Small sea with high traffic - what is the biofouling potential of commercial ships in the Baltic Sea.

Despite the Baltic Sea being one of the most intensive shipping regions in the world the potential magnitude of the biofouled hulls in this region is unknown. This study estimated the biofouling load to Baltic Sea Region (BSR) based on the wetted surface area (WSA) method with regard to country, ship type and donor bioregion. WSA flux reached 656 km2, of which 86% was associated with ships operating inside and 14% was WSA flux brought by ships from outside of the Baltic Sea. Most of the WSA was transported to Swedish, Finnish and Danish ports as well. The highest WSA flux was assigned to roll-on/roll-off, passenger and general cargo ships. The high biofouling potential in BSR indicates a potential high risk to the environment and, therefore there is an urgent need for appropriate guidelines to be introduced into daily use by the commercial shipping community.

Dietary citric acid decreased the theront number of Cryptocaryon irritans (Ciliata) in seawater-adapted tilapia (Oreochromis niloticus).

Cryptocaryoniasis remains a major parasitic disease and economic challenge for marine aquaculture. Cryptocaryoniasis in marine fish is caused by Cryptocaryon irritans (Ciliata). A theront is a motile, free-swimming stage in the life cycle of C. irritans, which is typically the infective stage that actively seeks out a host to initiate infection. Population density and growth rate of theronts were investigated in Nile tilapia, Oreochromis niloticus fed with citric acid-supplemented feed. The experiment involved feeding three diets with graded levels of citric acid (0, control diet, 0.5, 1 and 1.5 g kg-1 diet), to seawater-adapted Nile tilapia (O. niloticus) juveniles for 21 days. The results showed that citric acid in the fish feed had an impact on the theront number of C. irritans in a manner of dose-dependent. In the experimental cohort administered a diet supplemented with 1.5 g kg-1 citric acid, the population density of theronts was observed to be significantly reduced, measured at 29 ± 3.34, as opposed to 473.34 ± 16.48 in the control group at the culmination of the experiment. The observed population growth rate of theronts was significantly higher in the control group than in the group administered the citric acid feed (p < .005). The growth rate (r d-1 ) was 0.12 in control, 0.05 in 0.5 g kg-1 , 0.031 in 1 g kg-1 , and - 0.031 in 1.5 g kg-1 citric acid-supplemented groups. Fish growth and feed conversion ratio were not affected by the citric acid in the feed. In conclusion, the findings of this investigation provide a valuable addition to our understanding of the potential protective effects of citric acid supplementation for fish against the C. irritans parasite. This is evidenced by the observed reduction in theronts present in the water.

Microbial Composition of Freshwater Marsh Sediment Responds more Strongly to Microcosm Seawater Addition than Simulated Nitrate or Phosphate Eutrophication.

As sea level rise impacts coastal wetlands, saltmarsh will overtake coastal freshwater marsh in many areas, but changes in the sediment microbiome in response to saltwater intrusion are difficult to predict. Coastal freshwater marsh sediment was exposed to ambient, brackish, and saline conditions as well as to elevated nitrate and phosphate to model the combined stresses of saltwater intrusion and coastal eutrophication. Initially, sediment prokaryotic composition was similar to prior studies of freshwater marsh but diverged over time, reflecting the magnitude of increase in saltwater. There was no observed effect of nutrient amendment, potentially ranking seawater intrusion as a higher-importance compositional driver. Although the previously described loss of methanogenic populations and promotion of sulfate reducers in response to saltwater exposure was observed, taxonomic distribution was not similar to typical meso-polyhaline wetlands. Without colonization by marine taxa, such a community may be short-lived naturally, ultimately equilibrating with more common saltmarsh species. However, the recapitulation of salinity concentration by freshwater sediment microbial composition demonstrates the overwhelming nature of saltwater intrusion relative to other drivers like eutrophication.

Biofouling occlusion of ships' internal seawater systems: operational, economic, and biosecurity consequences.

Biofouling of ships' internal seawater systems (ISS) can cause significant operational issues and is a potential transfer mechanism for marine nonindigenous species. This study used an engine room simulator and economic evaluation to quantify impacts on commercial ship performance of biofouling occlusion within various ISS nodes (sea chest, strainer, and heat exchangers). A characteristic hockey-stick relationship between occlusion and impact emerged, whereby engine room systems could tolerate up to 55% occlusion of a single node without operational impact, followed by rapid performance deterioration. The relative magnitude of impacts varied by ISS node and in response to changes in ambient seawater temperatures. System tolerance was much lower when simultaneous occlusion of multiple nodes was assessed. In economic terms, consequences included required freight rate increases of 1-26% prior to forced (automatic) slowdown of the ship and up to 82% increases if slowdown conditions were required.

