Here we present a multidisciplinary, high-resolution investigation of Healy submarine volcano, located in the southern Kermadec arc, New Zealand, combining magnetic, sidescan, and hydrothermal plume datasets to constrain the structure and evolution of its magmatic–hydrothermal system.Near-seafloor magnetic and sidescan sonar data acquired by the Autonomous Underwater Vehicle (AUV) Sentry have been integrated with shipborne magnetic and gravity measurements, multibeam bathymetry, acoustic backscatter, and hydrothermal plume observations, as well as seafloor imagery and in situ temperature measurements collected by the Pisces V submersible, to develop a detailed geological and geophysical characterization of the volcano.High-resolution sidescan sonar data reveal fine-scale volcanic and tectonic structures, including lava flow textures, fracture networks, and cone morphology providing context for interpreting magnetic anomalies and hydrothermal plume results. Magnetic ‘lows’ are spatially associated with older, caldera-related structures and demarcate zones of ancient hydrothermal discharge, consistent with the loss of magnetite due to hydrothermal alteration. By contrast, younger basaltic cones emplaced along NNE–SSW-trending lineaments exhibit relatively high magnetization signatures and host the currently active hydrothermal venting, characterized by directly observed low-temperature discharge, while hydrothermal plume data (e.g. turbidity anomalies) suggest the possible presence of higher-temperature venting. Taken together, the spatial distribution of volcanic facies, structural lineaments, magnetization patterns, and hydrothermal activity suggests a temporal evolution in magma emplacement and fluid pathways. This evolution is consistent with a transition from caldera-related, arc-dominated volcanism toward more localized basaltic magmatism exploiting extensional structures, which may reflect the early development of back-arc extension.Our results highlight the important role of multi-sensor, high-resolution surveys in developing robust conceptual models of submarine volcanic systems, and demonstrate how combined gravity, magnetic, sidescan, and hydrothermal plume investigations are prerequisites for understanding hydrothermal processes and related resources in remote deep-sea environments.

The NOAA Vents program was established in 1983 at the Pacific Marine Environmental Laboratory (PMEL; Hammond et al., 2015), just six years after the discovery of hydrothermal vents and their unique chemosynthetic ecosystems (Corliss et al., 1979). Because seafloor hydrothermal venting contributes significantly to the transfer of heat and mass from the solid Earth to the ocean, the program’s mission was to systematically explore, discover, and characterize the environmental impacts of submarine volcanism and hydrothermal venting on ocean physical, chemical, and biological processes. The program initially focused on the mid-ocean spreading centers in PMEL’s “backyard” (i.e., the Gorda, Juan de Fuca, and Endeavour Ridges in the Northeast Pacific) where segment-scale surveys detected plumes in the water column above the ridge crest that led to the discovery of numerous individual vent fields (see Hammond et al., 2015, and references therein). New technologies and techniques were created and/or adapted to address the challenges of finding and studying these vents. Repeat visits to the Northeast Pacific sites documented spatial and temporal changes, stimulating the development of new hypotheses about their associated biogeochemical processes. However, testing how broadly applicable these hypotheses would be on a global scale required discovering new vent sites from a far wider range of geological settings, and global-scale exploration requires significant resources.

As previously summarized by Hammond et al. (2015), from 1983 to 2013, the NOAA Vents program conducted systematic and multidisciplinary exploration, discovery, and research related to hydrothermal vents, submarine volcanic eruptions, and associated ocean physical, chemical, and biological processes. In 2014, Vents divided into two programs, Earth-Ocean Interactions (EOI) and Acoustics, and considered a broader range of questions about how seafloor and subseafloor processes contribute to ocean health, biogeochemical cycles, ecosystem diversity, and climate change. Here, we highlight major accomplishments since 2014, including deep-sea technologies that EOI, Vents, and Pacific Marine Environmental Laboratory (PMEL) Engineering have developed to advance marine science. EOI research is driven by a need for better observational data on issues of global importance, including the role of continental margin seeps in the global methane/carbon cycle, benthic ecology, and fisheries habitat; the role of hydrothermal systems in global biogeochemical cycles, including carbon dioxide removal; the potential impact of deep-sea mining of metal sulfides on ecosystem services provided by hydrothermal vents; and how hydrothermal iron functions as an essential nutrient. NOAA Ocean Exploration, the Schmidt Ocean Institute, the Ocean Exploration Trust, and the National Science Foundation have supported and collaborated in this work. Global exploration of the deep sea with the purpose of understanding global ocean processes remains a cornerstone of EOI science.

