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We present a synthetic multi-scale, multi-physics dataset constructed from the Kimberlina 1.2 CO2 reservoir model based on a potential CO2 storage site in the Southern San Joaquin Basin of California. Among 300 models, one selected reservoir-simulation scenario produces hydrologic-state models at the onset and after 20 years of CO2 injection. Subsequently, these models were transformed into geophysical properties, including P- and S-wave seismic velocities, saturated density where the saturating fluid can be a combination of brine and supercritical CO2, and electrical resistivity using established empirical petrophysical relationships. From these 3D distributions of geophysical properties, we have generated synthetic time-lapse seismic, gravity and electromagnetic responses with acquisition geometries that mimic realistic monitoring surveys and are achievable in actual field situations. We have also created a series of synthetic well logs of CO2 saturation, acoustic velocity, density and induction resistivity in the injection well and three monitoring wells. These were constructed by combining the low-frequency trend of the geophysical models with the high-frequency variations of actual well logs collected at the potential storage site. In addition, to better calibrate our datasets, measurements of permeability and pore connectivity have been made on cores of Vedder Sandstone, which forms the primary reservoir unit. These measurements provide the range of scales in the otherwise synthetic dataset to be as close to a real-world situation as possible. This dataset consisting of the reservoir models, geophysical models, simulated time-lapse geophysical responses and well logs forms a multi-scale, multi-physics testbed for designing and testing geophysical CO2 monitoring systems as well as for imaging and characterization algorithms. The suite of numerical models and data have been made publicly available for downloading on the National Energy Technology Laboratory's (NETL) Energy Data Exchange (EDX) website.

Ammonia-oxidizing archaea (AOA) are among the most ubiquitous and abundant archaea on Earth, widely distributed in marine, terrestrial, and geothermal ecosystems. However, the genomic diversity, biogeography, and evolutionary process of AOA populations in subsurface environments are vastly understudied compared to those in marine and soil systems. Here, we report a novel AOA order Candidatus (Ca.) Nitrosomirales which forms a sister lineage to the thermophilic Ca. Nitrosocaldales. Metagenomic and 16S rRNA gene-read mapping demonstrates the abundant presence of Nitrosomirales AOA in various groundwater environments and their widespread distribution across a range of geothermal, terrestrial, and marine habitats. Terrestrial Nitrosomirales AOA show the genetic capacity of using formate as a source of reductant and using nitrate as an alternative electron acceptor. Nitrosomirales AOA appear to have acquired key metabolic genes and operons from other mesophilic populations via horizontal gene transfer, including genes encoding urease, nitrite reductase, and V-type ATPase. The additional metabolic versatility conferred by acquired functions may have facilitated their radiation into a variety of subsurface, marine, and soil environments. We also provide evidence that each of the four AOA orders spans both marine and terrestrial habitats, which suggests a more complex evolutionary history for major AOA lineages than previously proposed. Together, these findings establish a robust phylogenomic framework of AOA and provide new insights into the ecology and adaptation of this globally abundant functional guild.

Surface, interface, and subsurface in catalysts are broadly perceived as independent units in materials, relying on diverse bonding environments and are recurrently studied discretely because of experimental challenges in distinguishing the surface and subsurface effects. Metal crystals, isolated atoms, or metal nanoparticles in supported catalysts induce an electrophilic nature in subsurface, enhancing the catalysis efficiency. In this review, the influence of modification in subsurface of catalysts and their specific catalytic outputs are discussed. Key approaches and techniques for insertion of subsurface modifications and impact of electrophilicity upon catalysis upgradation are observed. A compilation of frequently used chemical reactions catalyzed by subsurface‐modified catalysts have been structured and thoroughly illustrated. [ABSTRACT FROM AUTHOR]

The terrestrial subsurface harbors unique microbial communities that play important biogeochemical roles and allow for studying a yet unknown fraction of the Earth's biodiversity. The Saint-Leonard cave in Montreal City (Canada) is of glaciotectonic origin. Its speleogenesis traces back to the withdrawal of the Laurentide Ice Sheet 13,000 years ago, during which the moving glacier dislocated the sedimentary rock layers. Our study is the first to investigate the microbial communities of the Saint-Leonard cave. By using amplicon sequencing, we analyzed the taxonomic diversity and composition of bacterial, archaeal and eukaryote communities living in the groundwater (0.1 µm- and 0.2 µm-filtered water), in the sediments and in surface soils. We identified a microbial biodiversity typical of cave ecosystems. Communities were mainly shaped by habitat type and harbored taxa associated with a wide variety of lifestyles and metabolic capacities. Although we found evidence of a geochemical connection between the above soils and the cave's galleries, our results suggest that the community assembly dynamics are driven by habitat selection rather than dispersal. Furthermore, we found that the cave's groundwater, in addition to being generally richer in microbial taxa than sediments, contained a considerable diversity of ultra-small bacteria and archaea. [ABSTRACT FROM AUTHOR]

On Mars, the lack of either plate tectonics or a prominent erosional hydrological cycle since the Noachian means geological changes caused by asteroid and comet impact events have been preserved. On Earth, surviving impact‐induced fractures are localized to the relatively few preserved craters on the planet. We estimate that the shell of impact‐fractured rock on Mars (the "impact‐sphere") could provide between 9,200 times the surface area of a Mars radius sphere and up to 100 times this value, depending on the assumptions made, as potential microbially accessible space. Although >93% of craters we consider are smaller than 10 km in diameter, they contribute only about 5% of the total fracture surface area generated by all craters, making complex craters the dominant process for potential habitat formation. Microbiological data from terrestrial impact craters suggest that these fractures could have significantly enhanced local habitability by providing pathways for fluid flow, and thus nutrients and energy. However, unlike on Earth, the geological history of Mars means that pervasive impact fractures may also have provided pathways for Hesperian and Amazonian brines to infiltrate the subsurface and locally reduce habitability. Combining the fracture data with previous microbiological observations provides testable hypotheses for Martian drilling missions. Plain Language Summary: The Martian surface and subsurface is pervasively fractured by asteroid and comet impacts, largely because, compared to Earth, they have not been subducted by plate tectonics or eroded by a vigorous water cycle. In this paper, we estimate the surface area of fractures generated by these impacts. We find that these impact fractures could be 9,200 times the equivalent surface area of a flat Mars‐sized sphere and up to a hundred times this, depending on the assumptions made. On the one hand, these fractures could have provided surfaces for life and improved the flow of nutrients, on the other hand they could have channeled deleterious salty waters into the subsurface, suggesting that habitability of the subsurface is profoundly influenced by impact, but its positive or negative effects depend on the history of water flow and brine formation. This study leads to several testable hypotheses about the subsurface habitability of Mars. Key Points: Impact have fractured the deep subsurface of Mars pervasivelyWe estimate this fracture area to be between 9,200 times the surface area of a Mars radius sphere and up to 100 times this valueThis fracturing has likely profoundly influenced habitability [ABSTRACT FROM AUTHOR]

