moons' internal structures—with and without oceans—relate to observable quantities. Here, we show that the amplitude of forced physical librations could be diagnostic of the presence or absence of subsurface oceans within the Uranian moons. In the presence of a decoupling global ocean, ice shell libration amplitudes at Miranda, Ariel, and Umbriel will exceed 100 m if the shells are <30 ${< } 30$km $\mathrm{k}\mathrm{m}$ thick. The presence of oceans could also imply significant tidal heating within the last few hundred million years. Combining librations with the quadrupole gravity field could provide comprehensive constraints on the internal structures and histories of the Uranian moons. Plain Language Summary: Several of the icy moons in the Jupiter and Saturn systems appear to possess internal liquid water oceans. Our knowledge of the Uranian moons is more limited but a future tour of the Uranus system has the potential to detect subsurface oceans. Planning for this requires an understanding of how the moons' internal structures—with and without oceans—relate to observable quantities. Here, we show that certain aspects of their rotational states could be diagnostic of the presence or absence of internal liquid water oceans within several of the Uranian moons and that combining this with measurements of the gravity field could provide comprehensive constraints on the internal structures and histories of the Uranian moons. Key Points: Measuring physical libration amplitudes can be used to detect subsurface liquid water oceans within the Uranian moonsCombining librations with gravity measurements can yield comprehensive constraints on the interiors of the Uranian moonsThick oceans are easier to detect but finding thin oceans may require libration amplitudes to be measured to within better than 10 m [ABSTRACT FROM AUTHOR]

Intense atmosphere‐ocean‐ice interactions in the Ross Sea play a vital role in global overturning circulation by supplying saline and dense shelf waters. Since the 1960s, freshening of the Ross Sea shelf water has led to a decline in Antarctic Bottom Water formation. However, during 2012–2018, salinity of the western Ross Sea has rebounded. This study adopts a global ocean‐sea ice model to investigate the causes of this salinity rebound. Model‐based surface salinity budget analysis indicates that the salinity rebound was driven by increased brine rejection from sea ice formation, triggered by nearly equal effects of local anomalous winds and surface heat flux. The local divergent wind anomalies promoted local sea ice formation by creating a thin ice area, while cooling heat flux anomaly decreased the surface temperature, increasing sea ice production as well. This highlights the importance of understanding local climate variability in projecting future dense shelf water change. Plain Language Summary: Previous research linked the recent salinity increase in the western Ross Sea to weakened easterly winds from the Amundsen Sea. However, insufficient observations limit the further investigation of the linkage and underlying mechanisms between atmospheric forcing and shelf water salinity changes. In this study, we use a global ocean‐sea ice coupled model to investigate the factors affecting the recent western Ross Sea shelf water salinity increase. Based on a surface salinity budget analysis, we show that the recent salinity increase was supplied by brine rejection induced by increased sea ice formation, triggered almost equally by local anomalous winds and surface heat flux. The local wind anomalies induced a divergent motion in sea ice, reducing sea ice thickness and promoting local sea ice formation. Meanwhile, a negative heat flux anomaly from the atmosphere cools the surface, increasing sea ice production as well. Our study highlights the impact of local climate variability on dense shelf water. Moreover, the model experiment design and salinity budget analysis undertaken here provide an essential reference for identifying the major drivers of the shelf water salinity variations. Key Points: Using a global ocean‐sea ice model, we simulate the recent rebound of Dense Shelf Water salinity in the western Ross Sea during 2012–2018A model‐based salinity budget analysis reveals increased sea ice formation as the primary driver of the observed salinity reboundExperiments indicate that this increased sea ice formation is triggered by the combined effect of local wind stress and surface heat flux [ABSTRACT FROM AUTHOR]

