Mobility Of Elements Research Articles

Agro-ecological processes under conditions of biogeochemical imbalance of molybdenum in agrolandscapes of the Forest-Step zone

A special place in the theory and practice of landscape geochemistry belongs to biogeochemical zoning. Biogenic migration of substances and chemical elements can rightfully be considered one of the criteria for the typological classification of geochemical landscapes, which is the basis for building a map of geochemical landscapes of Ukraine. The scientific result of zoning is the recognition of spatial boundaries and areas of the territory consisting of connected components with uniform conditions of geochemical migration of chemical elements. With a long-term violation of the ratio between microelements, various diseases appear, which are called endemic, and the phenomenon itself — biogeochemical endemics. The latter most often occur due to a lack or excess of some threshold value of the concentration of microelements or a violation of the ratio of other micro­elements associated with it. On the basis of landscape-geochemical analysis and zoning, the authors defined the territory of the biogeochemical provinces of the Forest Steppe, where a lack of molybdenum content in the soil for normal plant development was found. In addition, the features of the molybdenum province are determined by low biogenic accumulation and intensive physicochemical dispersion of essential trace elements, increased mobility of most toxic trace elements in natural waters, and the absence of conditions for the formation of barriers of hydroamphoteric elements, including Mo2+. Also, in the territories of biogeochemical provinces, there is a high probability of the development of certain endemic phytopathologies and microelement diseases due to the imbalance of biogeochemical food chains.

Geochemistry and mineralogy of legacy tailings under a composite cover

Remediation by a composite cover was implemented on partly oxidized sulfide-rich tailings in northern Ontario, Canada to reduce the production and release of acid mine drainage (AMD). The impact of the cover on sulfide oxidation rates and trace element mobility was initiated a decade after cover installation via multi-year measurements of pore-gas concentrations, pore-water and groundwater sampling and analysis, mineralogical studies of the tailings, selective chemical extractions, and synchrotron-based X-ray absorption experiments. Depleted pore-gas O2 concentrations, circumneutral pH, and improvement in water quality were observed at one detailed sampling location, suggesting that the cover decreased AMD generation and transport. Carbon and sulfur isotope ratios indicate sulfate reduction occurred at the base of the tailings. In contrast, near-atmospheric pore-gas O2 concentrations, low pH, and elevated aqueous concentrations of Fe, sulfate, Zn, Cu, As, and Pb were observed at another location, suggesting localized sulfide oxidation. Trace elements in the tailings are associated with secondary crystalline and amorphous Fe(III) oxyhydroxides, covellite, and Fe(III) hydroxysulfate phases, formed prior to cover installation. Substantial reductive dissolution of Fe(III) oxyhydroxides due to the isolation of the tailings from the atmosphere by the cover was not observed. Concentrations of Zn and Mn remained elevated due to limited sequestration under the current acidic to circumneutral pH. Although secondary Fe(III) oxyhydroxides contain As(V) and As(III), which were released by arsenopyrite oxidation, dissolved As persists. Due to localized sulfide oxidation, element remobilization, and limited capacity for sulfate reduction, diminished water quality, with elevated aqueous concentrations of sulfate, Zn, As, and Mn, may endure.

Enabling Smart Agriculture through Sensor-Integrated Microfluidic Chip to Monitor Nutrient Uptake in Plants

The soil microenvironment greatly influences a plant’s ability to absorb nutrients and germinate. Sensing these changes in soil medium is critical to understand plant nutrient requirements. Soil being dynamic represents changes in nutrient content, element mobility, texture, water-holding capacity, and microbiota which affects the nutrient levels. These minor changes affect the plant in early growth and development and studying these changes has always been challenging. Microfluidics provides a platform to study nutrient availability and exchange in small volumes of liquid or media resembling plant microenvironments. Here, we have developed a novel microfluidic chip-embedded molecular imprinted sensor for sensing nitrate and phosphate in the media. For data acquisition and recording we have implemented a potentiostat controlled via a microcontroller allowing data storage and transfer via a long-range radio module (LoRA). The microfluidic device’s functionality was validated by germination of the legume crimson red and recoding the nitrate and phosphate levels in media for 7 d. The MIP-based sensor measures nitrate and phosphate, in the range from 1 to 1000 mM. The accuracy of detection for nitrate and phosphate showed 99% and 95% respectively. The chip coupled with MIP based sensor for nutrient analysis serves as a platform technology for studying nitrate and phosphate nutrient exchange and interaction. This chip in the future can be implemented to study plant deficiencies, drought resistance, and plant immunity.