The effect of different irrigation methods (sprinkler, surface, surface-drip, and subsurface-drip) using treated wastewater, on alfalfa yield quantity and quality, was studied under semi-arid conditions. Randomized complete block design considering irrigation methods on 5 × 5 m plots replicated four times. Applied irrigation water was based on the Penman–Monteith equation using the FAO Cropwat software and accounting for the efficiencies of used irrigation systems. Surface irrigation gave the highest alfalfa fresh yield without significant difference compared to subsurface-drip. Average fresh production was 123, 120, 109, and 91 tons/h for surface, subsurface-drip, surface-drip, and sprinkler irrigation, respectively. Alfalfa fresh weight from subsurface-drip irrigation was 32 and 10% higher compared to sprinkler and surface-drip irrigation. Alfalfa dry weight from subsurface-drip irrigation was 10, 21, and 47% higher compared to surface-drip, surface, and sprinkler irrigation, respectively. N percentage in alfalfa leaves was significantly lower by 12% under subsurface-drip irrigation as compared to the other irrigation methods. Escherichia coli (E. coli) and fecal coliform (FC) were not detected on alfalfa leaves using subsurface-drip irrigation. E. coli and FC counts were high on leaves using sprinkler and surface irrigation. Subsurface-drip irrigation may be adapted as an efficient irrigation method when using non-conventional water under semi-arid conditions. HIGHLIGHTS Irrigation study: Examined methods using treated wastewater in semi-arid areas.; Subsurface-drip: Tops in dry yield, matches in fresh yield.; Health benefits: Subsurface-drip reduces E. coli and fecal coliform on alfalfa.; Smart water use: Advocates calculated use with FAO Cropwat insights.; Alternative water: Recommends subsurface-drip for treated wastewater in semi-arid regions.;

The basin area is at risk of geological disaster. The Bandung Basin is a crucial part of the country’s political, economic, and social. The Indonesian Disaster Risk Index show average value of 153.85 in 2015–2020 indicates that this region is extremely susceptible to natural disasters because may disaster event happened in this location. The Bandung Basin Region is a crucial economic and political hub for Indonesia. However, its natural environment and the region’s importance as a national strategic sector are at odds with one another. Geological subsurface conditions and vulnerability content must be understood to provide an overall picture of the situation in this location. The main goal of this research is to summarize how underground conditions affect natural disasters, which is the main factor of this event. Earthquakes, landslides, and liquefaction are only a few geological disasters strongly linked to conditions below ground. Due to the Holocene sedimentary layer, the stability of the basin is threatened. All these things happen naturally: liquefaction, subsidence caused by an intercalated sand layer, and structural failure by settlement. Considering the area’s capacity and population growth, more research related to mitigation and laboratory analysis is needed to decide if this area needs to be turned into a strategic city.

In order to evaluate the abrasive belt grinding performance, this paper proposes to conduct nickel-based superalloy robot abrasive belt grinding experiment based on different types of abrasive belts with multiple grit sizes. First, the single grinding performance evaluation is performed through five performance parameters: material removal rate, surface roughness, tangential force, specific grinding energy, and specific wear height. Then, based on the evaluation results of single grinding performance, a weighted evaluation function is established to comprehensively evaluate the grinding performance. It is found that the structured abrasive belt has relatively better grinding performance. The main factors affecting the abrasive belt grinding performance are identified through the evaluation results, with the effect of grit size being more significant. In addition, this paper analyzes the characteristics of material deformation based on the grinding subsurface microstructure, and discusses the effects of abrasive belts on material deformation. [ABSTRACT FROM AUTHOR]

Nickel-based single crystal superalloys have broad application prospects in the aerospace field. Their excellent physical properties enable the workpiece to serve in complex environments for a long time, and are often used in the most complex stress and the worst working conditions. However, the damage caused by mechanical material removal deteriorates the wafer surface flatness and die strength, while its surface and subsurface formation principle has yet to be revealed. This study aims to analyze the influence of abrasive particles on the load of the workpiece during machining was scrutinized through the lens of stress tensor, yield performance, and third invariant. The results indicate that, a substantial stress load is exerted on the front end of the abrasive grain, leading to the yield deformation of the workpiece. Conversely, the stress load at the bottom of the abrasive grain is comparatively lower, resulting in tensile deformation and the formation of a discernible plastic damage layer. To delve deeper into the workpiece's damage phenomenon, this study conducts a comparative analysis from the standpoints of chips, surface morphology, and subsurface characteristics of DD5. Experimental results indicate that the chips on the contact surface exhibits a relatively smooth texture, while the grinding surface manifests grooves of varying depths. Concurrently, subsurface analysis reveals the presence of slip deformation and elemental flow. This investigation elucidates the intricate interplay between the grinding process and subsurface loading, offering valuable insights to enhance the quality and precision of nickel-based single-crystal superalloy workpiece manufacturing. • The stress load is impacted by the variation in grinding parameters, but the stress value applied by abrasive is slightly affected. • Subsurface deformation is linked to the frequency of serrated chip formation. • Low wheel speed combined with high feed rate and grinding depth causes more noticeable scratches on the workpiece's surface. • Workpiece surface becomes more microhard than the substrate, and the microhardness is increased by about 15 μm. [ABSTRACT FROM AUTHOR]

This study investigates the nitrate gradients within the deep biosphere of karst carbonate rocks and their resident microbiota. Samples were taken from borehole cores at depths down to 350 m below the surface, collected during geological site investigations for proposed railway tunnels and analysed using 16S rRNA amplicon sequencing. 16S rRNA amplicon sequencing analysis revealed relatively low microbial diversity, which can serve as a reliable indicator of the pristine nature of deep karst. However, some local hotspots of diversity are independent of depth. Pseudomonadota dominated the samples, with Gammaproteobacteria dominating at the class level. The low nitrate content in deep karst, in contrast to higher values closer to the surface, serves as an additional marker of its undisturbed and unpolluted status. Based on the prediction of functional profiles from 16S rRNA sequencing data, nitrates remain low due to indigenous microbial denitrification and assimilatory nitrate reduction. Pathways related to nitrogen fixation, ammonia assimilation, and nitrification were not confirmed. When elevated nitrate levels are observed in karst, they are most probably related to anthropogenic activities. Environmental factors other than depth and nitrate content play an important role in shaping bacterial communities. [ABSTRACT FROM AUTHOR]

It is widely assumed that a taxonomic core community emerges among microbial communities from similar habitats because similar environments select for the same taxa bearing the same traits. Yet, a core community itself is no indicator of selection because it may also arise from dispersal and neutral drift, i.e. by chance. Here, we hypothesize that a core community produced by either selection or chance processes should be distinguishable. While dispersal and drift should produce core communities with similar relative taxon abundances, especially when the proportional core community, i.e. the sum of the relative abundances of the core taxa, is large, selection may produce variable relative abundances. We analyzed the core community of 16S rRNA gene sequences of 193 microbial communities occurring in tiny water droplets enclosed in heavy oil from the Pitch Lake, Trinidad and Tobago. These communities revealed highly variable relative abundances along with a large proportional core community (68.0 ± 19.9%). A dispersal-drift null model predicted a negative relationship of proportional core community and compositional variability along a range of dispersal probabilities and was largely inconsistent with the observed data, suggesting a major role of selection for shaping the water droplet communities in the Pitch Lake. [ABSTRACT FROM AUTHOR]

The marine subsurface is a long-term sink of atmospheric carbon dioxide with significant implications for climate on geologic timescales. Subsurface microbial cells can either enhance or reduce carbon sequestration in the subsurface, depending on their metabolic lifestyle. However, the activity of subsurface microbes is rarely measured. Here, we used nanoscale secondary ion mass spectrometry (nanoSIMS) to quantify anabolic activity in 3,203 individual cells from the thermally altered deep subsurface in the Guaymas Basin, Mexico (3-75 m below the seafloor, 0-14°C). We observed that a large majority of cells were active (83%-100%), although the rates of biomass generation were low, suggesting cellular maintenance rather than doubling. Mean single-cell activity decreased with increasing sediment depth and temperature and was most strongly correlated with porewater sulfate concentrations. Intracommunity heterogeneity in microbial activity decreased with increasing sediment depth and age. Using a dual-isotope labeling approach, we determined that all active cells analyzed were heterotrophic, deriving the majority of their cellular carbon from organic sources. However, we also detected inorganic carbon assimilation in these heterotrophic cells, likely via processes such as anaplerosis, and determined that inorganic carbon contributes at least 5% of the total biomass carbon in heterotrophs in this community. Our results demonstrate that the deep marine biosphere at Guaymas Basin is largely active and contributes to subsurface carbon cycling primarily by not only assimilating organic carbon but also fixing inorganic carbon. Heterotrophic assimilation of inorganic carbon may be a small yet significant and widespread underappreciated source of labile carbon in the global subsurface. [ABSTRACT FROM AUTHOR]