The crustacean family Ampithoidae is one of the most abundant invertebrate families associated with macroalgae in shallow marine waters. Ampithoe, the largest genus, was previously documented as non‐monophyletic by phylogenetic analyses based on morphological and molecular characters. Here, we reconstructed a multi‐gene phylogeny of Ampithoidae with the first data of the southwestern Atlantic Ocean. We performed the first biogeographic analyses for the family, which indicated its origin in the Indo‐West Pacific, with subsequent dispersion to the Atlantic Ocean around the Eocene. Divergence times suggest that the diversification of Ampithoidae is congruent with the brown algae crown radiation, which allowed the colonization of new environments. [ABSTRACT FROM AUTHOR]

Constructing highly efficient electrocatalysts is vital to enhance oxygen evolution reaction (OER) performance at industrially relevant current densities. Herein, three-phase coupled Ni3S2/r-NiS/h-NiS composites are grown in situ on Ni foam (NNSN/NF) via a one-step solvothermal approach. The as-prepared composites need overpotentials of only 377 mV, 451 mV and 476 mV at 1000 mA cm−2 for the OER in alkaline freshwater, simulated seawater and seawater, respectively. In addition, the optimized catalyst exhibited long-term durability at 300 mA cm−2. Our work clarifies designing and preparing cost-effective Ni-based sulfide electrocatalysts for the OER in alkaline freshwater/simulated seawater/seawater under industrially relevant current densities. [ABSTRACT FROM AUTHOR]

The development of efficient, stable and low-cost electrocatalysts towards the seawater oxidation is highly desirable for hydrogen-based industries. In this work, we report the efficient preparation of phosphate-decorated hierarchical porous CoNiFe medium-entropy alloys as promising electrocatalysts for the oxygen evolution reaction in seawater via the solution combustion synthesis. The hierarchical porous structure of CoNiFe medium-entropy alloys enhances exposure to catalytic sites and facilitates the efficient diffusion of gas products as well as electrolytes. Moreover, the in-situ formed PO 4 3− anions not only improve the electrocatalytic performance of CoNiFe medium-entropy alloys for oxygen evolution reaction, but also prevent Cl− from contacting the catalytic sites. Thanks to these structural benefits, the optimized CoNiFeP 0.1 @NF electrode demonstrates superior electrocatalytic performance for oxygen evolution reaction, showing an overpotential of 250 mV at 10 mA cm−2, a low Tafel slope of 47.6 mV dec−1, and satisfactory stability in the 1.0 M KOH +0.5 M NaCl electrolyte. • Phosphate-decorated CoNiFe alloys were prepared via solution combustion synthesis. • The hierarchical porous structure of CoNiFe benefits the exposure of active sites. • PO 4 3− anions enhance the performance of CoNiFe alloys for seawater oxidation. [ABSTRACT FROM AUTHOR]

Creating and building an integrated system that consists of a storage tank, an electrolysis cell with many electrolyzer types, and a green hydrogen generator that produces clean, sustainable gas using solar photovoltaic (PV) energy and renewable energy sources. Three different electrolyzer modules with six, eleven, and twenty-one plates each were created locally and meant to be utilized in the production of green hydrogen. The hydrogen storage system's design was also created. It is clear that the maximum value of hydrogen production is recorded in the following ordered: KOH (5.5 L/min) > NaOH (1.2 L/min) > NaCl (0.7 L/min) > MgSO 4 (0.4 L/min). Also, sea water was used as electrolyte solution with different dilution 5, 10, 15, and 20% using a natural sea water sample collected from the Mediterranean Sea. It is found that 15% sea water dilution reaches the maximum value of H 2 production (3.4 L/min). Using distilled water and tap water, respectively, the volume of generated H 2 gas reached its maximum value of 8 L/min and 6.5 L/min at 0.4 mols of KOH. It was observed that with increased time durations (0–90 min), enhance the rate of hydrogen production to be reaches 8.2 and 11.5 L/min when using 0.05 and 0.1 mols KOH, respectively. This approach reduces environmental effect and operational costs, providing a sustainable solution to the water and energy problems. The integrated system for using solar energy and photovoltaic (PV) for hydrogen production used the storage H 2 as a source of energy to operate the small water desalination plant. [Display omitted] • Creation of three different electrolyzer modules with six, eleven, and twenty-one plates. • Electrolysis cell and a storage tank with many electrolyzers using solar energy used for H 2 production. • KOH, NaOH, NaCl, and MgSO 4 used as an electrolyte solutions for H 2 productions. • Different dilution of a natural sea water sample used as electrolyte solution. • Numerous variables were estimated in order to influence the production of green H 2. [ABSTRACT FROM AUTHOR]