[ 1 ] The spatial density of hydrothermal activity along most mid-ocean ridges is a robust linear function of spreading rate (or magmatic budget), but extreme crustal properties may alter this relationship. In 2005– 2006 we tested the effect of thickened crust on hydrothermal activity using high-resolution mapping of plumes overlying the hot spot–affected Gala´pagos Spreading Center from 95 (cid:1) to 89 (cid:1) 42 0 W ( (cid:2) 560 km of ridge crest). Plume mapping discovered only two active, high-temperature vent fields, subsequently confirmed by camera tows, though strong plume evidence indicated minor venting from at least six other locations. Total plume incidence ( p h ), the fraction of ridge crest overlain by significant plumes, was 0.11 ± 0.014, about half that expected for a non–hot spot mid-ocean ridge with a similar magmatic budget. Plume distributions on the Gala´pagos Spreading Center were uncorrelated with abrupt variations in the depth of the along-axis

Xylella fastidiosa is a multi-continental, lethal, plant pathogenic bacterium that is transmitted by sharpshooter leafhoppers (Insecta: Hemiptera: Cicadellidae: Cicadellinae) and adult spittlebugs (Hemiptera: Aphrophoridae). The bacterium forms biofilms in plant xylem and the functional foregut of the insect. These biofilms serve as sources of inoculum for insect acquisition and subsequent inoculation to a healthy plant. In this study, 3D fluid dynamic simulations were performed for bidirectional cibarial propulsion of xylem sap through tube-like grapevine xylem and an anatomically accurate model of the functional foregut of the blue-green sharpshooter, Graphocephala atropunctata. The analysis supports a model of how fluid dynamics influence X. fastidiosa transmission. The model supports the hypothesis that X. fastidiosa inoculation is mostly driven by detachment of bacteria from the foregut due to high-velocity flow during egestion (outward fluid flow from the stylets). Acquisition occurs by fluid dynamics during both egestion and ingestion (fluid uptake through the stylets and swallowing). These simulation results are supported by previously reported X. fastidiosa colonization patterns in the functional foregut and sharpshooter stylet probing behaviors. The model indicates that xylem vessel diameter influences drag forces imposed on xylem wall-adherent bacteria; thus, vessel diameter may be an important component of the complex transmission process. Results from this study are directly applicable to development of novel grapevine resistance traits via electropenetrographic monitoring of vector acquisition and inoculation behaviors.

Methane gas plumes have been discovered to issue from the seafloor in the Puget Sound estuary. These gas emission sites are co‐located over traces of three major fault zones that fracture the entire forearc crust of the Cascadia Subduction Zone. Multibeam and single‐beam sonar data from cruises conducted in years 2011, 2018, 2019, 2020, and 2021 identified the acoustic signature of 349 individual bubble plumes. Dissolved CH4 gas from the plumes combines to elevate seawater methane concentrations of the entire Puget Sound estuary. Fluid samples from adjacent terrestrial hot springs and deep‐water wells surrounding the estuary contain a helium‐3 isotope signature, suggesting a deep fluid source located near the underlying Cascadia Subduction Zone plate interface. However, limited data from this pilot study suggest that Puget Sound seawater emission sites lack both similar chemical isotope signatures and elevated thermal anomalies that would be expected from association with a deep plate‐interface reservoir. A shallow reservoir within the Holocene sediments that cover the older Puget Sound basement with horizontal transfer to the thinly covered Alki Point and Kingston Arch anticlines is also a possibility, as has been suggested for other methane seep areas. The existence of vigorous marine methane plumes arising from areas of thin sediment cover associated with deeply penetrating forearc fault zones but presenting no thermal or chemical anomalies found in other similar forearc environments, remains an unresolved paradox.

Biodegradation of pollutants in the environment is directly affected by microbial communities and pollutant mixture at the site. Lab experiments using bacterial consortia and substrate mixtures are required to increase our understanding of these processes in the environment. One of the deficiencies of working with environmental cultures is the inability to culture and identify the active strains while knowing they are representative of the original environment. In the present study, we tested the aerobic microbial degradation of two brominated flame retardants, tribromo-neopentyl alcohol (TBNPA) and dibromo neopentyl glycol (DBNPG), by an assembled bacterial consortium of four strains. The four strains were isolated and plate-cultured from a consortium enriched from the impacted groundwater underlying the Neot Hovav industrial area (Negev, Israel), in which TBNPA and DBNPG are abundant pollutants. Total degradation (3–7 days) occurred only when the four-strain consortium was incubated together (25 °C; pH −7.2) with an additional carbon source, as both compounds were not utilized as such. Bacterial growth was found to be the limiting factor. A dual carbon–bromine isotope analysis was used to corroborate the claim that the isolated strains were responsible for the degradation in the original enriched consortium, thus ensuring that the isolated four-strain microbial consortium is representative of the actual environmental enrichment.

