A comprehensive scientific research roadmap is essential to bridge knowledge gaps and deepen the understanding of key geological, geochemical, and geophysical aspects of natural hydrogen (H2) as a potential new energy resource. This paper reviews major scientific uncertainties on natural H2, suggesting research priorities, as a guide for defining exploration strategies, techniques, and data interpretation. The uncertainties concern all phases of the natural H2 cycle, from generation (source rocks) through migration (advection and diffusion) and accumulation (reservoir and cap rocks) to the application and interpretation of subsurface and surface geochemical and geophysical exploration techniques. Understanding H2 sources and generation rates (the amount of H2 generated by a given volume of rock over time) is crucial for determining whether a geological H2 system operates as a short-term dynamic system with rapid H2 production and release, or as a conventional gas system with long-term accumulations, analogous to petroleum reservoirs. Preliminary estimates for serpentinisation, radiolysis, and organic matter degradation suggest that H2 generation is not inherently fast, especially for non-hydrothermal continental systems (crystalline basement of shields, ophiolites, peridotite massifs, sedimentary basins), and long-term accumulations, like those of fossil natural gas systems, represent the most likely scenario. The mechanisms of H2 migration through geological formations require application of fundamental principles of fluid-flow physics, distinguishing advection and diffusion, as well as their forms (from gas-phase, bubble flows to aqueous solutions). Additional studies of H2 accumulation and retention in subsurface reservoirs could improve understanding of mechanisms of H2 migration by focusing on the rock fluid-bearing properties and the factors affecting H2 preservation, such as the presence of cap rocks impermeable to H2, pressure conditions, residence times, and microbial or abiotic consumption. Advanced techniques, including reservoir modelling, flow simulations, 3D imaging (micro-CT) of H2-bearing rocks, and extraction and analysis of gas occluded in rocks, can provide insights into the stability and potential recoverability of H2 accumulations. The interpretation of surface exploration techniques, including gas geochemistry, geophysics, and remote sensing, long employed in mineral and energy resource exploration, is now being adapted for natural H2 studies, but challenges remain in the data interpretation. Distinguishing H2 seepage due to geological degassing from H2 produced near the surface by modern microbial processes or artificial sources, such as hammering or drilling for soil-gas sampling, drilling into aquifers, and corrosion in boreholes, is an essential step in exploration. The simple detection of H2 in soils, even in morphological structures like sub-circular depressions or “fairy circles”, cannot be cursorily interpreted as a signal of natural H2 seepage from a deep source. A holistic geochemical approach, including isotopic analyses of gases associated with H2, is recommended to distinguish among the variety of possible H2 origins. Observations of H2 in wells should be interrogated to rule out possible artifacts such as corrosion and drill bit metamorphism. The integration of multiple geophysical methods, including seismic, gravimetric, magnetic, and electro-magnetic surveys, is recommended to mitigate interpretation ambiguities regarding the structure of a subsurface H2 system (source and reservoir rocks, including fluid and gas storage), due to the non-uniqueness of rock-specific physical properties.

Protein tyrosine phosphatases (PTPs) are a family of enzymes that play important roles in regulating cellular signaling pathways. The activity of these enzymes is regulated by the motion of a catalytic loop that places a critical conserved aspartic acid side chain into the active site for acid-base catalysis upon loop closure. These enzymes also have a conserved phosphate binding loop that is typically highly rigid and forms a well-defined anion binding nest. The intimate links between loop dynamics and chemistry in these enzymes make PTPs an excellent model system for understanding the role of loop dynamics in protein function and evolution. In this context, archaeal PTPs, which have evolved in extremophilic organisms, are highly understudied, despite their unusual biophysical properties. We present here an engineered chimeric PTP (ShufPTP) generated by shuffling the amino acid sequence of five extant hyperthermophilic archaeal PTPs. Despite ShufPTP's high sequence similarity to its natural counterparts, ShufPTP presents a suite of unique properties, including high flexibility of the phosphate binding P-loop, facile oxidation of the active site cysteine, mechanistic promiscuity, and most notably, hyperthermostability, with a denaturation temperature likely >130 °C (>8°C higher than the highest recorded growth temperature of any archaeal strain). Our combined structural, biochemical, biophysical and computational analysis provides insight both into how small steps in evolutionary space can radically modulate the biophysical properties of an enzyme, and showcase the tremendous potential of archaeal enzymes for biotechnology, to generate novel enzymes capable of operating under extreme conditions.