We know that extremes in ocean temperature often extend below the surface, and when these extremes occur in shelf seas they can significantly impact ecosystems and fisheries. However, a key knowledge gap exists around the accuracy of model estimates of the ocean's subsurface structure, particularly in continental shelf regions with complex circulation dynamics. It is well known that subsurface observations are crucial for the correct representation of the ocean's subsurface structure in reanalyses and forecasts. While Argo floats sample the deep waters, subsurface observations of shelf seas are typically very sparse in time and space. A recent initiative to instrument fishing vessels and their equipment with temperature sensors has resulted in a step-change in the availability of in situ data in New Zealand's shelf seas. In this study we use Observing System Simulation Experiments to quantify the impact of the recently implemented novel observing platform on the representation of temperature and ocean heat content around New Zealand. Using a Regional Ocean Modelling System configuration of the region with 4-Dimensional Variational Data Assimilation, we perform a series of data assimilating experiments to demonstrate the influence of subsurface temperature observations at two different densities and of different data assimilation configurations. The experiment period covers the 3 months during the onset of the 2017-2018 Tasman Sea Marine Heatwave. We show that assimilation of subsurface temperature observations in concert with surface observations results in improvements of 44% and 38% for bottom temperature and heat content in shelf regions (water depths< 400m), compared to improvements of 20% and 28% for surface-only observations. The improvement in ocean heat content estimates is sensitive to the choices of prior observation and background error covariances, highlighting the importance of the careful development of the assimilation system to optimize the way in which the observations inform the numerical model estimates. [ABSTRACT FROM AUTHOR]

Abstract We present a synthetic multi‐scale, multi‐physics dataset constructed from the Kimberlina 1.2 CO2 reservoir model based on a potential CO2 storage site in the Southern San Joaquin Basin of California. Among 300 models, one selected reservoir‐simulation scenario produces hydrologic‐state models at the onset and after 20 years of CO2 injection. Subsequently, these models were transformed into geophysical properties, including P‐ and S‐wave seismic velocities, saturated density where the saturating fluid can be a combination of brine and supercritical CO2, and electrical resistivity using established empirical petrophysical relationships. From these 3D distributions of geophysical properties, we have generated synthetic time‐lapse seismic, gravity and electromagnetic responses with acquisition geometries that mimic realistic monitoring surveys and are achievable in actual field situations. We have also created a series of synthetic well logs of CO2 saturation, acoustic velocity, density and induction resistivity in the injection well and three monitoring wells. These were constructed by combining the low‐frequency trend of the geophysical models with the high‐frequency variations of actual well logs collected at the potential storage site. In addition, to better calibrate our datasets, measurements of permeability and pore connectivity have been made on cores of Vedder Sandstone, which forms the primary reservoir unit. These measurements provide the range of scales in the otherwise synthetic dataset to be as close to a real‐world situation as possible. This dataset consisting of the reservoir models, geophysical models, simulated time‐lapse geophysical responses and well logs forms a multi‐scale, multi‐physics testbed for designing and testing geophysical CO2 monitoring systems as well as for imaging and characterization algorithms. The suite of numerical models and data have been made publicly available for downloading on the National Energy Technology Laboratory's (NETL) Energy Data Exchange (EDX) website.

The present study investigates the dry sliding wear behavior of Wire arc additive manufactured (WAAM) eutectic Al-Si alloy, with a particular focus on the effects of solidification and microstructural characteristics on wear behavior. Microstructural analysis indicated that the secondary dendrite arm spacing (SDAS) for the WAAM sample was three times higher than that of the cast sample. The WAAM sample exhibited thin, long columnar dendrites, while the cast samples displayed coarse and ripened dendrites. Furthermore, EBSD analysis revealed that the WAAM sample had a higher percentage (88.6%) of low-angle grain boundaries (LAGBs), contributing to their increased strength compared to cast samples with 78.6% LAGBs. The maximum wear rate of 5.45 × 10–6 g/m was observed at a normal load of 25 N and a sliding speed of 1.1 m/s with a coefficient of friction (CoF) of 0.59 for WAAM samples while casting samples exhibited a lower wear rate of 3.06 × 10–6 g/m and a CoF of 0.55 under identical conditions. Delamination, severe adhesion, and abrasion were the primary wear mechanisms under maximum wear rate test conditions. The subsurface of WAAM samples contained a mechanical mixed layer (MML), while cast samples revealed a stable thin oxide layer. The study found that samples with higher texture strength and lower Taylor factor (TF) values were more prone to damage. [ABSTRACT FROM AUTHOR]

Because the functions of the subsurface are hidden from view, its important role in society is often ignored or taken for granted. The subsurface is, however, an essential part of the global ecosystem with important contributions to human well-being. Geodiversity is an important characteristic in this respect. Material supply is the more obvious role of the subsurface with projections of a doubling of global material use in 2060 as compared to 2017. Moreover, creating underground spaces and infrastructure are gaining importance in the urban environment. The main reason for the inadequate protection of geodiversity is the lack of a comprehensive and integrative framework. Linking socio-economic activities to biophysical system characteristics of the subsurface is facilitated by the geosystem services approach. Sustainable urban development strategies require including geodiversity in decision-making on human well-being and setting conditions for land use change. Spatial plans and decisions on the use of natural endowments should look at processes over much longer timeframes. In this paper, we explore the links between human well-being and the subsurface with an emphasis on the role of geodiversity. We set out a methodological framework and describe possible long term three-dimensional land use planning consequences for sustainable utilization of the subsurface. This article is part of the Theo Murphy meeting issue 'Geodiversity for science and society'. [ABSTRACT FROM AUTHOR]

A proliferation of examinations of vertical, voluminous, subsurface, subterranean/subaqueous, geological, or underground relationships has emerged in the last few years of geographic thought. This article seeks to summarize four key themes in which the subsurface has gained prominence: geopolitics, natural resource extraction, cultural geographies, and epistemological politics. The article nonetheless critiques ahistorical, presentist, and/or Eurocentric tendencies in accounts of subsurface spaces, topographical verticalities, and the desire to "fill" a supposed "hole" of subsurface geographies. Altogether, I call for more precise, comparative, and historicized interpretations of the varieties of spatial relations above and below the surface of the earth. [ABSTRACT FROM AUTHOR]

We present a synthetic multi‐scale, multi‐physics dataset constructed from the Kimberlina 1.2 CO2 reservoir model based on a potential CO2 storage site in the Southern San Joaquin Basin of California. Among 300 models, one selected reservoir‐simulation scenario produces hydrologic‐state models at the onset and after 20 years of CO2 injection. Subsequently, these models were transformed into geophysical properties, including P‐ and S‐wave seismic velocities, saturated density where the saturating fluid can be a combination of brine and supercritical CO2, and electrical resistivity using established empirical petrophysical relationships. From these 3D distributions of geophysical properties, we have generated synthetic time‐lapse seismic, gravity and electromagnetic responses with acquisition geometries that mimic realistic monitoring surveys and are achievable in actual field situations. We have also created a series of synthetic well logs of CO2 saturation, acoustic velocity, density and induction resistivity in the injection well and three monitoring wells. These were constructed by combining the low‐frequency trend of the geophysical models with the high‐frequency variations of actual well logs collected at the potential storage site. In addition, to better calibrate our datasets, measurements of permeability and pore connectivity have been made on cores of Vedder Sandstone, which forms the primary reservoir unit. These measurements provide the range of scales in the otherwise synthetic dataset to be as close to a real‐world situation as possible. This dataset consisting of the reservoir models, geophysical models, simulated time‐lapse geophysical responses and well logs forms a multi‐scale, multi‐physics testbed for designing and testing geophysical CO2 monitoring systems as well as for imaging and characterization algorithms. The suite of numerical models and data have been made publicly available for downloading on the National Energy Technology Laboratory's (NETL) Energy Data Exchange (EDX) website. [ABSTRACT FROM AUTHOR]