The trace element distribution in peat soils affected by natural burning events: A proxy of the original composition and metals mobility assessment

This work evaluates for the first time the effects on the trace element composition of peat soils affected by natural burning events, a recurrent phenomenon in the reclaimed wetland of the Mezzano Lowland (Padanian plain, NE Italy). The trace element distribution of two neighboring soil profiles, one pristine and one deeply affected by burning events, were compared to identify the original geochemical fingerprint of saltmarsh peat environment. The pre-combustion composition of the fired profile was reconstructed to infer the physico-chemical changes occurred as a consequence of the burning event, with a special attention to the mobility of elements of environmental concern, such as potentially toxic trace metals. The increase in concentration of potentially toxic elements (PTE) was particularly evident in two layers of the fired profile. V, Cr, Cu, Zn, Pb, and As contents progressively increase toward intermediate depths (30–75 cm) together with Th, Sr, Ba, U. On the contrary, Tl, Bi and Cd show a concentration peak in a thin, shallower (14–17 cm depth) horizon. The trace element composition of the unfired profile allowed the identification of specific ratios between immobile elements that can be used as geochemical fingerprint of the soils horizons with different soil organic matter (SOM) content. On the basis of Sr/Rb, Th/U and Ba/Sr it was possible to classify three types of sedimentary deposits characterizing both the unfired and fired profile, as well as to delineate the fire severity trends occurred in the different soil horizons of the fired profile. The distribution of immobile trace element, representative of the organic (U) and mineral (silicate, Th, Ba, REE and non-silicate, Sr) soil fractions with organic matter and bulk density in the non-fired profile, allowed the reconstruction of the original physico-chemical composition of the fired/burned profile and the accurate determination of the relative CO2 lost during the burning event. Moreover, the distribution of PTE with respect to immobile trace elements, used to estimate the element redistribution and mobility after burning in the fired profile, suggested that elements such as Cr, Ni, Zn, V were mainly immobile, whereas Pb, Mo and in particular Tl and Bi suffered a significant redistribution along the burned profile. Nonetheless, results of the gain/loss calculation for the whole soil profile suggested that no significant entry or leak of these elements occurred, limiting their redistribution inside the investigated soil system.

Transposable elements differ between geographic populations of the Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae).

Agricultural insect herbivores show a remarkable ability to adapt to modern agroecosystems, making them ideal for the study of the mechanisms underlying rapid evolution. The mobilization of transposable elements is one mechanism that may help explain this ability. The Colorado potato beetle, Leptinotarsa decemlineata, is a highly adaptable species, as shown by its wide host range, broad geographic distribution, and tolerance to insecticides. However, beetle populations vary in insecticide tolerance, with Eastern US beetle populations being more adaptable than Western US ones. Here, we use a community ecology approach to examine how the abundance and diversity of transposable elements differs in 88 resequenced genomes of L. decemlineata collected throughout North America. We tested if assemblages and mobilization of transposable elements differed between populations of L. decemlineata based on the beetle's geography, host plant, and neonicotinoid insecticide resistance. Among populations of North American L. decemlineata, individuals collected in Mexico host more transposable elements than individuals collected in the United States. Transposable element insertion locations differ among geographic populations, reflecting the evolutionary history of this species. Total transposable element diversity between L. decemlineata individuals is enough to distinguish between populations, with more TEs found in beetles collected in Mexico than in the United States. Transposable element diversity does not appear to differ between beetles found on different host plants, or relate to different levels of insecticide resistance.

Improving plant availability of recycled phosphorus with organic acids

Increasing the efficiency of phosphorus (P) use through nutrient circularity is essential for securing P sufficiency and reducing pollution. The release of P in recycled materials can be enhanced with organic acids produced from cellulose. In this study, fertilisers based on sewage sludge (SS) and poultry manure (BR) were treated with increasing levels (0 %, 8 %, and 20 %) of hydroxy carboxylic and carboxylic acid mixture to determine the effect of acidification on the availability of P and other selected elements. According to sequential extractions, acidification increased the share of labile P in both products. In SS, which was dominated by refractory metal phosphates, a higher acid dose was required for the effect, and a smaller share of total P was transformed than in the BR, which was already rich in easily accessible P. Besides P, acidification increased the mobility of several elements but induced no harmful element accumulation in ryegrass leaves. The increased P lability recorded by fractionation in SS was reflected in ryegrass P uptake, cumulative yield, apparent P recovery, and mineral-P equivalence. In BR exhibiting superiority to mineral P, the effect of acidification on plant growth and P uptake was negative. Acidification treatment offers an option to enhance the plant availability of circular P, but the treatment needs to be tailored according to product characteristics. Optimising the application rate and acid composition might allow increasing effectiveness while avoiding negative growth effects.