Steroids are indispensable components of the eukaryotic cellular membrane and the acquisition of steroid biosynthesis was a key factor that enabled the evolution of eukaryotes. The polycyclic carbon structures of steroids can be preserved in sedimentary rocks as chemical fossils for billions of years and thus provide invaluable clues to trace eukaryotic evolution from the distant past. Steroid biosynthesis consists of (1) the production of protosteroids and (2) the subsequent modifications toward "modern-type" steroids such as cholesterol and stigmasterol. While protosteroid biosynthesis requires only two genes for the cyclization of squalene, complete modification of protosteroids involves ~10 additional genes. Eukaryotes universally possess at least some of those additional genes and thus produce modern-type steroids as major final products. The geological biomarker records suggest a prolonged period of solely protosteroid production in the mid-Proterozoic before the advent of modern-type steroids in the Neoproterozoic. It has been proposed that mid-Proterozoic protosteroids were produced by hypothetical stem-group eukaryotes that presumably possessed genes only for protosteroid production, even though in modern environments protosteroid production as a final product is found exclusively in bacteria. The host identity of mid-Proterozoic steroid producers is crucial for understanding the early evolution of eukaryotes. In this perspective, we discuss how geological biomarker data and genetic data complement each other and potentially provide a more coherent scenario for the evolution of steroids and associated early eukaryotes. We further discuss the potential impacts that steroids had on the evolution of aerobic metabolism in eukaryotes, which may have been an important factor for the eventual ecological dominance of eukaryotes in many modern environments.

In order to analyze the effect of a new gelling agent for hydraulic fracturing, fluid samples from different stages of the operation (hydraulic fracturing fluid, coil tubing, flowback and produced waters) were collected from a well in the Vaca Muerta formation in Argentina. Collected samples were analyzed for major and trace elements, first within a few days after sampling, then reanalyzed 6 months later and again 2 years after sampling. Results show that the salinity of samples increased quickly with time, from 2000 mg/L up to 43,000 mg/l a month later, due to the mixing of hydraulic fracturing fluids with formation water. No evidence of water–rock reactions was observed. Results from the later analyses showed that the composition of the samples evolved with time with a sensible decrease of concentration for most trace elements over the course of these two years (e.g. Ba from 137 mg/L to 55 mg/L, Mn from 8 mg/L to 5 mg/L) and heavy metals (e.g. As 100μg/L to 1 μf/L, Co 160μg/L to 1.4μg/L, Cr from 160μg/L to 26μg/L). Interpretation of the results shows that delayed, post-sampling, precipitation of barite in the preserved samples is the reason for such a decrease. This opens a very interesting option for mitigation and remediation of wastewaters from hydraulic fracturing as natural or even triggered precipitation of barite could involve most of the dissolved heavy metals and decrease strongly their concentrations.

The analysis of tracer profiles of porewaters is a valuable tool to understand transport processes in argillaceous rocks and to unravel the paleo-hydrogeology of a site. In this contribution, anionic tracers (Cl, Br) from eight boreholes located in three study areas (-20 km apart) penetrating the -800 m thick Mesozoic sequence in northern Switzerland, were analysed. A specific focus was on the Opalinus Clay, a -100 m thick homogeneous claystone formation, foreseen as host rock for radioactive waste disposal in Switzerland, as well as its mostly clay-rich confining units. Using porewater extraction methods, such as high-pressure squeezing, advective displacement and aqueous extraction, a unique dataset of spatially highly resolved Cl and Br profiles could be obtained. These show systematic and comparable patterns suggesting common paleo-hydrogeological evolution paths for all three study areas. The scatter in the tracer profiles based on the aqueous extraction data are mostly related to the uncertainty in the estimation of the anion-accessible porosity fraction on one hand and in the water content data in the case of low-porosity calcareous rocks on the other. Differences between the study areas are in line with differences in aquifer characteristics. The current shape of the anion profiles is dominated by diffusive exchange with the bounding aquifers over the last several ten thousands to millions of years, as supported by numerical modelling. The Br/Cl signals also suggest the preservation of older signals related to halite dissolution and highly evolved evaporitic porewaters occurring in evaporite-bearing units of the Triassic. Overall, the adopted methodology has enabled to obtain a unique dataset of anionic tracers at regional scale providing a solid basis for understanding the regional paleo-hydrogeology of siting areas for a potential nuclear waste repository.

