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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]

In the present work, acrylonitrile-butadiene-styrene (ABS)/glass fiber (varying fiber orientation angle) and with different % of carbon black (CB) particles-based hybrid composites are fabricated by hot press compression molding technique. Prepared composites were examined under marine conditions in sea water medium and erosion behavior under erodent particles entrained in gas fluid and found reduced impact. Morphological studies are studied through scanning electron microscope. Material removal mechanism is found to be micro-cracking at the impingement angle of 90°. Additionally, numerical analysis for the composite material with respect to single particle impact for erosion was conducted using LS-DYNA. [ABSTRACT FROM AUTHOR]

Nickel-substituted FeMoO4 nanosheet arrays in situ assembled on a nickel foam skeleton are fabricated by a spontaneous redox reaction. Due to the synergistic effect of the increase of exposed active sites and improvement of electron transfer, the targeted catalyst exhibits excellent electrocatalytic performance for seawater oxidation. [ABSTRACT FROM AUTHOR]

In this work, we report Ti3C2Tx MXene bonded cationic perylene diimide (cPDI) as a redox charge storage host for seawater-based electrolytes. A reversible and stable charge storage capacity of ∼101 mA h g−1 is achieved in 3 M MgCl2 electrolytes at a current density of 0.25 A g−1 with an extended cycling stability of more than 8000 cycles. The redox charge storage dynamics of cPDI in metal-ion electrolytes are mapped through three-dimensional Bode plots. [ABSTRACT FROM AUTHOR]

Current methods for separating critical materials from feedstock solutions remain chemistry- and energy-intensive. We demonstrate the rapid extraction of a pure magnesium phase from seawater via precipitation with sodium hydroxide in a flow-gel device. Our approach is scalable, suitable for high-throughput extraction, and does not rely on specialty chemicals. [ABSTRACT FROM AUTHOR]

Per- and polyfluoroalkyl substances (PFASs), which have their origins in both industrial processes and consumer products, can be detected at all treatment stages in wastewater treatment plants (WWTPs). Quantifying the emissions of PFAS from WWTPs into the marine environment is crucial because of their potential impacts on receiving aquatic ecosystems. In this study, the levels of five PFAS were measured in both influent and effluent sewage water samples obtained from a municipal WWTP, the discharges of which flow into False Bay, on the Indian Ocean coast of Cape Town, South Africa. Additionally, seawater, sediment, and biota samples from eight sites along the False Bay coast were also analysed. Results showed high prevalence of PFAS in the different environmental matrices. Perfluorononanoic acid was most dominant in all these matrices with maximum concentration in wastewater, 10.50 ng/L; seawater, 18.76 ng/L; marine sediment, 239.65 ng/g dry weight (dw); invertebrates, 0.72–2.45 µg/g dw; seaweed, 0.36–2.01 µg/g dw. The study used the chemical fingerprint of five PFASs detected in WWTP effluents to track their dispersion across a large, previously pristine marine environment and examined how each chemical accumulated in different marine organisms. The study also demonstrates that primary and secondary wastewater treatment processes cannot fully remove such compounds. There is thus a need to improve effluent quality before its release into the environment and promote continuous monitoring focusing on the sources of PFAS, including their potential transformation products, their environmental fate and ecological risks, particularly in areas receiving effluents from WWTP. [ABSTRACT FROM AUTHOR]

The use of reverse osmosis (RO) for desalination holds great promise for addressing water scarcity issues in many parts of the world. However, membrane fouling is a significant impediment in this regard, as it reduces the quality and quantity of water produced, increases energy consumption, requires cleaning, and shortens membrane life. The use of granular activated carbon (GAC) adsorption in conjunction with ultrafiltration (UF) as a pre-treatment ensures that high-quality seawater enters the desalination process free of contaminants that could harm the plant. This method increases the efficiency and longevity of the equipment, lowers maintenance costs, and produces high-quality desalinated water for a variety of applications. In this study, GAC was made from commercially available charcoal and used to remove organic compounds, heavy metals, and microbiological contaminants from seawater. A preliminary study was conducted to determine GAC's effectiveness in removing methylene blue (MB). The removal efficiency was found to be 78 and 99% at initial MB concentrations of 50 and 10 mg/L, respectively. The isotherm modeling confirms that the adsorption process follows the Langmuir model. In addition, the kinetic study demonstrated that MB adsorption on GAC follows the pseudo-second-order model. GAC filtration removed more than 99% of COD and significantly reduced metal concentrations such as Zn, Cu, and Cd. Bacteriological analysis of seawater treated with GAC revealed a significant reduction in total and fecal coliforms, as well as fecal streptococci, indicating the efficacy of the GAC/adsorption filtration system. [ABSTRACT FROM AUTHOR]

Settleability is vital important for the stability of effluent quality from the widely used activated sludge (AS) process in wastewater treatment plants. In this study, filamentous algae and seawater condition were used to build a microalgae-bacteria (MB) consortia system with the objective of improving the settleability of AS. Filamentous algae were found to flourish more in aeration seawater reactor (R2) than non-aeration (R1). During 90 days, large contents of N, P were firstly released from the biomass, but were absorbed by the algae to relatively low concentrations (N 1.1 mg/L, P 1.4–2.3 mg/L). Meanwhile, the settleability of the two types of MB consortia both significantly increased, but was superiorly enhanced in aeration condition to a low 5-min sludge volume (SV5) (11.5%, 55 d). Filamentous algae Leptolyngbya, as the most dominant part (9.8%) of microbial community in R2, could tightly bind the bacteria cells and extracellular polymeric substances (EPS) to form larger particles, which greatly accelerated the sedimentation. This study is of interest for the potential use of sludge settleability promotion in wastewater treatment plants, which has promising prospects for preventing the sludge bulking or biomass loss in AS systems. Highlights: A modified MB consortia was studied to enhance the settleability of AS. Filamentous algae flourished in seawater MB consortia with aeration. Settleability was remarkably enhanced by the algae in seawater condition. N and P were released from AS but was mostly absorbed by algae. Filamentous Leptolyngbya was dominant algae in the MB consortia. [ABSTRACT FROM AUTHOR]