The exploration of high‐efficiency electrocatalysts is becoming indispensable for the production of H2 from electrochemcial seawater splitting. Herein, a feasible strategy is developed to realize the in situ encapsulation of Ni‐decorated Fe3N into porous N‐doped carbon nanolayer, abbreviated as Nix‐Fe3N@NCPs, by an association of wet‐impregnation treatment and thermal annealing. More concretely, the doping of Ni can initiate the synergistic effect to optimize the internal electronic structure, which strengthen the adsorption of intermediates and interface charge transfer. Meantime, the architecture of NCPs encapsulation nanolayer not only enhances the conductivity and the structural stability, but also effectively prevents Cl− ions transport from poisoning of electrocatalytic active sites. On these grounds, the preferred Ni0.10‐Fe3N@NCPs electrocatalyst delivers the exceptional bifunctional electrocatalytic performance in electrolytic seawater. The corresponding HER and OER overpotentials to attain the current densities of 10, 100, and 500 mA cm−2 are only required 47, 147, and 291 mV as well as 152, 249, and 312 mV, respectively. In addition, the Ni0.10‐Fe3N@NCPs electrocatalysts achieves an ultra‐low voltage of 1.80 V at 500 mA cm−2 with ultralong lifespan of 1200 h in zero‐gap alkaline electrolyzer. This work provides a cutting‐edge scientific research exploration for the development of electrocatalyst for seawater electrolysis. [ABSTRACT FROM AUTHOR]

In this study, Al 2 O 3 –20TiO 2 (AT) and Cr 2 O 3 –3TiO 2 –5SiO 2 (CT) coatings were prepared by atmospheric plasma spraying (APS), The microstructure, phase compositions and corrosion behavior were studied comparatively. The results indicated that both coatings had layered structure, with an average surface roughness RA around 6 μm, an adhesive strength around 35 MPa, and a porosity around 4 %. The AT coating mainly composed of γ-Al 2 O 3 and α-Al 2 O 3 , and the CT coating composed Cr 2 O 3 respectively. Moreover, the AT coating exhibited better corrosion resistance than the CT coating. In artificial seawater, the corrosion process was strongly related to the porosity. The corrosion rate (based on the corrosion current density) of the two coatings showed a same trend which decreased first and then increased. It was thought that the blocking of early corrosion products in holes was helpful to delaying the progress of corrosion. In contrast, the later corrosion products would promote the formation and propagation of cracks, accelerating the corrosion. In the simulated environment with high pressure and hydrogen sulfide seawater, the corrosion process was strongly related to the porosity as well as the brittleness of the coatings. The corrosion rate (based on the weight loss) of the AT coatings still remained the same trend as it in the artificial seawater. However, the CT coating showed a continuously increasing corrosion rate, due to higher porosity and brittleness resulted in a large number of cracks under external stress, which offered corrosion channels. [ABSTRACT FROM AUTHOR]

Antarctic Bottom Water (AABW), which supplies the lower limb of the thermohaline circulation, originates from dense shelf water (DSW) forming in Antarctic polynyas. Here, combining a long mooring record of DSW measurements with numerical simulations and satellite data, we show that significant correlation exists between interannual variability of DSW production in the Ross Sea polynyas, where DSW contributes between 20–40% of the global AABW production, and the Southern Annular Mode (SAM). The correlation is largest when the Amundsen Sea Low (ASL) is weakened and shifted east of the Ross Sea. During positive SAM phases, enhanced offshore winds and lower air temperatures over the western Ross Sea increase sea ice production and promote DSW formation, with the opposite response during negative SAM phases. These processes ultimately modulate AABW thickness in the open ocean. A projected positive shift of the SAM and eastward displacement of the ASL thus has implications for the future of DSW and AABW formation. This study shows that the formation of bottom water and the related sea ice processes in the Ross Sea are significantly affected by major climate patterns in the southern hemisphere's extratropical regions. [ABSTRACT FROM AUTHOR]