Sixty years ago, the geneticist James Neel proposed that the epidemics of obesity and diabetes today may have evolutionary roots. Specifically, he suggested that our ancestors may have accumulated mutations during periods of famine that provided a survival advantage at that time. However, the presence of this "thrifty genotype" in today's world, where food is plentiful, would predispose us to obesity and diabetes. The "thrifty gene" hypothesis, attractive to some, has been challenged over the years. The authors have previously postulated that the loss of the uricase gene, resulting in a rise in serum and intracellular uric acid levels, satisfies the criteria of a thrifty genotype mutation. This paper reviews and brings up-to-date the evidence supporting the hypothesis and discusses the current arguments that challenge this hypothesis. Although further studies are needed to test the hypothesis, the evidence supporting a loss of uricase as a thrifty gene is substantial and supports a role for evolutionary biology in the pathogenesis of the current obesity and diabetes epidemics.

Phyllosilicates may trap hydrogen (H-2) in the crust, but they may also produce it through various processes, including oxidative dehydrogenation. The dehydrogenation temperature depends on the type and composition of the phyllosilicates considered, but it may be as low as 300 degrees C. Here, we document the release of H-2 and CO during thermal treatment of chloritite (300 degrees C) and talc (500 degrees C) from the Trimouns deposits (Eastern Pyrenees, France). Thermal release of gases coupled to stable isotope analysis has been used to recover and characterize H-2 and CO, the two detected gases. Hydrogen content may be as high as 7 ppm with delta D-H2 values ranging from -258 parts per thousand to - 224 parts per thousand for sub-pure chloritite and - 140%0 for pure talc. CO content ranges between 3 ppm and 35.3 ppm with very homogeneous delta C-13(CO) values between -27.6 parts per thousand and - 25.7 parts per thousand. This study supports the idea that H-2 was produced during experiments by dehydrogenation. The origin of CO remains enigmatic, but its carbon isotope composition suggests a link to the few amounts of graphite documented in chloritite and talc from the deposit. This work also reports extensive hydrogen isotope fractionation between H-2 produced by dehydrogenation and both talc and chloritite. Dehydrogenation of phyllosilicates is a potential source term of H-2 in numerous magmatic-hydrothermal settings and must thus be accounted for in the budget of the H-2 geochemical cycle.

The need to investigate mineral precipitation in heterogeneous sedimentary rock with complex pore net-work and mineral composition arises with problems like pore clogging by barite precipitation during sulfate-rich water injection in geological reservoirs, the durability of long term storage of nuclear waste or the damage induced by crystallisation. At the LFCR (Laboratoire des Fluides Complexes et leurs Reservoirs, Anglet, France), we aim to reproduce geological objects in laboratory conditions. In this frame, we built a contra diffusive set up to precipitate a barite front in two sedimentary rock samples, a Lavoux oolitic limestone and a Vosges Sandstone with a fraction of clays. Two reservoirs filled respectively with BaCl2 and Na2SO4 dissolved in milli-Q water are in contact with a porous sample so that the ions diffuse through it. X-ray tomography shows that a barite front is precipitated in both samples at different positions depending on the diffusion of the different ions. SEM/EDS microanalysis on polish sections highlight both the barite front location and its connectivity. In the Lavoux limestone, a connected barite front is present. Fine barite aggregates preferentially precipitate in the smallest pores of the Lavoux sample, whilst the crystals precipitating in large macropores (> 20 lm) show a preferential orientation. We pro-pose that the Gibbs free energy barrier for barite heterogeneous nucleation in the limestone is lower in contact with micrite in small pores than in contact with euhedral calcite in large pores. Finally, the Gibbs energy barrier for barite homogeneous nucleation in large pores is the highest. In the Vosges sandstone, the barite front is scattered with well-crystallized barite precipitating in large pores, and a more striking thin layer of barite is precipitated in the interfoliar space of chlorite-smectite complex. Consequently, we propose that smectite can concentrate barium by adsorption. Then because sulfate and sodium concentrations increase, ultimately barium is desorbed and barite precipitate. (c) 2022 Elsevier Ltd. All rights reserved.