A Different Processing of Time-Domain Induced Polarisation: Application for Investigating the Marine Intrusion in a Coastal Aquifer in the SE Iberian Peninsula.

This study presents the developments regarding the time-domain induced polarisation method as a supporting tool for resistivity soundings during investigations of coastal detrital aquifers that are salinized by marine intrusion. The interpretation of resistivity measurements in such aquifers, which have variable hydrochemistry and lithology, involves uncertainties owing to the presence of low-resistivity lithologies, such as clays. To reduce these uncertainties, the use of other geophysical parameters is necessary; hence, this study focuses on induced polarisation since it can be measured simultaneously with resistivity. In detail, we propose the determination of induced polarisation using 1D techniques while developing a different algorithm for processing the induced polarisation data. The aim is to extend the results of this phenomenon, using, instead of chargeability, the concepts of polarisability and decay time, which are extracted from the decay curve, given that they represent more intrinsic properties of the various analyzed subsurface media. Results were obtained by applying this methodology to a Quaternary aquifer of the Costa del Sol in the SE Iberian Peninsula (in the province of Almería) during two different campaigns, one in mid-autumn and one late winter (i.e., in October and February, respectively) are presented. The results reveal the position of the saline front during each campaign while reflecting the seasonal movement of the marine intrusion.

Z-Scheme CuOx/Ag/TiO2 Heterojunction as Promising Photoinduced Anticorrosion and Antifouling Integrated Coating in Seawater.

In the marine environment, steel materials usually encounter serious problems with chemical or electrochemical corrosion and fouling by proteins, bacteria, and other marine organisms. In this work, a green bifunctional Z-scheme CuOx/Ag/P25 heterostructure coating material was designed to achieve the coordination of corrosion prevention and antifouling by matching the redox potential of the reactive oxygen species and the corrosion potential of 304SS. When CuOx/Ag/P25 heterostructure was coupled with the protected metal, the open circuit potential under illumination negatively shifted about 240 mV (vs. Ag/AgCl) and the photoinduced current density reached 16.6 µA cm-2. At the same time, more reactive oxygen species were produced by the Z-shape structure, and then the photocatalytic sterilization effect was stronger. Combined with the chemical sterilization of Ag and the oxide of Cu, the bacterial survival rate of CuOx/Ag/P25 was low (0.006%) compared with the blank sample. This design provides a strategy for developing green dual-functional coating materials with photoelectrochemical anticorrosion and antifouling properties.

A scoping review on the links between sustainable development goal 14 and early childhood caries.

BACKGROUND: The Sustainable Development Goal (SDG) 14 addresses life below the waters, an important source of protein and contributor to global food security and economic development. Our aim was to explore possible evidence on the links between life below water and early childhood caries (ECC). METHODS: This scoping review identified articles on the link between life below water and caries according to the PRISMA-ScR guidelines. Three electronic databases (PubMed, Web of Science, and Scopus) were systematically searched in January 2023, using specific search terms. Studies written in English, with full text available, addressing life under water, focusing on dental caries in humans, with results that can be extrapolated to control ECC in children less than 6 years of age were included in the review. Descriptive statistics were used to summarize the retrieved papers and graphical presentation was used for visualization. RESULTS: There were 224 publications retrieved of which 13 studies, published between 1960 and 2022, were included in the analysis. The papers originated from Asia (7/13), North America (3/13), Europe (1/13), and 2/13 had multi-country authorship. Also, four laboratory studies extracted agents from marine products to determine their efficacy in preventing caries formation and preventing/slowing plaque formation; four letters discussed the caries prevention potential of sea salt as a source of fluoride; and two review articles about the positive effects of extracted marine products for caries prevention. Most (11/13) studies addressed target 14.1 concerned with enriching the marine environment with nutrients and minerals; two addressed target 14.4 focused on ensuring fish stocks are within biologically sustainable levels; two addressed target 14.7 aimed at increasing the economic benefits through sustainable use of marine resources such as fisheries; and one focused on target 14.5 aimed at conserving marine areas by increasing protected areas. In addition, one ecological study assessed the association between the ecosystem and ECC. CONCLUSIONS: Currently, there is little known about the impact of protection of marine and coastal ecosystem from pollution and ocean acidification on the risk of ECC. Further evidence on possible associations between life below water and ECC management is needed.

