Freshwater has become increasingly scarce in many countries. To reduce the consumption of freshwater, the use of saline water resources in industry could provide an opportunity to meet the challenge of water-supply sustainability. However, the presence of electrolytes in saline water causes the coagulation of kaolinite, the colloid stability of which plays a key role in the processing of a number of minerals. Therefore, the dispersion of kaolinite in saline water was studied here. Electrophoretic mobility and colloid stability studies were conducted on a sodium hexametaphosphate-kaolinite system in the presence of NaCl, KCl, CaCl2, and MgCl2, the major electrolytes in saline water resources. The effect of each electrolyte on kaolinite dispersion was studied. Based on the studies of individual electrolytes, a method was developed to disperse kaolinite in 1:1 diluted synthetic seawater with distilled water, which may potentially reduce the consumption of freshwater by 50% when applied in industry.

Experimental illitization of smectite was studied by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Experiments were performed on the <2 µm fraction consisting entirely of smectite separated from a soil formed on subvolcanic rock located in the External Zone of the Betic Cordilleras (southern Spain). Amounts of 0.25 g were added to different solutions: seawater, and three K-enriched seawater solutions prepared by adding KOH to seawater whose final [K] values were 0.1, 0.5 and 1 M, respectively. The experiments were performed at 50°C over a period of 30 days. The XRD patterns showed no mineralogical changes in residues from seawater or from the 0.1 M [K] solution. With increasing pH and K molarity, the smectite peak, initially at 1.4 nm, became broader. This change in the smectite peak was more significant in the residue from the 1 M [K] solution. The appearance of a small shoulder at 1.0 nm in the residue from a 0.5 M [K] solution showed the beginning of illite formation. However, its appearance was clearer in XRD patterns of the residue corresponding to the 1 M [K] solution. The XRD data from air-dried, glycolated, and heated samples from the 1 M [K] solution indicated the presence of smectite, disordered interstratified illite-smectite (I-S) and illite.

The TEM/AEM studies were performed on the residue corresponding to the 1 M [K] experiment. The HRTEM images revealed that smectite and illite occurred as separated packets with a ferroan lizardite, as a by-product of the smectite-to-illite reaction, interstratified and intergrown with illite. Smectite occurs both as ‘rims’ on the illite packet and in its core. The presence of smectite in the core of illite packet indicates that the lateral transition from smectite to illite was incomplete, taking place by direct replacement of smectite layers as a whole through a dissolution-precipitation mechanism. The experimental study shows that smectite may transform in a wide range of geological and artificial environments involving high-pH K-rich solutions.

Radiocarbon observations (Δ14C) in dissolved inorganic carbon (DIC) of seawater provide useful information about ocean carbon cycling and ocean circulation. To deliver high-quality observations, the Laboratory of Ion Beam Physics (LIP) at ETH-Zurich developed a new simplified method allowing the rapid analysis of radiocarbon in DIC of small seawater samples, which is continually assessed by following internal quality controls. However, a comparison with externally produced 14C measurements to better establish an equivalency between methods was still missing. Here, we make the first intercomparison with the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility based on 14 duplicate seawater samples collected in 2020. We also compare with prior deep-water observations from the 1970s to 1990s. The results show a very good agreement in both comparisons. The mean Δ14C of 12 duplicate samples measured by LIP and NOSAMS were statistically identical within one sigma uncertainty while two other duplicate samples agreed within two sigma. Based on this small number of duplicate samples, LIP values appear to be slightly lower than the NOSAMS values, but more measurements will be needed for confirmation. We also comment on storage and preservation techniques used in this study, including the freezing of samples collected in foil bags.