Sun coral, identified as Tubastraea coccinea and Tubastraea tagusensis, are invasive marine species originally from the Pacific Ocean that have become a significant threat to native biodiversity and ecosystems in Brazil. The rapid growth and unique reproduction strategies of Tubastraea species have facilitated their success as invasive species. In the past two decades, Brazil has experienced a notable loss of biodiversity, partially attributed to invasive species, as reported by the Brazilian Platform on Biodiversity and Ecosystem Services. Current management efforts primarily involve manual removal, often employing sledgehammers and chisels, carried out by environmental government agencies, in partnership with NGOs and volunteers. However, the need for more efficient management strategies emphasizes the important role of engineering and technology in improving environmental management. To address this issue, our work focuses on the development and prototyping of two underwater tools: an impact hammer and a rotating brush. These tools are designed with ergonomic features, operating time, and size considerations suitable for use by SCUBA divers. Our prototypes have successfully met the required specifications and offer potential for large-scale manufacturing, promising more effective measures for controlling invasive sun coral in Brazil. [ABSTRACT FROM AUTHOR]

Clay minerals were studied in Pleistocene sediments from Hole 1038А (114.50 m deep) and Hole 1038Н (192.80 m deep) drilled near a hydrothermal vent with a temperature of 217°C on Central Hill, 275 m east of Hole 1038B. In sediments from Hole 1038A, at a depth of 8.52 m, <0.001-mm fraction consists completely of chlorite. In the rest of the sediment section in Hole 1038A, clay minerals consist of chlorite (from ~64 to ~98%) and illite. In sediments from Hole 1038H, clay minerals also consist of chlorite and illite. They were formed under conditions related to the intrusion of a basaltic melt as laccolith into the Escanaba Trough and the heating under its influence of a solution, during the interaction of which with sediments at a high-temperature stage biotite was formed. During the subsequent slow cooling of the laccolith and fluid, the newly formed biotite was replaced completely by chlorite. Illite was precipitated from a hydrothermal solution. At a depth of 183 m, in sediments from Hole 1038H, clay minerals consist of biotite, chlorite, and dioctahedral smectite, just as in sediments from Hole 1038B during their formation under conditions of rapid cooling of the laccolith flank and penetration of sea water into the sediments. The paper shows similarities and dissimilarities in the formation of clay minerals in Pleistocene sediments of the Central Hill, located above the slowly cooling part of the laccolith (Holes 1038A and 1038H) and in sediments located above the rapidly cooling laccolith flank (Hole 1038B). [ABSTRACT FROM AUTHOR]

In seawater flotation, some chemical properties of seawater affect the flotation separation of chalcopyrite and sphalerite. Using seawater instead of fresh water to separate copper – zinc can save fresh water resources and reduce lime consumption, which has broad prospects in terms of economic and environmental protection. In this paper, the flotation separation behavior of chalcopyrite and sphalerite in seawater was tested and the mechanism was analyzed. As a contrast, the copper grade of concentrate in seawater flotation declined from 23.7% to 22.6%. Meanwhile, the recovery of chalcopyrite declined from 66.2% to 42.8% and the SI value declined from 2.210 to 1.599. With the addition of sodium hexametaphosphate, sodium silicate and EDTA, the SI value increased from 1.599 to 2.176, 2.238 and 2.096, respectively. Nevertheless, when EDTA was excessive, the SI value was only 1.998. This indicated that excessive EDTA is unfavorable to flotation separation of chalcopyrite from sphalerite. Wettability analysis, zeta potential analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, density functional theory calculation and E-DLVO calculation verified the flotation separation behavior and revealed the mechanism. [ABSTRACT FROM AUTHOR]

The swash zone and its processes are very important in a beach system due to their significant effects on beach hydrodynamics, morphodynamics and ecosystems, including beach flows, aquifers, and sediment transport. It is important to develop efficient numerical models to evaluate hydrodynamic-morphodynamic processes, particularly in the swash zone. XBeach is a numerical model for beach simulations. Despite substantial advances, XBeach remains yet to be further developed since it is inefficient in modeling interactions between the aquifer level and seawater. This study aimed to cope with XBeach phase errors in the aquifer (seawater-aquifer interaction) estimations leading to an inaccurate simulation of hydrodynamic-morphodynamic processes in the swash zone. The XBeach process was evaluated by developing a numerical algorithm to tackle this drawback. Six experimental tests were performed using the proposed and original XBeach models. The average morphological beach change errors of the proposed and original models were 5% and 10%, respectively. The groundwater head estimation error of the original model was 8% compare with less than 3% of the proposed model. The proposed XBeach model effectively handled the phase error of the original XBeach and stimulated the hydrodynamic and morphodynamic processes in the swash zone more accurately. [ABSTRACT FROM AUTHOR]

Event deposition accounts for a large part of the preserved sedimentary record. Tempestites, tsunamites and turbidites are among the most common event deposits in marine and lacustrine systems. While facies models exist for these deposits, the challenge lies in the fact that diverse triggers can give rise to analogous depositional processes and comparable taphonomic features, making it difficult to pinpoint the precise trigger for an event bed. Hence, five distinct modern‐type shell concentrations are studied in Permian strata from the Paraná Basin, West Gondwana, to access the parameters to discriminate event phenomena, and their associated depositional and taphonomic processes. During this time interval, the basin underwent continuous continentalization due to orogenic events, leading to the entrapment of epeiric marine waters and the transformation of the system into a megalake, supporting a diverse and endemic freshwater bivalve fauna. While sedimentation was primarily influenced by meteorological events, certain stratigraphic intervals were also affected by tectonically active periods and meteor impact events. The different products are categorized into bioclastic sandstone, shell bed, shell‐rich phosclast rudstone and shell‐rich conglomerate that are interpreted as proximal and distal tempestites and tsunamites, respectively. Finally, the products and the processes that lead to the deposition of tempestites and tsunamites are compared to establish diagnostic signatures that may be applied to differentiate these event concentrations in analogous settings from the geological record. [ABSTRACT FROM AUTHOR]