The water supply in drylands mainly relies on groundwater, making it a crucial resource. Springs in southern Africa are often underutilized, and are neither protected nor monitored. Thus, the aim of this study was to evaluate their quality in a sample area in northwestern Namibia and to propose solutions for the sustainable use of springs. In total, 35 springs and hot springs were evaluated in the study area located in the drier part of Namibia (Pmean = 150–400 mm/year), an area highly impacted by ongoing climate change with longer and more frequent drought seasons. The springs there are mostly uncaptured and the discharge is in the form of surface runoff, which is mainly lost to the atmosphere by evaporation. Most of the studied springs were perennial, despite a severe drought period. Local communities rely on the springs mainly for livestock and human consumption, as well as for irrigation. However, 71% of the springs do not have any protective measures. The temperature, pH, conductivity and alkalinity were tested in situ. In total, 20 samples were collected and analyzed for major ions (boron, fluoride, silica and strontium) and total dissolved solids (TDS). The physical and inorganic results mostly indicated good and excellent quality water for human consumption, while the hot springs tended to have poor water quality in terms of Namibian standards, indicating that the water was not fit for human consumption.

The Lower Cretaceous oil reservoirs of the Santos Basin are subject of many debates concerning the sedimentology, diagenesis, and current fluid compositions (hydrocarbons, water, CO 2 ).The present study brings some new insights on (1) the origin of modern brines, (2) the spatial distribution of dissolved CO 2 integrated with the structural setting, (3) the modern diagenetic state of the reservoirs and their evolution through time due to complex fluid/rock interaction.This study integrates for the first time in this area element analysis (anions, cations, trace metals), and isotopic data (δ 18 O, δ 2 H, δ 7 Li, 87 Sr/ 86 Sr, δ 34 S SO4, δ 18 O SO4, δ 11 B), coupled with rock observations.Additionally, thermodynamic models using PHREEQC allowed (1) to compute the modern CO 2 partial pressure at reservoir conditions, and (2) to simulate the diagenetic evolution through the modelling of fluid/rock interaction.We show that fluid origins and fluid/rock interaction processes can be similar at basin scale.It also shows that isotopic equilibriums are reached for some isotopes (δ 7 Li, 87 Sr/ 86 Sr, δ 34 S SO4 ) with minerals of host formations.Very high

The utility of CRISPR-Cas9 to repair or reverse diseased states that arise from recent genetic mutations in the human genome is now widely appreciated. The use of CRISPR to "design" the outcomes of biology is challenged by both specialized ethicists and the general public. Less of a focus, however, is the ability of CRISPR to provide metabolic supplements or prophylactic molecules that improve long-term human health by overwriting ancient evolutionary events. Here, we use CRISPR to genomically integrate a functional uricase gene that encodes an enzymatically active protein into the human genome. These uricase-producing cells are able to reduce or even eliminate high concentrations of exogenous uric acid despite the enzyme being localized to peroxisomes. Our evolutionary engineered cells represent the first instance of the primate ape lineage expressing a functional uricase encoded in the genome within the last 20 million years. We anticipate that human cells expressing uricase will help prevent hyperuricemia (including gout) as well as hypertension and will help protect against fatty liver disease in the future.

Abstract Native hydrogen (H2) may represent a new carbon free‐energy resource, but to date there is no specific exploration guide to target H2‐fertile geological settings. Here, we present the first soil gas survey specifically designed to explore H2 migration in a region where no surface seepage has been documented so far. We choose the Pyrenean orogenic belt and its northern foreland basin (Aquitaine, France) as a test site for our strategy. The presence of mantle rocks at shallow depth (<10 km depth) under the Mauléon Basin connected to the surface by major faults is considered as preliminary requisites for H2 generation and drainage. On this basis, more than 1,100 in situ soil gas analysis (H2, CO, CO2, CH4, H2S, and 222Rn) were performed at ∼1 m depth at the regional scale along a 10 × 10 km grid spanning over 7,500 km2. The analysis campaign reveals several areas of high occurrence to the north of the Mauléon Basin where H2, CO2, and 222Rn concentrations exceed 1,000 ppmv, 10 vol%, and 50 kBq m−3, respectively. Most of these hot spots are located along the North Pyrenean Frontal Thrust and other related faults rooted in the mantle body. These results, together with evidence from the literature of fluid migration at depth, suggest that H2 may be sourced from mantle rocks serpentinization and carried to the surface along major thrusting faults. Traps containing hydrogen remain unidentified up to now but the presence of salt‐related structures (diapirs) near these hot spots is considered encouraging.