The modification of minerals with metals can promote changes in their surface and, consequently, in their physicochemical properties. Minerals could have played an important role in the origin of life as they can protect molecules against degradation by radiation and hydrolysis, pre-concentrate molecules from dilute solutions and catalyse the formation of polymers. Thus, the current work studied the modification of montmorillonite with Cu2+ and Fe3+ ions. These modified montmorillonites were used to study the interaction with adenine dissolved in distilled water and artificial seawater 4.0 Gy (Gy = billion years ago). The most important result of this work is that the adsorption of adenine onto modified montmorillonites is a complex interaction among adenine, salts in seawater and Cu2+/Fe3+-montmorillonite (Cu2+/Fe3+-Mont) . The adsorption of Cu2+ and Fe3+ onto montmorillonite decreased its surface area and pore volume. The Sips isotherm model showed the best fit of the data and n values indicate that the adenine adsorption process was homogeneous. The highest adenine adsorption was obtained in artificial seawater 4.0 Gy onto Fe3+-Mont at 60°C and the lowest in distilled water or artificial seawater 4.0 Gy onto montmorillonite [montmorillonite washed with distilled water (Mont-STD)] at 60°C. Adenine adsorption onto Mont-STD/montmorillonite modified with 500 ml of 0.1 mol l−1 of CuCl2 and Fe3+-Mont was an exothermic process and an endothermic process, respectively. For all adsorptions ΔG was negative. The adsorption of adenine onto Fe3+-Mont was ruled out by entropy and the other samples by enthalpy and entropy, being a major contribution for Gibbs free energy from enthalpy. The Fourier transform-infrared data indicate that the interaction of adenine with minerals may occur through the NH2 functional group.

In this work, the effect of γ-radiation on the decomposition of adenine dissolved in distilled water, saline solutions and artificial seawater was studied. As the composition of the major cations and anions of artificial seawater probably better resembles the composition of seawater on the Earth 4.0 billion years ago, this seawater was named artificial seawater 4.0 Ga. The main finding in this work is that artificial seawater 4.0 Ga demonstrated a better protective effect of adenine against γ-radiation. In addition, artificial seawater 4.0 Ga showed that adenine had no changes in pH after radiation exposure and the minor radiation-chemical yield G. The radiolysis of adenine promoted modifications in Fourier-transform infrared spectra. The deconvolution of some bands demonstrated the formation of a new frequency at 1713 cm−1. High performance liquid chromatography-mass detected a product of decomposition with 151 atomic units. Using the geometry optimization and simulated vibrational spectra it was possible to show that the main species formed are hydroxyl and oxide modified adenine. The data point to the formation of hydroxyl-adenine and adenine Nx-oxide. These products have biological relevance and could be available for chemical evolution.

A new method to extract CO2 in seawater samples for the determination of F14C has been developed in the Laboratory of Ion Beam Physics at ETH Zurich. The setup consists of an automated sampler designed to extract dissolved inorganic carbon (DIC) from 7 samples in a row, by flushing the seawater with He gas to extract CO2. The fully automated method is controlled via a LabVIEW program that runs through all consecutive steps: catalyst preconditioning, CO2 extraction, CO2 trapping, thermal CO2 release from the trap into the reactor and finally the graphitization reaction which is performed simultaneously in the 7 reactors. The method was optimized by introducing a Cu-Ag furnace that was placed between the water and zeolite traps, which resulted in a better and faster graphitization performance (<2 hr) compared to previously used techniques. The method showed to be reproducible with an unprecedented precision of 1.7‰ even though consuming only 50–60 mL of seawater. The high throughput of 21 samples per day allows for coverage of future oceanographic transects with high spatial resolution, thus fostering the use of radiocarbon (14C) as water mass tracer.