Mesozoic oceanic anoxic events were characterized by relatively low seawater sulphate concentrations ([SO42−]), which likely regulated the development and evolution of these major palaeoceanographic phenomena. However, there is little reliable sedimentary evidence for low [SO42−] in ancient marine waters and understanding of how such a seawater chemistry potentially impacted oceanic anoxic events is limited. This study presents an integrated sedimentological, mineralogical and geochemical investigation of the mineral siderite hosted in dark grey shale and sideritic concretions of Early Aptian (coeval with Oceanic Anoxic Event 1a) from the Tibetan Himalaya. Siderite is present throughout the section and possesses similar morphological characteristics whether in dark grey shale or concretions. Siderite can be present as disseminated and rhombic crystals formed during early diagenesis, or minor spherical crystals formed during late diagenesis. The evidence from redox elements, middle rare‐earth element bulge patterns and extremely low carbon‐isotope values of the sideritic concretions indicates that the iron carbonate was formed in the Fe‐reduction zones by the process of dissimilatory iron reduction. This process would have required conditions of low [SO42−], reducing environment, abundant iron and high alkalinity. Additionally, the coexistence of siderite and pyrite may indicate that dissimilatory iron reduction occurred close to the microbial sulphate reduction zone, with seawater [SO42−] hovering around the tipping point at which pyrite could form once seawater sulphate increased. Such an increase during Oceanic Anoxic Event 1a could have resulted from basalt–seawater interaction and associated enhanced continental weathering, and/or hydrothermal activity. This study's observations support the previous hypothesis that low [SO42−] for Oceanic Anoxic Event 1a was probably caused by massive gypsum burial in the proto‐South Atlantic. Subsequently, enhanced sulphate input could have promoted microbial sulphate reduction and accompanying oxidation of organic matter, which likely further enhanced nutrient recycling, increased primary productivity and organic‐carbon burial, leading to more oxygen consumption and expansion of oxygen minimum zones, as reconstructed for many oceanic anoxic events. [ABSTRACT FROM AUTHOR]

The construction of island reef projects using natural seawater, tailored to local conditions, holds significant importance for the advancement of environmentally-friendly geotechnical engineering practices. Previous studies on the application of MICP technology in a seawater environment have been scarce. In this study, Sporosarcina pasteurii were acclimatized to a seawater environment and employed for MICP mineralization reinforcement of calcareous sand, resulting in an enhanced mineralization effect compared to previous attempts under similar conditions. Both direct domestication and gradient domestication methods proved successful in enabling Sporosarcina pasteurii to adapt effectively within a seawater environment. Following domestication, the amount of CaCO3 generated through MICP solidification increased from 2.30% to 4.47%, resulting in a corresponding increase in the Ca2+ conversion rate from 5.19% to 10.02%. Additionally, after domestication, the unconfined compressive strength (UCS) reached up to 309kPa – representing an impressive improvement of 35.53% compared to pre-domestication levels, however, it should be noted that its reinforcement effect still falls short when compared with pure water conditions. The CaCO3 minerals formed after MICP reinforcement using seawater nutrient solution in domesticated Sporosarcina pasteurii predominantly consist of needle-shaped aragonite and granular anorthite minerals, as opposed to the previously observed calcite-type CaCO3 minerals. [ABSTRACT FROM AUTHOR]

Background: Toxoplasma gondii is a very common zoonotic parasite in humans and animals worldwide. Human seroprevalence is high in some regions of Canada's North and is thought to be associated with the consumption of traditionally prepared country foods, such as caribou, walrus, ringed seal and beluga. While numerous studies have reported on the prevalence of T. gondii in these animals, in the general absence of felid definitive hosts in the North there has been considerable debate regarding the source of infection, particularly in marine mammals. It has been proposed that fish could be involved in this transmission. Aims: The objectives of the present study were to perform a targeted survey to determine the prevalence of T. gondii DNA in various tissues of anadromous Arctic charr sampled in Nunavik, Québec, and to investigate the possible role of this commonly consumed fish in the transmission of infection to humans and marine mammals in Canada's North. Methods and Results: A total of 126 individual Arctic charr were sampled from several sites in Nunavik, and various tissues were tested for the presence of T. gondii DNA using PCR. Overall, 12 out of 126 (9.5%) Arctic charr tested in the present study were PCR‐positive, as confirmed by DNA sequencing. Brain tissue was most commonly found to be positive, followed by heart tissue, while none of the dorsal muscle samples tested were positive. Conclusions: Although the presence of T. gondii DNA in brain and heart tissues of Arctic charr is very intriguing, infection in these fish, and their possible role in the transmission of this parasite to humans and marine mammals, will need to be confirmed using mouse bioassays. Arctic charr are likely exposed to T. gondii through the ingestion of oocysts transported by surface water and ocean currents from more southerly regions where the definitive felid hosts are more abundant. If infection in Arctic charr can be confirmed, it is possible that these fish could play an important role in the transmission of toxoplasmosis to Inuit, either directly through the consumption of raw fish or indirectly through the infection of fish‐eating marine mammals harvested as country foods. [ABSTRACT FROM AUTHOR]

Chlorination of seawater forms a range of secondary oxidative species – collectively called "chlorine-produced oxidants" (CPOs) – having different biocidal, environmental and ecotoxicological properties. The chemical speciation of these compounds is an important step in attempts to assess the effectiveness of chlorination and the potential impacts of its releases. However, comprehensive determination of CPOs represents a significant analytical challenge for many reasons, including the following: CPO species are numerous, highly reactive, with short-lifetimes, difficult to isolate and generally present at low concentrations in a complex salt matrix. Literature review reveals the development of a wide variety of analytical approaches for analysis of CPOs, either collectively via group parameters or individually. A first category of these approaches was the subject of article II (also including sampling and sample preparation) of a trilogy devoted to the chemical speciation of CPOs in seawater. In this third article – which closes the trilogy – emphasis is placed on chromatographic- and mass spectrometric-based approaches. It reviews more than 80 methods, reported from 1981 to date, and thoroughly discusses their principles and performances. Methodologies involving chemical derivatization of CPOs prior to their analysis by gas or liquid chromatography coupled to mass spectrometry provide the best sensitivities, achieving sub-ppb detection limits for species for which suitable derivatization reagents are available. Online mass spectrometry approaches are attracting increasing interest for their ability to analyze multiple CPO species in real time without extensive sample preparation steps, reaching detection limits of about ppb for less polar oxidants. At the current state of metrological development, neither the methodologies based on chromatography nor those based on online mass spectrometry allow complete speciation of CPOs. Future trends and major challenges related to these approaches are discussed. [ABSTRACT FROM AUTHOR]