We investigated the speciation of Fe and distributions of Fe-binding ligands in the hydrothermal plumes over highand low-temperature vents and over diffuse venting fields above the Mariana back-arc spreading center. The concentrations of ligands ([L]) and conditional stability constants (K'FeL) of the natural Fe ligand pool were measured by a reverse titration-competitive ligand exchange-adsorption cathodic stripping voltammetry (RT-CLE-ACSV). The results showed that the buoyant and non-buoyant plume samples over the low-temperature Burke had the highest dissolved Fe/total Fe (DFe/TFe) of 82.2 + 8.8% and labile Fe/total Fe (Fe-Lab/TFe) of 43.3 + 5.6%. In contrast, in the plume samples above the high-temperature Perseverance field, TFe had the lowest proportions of DFe (48.8 +/- 12.2%) and Fe-Lab (19.4 +/- 8.8%). The linear relationships between Fe species and total Mn (TMn) in the buoyant plume over Burke suggest a simple conservative mixing with ambient seawater, which resulted in constant values of DFe/TFe. However, in the non-buoyant plume over Burke, DFe/TFe decreased with plume dilution. The plume samples sourced from the diffuse flow over newly erupted lava had the highest proportion of DFe present as Fe-Lab (74.6 +/- 4.0%). The [L] in the buoyant plumes over low-temperature Burke vent were up to 113.6 nM, and the logK'FeL decreased with increasing DFe and [L], suggesting the importance of weaker ligands in stabilizing Fe. For all the plume samples, the organically complexed Fe (FeL) constituted significant proportions of the DFe (29.0 +/- 9.3%) and Fe-Lab (57.5 +/- 15.6%) fractions. These Fe-binding ligands were likely sourced from diffuse venting fluids adjacent to the venting sites, and may be also produced by microbes within the hydrothermal plumes. (c) 2020 Elsevier Ltd. All rights reserved.

Biofilm formation is often attributed to postharvest bacterial persistence on fresh produce and food handling surfaces. In this study, a predicted glycosyl hydrolase enzyme was expressed, purified, and validated for the removal of microbial biofilms from biotic and abiotic surfaces under conditions used for chemical cleaning agents. Crystal violet biofilm staining assays revealed that 0.1 mg/ml of enzyme inhibited up to 41% of biofilm formation by Escherichia coli O157:H7, E. coli 25922, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes. Furthermore, the enzyme was effective at removing mature biofilms, providing a 35% improvement over rinsing with a saline solution alone. Additionally, a parallel-plate flow cell was used to directly observe and quantify the impact of enzyme rinses on E. coil O157:H7 cells adhering to spinach leaf surfaces. The presence of 1 mg/liter enzyme resulted in nearly 6-times-higher detachment rate coefficients than a deionized (DI) water rinse, while the total cells removed from the surface increased from 10% to 25% over the 30-min rinse time, reversing the initial phases of biofilm formation. Enzyme treatment of all 4 cell types resulted in significantly reduced cell surface hydrophobicity and collapse of negatively stained E. coli 25922 cells imaged by electron microscopy, suggesting potential polysaccharide surface modification of enzyme-treated bacteria. Collectively, these results point to the broad substrate specificity and robustness of the enzyme for different types of biofilm stages, solution conditions, and pathogen biofilm types and may be useful as a method for the removal or inhibition of bacterial biofilm formation. IMPORTANCE In this study, the ability of an engineered enzyme to reduce bacterial adhesion and biofilm formation of several foodborne pathogens was demonstrated, representing a promising option for enhancing or replacing chlorine and other chemical sanitizers in food processing applications. Specifically, significant reductions of biofilms of the pathogens Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes are observed, as are reductions in initial adhesion. Enzymes have the added benefits of being green, sustainable alternatives to chemical sanitizers, as well as having a minimal impact on food properties, in contrast to many alternative antimicrobial options such as bleach that aim to minimize food safety risks.