Native hydrogen (H 2 ) is usually considered as a possible energy resource for the development of a carbon-free society. Throughout the world, and since more than one century, lots of natural H 2 -bearing seepages have been discovered [1, 2], but to date, neither nor any resource assessment exist, as practical guidelines for hydrogen targeting are still missing. Here, we propose of a new exploration prospection strategy dedicated to native H 2 , using the Pyrenean orogenic belt and its northern foreland basin as a playground for the implementation of a regional campaign of soil gases analysis. Pyrenean geological setting represents a promising framework to investigate the potential of a native H 2 system because all the fertile conditions of production, migration, and trapping have been identified. Indeed, the North-Western Pyrenees and especially the Mauléon Basin, are characterized by the occurence of a massive fresh mantle body located under favorable P-T conditions (<10 km depth) allowing serpentinization processes. This crustal-scale architecture is also prone to drain deep-seated fluids along major faults suggested by geophysical data. Hydrogen traps remain poorly described and understood, but the presence of salt-related structures (domes and diapirs) and flysch correspond to lithologies that could play this role. Based on geophysical, geological and seismic datasets, we carried out a large campaign of soil gas analyses (H2, CO2, CH4, 222 Rn, He) at the regional scale measured in the soil (mostly grassland). More than 1,100 in situ gas analyzes were carried out

Summary In the URG, the terminal Jurassic and Cretaceous formations are missing. It remains uncertain whether their absence is related to a sedimentary hiatus or a period of erosion. The geochemical analyses of the Jurassic outcrops of Pechelbronn area show that the Mesozoic formations are immature. It suggests that these deposits were not sufficiently buried before the Cretaceous. By using molecular markers, vitrinite reflectance, kinetic properties of source rocks, artificial maturation and 1D thermal basin models, we can estimate a maximum paleo-burial, evaluate the heat flux and simulate the oil generation.

Ancestral sequence reconstruction provides a unique platform for investigating the molecular evolution of single gene products and recently has shown success in engineering advanced biological therapeutics. To date, the coevolution of proteins within complexes and protein-protein interactions is mostly investigated in silico via proteomics and/or within single-celled systems. Herein, ancestral sequence reconstruction is used to investigate the molecular evolution of 2 proteins linked not only by stabilizing association in circulation but also by their independent roles within the primary and secondary hemostatic systems of mammals. Using sequence analysis and biochemical characterization of recombinant ancestral von Willebrand factor (VWF) and coagulation factor VIII (FVIII), we investigated the evolution of the essential macromolecular FVIII/VWF complex. Our data support the hypothesis that these coagulation proteins coevolved throughout mammalian diversification, maintaining strong binding affinities while modulating independent and distinct hemostatic activities in diverse lineages.

The Limagne Basin (Massif Central, France) originated during a major, European-scale, extensive event (European Cenozoic Rift System), which led to the formation of several rift systems in the foreland of the Alps between the Upper Eocene and Pliocene. A fluvio-lacustrine system emplaced in the basin and resulted in a mixed carbonate-siliciclastic sedimentation in which microbial and metazoan buildups occupy an important place. However, microbial deposits are not exclusive to the Cenozoic history of the Limagne Basin; nowadays, in the basin, they still form in association with thermal spring systems. A fieldtrip was carried out in the Limagne Basin as part of the Microbialites: formation, evolution and diagenesis (M-Fed) meeting (October 2019). The objective of this excursion was to assess the diversity of modern and fossil (Chattian to Aquitanian) microbial sediments and structures in three prime locations (the Jussat and Chadrat outcrops and the Grand Gandaillat quarry). A detailed description of the morphologies and fabrics of the buildups and their associated biotic components can be used to discuss the spatio-temporal distribution pattern. Different basin margin models are proposed based on the changes in the distribution, morphology and size of the microbial and metazoan-rich deposits through time. The Jussat outcrop offers novel perspectives to unravel the evolution of the lacustrine/palustrine cycles over time and to establish a long-term paleoenvironmental history of the western margin of the basin during the Aquitanian. These cycles are composed of (i) lacustrine sedimentation comprising microbial and metazoan buildups and organic matter-rich marls reflecting a period of high accommodation, and (ii) palustrine deposits made of mudstones and clayey paleosoils, indicative of a period of low accommodation. It is suggested that climatic, tectonic, volcanic and local parameters (physiography, substrate) control the deposition of the buildups in each of the different cycles. In addition, the modern microbial mats of the Sainte-Marguerite and La Poix outcrops offer an opportunity to constrain the controlling processes at the origin of the mineralization involved in the formation of the microbialites and their preservation in the fossil record.