Land reclamation is important for countries with limited land resources, and it requires a huge volume of filling materials. Traditional filling materials such as sand are depleting, which urges the discovery of new filling materials. The rapid growth of population and urbanization has also witnessed increasing solid waste generation. In this context, it is beneficial to turn the solid wastes into filling materials for land reclamation. This study, therefore, intended to reuse three solid wastes/byproducts, namely excavated marine clay (MC), incineration bottom ash (IBA), and ground granular blast-furnace slag (GGBS) to produce pumpable filling materials for land reclamation. Ordinary Portland cement (OPC) was utilized as a reference binder for comparison with GGBS. To this end, the workability (flowability and bleeding), appearance, unconfined compressive strength (UCS), mineralogy and microstructure, and leaching of heavy metals of the proposed materials were investigated. Considering the seawater exposure at land reclamation sites, the integrity of materials in water environments was examined. The results highlighted that for air-cured specimens, to achieve a target UCS of 100–200 kPa, the binder usage of IBA–MC–GGBS could be only half that of IBA–MC–OPC. In water environments, IBA–MC and IBA–MC–OPC generated cracks or were even dismantled, especially when soaked in seawater, posing a significant concern for land reclamation. However, IBA–MC–GGBS showed much higher resistance against seawater than IBA–MC and IBA–MC–OPC. The formation and growth of ettringite was the primary cause of the instability of IBA–MC and IBA–MC–OPC. The hydration of GGBS in IBA–MC–GGBS consumed alkaline minerals, which in turn suppressed the formation of ettringite. The results indicated the feasibility of using IBA–MC–GGBS as pumpable filling materials for land reclamation. [ABSTRACT FROM AUTHOR]

Using fine-scale measurements in the northwestern Sea of Japan, we estimated the vertical mixing parameters in the sea water column extended from the lower part of the thermocline downward to the near-bottom layer above the continental slope. The vertical scales of the turbulent patches were determined together with the turbulent dissipation rate and diapycnal diffusivity based on the conductivity, temperature, and depth data obtained by an Aqualog moored profiler from April through October 2015. The Thorpe-scale method was used to estimate the vertical mixing parameters as well as the vertical heat and salt fluxes. The enhanced vertical mixing, as well as enhanced downward heat flux and upward salt flux, occurred below the mixed layer despite strong density stratification. By comparing the turbulent dissipation rate and diapycnal diffusivity estimates derived via the Thorpe-scale method and the estimates of the same parameters obtained earlier by applying the finescale parameterization method to the same dataset in addition to the collocates of the current velocity measurements, the comparative accuracy evaluation of both methods was carried out. Finally, by compiling the vertical mixing data obtained by the Thorpe-scale method and the finescale parameterization approach, the generalized depth profile for the diapycnal diffusivity is presented for the depth range from 70 to 350 m. [ABSTRACT FROM AUTHOR]

The influence of water temperature on the size–age structure and size of the population of mollusks Hydrobia acuta and their invasion with parthenites of the microphallid trematode Gynaecotyla adunca in Kazachya Bay (Black Sea) has been studied. It was revealed that temperature changes explain about 60% of the variance in the invasion extensity, and about 30% of the variance in the abundance of mollusks. The established correlation dependencies can be used for an approximate assessment of the influence of water temperature on the indicators of the population size of mollusks and their infestation with parthenites of trematodes in the Black Sea water area. [ABSTRACT FROM AUTHOR]

Enhanced continental phosphorus (P) input into the oceans has been proposed as a potential trigger for the 1.57 Ga oxygenation event; however, uncertainty remains due to the absence of direct evidence for seawater P concentrations. Here, we investigate shallow marine carbonate rocks of the Gaoyuzhuang Formation in the North China Platform, using the carbonate‐associated phosphate (CAP) proxy to directly reconstruct seawater P levels at that time. Two significant CAP/(Ca + Mg) increases correspond with rises in I/(Ca + Mg) during the oxygenation event suggesting that elevated seawater P concentrations were important in triggering the oxygenation event. Furthermore, a concurrent positive shift in εNd(t) values from −12.3 to −0.9 suggests that a transition in weathering source rocks from intermediate to mafic lithologies significantly contributed to the elevated P fluxes to the oceans during the oxygenation event. This study provides new insights into assessing seawater P levels and their role in the mid‐Proterozoic oxygenation events. Plain Language Summary: Phosphorus (P), as a bio‐limiting nutrient for marine organisms, influences primary productivity, organic carbon burial, and therefore the redox conditions of the atmosphere‐ocean system on geological timescales. Previous studies have linked the transient oxygenation event at ∼1.57 Ga to an increase in oceanic P concentrations. However, uncertainty persists due to a lack of direct evidence for seawater P concentrations. Here, we investigate shallow marine carbonate rocks of the Gaoyuzhuang Formation in the North China Platform, using the carbonate‐associated phosphate (CAP) proxy to reconstruct seawater P levels at that time. The results revealed two significant increases in seawater P concentrations contemporaneously with evidence for increasing dissolved oxygen levels during the oxygenation event, suggesting that elevated seawater P concentrations may have played a crucial role in triggering this oxygenation event. Furthermore, a transition in weathering source rocks—from intermediate with relatively low P content to mafic with relatively high P content—has been identified, which likely contributed significantly to the elevated P levels during the oxygenation event. This study provides new insights into the assessment of seawater P levels and their significance during the mid‐Proterozoic oxygenation events. Key Points: Carbonate‐associated phosphate (CAP) is used to track seawater phosphorus (P) levels during the 1.57 Ga oxygenation eventTwo significant CAP increases corresponding with rises in I/(Ca + Mg) implicating P as a driver of rising O2 levelsA positive shift in εNd(t) shows enhanced P influx into seawater from the weathering of intermediate to mafic source rocks [ABSTRACT FROM AUTHOR]