Abstract Four new hydrothermal vent fields were discovered on the slow spreading Central Indian Ridge (8–12°S; Segments 1–3), all located off‐axis on abyssal hill structures or Ocean Core Complexes (OCCs). Each site was characterized using seafloor observation (towed camera system), plume chemistry (Fe, Mn, and CH4; Conductivity, Temperature, and Depth sensor [CTD]/Miniature Autonomous Plume Recorder [MAPR]), and rock sampling (TVgrab/dredges). Different styles of venting on each segment reflect different geological settings, rock types, likely heat sources, and fluid pathways. The segment 1 field was located on the western flank of the axial valley at the base of OCC‐1‐1. High‐temperature venting was inferred from plume characteristics and extensive seafloor sulfide mineralization, but only diffuse venting was observed. This site appears to be a magmatic‐influenced basaltic‐hosted system despite its off‐axis location. Two low‐temperature diffusely venting sites were located on abyssal hills 6 and 9 km off‐axis on Segment 2. Plume particle, metal, and CH4 concentrations were all very low, suggesting dilution of hydrothermal fluids by intrusion of seawater into the highly permeable flank area fault zone. The “Onnuri Vent Field” (OVF), located at the summit of OCC‐3‐2, vented clear, low‐temperature fluids supporting abundant vent organisms (21 macrofaunal taxa). The plume particle signal was low to absent, but strong ORP anomalies correlated with high CH4 and low metal concentrations. Sulfide mineralization was present, which suggests both serpentinization and magmatic/lithospheric influence on fluid composition. The detachment fault is the likely pathway for hydrothermal fluid circulation at this off‐axis location. These new vent field discoveries, especially the OVF, contribute valuable information toward understanding Indian Ocean hydrothermal systems and their ecology/biogeography.

Enhancing ammonium rejection by PEI modification.

In this investigation, the utility of a static light scattering (SLS) technique to characterize aggregate morphology of two-dimensional engineered nanomaterials (2D ENMs) was systematically evaluated. The aggregation of graphene oxide (GO) and lithiated-molybdenum disulfide (Li-MoS2) were measured and compared to that of a spherical reference colloid, carboxylate-modified latex (CML) nanoparticles. The critical coagulation concentration (CCC) for all dispersions was determined via analysis of aggregation kinetics using time-resolved dynamic light scattering. This technique allowed for the elucidation of the transition from the reaction-limited aggregation (RLA) regime to diffusion-limited aggregation (DLA). The findings of this study support the aggregation trends predicted by Derjaguin-Landau-Verwey-Overbeek (DLVO) theory and recent computer simulations of aggregation kinetics. For all nanomaterials, as ionic strength increased towards the respective the CCC, fractal dimension decreased; any increase in ionic strength beyond the CCC did not yield significant change in fractal dimension. Across comparable primary particle sizes and using both carbonaceous (GO) and inorganic (Li-MoS2) 2D ENMs, this study further supports the use of SLS for the measurement of fractal dimension for 2D materials. To further support this claim, the aggregate morphology of GO in both RLA and DLA regimes was measured via cryogenic transmission electron microscopy.

Brackish water desalination has become increasingly important in arid inland regions for reliable water supplies, but the management of desalination brine waste is costly.

Growing evidence suggests that agricultural water quality is closely tied to food safety risks. Therefore, the presence of nanoparticles in environmental waters due to utilization as pesticides and fertilizers may have unintended consequences, as the effects of their interactions with foodborne bacteria are not well understood. This investigation utilizes a 2D parallel-plate flow cell and a 3D saturated sand column to systematically examine changes in bacterial transport trends due to nano-bio interactions under dynamic flow conditions. Two Escherichia coli species, O157:H7 and 25922, exposed to nano-CuO (<50 nm) and nano-TiO2 (<150 nm), were used to mimic agriculturally relevant conditions. In flow cell experiments, the presence of nano-CuO increased deposition and minimized release of pathogenic E. coli O157:H7 on a model spinach surface, while nano-TiO2 had no significant effects (p > 0.05). Attachment and detachment - as quantified by mass transfer rate coefficients - of E. coli 25922 from the leaf surface were not impacted by the presence of nanoparticles. No breakthrough was observed in the column experiments, with the exception of nano-TiO2 eluted in the presence of E. coli O157:H7. However, column dissection revealed higher proportions of suspended particles retained in the upper portion of the column when either nanoparticle was present. This provides further evidence that nanoparticles affect bacterial deposition and release, potentially promoting biofilm formation and foodborne illness risks.