Hydrogen (H2) is among the most common and widely utilized electron donors in microbial metabolism. This is particularly true for microorganisms that inhabit subsurface environments where H2 concentrations can be high due to H2 generation via one or more abiotic and biotic processes, such as serpentinization, radiolysis, cataclasis, and microbial fermentation. A surge in interest in the exploration for and exploitation of geologic (i.e., white and orange) H2 as a clean low carbon fuel therefore necessitates an evaluation of the influence of microorganisms on its flux and potential recovery from subsurface systems. The widespread application of high throughput metagenomic sequencing approaches to rock-hosted ecosystems now makes it possible to readily identify microorganisms that harbor the potential to metabolize H2 and to predict their mode of coupling H2 oxidation with available oxidants using comparative genomic data from natural samples alone. When combined with several recent reports of measured rates of net microbial H2 consumption in rock-hosted ecosystems, such information provides new perspective on the potential for microorganisms to impact the economics of H2 recovery from geologic systems. In this perspective, the different classes of enzymes that microorganisms use to reversibly oxidize H2 to fuel their energy metabolism are introduced and their distribution in several rock-hosted ecosystems is discussed. A compilation of net microbial H2 oxidation activities in rockhosted ecosystems is also presented to enable estimates of potential H2 loss from natural or stimulated geologic reservoirs during mining activities, with an example provided from the Samail Ophiolite that indicates >90% of geologic H2 produced could be lost to microbial consumption. Finally, avenues to guide future microbial research in environments where geologic H2 mining is planned are discussed. [ABSTRACT FROM AUTHOR]

The study area is located in Jos South Local Government Area of Plateau State, northcentral Nigeria. Artisanal mining activity is dominant in the area with a form of sub-surface extraction of the tin through underground cavities. This research aimed at detecting subsurface cavity using 2D Electrical Resistivity Tomography (ERT) at some mining sites in the study area. Campus Omega Terra-meter was used for the survey and Wenner-Schlumberger electrode configuration was adopted with inter-electrode spacing for the various sites ranged from 2m, 5m, and 10m. Active and non-active mine sites was selected for the study and field data where interpreted using the RES2DINV software. The smoothness constrain in version formulation was adopted. In Kuru area an oval shaped high resistivity values of about 736 to 1448Om suggests an air-filled cavity and a low resistivity values of 49.1 to 33Om indicates water filled cavity while control profile shows a low resistivity values of 64.6 to 98.7Om at a depth of 31.9m as a very good aquifer, for locating a deep well. In NTA college area, three geoelectric materials namely: clay, lateritic and sandy clay were observed. The resistivity value of about 77.7Om which was lower than ressistivity value of the host country rocks of 236Om suggests a water filled cavity and lower resistivity value of 97.2Om at Profile 2 attested to water filled cavity while resistivity value of above 822Om may indicate extension of air-filled cavity at Control Profile. A high resistivity value of 1483Om characterised the top soil at a depth of about 7m at control profile in Dura-Du area and A low resistivity value 80.1 to 122 Om at depth of about 13m to 15.9m indicates fresh water. The 2D ERT geophysical method has been used succefully to identify air-filled, waterfilled and fresh water zones in the study area.. [ABSTRACT FROM AUTHOR]

European Union (EU) policy is clear in its ambition to deliver a sustainable urban future for Europe. In this paper, we consider the role of urban geoscience to help achieve these ambitions. We highlight the relevance of geology to urban subsurface planning and wider EU policy and strategy. Despite the lack of explicit mention of urban underground space in key policy documents, we identify a significant number of priority urban issues for which geological characterisation is a pre-requisite and for which the geological system forms part of the solution, such as mitigation of climate impacts, delivering net zero energy, and implementing nature-based solutions. We reflect on the paradigm shift of urban geoscience as a geological discipline, rooted initially in engineering geology but which has moved towards an interdisciplinary, solution-focused science operating at the inter-section of environmental–social–built systems. In this regard, we highlight cutting-edge urban geoscience research aligned to current urban challenges and note, in particular, the significance of digital technologies to enable 3D urban characterisation, support data-driven decision-making for planning and development, and serve as a means to communicate geology to urban practitioners. The role of the urban geoscientist as an agent of change to enhance integrated science, improve the accessibility of geological issues, and accelerate the translation of national–regional geology to local settings and to urban policy drivers should not be underestimated. [ABSTRACT FROM AUTHOR]

This study investigates the microstructure damage mechanism of the difficult-to-machine material nickel-base single crystal superalloy DD5 by analyzing the working condition load and crystal deformation. The complexity of the macroscopic and microscopic deformation phenomena during the machining process makes it challenging to study the damage mechanism of the workpiece. Hence, crystal kinematics equation is established using true stress-true strain theory, and the internal force balance and constitutive model of the crystal are analyzed. The proposed theory is applied to finite element processing and experimental analysis of the workpiece, and the subsurface deformation behavior is studied from a mechanistic perspective.The stress model is employed to explore the plastic flow phenomenon of the material during the machining process, and the influence of stress and shear force on the subsurface of the workpiece is discussed. The theoretical analysis of crystal deformation, based on the principles of materials science and mechanics, uncovers the relationship between subsurface deformation curvature and stress. The study delves into the effects of the grinding process on subsurface damage and deformation by analyzing the phenomena of plastic flow, plastic slip, and plastic winding in the subsurface microstructure. The results indicate that at grinding speed v s = 25 m/s and grinding depth a p = 60 μm, the damage to the subsurface deformation layer is minimal. The grinding process considerably impacts the stress exerted on the workpiece, with an amplitude ranging from 1.255 × 103 to 1.286 × 103. Conversely, the strain on the workpiece is relatively less affected by the grinding process, exhibiting an amplitude of 2.366–3.568. Moreover, when the normal stress and shear force of the abrasive particles form 45° angle, the subsurface deformation of DD5 manifests a distinct slip distortion at an approximate 45° curvature. • When the subsurface reaches internal stress balance f + div ∑ = 0 , the shear force is ν and the internal force is 1 − 2 ν. • With the development of technology, a grinding speed of v s = 25 m/s and grinding depth of a p = 60 μm can result in an effective removal of nickel-based superalloy DD5. • During grinding, the grinding depth is directly proportional to the true strain, whereas the grinding speed is inversely proportional to the true strain. • Subsurface crystal plastic slip and grinding direction mostly display 45° angle slip. [ABSTRACT FROM AUTHOR]