In the Arctic Ocean (AO), net community production (NCP $NCP$) has displayed spatially heterogeneous responses to sea ice reduction and associated environmental changes. Using a random forest machine learning model trained with >42,000 in situ measurements and concurrent, collocated environmental predictors, we reconstructed 19 years of 8‐day, 6‐km NCP $NCP$ maps. During 2015–2021, the integrated NCP $NCP$ between late‐May and early‐September (NCPint ${}_{\mathit{int}}NCP$) over the western AO was 10.95±3.30TgC $10.95\pm 3.30\,\text{Tg}\,\mathrm{C}$ per year, with interannual variations positively tracking open water area. While the relationship between NCPint ${}_{\mathit{int}}NCP$ and open water area was quasi‐linear at high latitudes, strong nonlinearity was detected on the inflow shelf. The nonlinearity highlights that the NCPint ${}_{\mathit{int}}NCP$ increase resulted from area gain could be compounded by sea‐ice loss induced ecosystem adjustments. Additional retrospective analysis for 2003–2014 suggests a potential long‐term increase of export production and efficiency in the western AO with sea ice loss. Plain Language Summary: Net community production (NCP $NCP$) refers to the portion of phytoplankton production that remains unused by consumers and can be exported to the deeper part of the ocean. In the western Arctic Ocean (AO), NCP $NCP$ patterns are uneven due to complex interactions between the physical environment and the ecosystem. In this study, we developed a machine learning model of NCP $NCP$ in the western AO. The model used publicly available underway measurements and the associated environmental variables to create long‐term, high‐resolution maps of NCP $NCP$. For the period of 2015–2021, we found that the integrated NCP $NCP$ between late‐May and early‐September (NCPint ${}_{\mathit{int}}NCP$) was 10.95±3.30TgC $10.95\pm 3.30\,\text{Tg}\,\mathrm{C}$ per year in the western AO. NCPint ${}_{\mathit{int}}NCP$ varied from year to year and was higher when the open water area was larger. Notably, on the inflow shelf, NCPint ${}_{\mathit{int}}NCP$ increased at a faster rate than a linear relationship would suggest, due to both area expansion and ecosystem adjustments induced by sea ice loss. Our findings indicate that with long‐term sea ice loss, the western AO is likely to export more phytoplankton production to deeper ocean waters. Key Points: A multiyear, gap‐free net community production (NCP $NCP$) product was constructed using a machine learning model for the western Arctic OceanSeasonally and regionally integrated NCP $NCP$ responded to sea ice loss quasi‐linearly at high latitudes but nonlinearly on the inflow shelfCompared with the 2010s, carbon export production has increased in recent years, accompanying sea ice loss in the western Arctic Ocean [ABSTRACT FROM AUTHOR]

Context: Myxosporean endoparasites (phylum cnidarian) are critical pathogens that affect both wild and cultured freshwater and marine water fishes globally causing huge economic losses and high mortalities. Study objective: The present study investigated myxosporean infections in Nile tilapia and African catfish collected from the natural resources. Methods: A total of four hundred Nile tilapia with an average weight (60 ± 5 g) and two hundred African catfish with an average weight (185 ± 30 g) were collected seasonally from Qalyubia Governorate, Egypt for parasitological and molecular diagnosis of isolated myxozoan species. Results: Microscopic examination revealed Myxobolus heterosporous, Myxobolus brachysporus, Myxobolus tilapiae, and Myxobolus amieti in Nile tilapia and Henneguya suprabranchiae, and Myxobolus brachysporus in African catfish. Sequencing of 18S rDNA gene for isolated Myxozoan spp. from Nile tilapia revealed Myxobolus tilapiae deposited in GenBank under accession numbers (OR766325 and OR766326). In African catfish, the isolated Myxobolus brachysporus sequence was deposited under accession numbers (OR766327 and OR766328). Henneguya suprabranchiae was also identified in African catfish (accession. No. OR763724 and OR763433). Conclusion: Overall, these results indicate a high prevalence of myxozoan infection in naturally inhabiting Nile tilapia and African catfish. Curiously, Henneguya suprabranchiae was detected in the digestive tract and kidneys of African catfish, which is considered a rare form. Implication: This study highlighted the importance of parasitic surveys in natural resources that impact fish production. [ABSTRACT FROM AUTHOR]

Direct seawater electrolysis confronts pivotal challenges in both catalytic efficiency and process engineering domains. Herein, a metal hybridization strategy is proposed for crafting an HER catalyst featuring Ru nanoparticles anchored on the surface of CeO2 and integrated with conductive carbon (Ru/CeO2/C). Ru/CeO2/C heterostructure catalyst exhibits remarkable electrocatalytic prowess towards HER, manifesting overpotentials of merely 30 mV at a current density of 10 mA cm−2 in 1 M KOH, surpassing the performance of commercial Pt/C. Notably, the overpotentials escalate to 41 and 338 mV respectively, in environments of 1 M KOH supplemented with 0.5 M NaCl and 3.5% NaCl. Meanwhile, Ru/CeO2/C || RuO2 exhibits 1.68 V at 10 mA cm−2 in alkaline seawater for overall water splitting. Experimental data underscores the Ru‐CeO2 interface's pivotal role in modulating charge, intensifying electronic coupling, and refining adsorption/desorption energies. High surface area carbon integration amplifies activity, stability, and kinetics via robust interfacial dynamics, yielding the Ru/CeO2/C heterostructure catalyst's remarkable hydrogen production efficiency in alkaline and seawater media. This work may provide new options for the design and preparation of potential HER directly used seawater electrocatalysts. [ABSTRACT FROM AUTHOR]