The first ultraviolet photochemical oxidation (UVox) extraction method for marine dissolved organic carbon (DOC) as CO2 gas was established by Armstrong and co-workers in 1966. Subsequent refinement of the UVox technique has co-evolved with the need for high-precision isotopic (Δ14C, δ13C) analysis and smaller sample size requirements for accelerator mass spectrometry radiocarbon (AMS 14C) measurements. The UVox line at UC Irvine was established in 2004 and the system reaction kinetics and efficiency for isolating seawater DOC rigorously tested for quantitative isolation of ∼1 mg C for AMS 14C measurements. Since then, improvements have been made to sampling, storage, and UVox methods to increase overall efficiency. We discuss our progress, and key UVox system parameters for optimizing precision, accuracy, and efficiency, including (1) ocean to reactor: filtration, storage and preparation of DOC samples, (2) cryogenic trap design, efficiency and quantification of CO2 break through, and (3) use of isotopic standards, blanks and small sample graphitization techniques for the correction of DOC concentrations and Fm values with propagated uncertainties. New DOC UVox systems are in use at many institutions. However, rigorous assessment of quantitative UVox DOC yields and blank contributions, DOC concentrations and carbon isotopic values need to be made. We highlight the need for a community-wide inter-comparison study.

The adsorption and desorption of cesium onto layered minerals, zeolite and geochemical reference samples were studied. 0.5 g of bentonite and mica were able to adsorb 71.2 and 51.5 mg of cesium, respectively, from 50 mL of deionized water containing 200 mg/L of cesium under neutral pH condition. These amounts of cesium adsorption were greater than those reported for vermiculites (8.9 and 5.6 mg, respectively). Additionally, the cesium adsorption on mica and vermiculite remained essentially unchanged under seawater conditions, but it decreased drastically on zeolite. The cesium desorption from the layered minerals was promoted by the addition of ammonium ions, namely trioctylmethylammonium chloride and zephiramine. These ammonium ions desorb cesium from the interlayers of the minerals without destroying the mineral structure. The cesium desorption procedure using quaternary ammonium ions would be extremely useful for decontamination of soil containing the layered minerals with adsorbed radioactive cesium.

The standard procedure for storing/preserving seawater dissolved organic carbon (DOC) samples after field collection is by freezing (–20°C) until future analysis can be made. However, shipping and receiving large numbers of these samples without thawing presents a significant logistical problem and large monetary expense. Access to freezers can also be limited in remote field locations. We therefore test an alternative method of preserving and storing samples for the measurement of DOC concentrations ([DOC]), stable carbon (δ13C), and radiocarbon (as ∆14C) isotopic values via UV photooxidation (UVox). We report a total analytical reproducibility of frozen DOC samples to be [DOC]±1.3 µM, ∆14C±9.4‰, and δ13C±0.1‰, comparable to previously reported results (Druffel et al. 2013). Open Ocean DOC frozen versus acidified duplicates were on average offset by ∆DOC±1.1 µM, ∆∆14C± –1.3‰, and ∆δ13C± –0.1‰. Coastal Ocean frozen vs. acidified sample replicates, collected as part of a long-term (380-day) storage experiment, had larger, albeit consistent offsets of ∆DOC±2.2 µM, ∆∆14C±1.5‰, and ∆δ13C± –0.2‰. A simple isotopic mass balance of changes in [DOC], ∆14C, and δ13C values reveals loss of semi-labile DOC (2.2±0.6 µM, ∆14C=–94±105‰, δ13C=–27±10‰; n=4) and semi-recalcitrant DOC (2.4±0.7 µM, ∆14C=–478±116‰, δ13C=–23.4±3.0‰; n=3) in Coastal and Open Ocean acidified samples, respectively.

The adsorption of amino acids onto minerals in prebiotic seas may have played an important role for their protection against hydrolysis and formation of polymers. In this study, we show that the adsorption of the prebiotic amino acids, glycine (Gly), α-alanine (α-Ala) and β-alanine (β-Ala), onto Na+-montmorillonite was dependent on salinity and pH. Specifically, adsorption decreased from 58.3–88.8 to 0–48.9% when salinity was increased from 10 to 100–150% of modern seawater. This result suggests reduced amino acid adsorption onto minerals in prebiotic seas, which may have been even more saline than the tested conditions. Amino acids also formed complexes with metals in seawater, affecting metal adsorption onto Na+-montmorillonite, and amino acid adsorption was enhanced when added before Na+-montmorillonite was exposed to high saline solutions. Also, the dissolution of Na+-montmorillonite was reduced in the presence of amino acids, with β-Ala being the most effective. Thus, prebiotic chemistry experiments should also consider the integrity of minerals in addition to their adsorption capacity.