The global spread of multidrug-resistant Escherichia coli threatens human, animal, and environmental health. Despite the recognition of water bodies as potential reservoirs, research on antimicrobial resistance (AMR) and antibiotic residues in the Baltic Sea is limited. In this study, we examined the presence of ESBL-producing E. coli in surface water in northeastern Germany. We then conducted phenotypic and genotypic analyses of the strains, which encompassed AMR and heavy metal/metalloid tolerance, biofilm formation, and detailed plasmid examination. In addition, we used solid-phase extraction with ultra-high performance liquid chromatography and mass spectrometry to quantify antibiotic residues. Our analysis identified 30 ESBL-producing E. coli isolates, some of which were associated with clinically relevant high-risk clonal lineages. We detected antibiotic residues in the environmental samples, but the antibiotic concentrations were significantly lower compared to wastewater samples. These results suggest that the Baltic Sea surface water could serve as a reservoir for ESBL-producing E. coli and clinically relevant antibiotics. [ABSTRACT FROM AUTHOR]

Based on the WAVEWATCH III wave model, China's National Marine Environmental Forecasting Center has developed an operational global ocean wave forecasting system that covers the Arctic region. In this study, in situ buoy observations and satellite remote sensing data were used to perform a detailed evaluation of the system's forecasting results for 2022, with a focus on China's offshore and global ocean waters, so as to comprehensively understand the model's forecasting performance. The study results showed the following: In China's coastal waters, the model had a high forecasting accuracy for significant wave heights. The model tended to underestimate the significant wave heights in autumn and winter and overestimate them in spring and summer. In addition, the model slightly underestimated low (below 1 m) wave heights, while overestimating them in other ranges. In terms of spatial distribution, negative deviations and high scatter indexes were observed in the forecasting of significant wave heights in semi-enclosed sea areas such as the Bohai Sea, Yellow Sea, and Beibu Gulf, with the largest negative deviation occurring near Liaodong Bay of the Bohai Sea (−0.18 m). There was a slight positive deviation (0.01 m) in the East China Sea, while the South China Sea exhibited a more significant positive deviation (0.17 m). The model showed a trend of underestimation for the forecasting of the mean wave period in China's coastal waters. In the global oceanic waters, the forecasting results of the model were found to have obvious positive deviations for most regions, with negative deviations mainly occurring on the east coast and in relatively closed basins. There were latitude differences in the forecasting deviations of the model: specifically, the most significant positive deviations occurred in the Southern Ocean, with smaller positive deviations toward the north, while a slight negative deviation was observed in the Arctic waters. Overall, the global wave model has high reliability and can meet the current operational forecasting needs. In the future, the accuracy and performance of ocean wave forecasting can be further improved by adjusting the parameterization scheme, replacing the wind fields with more accurate ones, adopting spherical multiple-cell grids, and data assimilation. [ABSTRACT FROM AUTHOR]