Quantification of groundwater discharge into a shallow coastal lagoon applying a multi-tracer approach.

In many cases, shallow coastal lagoons are, on the one hand, vulnerable habitats for birds and marine ecosystems and, on the other hand, threatened by discharging nutrient-laden surface waters and groundwater. In particular, the localization and quantification of submarine groundwater discharge (SGD) is of key concern in this regard. The presented study aimed at investigating SGD into a vulnerable coastal lagoon that is strongly impacted by evaporation applying a multi-tracer approach. The joint application of radionuclides (222Rn, 223Ra, 224Ra), stable water isotopes (δ18O, δ2H) and the water salinity as environmental water tracers allowed evaluating the suitability of the individual parameters in this specific type of environment. Whilst stable isotope and salinity data were difficult to construe in terms of SGD occurrence due to the intense impact of evaporation, a radon mass balance allowed localising SGD areas within the lagoon and quantifying the related SGD flux rates. In addition, a 224Ra/223Ra ratio analysis revealed information on the apparent age of the discharged groundwater, and hence on the flushing intensity of the lagoon. Besides these site-specific results, the study allowed the following general conclusions regarding the suitability of the applied tracers: (i) we verified the suitability of a radon mass balance approach for proving/disproving SGD occurrence and quantifying SGD fluxes in shallow coastal lagoons strongly impacted by evaporation; (ii) we showed that the impact of evaporation may impede the use of water stable isotope and salinity data as SGD indicators in such specific environments; (iii) we demonstrated that the tidal impact on a lagoon water body during a sampling campaign can be compensated by adapting sampling schedule and cruise track to the tidal cycle.

Rapid cycling of reactive nitrogen in the marine boundary layer.

Nitrogen oxides are essential for the formation of secondary atmospheric aerosols and of atmospheric oxidants such as ozone and the hydroxyl radical, which controls the self-cleansing capacity of the atmosphere. Nitric acid, a major oxidation product of nitrogen oxides, has traditionally been considered to be a permanent sink of nitrogen oxides. However, model studies predict higher ratios of nitric acid to nitrogen oxides in the troposphere than are observed. A 'renoxification' process that recycles nitric acid into nitrogen oxides has been proposed to reconcile observations with model studies, but the mechanisms responsible for this process remain uncertain. Here we present data from an aircraft measurement campaign over the North Atlantic Ocean and find evidence for rapid recycling of nitric acid to nitrous acid and nitrogen oxides in the clean marine boundary layer via particulate nitrate photolysis. Laboratory experiments further demonstrate the photolysis of particulate nitrate collected on filters at a rate more than two orders of magnitude greater than that of gaseous nitric acid, with nitrous acid as the main product. Box model calculations based on the Master Chemical Mechanism suggest that particulate nitrate photolysis mainly sustains the observed levels of nitrous acid and nitrogen oxides at midday under typical marine boundary layer conditions. Given that oceans account for more than 70 per cent of Earth's surface, we propose that particulate nitrate photolysis could be a substantial tropospheric nitrogen oxide source. Recycling of nitrogen oxides in remote oceanic regions with minimal direct nitrogen oxide emissions could increase the formation of tropospheric oxidants and secondary atmospheric aerosols on a global scale.

Quantification of a Sulfated Marine-Inspired Antifouling Compound in Several Aqueous Matrices: Biodegradation Studies and Leaching Assays from Polydimethylsiloxane Coatings.

The development of marine-inspired compounds as non-toxic antifouling (AF) agents has been pursued in the last years. Sulfur is the third most common element in seawater. Sulfur is present in oxygenated seawater as sulfate anion (SO42-), which is the most stable combination of sulfur in seawater, and several promising AF secondary metabolites with sulfate groups have been described. However, sulfated compounds proved to be an analytical challenge to quantify by HPLC. Taking these facts into consideration, this work presents the development and validation of a method for the quantification of gallic acid persulfate (GAP) in seawater and ultrapure water matrix, based on hydrophilic interaction liquid chromatography (HILIC). This method was used to evaluate GAP stability following several abiotic and biotic degradation assays, and to quantify its release in seawater from room-temperature-vulcanizing polydimethylsiloxane commercial coating. GAP was very stable in several water matrices, even at different pH values and in the presence/absence of marine microorganisms and presented a leaching value lower than 0.5%. This work discloses HILIC as an analytical method to overcome the difficulties in quantifying sulfated compounds in water matrices and highlights the potential of GAP as a promising long-lasting coating.