The concentrations of organophosphoric acid triesters (OPEs) in water samples from Maizuru Bay were in the range of 3.0–62 ng/l. In general, the concentrations of OPEs were found in the order of TBXP > TDCPP > TCEP > TBP > TCP > TPP > TEP. The organophosphorous pesticides (OPPs) diazinon, fenitrothion, iprobenfos and chlorpyrifos were detected in water samples. The concentrations of OPEs in sediment from Maizuru Bay were in the range of <0.5–56 µg kg−1 dry weight (dw). Among OPPs, diazinon in sediment samples were in the range of 1.8–71 µg kg−1 dw. However, the detection frequencies of fenitrothion and chlorpyrifos in sediment were low. The concentrations of OPEs in mussels from Maizuru Bay were in the range of <1–34 µg kg−1 wet weight (ww). The concentrations of OPEs were found in the order of TBP > TDCPP > TCP > TBXP = TPP = TCEP. Pesticides were detected in mussels, but these concentrations were lower than the acceptable daily intake (ADI) values. The partition coefficients between water and sediment (Kws) of diazinon and fenitrothion were 200–1300 and 200–300, respectively and the partition coefficients between water and biological samples (Kwb) of diazinon and fenitrothion were 700–3300 and 450–700, respectively, suggesting that these pesticides accumulate in biological samples at higher rates than in sediment.

The technological development of all kinds of lightweight transportation devices including vehicles, aircraft, ships, etc. has progressed markedly with the demand for energy saving and environmental protection. Aluminum alloy is in the spotlight as it is a suitable environmentally friendly material. However, deformation is a major problem during the welding process because aluminum alloy has a large thermal expansion coefficient. In addition, it is known that its corrosion resistance is excellent; nevertheless, in practice, considerable corrosion is generated and this is a major problem. To solve this problem, the friction stir welding (FSW) technology is applied extensively at various industrial fields as a new welding technique. This method involves a process in which materials are joined by frictional heat and physical force. Therefore, we evaluated improvements in mechanical properties and corrosion resistance through annealing heat treatment after FSW. The electrochemical experiment did not show a significant difference. However, the microstructure observation showed defectless, fine crystal particles, indicating excellent properties at 200–225°C.

In the present work, the interactions between forsterite-91 with distilled water and forsterite-91 with artificial seawater were studied at two pHs (2.0 and 8.0) using different techniques. A large increase in pH was observed for samples incubated at an initially acidic pH (2.0) due to the dissolution of forsterite-91 in distilled water and artificial seawater. Thus, in acidic hydrothermal vents, an increase in the amount of hydrocarbons and magnetite should be expected due to the release of Fe(II). The pHPZC decreased and the pHIEP increased when forsterite-91 was treated with distilled water and artificial seawater. The ions from the artificial seawater had an effect on zeta potential. Scanning electron microscopy (SEM) images and X-ray diffractograms showed halite in the samples of forsterite-91 mixed with artificial seawater. The presence of halite or adsorption of ions on the surface of forsterite-91 could affect the synthesis of magnetite and hydrocarbons in hydrothermal vents, due to a decrease in the dissolution rates of forsterite-91. The dissolution of forsterite-91 yields low concentrations of Fe(III) and Mn(II) as detected by electron paramagnetic resonance (EPR) spectroscopy. Microanalysis of forsterite-91 showed a higher amount of Mn, with an oxidation that was likely not +II, as Mn in supernatant solutions was only detected by EPR spectroscopy after mixing with artificial seawater at pH 2.0. As Fe(III) and Mn(II) are catalyst constituents of magnetite and manganese oxide, respectively, their presence is important for synthesis in hydrothermal vents. Etch pits were observed only in the forsterite-91 sample mixed with distilled water at pH 8.0. Na, Cl, S, Ca and K were detected in the samples mixed with artificial seawater by SEM–EDS. Si, Mg, Fe and Al were detected in almost all supernatant samples due to forsterite-91 dissolution. Cr was not dissolved in the experiments, thus Cr in the mineral could serve as an effective catalyst for Fischer Tropsch Types (FTT) reactions in hydrothermal vent systems. X-ray diffractograms of the original forsterite-91 also showed peaks arising from zeolites and clinochlore. After the samples were treated with artificial seawater, X-ray diffractograms showed the dissolution of zeolite. Experiments should be performed in the natural environment to verify the potential for zeolites to act as a catalyst in hydrothermal vents.