Climate change is projected to substantially alter the Southern Ocean's physical and chemical properties, thereby impacting its marine ecosystems and species, particularly those in Antarctic and sub-Antarctic regions. This study focuses on Neobuccinum eatoni, a polar marine 'true whelk' endemic to these regions, utilizing 166 spatially independent occurrence data records to model potential distribution shifts under future climate scenarios. Employing Species Distribution Models (SDMs) on spatially cross-validated occurrences, we achieved high predictive accuracy, identifying "sea water salinity range" at mean bottom depth as the most significant predictor of habitat preferences. Additionally, dissolved iron (minimum), ocean temperature (range), and pH (long-term maximum) emerged as critical factors influencing the species' modeled distribution. By 2050, future projections under the SSP2-4.5 scenario predict an eastward expansion, particularly in the Antarctic Peninsula, the Scotia Arc and the Weddell Sea, with an expansion in the latter region also predicted under the SSP5-8.5 scenario. However, in both scenarios, a reduction in habitat suitability is expected in certain sectors around the Antarctic continent and the Kerguelen Archipelago. By 2100, under the moderate emissions scenario (SSP2-4.5), the species is projected to move to deeper areas and lower latitudes, with notable expansions in the Weddell Sea and in the Southern Ocean surrounding the Kerguelen Archipelago. However, under the SSP5-8.5 scenario, expansion is projected in the Weddell Sea and reductions in Antarctic and subantarctic regions. This study highlights the critical influence of changing salinity on N. eatoni's distribution, predicting a significant habitat reduction under high CO2 emissions scenarios (SSP5-8.5). The findings underscore the urgent need for focused research on the vulnerability of endemic marine invertebrates to develop effective conservation strategies in the face of rapid climatic changes. [ABSTRACT FROM AUTHOR]

Purpose: This study aims to quantitatively analyze the impact of split times on overall performance in standard distance triathlon events. It also examines how environmental factors such as water type, temperature, and altitude affect overall race outcomes. Methods: Quantile regression was employed to analyze the race records of 1,580 triathletes participating in 46 standard distance events in China. Results: Swim time significantly influences race performance among the top 50% of elite athletes (p < 0.05). For slower elite athletes, bike time is more critical. Temperature has a positive effect on race times, while altitude also shows a significant positive impact, with race times decreasing as altitude increases (up to 1,600 meters in this study's dataset). River water enhances race times compared to still water, whereas sea water generally slows athletes down. Conclusion: The influence of split times and environmental factors on overall race rime varies according to the athletes' performance levels. To optimize results, training plans and race strategies should be tailored to each athlete's capabilities. Additionally, understanding and adapting to environmental conditions in advance is crucial. [ABSTRACT FROM AUTHOR]

The aim of this study was to decouple and quantify the influence of various biological and physical processes on the structure and variability of the marine carbonate system in the surface waters of the eastern part of the Fram Strait area. This productive region is characterized by its complex hydrographic and sea ice dynamics, providing an ideal set up to study their influence on the variability of the marine carbonate system. Different variables of the marine CO2 system: Total Alkalinity (TA), Dissolved Inorganic Carbon (DIC), partial pressure of CO2 (pCO2), and pH, were analysed together with temperature, salinity, sea ice extension, and chlorophyll a distribution during three consecutive summers (2019, 2020 and 2021), each of them having a unique oceanographic setting. The data revealed that TA and DIC are mostly controlled by the mixing of Atlantic water and sea ice meltwater. The combined effects of organic matter production/remineralization, calcium carbonate precipitation/dissolution, and air/sea CO2 gas exchange cause deviations from this salinity-related mixing. The scale of these deviations and the proportion between the effects observed for TA and DIC suggest interannual shifts in net primary production and dominant phytoplankton species in the area. These shifts are correlated with the sea ice extent and the spread of the Polar Surface Waters in the region. Net primary production is the main factor controlling the temporal and spatial variability of pH and pCO2 in the study area followed by the influence of temperature and, mixing of water masses expressed with salinity (seawater freshening). Surface waters of the Fram Strait area were generally undersaturated in CO2. The lowest pCO2 values, coinciding with an increase in oxygen saturation, were observed in areas of mixing of Arctic and Atlantic-derived water masses. However, as shown for 2021, a reduction of the sea ice extent may induce a westward shift of the chlorophyll maximum, resulting in pCO2 increase and pH decrease in the eastern part. This indicates that sea ice extent and associated spread of Polar Surface Waters may be important factors shaping primary production, and thus pCO2 and pH, in the Fram Strait area. [ABSTRACT FROM AUTHOR]

Incident shortwave radiation can penetrate and heat the upper ocean water column, acting to modulate the stratification, vertical mixing and sea surface temperature. As a light-absorbing constituent, ocean chlorophyll (CHL) plays an important role in regulating these processes; however, its heating effect on the ocean state remains controversial and exhibits strong model dependence on ways the solar radiation transmission and the related CHL-induced heating are represented. In this study, we implement a chlorophyll-based two-way coupling between physical and ecological processes within the Regional Ocean Modeling System (ROMS). The bio-physics coupled model performs well in simulating the structure and variability of oceanic physical and ecological fields in the tropical Indo-Pacific region. Three CHL-related heating terms are analyzed based on the model output to diagnose the ocean biology-induced heating effects, namely the shortwave radiation part penetrating out of the base of the mixed layer (ML; Qpen), the portion absorbed within the ML (Qabs), and the rate of temperature change of the ML resulting from the Qabs effects (Rsr). Results show that the spatio-temporal distributions of the three heating terms are mainly determined by the ML depth (MLD). However, Qpen can also be regulated by the euphotic depth (ED), especially in the western-central equatorial Pacific. This moderating effect is particularly evident during El Niño when the ED tends to be greater than the MLD; positive ED anomalies act to enhance the positive Qpen anomalies caused by negative MLD anomalies. For the first time, the bio-heating effects are quantified within the ROMS-based two-way coupling context between the physical submodel and ecological submodel over the tropical Indo-Pacific Ocean, providing a basis for further understanding of the bio-effects and mechanisms. It is expected that the methodology and understanding developed in this study can help explore the chlorophyll-related processes in the ocean and the interactions with the atmosphere. [ABSTRACT FROM AUTHOR]