Studies of the effects of volcanic activity on the Hawaiian Islands are extremely relevant due to the past and current co‐eruptions at both Mauna Loa and Kīlauea. The Big Island of Hawaiʻi is one of the most seismically monitored volcanic systems in the world, and recent investigations of the Big Island suggest a widespread subsurface connectivity between volcanoes. Volcanic activity has the potential to add mineral contaminants into groundwater ecosystems, thus affecting water quality, and making inhabitants of volcanic islands particularly vulnerable due to dependence on groundwater aquifers. As part of an interdisciplinary study on groundwater aquifers in Kona, Hawaiʻi, over 40 groundwater wells were sampled quarterly from August 2017 through March 2019, before and after the destructive eruption of the Kīlauea East Rift Zone in May 2018. Sample sites occurred at great distance (~80 km) from Kīlauea, allowing us to pose questions of how volcanic groundwater aquifers might be influenced by volcanic subsurface activity. Approximately 400 water samples were analyzed and temporally split by pre‐eruption and post‐eruption for biogeochemical analysis. While most geochemical constituents did not differ across quarterly sampling, microbial communities varied temporally (pre‐ and post‐eruption). When a salinity threshold amongst samples was set, the greatest microbial community differences were observed in the freshest groundwater samples. Differential analysis indicated bacterial families with sulfur (S) metabolisms (sulfate reducers, sulfide oxidation, and disproportionation of S‐intermediates) were enriched post‐eruption. The diversity in S‐cyclers without a corresponding change in sulfate geochemistry suggests cryptic cycling may occur in groundwater aquifers as a result of distant volcanic subsurface activity. Microbial communities, including taxa that cycle S, may be superior tracers to changes in groundwater quality, especially from direct inputs of subsurface volcanic activity. [ABSTRACT FROM AUTHOR]

Subsurface impacts associated with Marine Heatwaves (MHWs) in estuaries are not well understood, largely due to data scarcity. Using over three decades (1986–2021) of observations from several monitoring programs, this study investigates subsurface temperature and dissolved oxygen (DO) anomalies associated with surface MHWs in the Chesapeake Bay (CB). Seasonal variability in temperature anomalies followed a simple 1‐D response to surface heating with downward heat transport and diffusion controlled by seasonally variable stratification and mixing. Two distinct temperature regimes were found: a thermally stratified spring‐summer regime, when positive temperature anomalies were confined to the surface mixed layer (SML); and a homogeneous fall‐winter regime. Additionally, surface (subsurface) temperatures were elevated for months (days to weeks) before and after MHWs, indicating individual events were shorter than the timescales of elevated temperatures. A simple 1‐D SML heat budget identified air‐estuary heat flux changes as the leading driver of MHW onsets and declines, with latent heat flux being the dominant term. DO anomaly patterns were more complex, with considerable along‐channel gradients. Notable DO decreases (1–4 mg L−1) primarily occurred in the winter/spring below the SML, and the hypoxic zone expanded from spring through fall. Only a small fraction of these DO anomalies could be attributed to MHW temperature‐induced solubility changes, demonstrating that other physical and/or biogeochemical processes dominate changes in DO during these events. In CB, concurrent low DO and persistent high temperatures could compound the impacts of MHWs on this valuable ecosystem, with MHW event impacts likely to be exacerbated by climate change. Plain Language Summary: Marine heatwaves (MHWs), prolonged events with elevated water temperatures comparable to atmospheric heatwaves, have not been well studied in the subsurface (depths >1 m) due to data scarcity. Using three decades (1986–2021) of observations from several monitoring programs, we were able to investigate subsurface warming and changes in dissolved oxygen (DO) during surface MHW in the Chesapeake Bay main stem. We found that two seasonal regimes of subsurface warming occurred: a fall/winter "Homogeneous Regime," when extreme warming occurred throughout the water column; and a spring/summer "Stratified Regime," when extreme warming occurred only in the surface (top 15 m) and not the bottom. These regimes were caused by surface heating from the atmosphere and regulated by the seasonal changes in freshwater present in the Bay, which can inhibit heat penetration. During MHW, DO concentrations decreased, especially at the bottom of the deep channel during the winter/spring. These DO decreases were also associated with a hypoxic‐zone expansion; the region of harmfully low DO. Additionally, we found that surface and subsurface warming occurred days to months before and after marine heatwave events. These findings indicate that persistent warming and concurrent low DO could exacerbate the impacts of MHW on Bay ecosystem. Key Points: Subsurface temperature anomalies during Marine Heatwaves (MHWs) are controlled by seasonal stratification resulting in two seasonal regimesMHWs are associated with a hypoxic zone expansion and large negative bottom dissolved oxygen anomalies during the winter/springThe leading driver of estuarine MHWs is air‐sea heat flux, with latent heat flux changes being the dominant constituent [ABSTRACT FROM AUTHOR]

Due to the low thermal conductivity of CFRP and serious axial heat accumulation in dry drilling condition, the excessive cutting temperature simulation and suppression analysis have been the main research fields to analyze and improve borehole quality with the wide application of thick CFRP component in main load-carrying structures of aircraft. This paper proposed a three-dimensional drilling temperature simulation model to investigate the complex cutting temperature characteristics and predict the overheating area distribution during thick UD-CFRP drilling with dry condition and Boelube lubricant, thereby revealing its effects on occurrence of thermal-mechanical damages. Different from the previous drilling temperature simulation models, the material continuous removal process in this model was considered and discretized into finite chip layers removal process to model its effects on drilling heat transfer. Based on thermography method, a drilling temperature measurement experiment was conducted to validate the simulation model. Meanwhile, the overheating area distribution was predicted and the obvious reduction effects of ECL method on the overheating area ranges were confirmed. Moreover, the size of overheating area was proved to be a qualitative index of whether the hole wall subsurface damage at against fiber cutting zone is serious or not. [ABSTRACT FROM AUTHOR]

Biological soil crusts (biocrusts) are widespread in dryland ecosystems worldwide and were only recently discovered in agroecosystems. As agroecosystem biocrusts complete biological nitrogen (N) fixation, this research investigated if biocrust N could be released to biocrust subsoil and assimilated by a perennial tree crop. Biocrust was pulse labeled with 15NH4Cl (15N) in the greenhouse for eight weeks prior to application in a citrus (Citrus spp.) orchard in Southwest Florida, USA. Patches of labeled biocrust were applied to twelve citrus trees in September, with twelve trees in the same orchard not receiving biocrust (controls). The 15N in the biocrust, subsoil, crop fibrous roots, and crop leaves was quantified at seven dates leading up to fruit harvest 158 days after application. Sampling dates overlapped with citrus root (September–October) and shoot (March) flush periods. Isotopically labeled biocrust N was present in subsoil and crop roots one day after biocrust application and in leaves after three days. Results revealed that N was released from biocrust at a rate of 0.63% 15N released per day leading up to fruit harvest when 91.7% of 15N had been released. The amount of biocrust 15N in the fibrous roots increased during a root flush period (September–October) until 28 days after biocrust application and then decreased leading up to a leaf flush period and fruit harvest. Approximately 23.8% of total biocrust 15N was in the crop tissue at fruit harvest. Overall, these results indicate agroecosystem biocrusts have the potential to support tree crop growth during N demanding growth stages. [ABSTRACT FROM AUTHOR]

ABSTRACT We use metagenome-assembled genomes (MAGs) to understand single-carbon (C1) compound-cycling—particularly methane-cycling—microorganisms in montane riparian floodplain sediments. We generated 1,233 MAGs (>50% completeness and 50% abundance in the MAG library) in one sample that also contained aceticlastic methanogens, indicating a potential C1/methane-cycling hotspot. Ca. Methylomirabilis MAGs from SR encode pathways for methylotrophy but do not harbor methane monooxygenase or nitrogen reduction genes. Comparative genomic analysis supports that one clade within the Ca. Methylomirabilis genus is not methanotrophic. The genetic potential for methylotrophy was widespread, with over 10% and 19% of SR MAGs encoding a methanol dehydrogenase or substrate-specific methyltransferase, respectively. MAGs from uncultured Thermoplasmata archaea in the Ca. Gimiplasmatales (UBA10834) contain pathways that may allow for anaerobic methylotrophic acetogenesis. Overall, MAGs from SR floodplain sediments reveal a potential for methane production and consumption in the system and a robust potential for methylotrophy.IMPORTANCEThe cycling of carbon by microorganisms in subsurface environments is of particular relevance in the face of global climate change. Riparian floodplain sediments contain high organic carbon that can be degraded into C1 compounds such as methane, methanol, and methylamines, the fate of which depends on the microbial metabolisms present as well as the hydrological conditions and availability of oxygen. In the present study, we generated over 1,000 MAGs from subsurface sediments from a montane river floodplain and recovered genomes for microorganisms that are capable of producing and consuming methane and other C1 compounds, highlighting a robust potential for C1 cycling in subsurface sediments both with and without oxygen. Archaea from the Ca. Methanoperedens genus were exceptionally abundant in one sample, indicating a potential C1/methane-cycling hotspot in the Slate River floodplain system.