This study investigated the synthesis of goethite under conditions resembling those of the prebiotic Earth. The artificial seawater used contains all the major elements as well as amino acids (α-Ala, β-Ala, Gly, Cys, AIB) that could be found on the prebiotic Earth. The spectroscopic methods (FT-IR, EPR, Raman), scanning electron microscopy (SEM) and X-ray diffraction showed that in any condition Gly and Cys favoured the formation of goethite, artificial seawater plus β-Ala and distilled water plus AIB favoured the formation of hematite and for the other synthesis a mixture of goethite and hematite were obtained. Thus in general no protein amino acids (β-Ala, AIB) favoured the formation of hematite. As shown by surface enhanced Raman spectroscopy (SERS) spectra the interaction between Cys and Fe3+ of goethite is very complex, involving decomposition of Cys producing sulphur, as well as interaction of carboxylic group with Fe3+. SERS spectra also showed that amino/CN and C-CH3 groups of α-Ala are interacting with Fe3+ of goethite. For the other samples the shifting of several bands was observed. However, it was not possible to say which amino acid groups are interacting with Fe3+. The pH at point of zero charge of goethites increased with artificial seawater and decreased with amino acids. SEM images showed when only goethite was synthesized the images of the samples were acicular and when only hematite was synthesized the images of the samples were spherical. SEM images for the synthesis of goethite with Cys were spherical crystal aggregates with radiating acicular crystals. The highest resonance line intensities were obtained for the samples where only hematite was obtained. Electron paramagnetic resonance (EPR) and Mössbauer spectra showed for the synthesis of goethite with artificial seawater an isomorphic substitution of iron by seawater cations. Mössbauer spectra also showed that for the synthesis goethite in distilled water plus Gly only goethite was synthesized and in artificial seawater plus Cys a doublet due to interaction of iron with artificial seawater/Cys was observed. It should be pointed out that EPR spectroscopy did not show the interaction of iron with artificial seawater/Cys.

The accident at the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) in March 2011 led toan unprecedented direct input of artificial radioactivity into the marine environment. TheInstitute for Radioprotection and Nuclear Safety was requested by the French authoritiesto investigate the radioecological impact of this input, in particular the potentialcontamination of products of marine origin used for human consumption. This articledescribes the close link between the responses provided and the availability of the data,as well as their nature and ability to meet the requirements of expert investigation.These responses were needed: (i) to evaluate the inputs of radionuclides into the marineenvironment, (ii) to understand their dispersion in seawater, and (iii) to estimate theirtransfer to the biota and sediments. Three phases can be distinguished which characterisethese processes during the accident and post-accident periods. The first phase correspondsto an emergency phase during which no measurements were available on samples from themarine environment. It involved the formulation of hypotheses based solely on theexpertise of the Institute for Radioprotection and Nuclear Safety. The second phasestarted when the Japanese authorities provided measurements of the concentrations ofradionuclides in seawater. Although these data were not yet adapted to addressing theproblems of radioecology, the scenarios could then be refined and the estimates developedin more detail. During the third phase, the accumulation of data over the course of timemade it possible to study the phenomena in an appropriate way. The chronology of theevents shows that it is essential to have (i) significant measurements of concentrationfrom samples collected in the various matrices of the marine environment, regularlyupdated and sufficiently well-documented, (ii) samples of seawater collected at theearliest opportunity as close as possible to the damaged site to characterise the sourceterm, and (iii) a numerical tool allowing rapid modelling of the dispersion ofradionuclides in seawater, as well as their transfer to sediments and the biota,ultimately for the purpose of estimating the dose to humans.