Radon (222Rn) as tracer for submarine groundwater discharge investigation-limitations of the approach at shallow wind-exposed coastal settings.

Mapping radon (222Rn) distribution patterns in the coastal sea is a widely applied method for localizing and quantifying submarine groundwater discharge (SGD). While the literature reports a wide range of successful case studies, methodical problems that might occur in shallow wind-exposed coastal settings are generally neglected. This paper evaluates causes and effects that resulted in a failure of the radon approach at a distinct shallow wind-exposed location in the Baltic Sea. Based on a simple radon mass balance model, we discuss the effect of both wind speed and wind direction as causal for this failure. We show that at coastal settings, which are dominated by gentle submarine slopes and shallow waters, both parameters have severe impact on coastal radon distribution patterns, thus impeding their use for SGD investigation. In such cases, the radon approach needs necessarily to allow for the impact of wind speed and wind direction not only during but also prior to the field campaign.

Cyclic Copper Uptake and Release from Natural Seawater-A Fully Sustainable Antifouling Technique to Prevent Marine Growth.

Unwanted growth of fouling organisms on underwater surfaces is an omnipresent challenge for the marine industry, costing billions of dollars every year in the transportation sector alone. Copper, the most widely used biocide in antifouling paints, is at the brink of a total ban in being used in antifouling coatings, as it has become an existential threat to nontargeted species due to anthropogenic copper inputs into protected waters. In the current study, using a porous and cross-linked poly(ethylene imine) structure under marine and fouling environments, available copper from natural seawater was absorbed and electrochemically released back as a potent biocide at 1.3 V vs Ag|AgCl, reducing marine growth by 94% compared to the control electrode (coupon) at 0 V. The coating can also function as an electrochemical copper sensor enabling real-time monitoring of the electrochemical uptake and release of copper ions from natural seawater. This allows tailoring of the electrochemical program to the changing marine environments, i.e., when the vessels move from high-copper-contaminated waters to coastal regions with low concentrations of copper.

Sea Spray Aerosols Contain the Major Component of Human Lung Surfactant.

Marine phytoplankton influence the composition of sea spray aerosols (SSAs) by releasing various compounds. The biogenic surfactant dipalmitoylphosphatidylcholine (DPPC) is known to accumulate in the sea surface microlayer, but its aerosolization has never been confirmed. We conducted a 1 year SSA sampling campaign at the Belgian coast and analyzed the SSA composition. We quantified DPPC at a median and maximum air concentration of 7.1 and 33 pg m-3, respectively. This discovery may be of great importance for the field linking ocean processes to human health as DPPC is the major component of human lung surfactant and is used as excipient in medical aerosol therapy. The natural airborne exposure to DPPC seems too low to induce direct human health effects but may facilitate the effects of other marine bioactive compounds. By analyzing various environmental variables in relation to the DPPC air concentration, using a generalized linear model, we established that wave height is a key environmental predictor and that it has an inverse relationship. We also demonstrated that DPPC content in SSAs is positively correlated with enriched aerosolization of Mg2+ and Ca2+. In conclusion, our findings are not only important from a human health perspective but they also advance our understanding of the production and composition of SSAs.

Positively charged conjugated microporous polymers with antibiofouling activity for ultrafast and highly selective uranium extraction from seawater.

Uranium high-efficiency separation from seawater still has some obstacles such as slow sorption rate, poor selectivity and biofouling. Herein, we report a strategy for ultrafast and highly selective uranium extraction from seawater by positively charged conjugated microporous polymers (CMPs). The polymers are synthesized by Sonogashira-Hagihara cross-coupling reaction of 1,3-dibromo-5,5-dimethylhydantoin and 1,3,5-triethynylbenzene, and then modified with oxime and carboxyl via click reaction. The CMPs show an ultrafast sorption (0.46 mg g-1 day-1) for uranium, and possess an outstanding selectivity with a high sorption capacity ratio of U/V (8.4) in real seawater. The study of adsorption process and mechanism indicate that the CMPs skeleton exhibits high affinity for uranium and can accelerate the sorption, and uranium(VI) is adsorbed on the materials by the interaction of oxime/carboxyl ligands and hydantoin. Moreover, the material can be simply loaded onto the filter membrane, and shows remarkable antibiofouling properties against E. coli and S. aureus and excellent uptake capacity for uranium with low concentration in real seawater. This work may provide a promising approach to design adsorbents with fast adsorption rate, high selectivity and antibacterial activity, and expand the thinking over the development of novel and highly efficient adsorbents for uranium extraction from seawater.