We apply the Canny edge algorithm to imagery from the Utqiaġvik coastal sea ice radar system (CSIRS) to identify regions of open water and sea ice and quantify ice concentration. The radar-derived sea ice concentration (SIC) is compared against the (closest to the radar field of view) 25 km resolution NSIDC Climate Data Record (CDR) and the 1 km merged MODIS-AMSR2 sea ice concentrations within the ∼11 km field of view for the year 2022–2023, when improved image contrast was first implemented. The algorithm was first optimized using sea ice concentration from 14 different images and 10 ice analysts (140 analyses in total) covering a range of ice conditions with landfast ice, drifting ice, and open water. The algorithm is also validated quantitatively against high-resolution MODIS-Terra in the visible range. Results show a correlation coefficient and mean bias error between the optimized algorithm, the CDR and MODIS-AMSR2 daily SIC of 0.18 and 0.54, and ∼−1.0 and 0.7%, respectively, with an averaged inter-analyst error of ±3%. In general, the CDR captures the melt period correctly and overestimates the SIC during the winter and freeze-up period, while the merged MODIS-AMSR2 better captures the punctual break-out events in winter, including those during the freeze-up events (reduction in SIC). Remnant issues with the detection algorithm include the false detection of sea ice in the presence of fog or precipitation (up to 20%), quantified from the summer reconstruction with known open water conditions. The proposed technique allows for the derivation of the SIC from CSIRS data at spatial and temporal scales that coincide with those at which coastal communities members interact with sea ice. Moreover, by measuring the SIC in nearshore waters adjacent to the shoreline, we can quantify the effect of land contamination that detracts from the usefulness of satellite-derived SIC for coastal communities. [ABSTRACT FROM AUTHOR]

The unique localized environments (Ni- N -Fe structures and unsaturated O- and N -coordination) due to dual-defect strategy can make the motif more reactive. The N -v Fe -NiFe 2 O 4 /NF catalyst containing N doping and Fe vacancies exhibits overpotentials of 210, 213 and 222 mV at 100 mA cm−2 in 1.0 M KOH, 1.0 M KOH + 0.5 M NaCl and 1.0 M KOH + seawater electrolytes, respectively. [Display omitted] Developing simple and energy-saving pathways to prepare high-efficient and robust non-noble metal based electrocatalysts remains a huge challenge to hydrogen production from seawater electrolysis. Here we demonstrate a facile hydrothermal-calcination-etching approach that simultaneously achieves the required surface N doping and Fe vacancies generation to activate the Ni-O-Fe active motifs in N -v Fe -NiFe 2 O 4 /NF. The unique localized environments (Ni- N -Fe structures and unsaturated O- and N -coordination) due to dual-defect strategy can effectively regulate the electronic structure of the Ni-O-Fe motif to make the motif more reactive. As a result, the N -v Fe -NiFe 2 O 4 /NF catalyst exhibits overpotentials of 210, 213 and 222 mV to deliver 100 mA cm−2 in 1.0 M KOH, simulated seawater and alkaline seawater environments, respectively. Theoretical calculations prove that the Ni-O-Fe structure is the active motif and that the presence of special localized environments can optimize the adsorption of key intermediates on the activated active motifs. [ABSTRACT FROM AUTHOR]

In the Casablanca-Mohammedia corridor (Morocco), flooding episodes have happened frequently over the past 20 years, damaging coastal settlements through overtopping and overflowing processes. In this context, a realistic assessment of the flood risk on this coastline is required. For this, the marine water level variations were computed by combining the involved variables (astronomical tide, storm surge, wave run-up, and sea level rise) during energetic events. They were compared with the seafront altitude to delineate the maximum spatial extent of flooded areas for the current and future (2100) time horizons. These variables were obtained through numerical and empirical modeling using topobathymetry, tide gauge, wind, and reanalysis data for wave and atmospheric pressure. Statistical methods were used to determine trends and distributions, including linear regression and the GEV model. Our approach was validated by comparing the estimated results of the total water level with the observations made in situ during previous events. Results show that flooding occurs mainly at high tides. The run-up is the largest contributor to total water level during energetic events (45–60% in structure defense areas against ~ 35% in natural areas). Currently, the floodable area for all of Casablanca-Mohammedia's coastline (109 km2) is estimated to be ~ 23.5 km2, of which ~ 13.9 km2 is urban. This area would grow by 10.87% and 20.9% by 2100, respectively. The most vulnerable zones are Mohammedia, Ain Sbâa, and Merzeg quarters, as well as Tamaris beaches. The touristic quarters of Ain Diab and the promenades on either side of the Hassan II Mosque are also vulnerable and can be dangerous for pedestrians. This study is crowned by the proposal of numerous necessary protection and adaptation measures, considering the specificities of the sections characterizing this coastline. [ABSTRACT FROM AUTHOR]