An investigation of the latitudinal distribution of concentrationsof 137Cs at 19 stations in the surface water of the SouthernOcean on cross-sections to the South from the Cape of Good Hope(section SR2) and in the Drake Passage (30th cruise "Academic Ioffe",01.12.2009–09.01.2010) was performed. The data obtained reinforcedthe time-dependent exponential decrease in the 137Csconcentrations in the surface water of the Atlantic sector of theSouthern Ocean. Increased 137Cs concentrations were foundin the Drake Passage and in the section SR2 in the vicinity of thePolar Front. The average value of 137Cs concentrationsfor all measurements equals 0.18 Bq.m–3 σ = 0.11.

Phylogenetic analyses of SSU rDNA sequences have previously revealed the existence of 2 Ichthyobodo species able to infect Atlantic salmon (Salmo salar L.). Ichthyobodo necator sensu stricto (s.s.) is assumed to be a freshwater parasite, while a genetically distinct but undescribed species, Ichthyobodo sp. II sensu Todal et al. (2004) have been detected on Atlantic salmon in both fresh- and seawater. In the present study a morphological description of Ichthyobodo sp. II from the gills of salmon reared in fresh-, brackish- and seawater is presented, using both light- and electron microscopy. Comparative morphometry show that Ichthyobodo sp. II from both freshwater and seawater displays a different cell shape, and is significantly smaller than I. necator s.s. Also, ultrastructural characteristics distinguish these two species, notably differences in the attachment region and the presence of spine-like surface projections in Ichthyobodo sp. II. Based on both unique SSU rDNA sequences and morphological characteristics, we conclude that Ichthyobodo sp. II. represents a novel species for which we propose the name Ichthyobodo salmonis sp. n.

Since contradictory data can be found in the literature, it is often difficult to assess the susceptibility of crevice corrosion of stainless steels in service conditions for a given marine application. The initiation and propagation of crevice corrosion in natural seawater were evaluated for five different duplex stainless steel grades together with some austenitic grades. A CREVCORR-type assembly was used to simulate crevice configurations involving the use of plastic crevice formers. The standard pressure applied on the crevice assembly was 3 N/mm2. Pressure of about 20 N/mm2 was also applied on some selected specimens in order to assess the effect of crevice geometry on crevice corrosion. The effect of environmental parameters (i.e. temperature, flowing conditions, residual chlorine, and dissolved oxygen content) and of surface roughness on the crevice corrosion initiation and propagation were investigated, allowing the assessment of limits of applications for some tested stainless steel grades. The less alloyed duplex stainless steels were evaluated in stagnant seawater at 5 °C and 20 °C. The duplex stainless steel UNS S32205, with PREN = 37, was also evaluated under the same conditions of exposure. The high alloyed stainless steels with PREN above 40 were evaluated in the expected most severe conditions of exposure, namely in 0.5 ppm-chlorinated seawater at 20 °C, in seawater at 30 °C (not chlorinated and with 0.5 ppm of residual chlorine) and in seawater at 50 °C (not chlorinated and with 0.5 ppm of residual chlorine). As expected the less alloyed duplex stainless steels showed limited crevice corrosion resistance in the tested media while UNS S32205 showed better resistance in the less severe tested condition of exposure. In demanding media it was shown that the limits of application of highly alloyed stainless steels are highly dependent on the crevice geometry (i.e. specimen roughness and applied pressure at gasket location).