Compost, plants and endophytes versus metal contamination: choice of a restoration strategy steers the microbiome in polymetallic mine waste

Finding solutions for the remediation and restoration of abandoned mining areas is of great environmental importance as they pose a risk to ecosystem health. In this study, our aim was to determine how remediation strategies with (i) compost amendment, (ii) planting a metal-tolerant grass Bouteloua curtipendula, and (iii) its inoculation with beneficial endophytes influenced the microbiome of metal-contaminated tailings originating from the abandoned Blue Nose Mine, SE Arizona, near Patagonia (USA). We conducted an indoor microcosm experiment followed by a metataxonomic analysis of the mine tailings, compost, and root samples. Our results showed that each remediation strategy promoted a distinct pattern of microbial community structure in the mine tailings, which correlated with changes in their chemical properties. The combination of compost amendment and endophyte inoculation led to the highest prokaryotic diversity and total nitrogen and organic carbon, but also induced shifts in microbial community structure that significantly correlated with an enhanced potential for mobilization of Cu and Sb. Our findings show that soil health metrics (total nitrogen, organic carbon and pH) improved, and microbial community changed, due to organic matter input and endophyte inoculation, which enhanced metal leaching from the mine waste and potentially increased environmental risks posed by Cu and Sb. We further emphasize that because the initial choice of remediation strategy can significantly impact trace element mobility via modulation of both soil chemistry and microbial communities, site specific, bench-scale preliminary tests, as reported here, can help determine the potential risk of a chosen strategy.

Changes of wettability of shale exposed to supercritical CO2-water and its alteration mechanism: Implication for CO2 geo-sequestration

The wettability of shale are the key factors determining the shale gas production efficiency and CO2 storage safety. However, the effects of the supercritical CO2 (ScCO2)-water-shale interactions on the wettability in shale is unclear. To address this issue, water wettability alterations in shale at different ScCO2-water exposure pressure and temperature conditions were evaluated based on a nuclear magnetic resonance (NMR) test method, and the mineral composition, element mobilization and pore of shale were analyzed to interpret the alterations. After ScCO2-water exposure, the water wettability of shale was reduced, and the reduction enhanced with the increase of exposure pressure while weakened with the increase of exposure temperature. The weakening of water wettability in shale is closely related to the exposure pressure and temperature dependent mineral and pores alteration in shale. ScCO2-water exposure induced the increase in the content of hydrophobic quartz, and the decrease in the contents of hydrophilicity clay and carbonate minerals, leading to the weakening of water wettability in shale. In addition, the micro and mesopores gradually transfer to larger pores after ScCO2-water exposure, reducing capillary pressure and the hydrophilicity of shale, also responsible for the decrease of water wettability in shale. The weakening of water wettability may enhance the sweep efficiency of CO2 in shale reservoirs or reduce the capillary trapping capacity of CO2 when shale served as caprocks. Thus, this study contributes to the evaluation of CO2 storage capacity and security in shale reservoirs.

Relationship between physical, mechanical and thermal properties of flexible chain polymers

The results of the study on the relationship between the physical, mechanical and thermal properties of linear flexible polymers due to the harmonic and anharmonic components of the interatomic and intermolecular interaction force are presented. Using the example of polyvinyl chloride (PVC), polyvinyl butyral (PVB), polystyrene (PS), it is shown that in the region of 300 K < = T < = 400 K, the relaxation state of the system is realized due to the mobility of the structural elements, which makes it possible to apply the terms of thermodynamics and statistics of small systems to the properties of the material, and to treat the polymeric state as a special form of condensation of matter. The quantitative relationship between the properties of systems has been established, which is of interest for creating scientific foundations for predicting, obtaining and operating materials under the action of external fields of various nature.