Extraction of uranium from seawater is considered to be an effective way to solve the shortage of uranium resources, and the development of efficient adsorption functional groups is the key to uranium extraction. In this work, the complexation of uranyl cations with a series of diamidoxime and bifunctional (amidoximate‐carboxylate, amidoximate‐phosphate) ligands has been probed by quantum chemical calculations. For most of the uranyl complexes, the amidoxime groups adopt η2 mode to uranyl cations. Based on bonding analyses, we found that the uranyl complexes with methyl‐substituted ligands (H2L′) possess stronger covalent interactions than those with phenyl‐substituted ligands (H2L). Consequently, the uranyl complexes with H2L' are more stable in the extraction process according to thermodynamic analysis. The amidoximate‐phosphate bifunctional ligand (H2L3′) has stronger extraction capacity to uranyl cations than other ligands, which is related to the relatively lower decomposition energy, and it shows selectivity in seawater for uranyl cations over vanadium ions, which may be a potential ligand for uranium extraction. Therefore, the introduction of synergistic functional groups, i. e. the bifunctional ligands, enhance the extraction properties of uranyl cations. This work improves understanding of synergistic ligands, and may contribute to design and development of efficient ligands for recovery of uranium from seawater. [ABSTRACT FROM AUTHOR]

Undersea mining encounters challenges due to the presence of seawater. An influx of seawater into stop in undersea can result in enormous disaster. Predicting strata settlement is a crucial measure to ensure the safety of undersea mining. This study proposed an intelligent model based on deep forest (DF) to evaluate the strata settlement during undersea mining. Initially, the strata displacement was monitored in the Xishan mining area of Sanshandao gold mine, China. Comprehensive datasets encompassing roof displacement and twelve influencing factors were compiled from 120 observations. Then, these datasets were statistically analyzed and used to train the DF model. The developed DF model achieved a training R2 of 0.971 and a testing R2 of 0.936. Compared with other machine learning models, the DF model has superior performance in the prediction of strata settlement. Moreover, a graphical user interface was designed to facilitate the application of the DF model. Finally, to validate model feasibility, displacement monitoring was conducted in the Xinli mining area of Sanshandao gold mine. Additional datasets were collected to validate the capability of the DF model. The results suggested that the DF model can be used to predict strata subsidence in undersea mining effectively. [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]

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]

Over recent decades, the global occurrence of pesticide residues in aquatic environments has been a pivotal issue; however, their trace-level concentrations necessitate the establishment of ultra-sensitive and reliable analytical approaches. To this end, the present study describes the optimization and validation of an LC-HRMS-based method for the accurate determination of 18 pesticides in river and sea water, accompanied by a measurement uncertainty estimation. This method was applied to analyze 17 real samples from agriculture and aquaculture-impacted areas in Greece and Albania. Different solid-phase extraction (SPE) protocols were tested. For the analysis, cutting-edge Orbitrap MS technology and MS/MS fragmentation, along with the use of matrix-matched calibration curves, provided unprecedented accuracy (<5 ppm) and sensitivity for the confirmation of positive detections. Regarding method performance, exceptional linearity was obtained; the limits of quantification ranged from 1.7 ng L−1 to 90 ng L−1, recoveries varied from 61% to 96% in river water, while slightly higher recoveries (60–111%) were observed in seawater. In all cases, repeatability and intra-laboratory reproducibility were below 15%. The measurement expanded uncertainty (U′, k = 2) was estimated considering precision and bias. MU% values were lower than 50% in all cases, as recommended in SANTE guidelines and applied to the quantified results. The matrix effect study exhibited negative values (<20%) for all compounds. Application to real samples showed a low pesticide contamination load that should not be underestimated. [ABSTRACT FROM AUTHOR]

Biobased plastics are fully or partially made from biological resources but are not necessarily biodegradable or compostable. Poly (lactic acid) (PLA), one of the most diffused bioplastics, is compostable in industrial environments, but improving degradation in home composting conditions, in soil and in seawater could be beneficial for improving its end of life and general degradability. Blends obtained by the extrusion of PLA with different amounts of poly (butylene succinate-co-adipate) (PBSA) or poly (caprolactone) (PCL) were characterized in terms of their home composting, soil, marine and freshwater biodegradation. The blending strategy was found to be successful in improving the home compostability and soil compostability of PLA. Thanks to the correlations with morphological characterization as determined by electron microscopy, it was possible to show that attaining an almost co-continuous phase distribution, depending on the composition and melt viscosity of the blend components, can enhance PLA degradation in home composting conditions. Tests in marine and freshwater were also performed, and the obtained results showed that in marine conditions, pure PLA is degradable. A comparison of different tests evidenced that salt dissolved in marine water plays an important role in favoring PLA's degradability. [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]

As global demand for freshwater grows, seawater desalination has become one of the most promising methods for obtaining freshwater. Many coastal nations have included it in their sustainable development plans and are actively advancing related technologies. Compared with traditional desalination methods, such as distillation and membrane-based desalination, seawater freezing desalination offers the benefit of producing large amounts of freshwater at lower costs. This study provides an overview of the main methods and principles of seawater freezing desalination and summarizes the latest research progress. This paper also discusses experimental and simulation studies of different principles. Current research shows that both direct and indirect seawater freezing desalination technologies have become relatively mature, laying a foundation for practical applications. Hydrate-based desalination, eutectic freezing technology, and vacuum freezing technology offer cost-reduction benefits, but existing technologies have limitations, making these areas hot topics in research. Additionally, this paper discusses the experimental progress and simulation methods associated with this, elaborates upon, and analyzes the freezing crystallization process and desalination efficiency from the perspective of the bottom layer of crystal growth, offering valuable insights for future research. It concludes by summarizing and predicting the development of these technologies, emphasizing their great potential due to their low-cost and sustainable features. [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]

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]

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]