Herein, a hollow spherical pillar[5]arene-based polymer (P5-AO) adsorbent was synthesized. The P5-AO adsorbent was capable of effectively capturing uranium from simulated seawater (139.5 mg g−1) and real seawater (8.1 mg g−1). We also elucidated the uranium adsorption mechanism of P5-AOvia extended X-ray absorption fine structure (EXAFS). This study provides a novel direction for the development of uranium capture adsorbents. [ABSTRACT FROM AUTHOR]

The quest for cost effective but active electrocatalysts for water oxidation is at the forefront of research towards hydrogen economy. In this regard, bamboo as biomass derived N-doped cellulosic carbon has shown potential electrocatalytic performance towards water oxidation. The impregnation of optimum metallic Fe boosts the performance further, achieving an over potential value of 238 mV at a benchmark current density of 10 mA cm-2. Owing to its promising OER performances in alkaline freshwater, the electrocatalyst was further explored in alkaline saline water and alkaline real seawater, exhibiting overpotentials of 272 mV and 280 mV, respectively, to reach 10 mA cm-2 current density. Most importantly, the protective graphitic multilayer surrounding the metallic Fe allowed the electrocatalyst to demonstrate excellent durability over 30 h even at a high current density in alkaline real seawater electrolyte. [ABSTRACT FROM AUTHOR]

The exploitation of highly activity oxygen evolution reaction (OER) electrocatalysts is critical for the application of electrocatalytic water splitting. Triggering the lattice oxygen mechanism (LOM) is expected to provide a promising pathway to overcome the sluggish OER kinetics, however, effectively enhancing the involvement of lattice oxygen remains challenging. In this study, the fabrication of B, Fe co‐doped CoP (B, Fe─CoP) nanofibers is reported, which serve as highly efficient OER electrocatalyst through phosphorization and boronation treatment of Fe‐doped Co3O4 nanofibers. Experimental results combined with theoretical calculations reveal that simultaneous incorporation of both B and Fe can more effectively trigger the participation of lattice oxygen in CoFe oxyhydroxides reconstructed from B, Fe─CoP nanofibers compared to incorporating only B or Fe. Therefore, the optimized B, Fe─CoP nanofibers exhibit superb OER activity with low overpotentials of 361 and 376 mV at 1000 mA cm−2 in alkaline freshwater and alkaline natural seawater, respectively. The present work provides significant guidelines and innovative design concepts for the development of OER electrocatalysts following the LOM pathway. [ABSTRACT FROM AUTHOR]

Piezocatalytic water‐splitting to simultaneously produce H2 and H2O2 has many potential advantages. However, the necessity to utilize materials having polar structures limits the choice of piezocatalysts. Herein, it is demonstrated that centrosymmetric BiOBr with oxygen defects can simultaneously produce H2 and H2O2 with ultrahigh efficiencies from pure and seawater without needing assistance from noble metals or scavengers. High‐pressure studies confirm that there are no non‐polar‐to‐polar phase transitions in BiOBr, though a novel isostructural phase is discovered. Computational studies reveal that oxygen vacancy distorts the BiOBr structure to induce charge‐localization and polarization. Furthermore, high pressure (i) reduces carrier effective masses and (ii) increases relative O‐2p contribution in the valence band maximum to assist catalysis and improve stability. The role of oxygen vacancy is confirmed by changing its concentration, which proportionally affects H2 evolution. The work paves the way for defect engineering to develop piezocatalysts from a large pool of non‐polar materials. [ABSTRACT FROM AUTHOR]

In this study, we developed a nitrate-coordinated iron–nickel hydroxide [NC–FeNi(OH)2] catalyst for hydrazine oxidation-assisted seawater splitting. Replacement of O2 evolution by hydrazine oxidation in a two-electrode setup resulted in a cell voltage of 1.20 V at 100 mA cm−2. This represents a voltage reduction of 470 mV compared to conventional seawater splitting. Additionally, NC–FeNi(OH)2 demonstrated remarkable stability over a period of 60 hours. [ABSTRACT FROM AUTHOR]