The terrestrial subsurface harbors unique microbial communities that play important biogeochemical roles and allow for studying a yet unknown fraction of the Earth’s biodiversity. The Saint-Leonard cave in Montreal City (Canada) is of glaciotectonic origin. Its speleogenesis traces back to the withdrawal of the Laurentide Ice Sheet 13,000 years ago, during which the moving glacier dislocated the sedimentary rock layers. Our study is the first to investigate the microbial communities of the Saint-Leonard cave. By using amplicon sequencing, we analyzed the taxonomic diversity and composition of bacterial, archaeal and eukaryote communities living in the groundwater (0.1 µm- and 0.2 µm-filtered water), in the sediments and in surface soils. We identified a microbial biodiversity typical of cave ecosystems. Communities were mainly shaped by habitat type and harbored taxa associated with a wide variety of lifestyles and metabolic capacities. Although we found evidence of a geochemical connection between the above soils and the cave’s galleries, our results suggest that the community assembly dynamics are driven by habitat selection rather than dispersal. Furthermore, we found that the cave’s groundwater, in addition to being generally richer in microbial taxa than sediments, contained a considerable diversity of ultra-small bacteria and archaea.

Noninvasive and depth‐sensitive measurements of dielectric properties are becoming of great interest in advanced and complex nanostructured architectures. Here, a straightforward parallel approach applicable in peak force Kelvin probe force microscopy for a 3D measurement of dielectric constants at the nanoscale is demonstrated. The proposed approach features a simultaneous measurement of the mechanical, electrical, and depth‐dependent dielectric properties applied to embedded nanostructures. The findings provide initial elements for further development of experimental dielectric nano‐tomography methods for characterizing buried and embedded systems and dielectric interfaces. [ABSTRACT FROM AUTHOR]

The nature of catalysis has been hotly pursued for over a century, and current research is focused on understanding active centers and their electronic structures. Herein, the concept of conductive catalysis is proposed and verified by theoretical simulations and experimental observations. Metallic systems containing buried catalytically active transitional metals and exposed catalytically inert main group metals are constructed, and the electronic interaction between them via metallic bonding is disclosed. Through the electronic interaction, the catalytic properties of subsurface transitional metals (Pd or Rh) can be transferred to outermost main group metals (Al or Mg) for several important transformations like semi-hydrogenation, Suzuki-coupling and hydroformylation. The catalytic force is conductive, in analogy with the magnetic force and electrostatic force. The traditional definition of active centers is challenged by the concept of conductive catalysis and the electronic nature of catalysis is more easily understood. It might provide new opportunities for shielding traditional active centers against poisoning or leaching and allow for precise regulation of their catalytic properties by the conductive layer. [ABSTRACT FROM AUTHOR]

Accelerators have been integral to subsurface probing for decades. Tools with deuterium-tritium (D-T) generators and scintillators utilizing gamma rays from thermal neutron capture, inelastic scattering, and activation are routine in cased-hole logging tools for reservoir and well monitoring to locate and quantify remaining hydrocarbons prior to initiating secondary or tertiary production. X-ray and neutron generators field-tested to, respectively, replace 137Cs and americium-beryllium (Am-Be) source tools that measure two bulk parameters, formation density and neutron porosity critical for initial characterization of formations, have yielded mixed results. D-T generator-based spectroscopy tools with advanced scintillators that can record both inelastic and capture n-gamma spectra, faster and with much better energy resolution, to provide a more complete mineralogy appear poised to replace Am-Be–based mineralogy tools. In view of their ability to measure both bulk and spectral parameters, accelerator-based nuclear methods appear attractive to extract additional geological information needed to transition to a low-carbon energy future. The paper discusses the current state of application of accelerator-based subsurface probing techniques, notes their potential for nonpetroleum applications, and concludes by briefly exploring technology advances that could significantly advance the state of the art. [ABSTRACT FROM AUTHOR]

This study was performed to evaluate the AquaCrop model in the crop yield, biomass, crop, and biomass water use efficiency of greenhouse cucumber with two methods of the capillary wick and drip irrigation and three soil textures including Clay-Loam marked with (S1), Sandy-Clay-Loam (S2) and Sandy-Loam (S3) in three replications and two cultivation periods in spring 2018 period (1) and autumn 2018 period (2). Data analysis was done based on compound analysis of variance and mean comparison was done based on Duncan's multi-range test. The data of the first period was used for calibration and sensitivity analysis, and the data of the second period was used to validate the model. The root-mean-square error (nRMSE) and coefficient of determination (R²) were used to validate the model. Based on results in the drip irrigation system, the maximum yield, and water use productivity were observed with 79.64 ton/ha and 46.54 kg/m³ in T2S1 treatment, and in the capillary wick irrigation system, the highest yield, and water use efficiency were observed with 62.05 ton/ha and 44.76 kg/m3 in W2S3. The model investigation results revealed that the highest simulation accuracy was observed in W2S3 treatment so that the nRMSE index in crop yield, biomass yield, crop water use efficiency and biomass water use efficiency were respectively 2.80, 1.70, 1.10, and 1.70 percent were calculated. Due to the optimality of all conditions in the model, most of the estimated parameters were higher than the observational data, still, the increasing and decreasing trend of model simulation in estimating product performance values was completely consistent with the observed data. [ABSTRACT FROM AUTHOR]

We know that extremes in ocean temperature often extend below the surface, and when these extremes occur in shelf seas they can significantly impact ecosystems and fisheries. However, a key knowledge gap exists around the accuracy of model estimates of the ocean’s subsurface structure, particularly in continental shelf regions with complex circulation dynamics. It is well known that subsurface observations are crucial for the correct representation of the ocean’s subsurface structure in reanalyses and forecasts. While Argo floats sample the deep waters, subsurface observations of shelf seas are typically very sparse in time and space. A recent initiative to instrument fishing vessels and their equipment with temperature sensors has resulted in a step-change in the availability of in situ data in New Zealand’s shelf seas. In this study we use Observing System Simulation Experiments to quantify the impact of the recently implemented novel observing platform on the representation of temperature and ocean heat content around New Zealand. Using a Regional Ocean Modelling System configuration of the region with 4-Dimensional Variational Data Assimilation, we perform a series of data assimilating experiments to demonstrate the influence of subsurface temperature observations at two different densities and of different data assimilation configurations. The experiment period covers the 3 months during the onset of the 2017-2018 Tasman Sea Marine Heatwave. We show that assimilation of subsurface temperature observations in concert with surface observations results in improvements of 44% and 38% for bottom temperature and heat content in shelf regions (water depths< 400m), compared to improvements of 20% and 28% for surface-only observations. The improvement in ocean heat content estimates is sensitive to the choices of prior observation and background error covariances, highlighting the importance of the careful development of the assimilation system to optimize the way in which the observations inform the numerical model estimates.