The pearlspot, Etroplus suratensis is a climate resilient cichlid fish that exhibits unusual adaptation to salinity. The fish is able to complete full life cycle in diverse salinity habitats ranging from fresh water to marine environments. High-quality primary and phased genome assemblies were generated for pearlspot fish using PacBio HiFi and Arima HiC sequencing technologies, for the first time. The primary assembly is highly contiguous with contig N50 length of 36 Mb. The final assembly is of 1.247 Gb with N50 length of 51.57 Mb and 98% of the genome length anchored to 24 chromosomes. The genome was assessed to be 99.9% complete based on BUSCO evaluation and was predicted to contain 52.96% repeat elements. We have predicted 27,192 protein encoding genes, of which 21,580 were functionally annotated. The genome offers an invaluable resource to understand adaptation of pearlspot fish to diverse salinity habitats. [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]

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]

The Arabian goby, Cryptocentroides arabicus (Gobiidae: Gobiinae), is a significant species in marine and brackish water ecosystems. However, limited information is available about the reproductive biology and the early life history of this species. This study aimed to understand the embryonic and pre‐larval development of C. arabicus under controlled laboratory conditions using light microscopy. Ten fish pairs were placed in five 70‐L glass aquaria, and environmental parameters were carefully monitored. After 4 months, spawning began, with each event yielding between 700 and 1500 eggs, totaling 10 spawning events. The elliptical‐shaped eggs, measuring 3.9 ± 0.1 mm in length and 1.6 mm in maximum width, hatched after 7 days and 4 h at a water temperature of 28°C. This process resulted in the identification of eight distinct larval developmental stages. Parental care by both the male and female was observed during the incubation period. Documenting the morphological changes during incubation contributes to a better understanding of the reproductive behaviour and early life history of C. arabicus. This is essential for the conservation management of marine and brackish water environments. [ABSTRACT FROM AUTHOR]

In recent years, solar evaporation desalination has been recognized as one of the most promising sustainable technologies and an efficient way to generate clean water and seawater desalination. In this paper, we introduce a three-dimensional (3D) photothermal evaporator with ZnFe2O4: Activated carbon (AC) ferrite photothermal nanocomposite including glutaraldehyde (GA) and polyvinyl alcohol (PVA). Then, physical, optical absorption, and structural properties and removal of water salinity and pollutants of ZnFe2O4/PVA:GA:AC nanocomposite were studied by X-ray diffraction analysis (XRD), Field emission scanning electron microscopy (FESEM), UV–Vis spectrophotometer, Fourier-transform infrared spectroscopy (FTIR), inductively coupled plasma (ICP) and Total dissolved solids (TDS) analysis. Under one sun irradiation, the ZnFe2O4/PVA:GA:AC nanocomposite hydrogel can reach a record high evaporation rate of 1.80 Kgm−2h−1. In addition, the hydrogel micropores and nanopores channels have a higher freshwater collection rate of 1 mlh−1 with very low hardness and ion conductance from 6648 to 138 ppm and 8651 µS to 293 µS, respectively for casspian sea water. Also, ICP spectroscopy result indicated that the reduction of the concentrations of k+, Na+, Mg2+ Hg2+ ions after distillation for casspian sea to 0.44 ppm, 3.49 ppm 1.14 ppm and 0 ppm, which was far below the salinity level of drinkable desalinated water defined by the World Health Organization. These results demonstrate the potential of ZnFe2O4/PVA:GA:AC nanocomposite hydrogel evaporator for practical application of water purification and high surface evaporator. [ABSTRACT FROM AUTHOR]

Mesoscale eddies have attracted increased attention due to their central role in ocean energy and mass transport. The observations of their three-dimensional structure will facilitate the understanding of nonlinear eddy dynamics. In this paper, we propose a novel framework, the mesoscale eddy characterization from ordinal modalities recurrence networks method (MeC-OMRN), that utilizes a Petrel-II underwater glider for in situ observations and vertical structure characterization of a moving mesoscale eddy in the northern South China Sea. First, higher resolution continuous observation profile data collected throughout the traversal by the underwater glider are acquired and preprocessed. Subsequently, we analyze and compute these nonlinear data. To further amplify the hidden structural features of the mesoscale eddy, we construct ordinal modalities sequences rich in spatiotemporal characteristics based on the measured vertical density of the mesoscale eddy. Based on this, we employ ordinal modalities recurrence plots (OMRPs) to depict the vertical structure inside and outside the eddy, revealing significant differences in the OMRPs and the unevenness of density stratification within the eddy. To validate our intriguing findings from the perspective of complex network theory, we build the multivariate weighted ordinal modalities recurrence networks, through which network measures exhibit a more random distribution of vertical density stratification within the eddy, possibly due to more intense vertical convection and oscillations within the eddy's seawater micelles. These framework and intriguing findings are anticipated to be applied to more data-driven in situ observation tasks of oceanic phenomena. [ABSTRACT FROM AUTHOR]

Objectives: The aim of the current report is to present three cases of necrotizing fasciitis and sepsis caused by Vibrio vulnificus on the Bulgarian Black Sea coast. Materials and Methods: Two of the patients are males, 70 and 86 years of age, respectively, and one is an 86-year-old female. Data were collected from the patients' examination records. V. vulnificus was isolated on 5% sheep blood agar from wound and blood samples and identified by the automated system Phoenix M50 (BD, Franklin Lakes, NJ, USA). Antimicrobial susceptibility was tested with two well-known methods (disk diffusion and broth microdilution). Results: All of the patients were admitted to our hospital due to pain, swelling, ulceration, and bullae on the legs and were febrile. They underwent surgery and received intensive care support. One of the patients developed septicemia and septic shock; one of his legs was amputated, but the outcome was fatal. The other patient received immediate approptiate antibiotic and surgical treatment, and the outcome was favorable. The third patient underwent emergency fasciotomy but died a few hours after admission. Conclusions: Global climate change is affecting the distribution of Vibrio spp., and their incidence is expected to increase. It is important to highlight the need for awareness among immunocompromised and elderly patients of the potential threat posed by V. vulnificus infections. [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]

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]