This investigation focused on the affect that food-grade (FG) titanium dioxide (TiO2) nanoparticles (NPs), commonly found in consumer products, can have on the instrumental biological process of degrading household waste in septic systems. Microbial communities are instrumental in the sustainability of natural and engineered environments by degrading organic matter to products easily removed by other organisms. Wastewater treatment is one such engineered environment, where large-scale facilities use activated sludge and other processes to reduce organic matter and waste reintroduced into water systems. TiO2 NPs represent a commonly detected contaminant in the wastewater influent reaching treatment facilities. However, while influence of TiO2 NPs in large-scale, multistage treatment operations has been well studied, decentralized septic systems, utilized in 25% of U.S. homes, are neglected. Unlike centralized water treatment facilities, septic system function is entirely dependent on the health of the microbial community. Thus, this study focused on characterization of the septic system's microbial community and water quality in response when exposed to a common consumer product, FG TiO2, and an extensively researched NP, industrial-grade (IG) TiO2. Notably, FG and IG TiO2 exposure resulted in distinct responses in select microbial and effluent quality parameters. In addition, a more diverse microbial community composition developed during FG TiO2 exposures, indicating that FG TiO2 may alter microbial relationships affecting anaerobic digestion efficiency. Results indicate that nano-FG TiO2 may cause considerable changes to microbial function in septic systems and that understanding downstream effects requires studying ecologically relevant forms of NPs.

Increased demand for water, energy and food requires new ways to produce fertilizers, fuels and reusable water. Recovery of resources from wastes could lead to an additional source of energy and nutrients, and also reduce the waste to be disposed. In this work, we used hydrothermal liquefaction to produce a biocrude oil product, followed by membrane distillation of the aqueous effluents to concentrate a nutrient-rich stream that can be used as fertilizer. The motivation for this work is that residual heat from the hydrothermal liquefaction process could be utilized to drive the membrane distillation process, which would improve the efficiency and reduce the cost of the distillation process. The membrane distillation system was demonstrated to be able to recover 75% of the water. The membrane distillation retentate had very high ammonium and phosphate concentrations, making it suitable as a fertilizer. Membrane permeate contained high concentrations of volatile organics.

In April 2015, pressure recorders, seismometers, and hydrophones attached to the Ocean Observatories Initiative (OOI) Cabled Array on Axial Seamount detected, in real time, a volcanic eruption predominantly located along the north rift zone (NRZ). Real-time detection enabled a rapid response cruise to augment OOI data with ship-based physical, chemical, and biological sampling of the eruption and the new lava flows. The combined data set demonstrates the synergistic value of real-time monitoring combined with rapid response efforts that sample beyond the boundaries of a fixed cabled array. These combined data show that the 2015 eruption gave rise to chemically and microbiologically variable hydrothermal plumes over new NRZ lava flows, reflecting chemical and biological linkages between the subsurface lithosphere and the oceanic hydrosphere. The warmest and least diluted plume near the new lava flows was 0.119 degrees C above background seawater and hosted thermophilic and hyperthermophilic taxa that are typically identified in hydrothermal fluids emanating from the warm subsurface. Cooler and more diluted hydrothermal plumes farther from a hydrothermal fluid source were 0.072 degrees-0.078 degrees C above background seawater and hosted mesophilic and psychrophilic taxa that are typically identified in neutrally buoyant plumes at persistent hydrothermal venting sites. Potentially chemosynthetic microbial lineages, including Epsilonproteobacteria, Gammaproteobacteria, and Methanococcales, were positively correlated with elevated temperature anomalies. These data suggest that hydrothermal fluid flow through new lava flows on the NRZ supported diverse microbial communities for several months following the 2015 eruption and that subsurface heterogeneity contributed to the structure of unique hydrothermal-plume-hosted microbial communities.

Engineered nanomaterials (ENMs) are commonly incorporated into food and consumer applications to enhance a specific product aspect (i.e., optical properties). Life cycle analyses revealed ENMs can be released from products during usage and reach wastewater treatment plants (WWTPs), with titanium dioxide (TiO2) accounting for a large fraction. As such, food grade (FG) TiO2, a more common form of TiO2 in wastewater, was used in this study. Nanomaterials in WWTPs have been well characterized, although the problematic septic system has been neglected. Elution and bioaccumulation of TiO2 ENMs from WTTPs in downriver sediments and microorganisms has been observed; however, little is known about mechanisms governing the elution of FG TiO2 from the septic drainage system. This study characterized the transport behavior and mechanisms of FG TiO2 particles in porous media conditions after septic waste treatment. FG and industrial grade (IG) TiO2 (more commonly studied) were introduced to septic tank effluent and low-ionic strength electrolyte solutions prior to column transport experiments. Results indicate that FG TiO2 aggregate size (200–400 nm) remained consistent across solutions. Additionally, elution of FG and IG TiO2 was greatest in septic effluent at the higher nanoparticle concentration (100 ppm). FG TiO2 was well retained at the low (2 ppm) concentration in septic effluent, suggesting that particles that escape the septic system may still be retained in drainage field before reaching the groundwater system, although eluted particles are highly stabilized. Findings provide valuable insight into the significance of the solution environment at mediating differences observed between uniquely engineered nanomaterials.