This study investigates the nitrate gradients within the deep biosphere of karst carbonate rocks and their resident microbiota. Samples were taken from borehole cores at depths down to 350 m below the surface, collected during geological site investigations for proposed railway tunnels and analysed using 16S rRNA amplicon sequencing. 16S rRNA amplicon sequencing analysis revealed relatively low microbial diversity, which can serve as a reliable indicator of the pristine nature of deep karst. However, some local hotspots of diversity are independent of depth. Pseudomonadota dominated the samples, with Gammaproteobacteria dominating at the class level. The low nitrate content in deep karst, in contrast to higher values closer to the surface, serves as an additional marker of its undisturbed and unpolluted status. Based on the prediction of functional profiles from 16S rRNA sequencing data, nitrates remain low due to indigenous microbial denitrification and assimilatory nitrate reduction. Pathways related to nitrogen fixation, ammonia assimilation, and nitrification were not confirmed. When elevated nitrate levels are observed in karst, they are most probably related to anthropogenic activities. Environmental factors other than depth and nitrate content play an important role in shaping bacterial communities.

This work aims to determine the hydrogeological potential in the community of Langos-San Andrés, belonging to the canton Guano. This was done by interpreting the regional geology–specific and subsurface stratigraphy. Stratigraphy was obtained by mathematical modeling of the electrical resistivity tomography results obtained in the study area. The interpretation of this information allowed us to know the structure of the soil and the levels at which the groundwater was located. Also, determining the optimal level of extraction of groundwater is a partition of 50 m depth onwards. Furthermore, the location of this water level will allow 1000 families in this area to obtain good quality water, reducing the water access gap that exists in the region and in Ecuador.

Despite the remoteness of the Antarctic continent and Southern Ocean, microplastic (MPs) contamination has been evidenced in recent years. However, the deep-sea compartments of the Southern Ocean are yet to be investigated. In the present study, we conducted a baseline MP assessment of the deep-sea waters and bottom sediments of the Bransfield Strait, Antarctica. A low abundance of suspected MPs was found. The average MP abundances in bottom sediments and water samples were 0.09 MP/g (range of 0–0.2 MP/g) and 7.00 MP/L (range of 0–16 MP/L), respectively. The majority of the particles were fibers identified as cellulose, although polyethylene terephthalate (PET) and polyacrylonitrile (PAN) was also detected. These results suggest low MP contamination levels in the Southern Ocean's deepest environmental compartments. However, future studies must aim to investigate the smallest MP fractions and, if possible, nanoplastic (<1 μm) contamination in these remote compartments. [Display omitted] • Microplastics were investigated in the Bransfield Strait. • There was a low prevalence of microplastic contamination in sediments (0–0.2 MP/g). • as well as water samples (0–16 MP/L). • Particles were mostly in the shape of fibers (100% and 90.5% in sediments and water). • Particles were mainly composed of cellulose (73.3% and 90.9% in sediments and water). [ABSTRACT FROM AUTHOR]

Mars' crust has an extensive graben system that covers a region more than 8,000 km in diameter and nearly one-third of the planet's circumference. Many of them trend radially outward from the Tharsis Montes. They are long-lived crucial features to determining the evolution of the tectonic and volcanic history of Mars. These thousands of grabens were discovered in the early 1970s and have been studied extensively with different hypotheses about their formation throughout the literature. These hypotheses include the formation process being either tectonic or a combination of tectonic and magmatic processes, but no consensus has been reached so far. In this study, for the first time, we explore the subsurface of narrow graben systems using SHARAD data to understand and support the formation hypothesis of the martian graben system. We found multiple subsurface reflections in a narrow range of time delay at the rim of Mangala Fossa and at the floor of Labeatis Fossa. The loss tangent of the subsurface unit is in the range of 0.009 to 0.03, consistent with low to moderate-density basalt. The presence of a basaltic subsurface unit at these locations confirms that magmatism is involved during the formation process of these two graben systems. • SHARAD detects subsurface reflections at the rim of Mangala Fossa and the floor of Labeatis Fossa. • First-ever confirmation of SHARAD subsurface detections directly associated with the Tharsis graben system. • Basaltic subsurface unit confirms that magmatism is involved in the formation process of these two graben systems. [ABSTRACT FROM AUTHOR]

The annealing-promoted He release process in irradiated SiC remains unclear. Herein the atomistic release behavior of a He atom from 3 C -SiC(1 0 0) subsurface is investigated by density functional theory calculations. The results show that the interstitial He atom in the 3 C -SiC(1 0 0) subsurface tends to diffuse to the surface by overcoming a diffusion barrier of 0.72 eV, rather than to infiltrate into the slab interior, supporting a bulk-diffusion-limited mechanism for He release from SiC. The He atom can spontaneously diffuse on the 3 C -SiC(1 0 0) surface, suggesting a retarding effect on He release from irradiated SiC. The results provide deeper insight into the release mechanism of He defects in irradiated SiC and are useful for improving defect recovery strategies. [ABSTRACT FROM AUTHOR]

Hydrogen selective metallic membranes made of palladium and its alloys are superior to membranes made of other metallic materials due to their unique surface properties. However, the prohibitive cost of Pd has prevented their widespread application. Although the basic mechanisms are known, the link between hydrogen at the surface and that in the bulk has been missing to explain the prominent position of Pd. To provide the missing link between surface and bulk, we measured the hydrogen concentration and depth distribution on the downstream side of a Pd membrane at realistic permeation conditions (temperature and pressure) using a membrane electron spectroscopy setup. We find hydrogen in the vicinity of the surface with intermediate stability. In general, hydrogen on the surface is more stable and thus more concentrated than in the bulk. Subsurface hydrogen with intermediate stability mitigates the difference between surface and bulk concentration and thereby facilitates overall hydrogen permeation. The observations link the results of UHV-compatible hydrogen adsorption experiments with observations made on hydrogen permeation in membranes under technical conditions. This link enables the application of the wealth of surface science based knowledge to the optimization of hydrogen permeable membrane materials. [Display omitted] • H-selective Pd alloys are superior to other metallic membrane materials due to the unique surface. • Understanding requires the determination of surface and subsurface H under operation conditions. • Reflecting electron energy loss spectroscopy is used to quantify hydrogen in a Pd membrane. • The measurements reveal that the subsurface hydrogen has intermediate stability. • Subsurface H with intermediate stability facilitates overall hydrogen permeation. [ABSTRACT FROM AUTHOR]

We use metagenome-assembled genomes (MAGs) to understand single-carbon (C1) compound-cycling-particularly methane-cycling-microorganisms in montane riparian floodplain sediments. We generated 1,233 MAGs (>50% completeness and <10% contamination) from 50- to 150-cm depth below the sediment surface capturing the transition between oxic, unsaturated sediments and anoxic, saturated sediments in the Slate River (SR) floodplain (Crested Butte, CO, USA). We recovered genomes of putative methanogens, methanotrophs, and methylotrophs ( n = 57). Methanogens, found only in deep, anoxic depths at SR, originate from three different clades ( Methanoregulaceae , Methanotrichaceae , and Methanomassiliicoccales ), each with a different methanogenesis pathway; putative methanotrophic MAGs originate from within the Archaea ( Candidatus Methanoperedens) in anoxic depths and uncultured bacteria ( Ca . Binatia) in oxic depths. Genomes for canonical aerobic methanotrophs were not recovered. Ca. Methanoperedens were exceptionally abundant (~1,400× coverage, >50% abundance in the MAG library) in one sample that also contained aceticlastic methanogens, indicating a potential C1/methane-cycling hotspot. Ca . Methylomirabilis MAGs from SR encode pathways for methylotrophy but do not harbor methane monooxygenase or nitrogen reduction genes. Comparative genomic analysis supports that one clade within the Ca . Methylomirabilis genus is not methanotrophic. The genetic potential for methylotrophy was widespread, with over 10% and 19% of SR MAGs encoding a methanol dehydrogenase or substrate-specific methyltransferase, respectively. MAGs from uncultured Thermoplasmata archaea in the Ca . Gimiplasmatales (UBA10834) contain pathways that may allow for anaerobic methylotrophic acetogenesis. Overall, MAGs from SR floodplain sediments reveal a potential for methane production and consumption in the system and a robust potential for methylotrophy.IMPORTANCEThe cycling of carbon by microorganisms in subsurface environments is of particular relevance in the face of global climate change. Riparian floodplain sediments contain high organic carbon that can be degraded into C1 compounds such as methane, methanol, and methylamines, the fate of which depends on the microbial metabolisms present as well as the hydrological conditions and availability of oxygen. In the present study, we generated over 1,000 MAGs from subsurface sediments from a montane river floodplain and recovered genomes for microorganisms that are capable of producing and consuming methane and other C1 compounds, highlighting a robust potential for C1 cycling in subsurface sediments both with and without oxygen. Archaea from the Ca . Methanoperedens genus were exceptionally abundant in one sample, indicating a potential C1/methane-cycling hotspot in the Slate River floodplain system., Competing Interests: The authors declare no conflict of interest.

Ecosystems subject to mantle degassing are of particular interest for understanding global biogeochemistry, as their microbiomes are shaped by prolonged exposure to high CO 2 and have recently been suggested to be highly active. While the genetic diversity of bacteria and archaea in these deep biosphere systems have been studied extensively, little is known about how viruses impact these microbial communities. Here, we show that the viral community in a high-CO 2 cold-water geyser (Wallender Born, Germany) undergoes substantial fluctuations over a period of 12 days, although the corresponding prokaryotic community remains stable, indicating a newly observed "infect to keep in check" strategy that maintains prokaryotic community structure. We characterized the viral community using metagenomics and metaproteomics, revealing 8 654 viral operational taxonomic units (vOTUs). CRISPR spacer-to-protospacer matching linked 278 vOTUs to 32 hosts, with many vOTUs sharing hosts from different families. High levels of viral structural proteins present in the metaproteome (several structurally annotated based on AlphaFold models) indicate active virion production at the time of sampling. Viral genomes expressed many proteins involved in DNA metabolism and manipulation, and encoded for auxiliary metabolic genes, which likely bolster phosphate and sulfur metabolism of their hosts. The active viral community encodes genes to facilitate acquisition and transformation of host nutrients, and appears to consist of many nutrient-demanding members, based on abundant virion proteins. These findings indicate viruses are inextricably linked to the biogeochemical cycling in this high-CO 2 environment and substantially contribute to prokaryotic community stability in the deep biosphere hotspots., Competing Interests: The authors declare no conflict of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of FEMS.)

The combined application of geotechnical and geophysical methods provides an effective means of subsurface exploration. The insufficient correlation between geotechnical and geophysical methods prevents the conversion of geophysical data to geotechnical information and vice versa. In the present study, a correlation has been proposed between the geotechnical and geoelectrical properties of two soil deposits in India. Eleven boreholes along with a Standard Penetration Test (SPT) and different laboratory tests have been conducted to obtain the different engineering and physical properties of the soil layers. Twelve Electrical Resistivity Tomography (ERT) profiles have also been conducted to obtain the resistivity profile of the subsurface layers. The variation of the resistivity of the soil layers is analyzed and explained. Results show a strong linear correlation between resistivity and SPT blow counts (N′) of the soil layer for one site while a weak correlation for another site. A strong linear correlation between transverse resistivity (T) and N′ values has been observed for both sites. A comparison with the other existing correlation between resistivity/transverse resistivity and N′-values has also been presented. The range of resistivity values and engineering properties of soil layers are mentioned. The study is useful for the development of similar correlations and provides an approximate estimation of different geotechnical parameters for infrastructure design. • The study investigates the site-specific correlation between geotechnical and geoelectrical properties of two sites in India. • The subsurface exploration of the site has been conducted through SPT N and resistivity measurement. • Correlation between N and resistivity has been developed and presented. • Correlation between N and transverse resistivity has been developed and presented. • A comparison between the previous and present study has been made. [ABSTRACT FROM AUTHOR]

Desert environments constitute one of the largest and yet most fragile ecosystems on Earth. Under the absence of regular precipitation, microorganisms are the main ecological component mediating nutrient fluxes by using soil components, like minerals and salts, and atmospheric gases as a source for energy and water. While most of the previous studies on microbial ecology of desert environments have focused on surface environments, little is known about microbial life in deeper sediment layers. Our study is extending the limited knowledge about microbial communities within the deeper subsurface of the hyperarid core of the Atacama Desert. By employing intracellular DNA extraction and subsequent 16S rRNA sequencing of samples collected from a soil pit in the Yungay region of the Atacama Desert, we unveiled a potentially viable microbial subsurface community residing at depths down to 4.20 m. In the upper 80 cm of the playa sediments, microbial communities were dominated by Firmicutes taxa showing a depth-related decrease in biomass correlating with increasing amounts of soluble salts. High salt concentrations are possibly causing microbial colonization to cease in the lower part of the playa sediments between 80 and 200 cm depth. In the underlying alluvial fan deposits, microbial communities reemerge, possibly due to gypsum providing an alternative water source. The discovery of this deeper subsurface community is reshaping our understanding of desert soils, emphasizing the need to consider subsurface environments in future explorations of arid ecosystems., (© The Author(s) 2024. Published by Oxford University Press on behalf of National Academy of Sciences.)

[Display omitted] • Subsurface hydrogen production technologies were introduced. • The potential of the approach to significantly reduce CO 2 emissions was highlighted. • An overview of major barriers to subsurface technologies was provided. • Finally, the operational challenges faced in subsurface hydrogen production were addressed. Subsurface technologies present an excellent opportunity to produce hydrogen from hydrocarbon resources. It refers to the production of hydrogen directly from underground resources, particularly hydrocarbon resources. This method often involves injecting steam or oxygen into the reservoirs to initiate reactions that produce hydrogen. In some cases, subsurface method can also involve the process of in-situ gasification (ISG), and in-situ combustion (ISC) (also known as subsurface combustion and gasification). The produced hydrogen is extracted from the reservoir, leaving the carbon dioxide and other byproducts underground. This approach could offer a sustainable and carbon-free pathway to produce hydrogen because of reduced CO 2 emissions compared to conventional methods. A comprehensive review of the status and progress of ISC and ISG of hydrocarbon for hydrogen production is presented. The advantages and limitations of the technologies were discussed as well as the underlying reaction mechanism. Techno-economic and lifecycle assessment studies of ISG and ISC are presented. One of the main economic limitations of subsurface hydrogen production is the high cost of building and operating the required infrastructure. However, utilizing pre-existing horizontal wells for air or oxygen injection can significantly reduce the initial infrastructure investment costs. Moreover, the overall process cost of ISG can vary significantly due to various factors, including membrane costs, oxygen production costs and the cost of hydrocarbon. The findings from the environmental evaluation indicate that the primary contributors to greenhouse gas emissions in subsurface technologies are the CO 2 emissions produced during gas combustion for heat generation and the electricity consumed during the gasifying agents' preparation stage. Subsurface methods for producing hydrogen encounter numerous challenges, including choosing the right locations and selecting cost-effective drilling techniques. [ABSTRACT FROM AUTHOR]