Big geochemical data through remote sensing for dynamic mineral resource monitoring in tailing storage facilities

Evolution in geoscientific data provides the mineral industry with new opportunities. A direction of geochemical data generation evolution is towards big data to meet the demands of data-driven usage scenarios that rely on data velocity. This direction is more significant where traditional geochemical data are not ideal, which is the case for evaluating unconventional resources, such as tailing storage facilities (TSFs), because they are not static due to sedimentation, compaction and changes associated with hydrospheric and lithospheric processes (e.g., erosion, saltation and mobility of chemical constituents). In this paper, we generate big secondary geochemical data derived from Sentinel-2 satellite-remote sensing data to showcase the benefits of big geochemical data using TSFs from the Witwatersrand Basin (South Africa). Using spatially fused remote sensing and legacy geochemical data on the Dump 20 TSF, we trained a machine learning model to predict in-situ gold grades. Subsequently, we deployed the model to the Lindum TSF, which is 3 km away, over a period of a few years (2015-2019). We were able to visualize and analyze the temporal variation in the spatial distributions of the gold grade of the Lindum TSF. Additionally, we were able to infer extraction sequencing (to the resolution of the data), acid mine drainage formation and seasonal migration. These findings suggest that dynamic mineral resource models and live geochemical monitoring (e.g., of elemental mobility and structural changes) are possible without additional physical sampling.

Pangenome-level analysis of nucleoid-associated proteins in the Acidithiobacillia class: insights into their functional roles in mobile genetic elements biology.

Mobile genetic elements (MGEs) are relevant agents in bacterial adaptation and evolutionary diversification. Stable appropriation of these DNA elements depends on host factors, among which are the nucleoid-associated proteins (NAPs). NAPs are highly abundant proteins that bind and bend DNA, altering its topology and folding, thus affecting all known cellular DNA processes from replication to expression. Even though NAP coding genes are found in most prokaryotic genomes, their functions in host chromosome biology and xenogeneic silencing are only known for a few NAP families. Less is known about the occurrence, abundance, and roles of MGE-encoded NAPs in foreign elements establishment and mobility. In this study, we used a combination of comparative genomics and phylogenetic strategies to gain insights into the diversity, distribution, and functional roles of NAPs within the class Acidithiobacillia with a special focus on their role in MGE biology. Acidithiobacillia class members are aerobic, chemolithoautotrophic, acidophilic sulfur-oxidizers, encompassing substantial genotypic diversity attributable to MGEs. Our search for NAP protein families (PFs) in more than 90 genomes of the different species that conform the class, revealed the presence of 1,197 proteins pertaining to 12 different NAP families, with differential occurrence and conservation across species. Pangenome-level analysis revealed 6 core NAP PFs that were highly conserved across the class, some of which also existed as variant forms of scattered occurrence, in addition to NAPs of taxa-restricted distribution. Core NAPs identified are reckoned as essential based on the conservation of genomic context and phylogenetic signals. In turn, various highly diversified NAPs pertaining to the flexible gene complement of the class, were found to be encoded in known plasmids or, larger integrated MGEs or, present in genomic loci associated with MGE-hallmark genes, pointing to their role in the stabilization/maintenance of these elements in strains and species with larger genomes. Both core and flexible NAPs identified proved valuable as markers, the former accurately recapitulating the phylogeny of the class, and the later, as seed in the bioinformatic identification of novel episomal and integrated mobile elements.

The Polycomb repressive complex 2 deposits H3K27me3 and represses transposable elements in a broad range of eukaryotes

The mobility of transposable elements (TEs) contributes to evolution of genomes. Their uncontrolled activity causes genomic instability; therefore, expression of TEs is silenced by host genomes. TEs are marked with DNA and H3K9 methylation, which are associated with silencing in flowering plants, animals, and fungi. However, in distantly related groups of eukaryotes, TEs are marked by H3K27me3 deposited by the Polycomb repressive complex 2 (PRC2), an epigenetic mark associated with gene silencing in flowering plants and animals. The direct silencing of TEs by PRC2 has so far only been shown in one species of ciliates. To test if PRC2 silences TEs in a broader range of eukaryotes, we generated mutants with reduced PRC2 activity and analyzed the role of PRC2 in extant species along the lineage of Archaeplastida and in the diatom P.tricornutum. In this diatom and the red alga C.merolae, a greater proportion of TEs than genes were repressed by PRC2, whereas a greater proportion of genes than TEs were repressed by PRC2 in bryophytes. In flowering plants, TEs contained potential cis-elements recognized by transcription factors and associated with neighbor genes as transcriptional units repressed by PRC2. Thus, silencing of TEs by PRC2 is observed not only in Archaeplastida but also in diatoms and ciliates, suggesting that PRC2 deposited H3K27me3 to silence TEs in the last common ancestor of eukaryotes. We hypothesize that during the evolution of Archaeplastida, TE fragments marked with H3K27me3 were selected to shape transcriptional regulation, controlling networks of genes regulated by PRC2.

Carbon effect on thermo-kinetics of Co-Cr-Fe-Mn-Ni high entropy alloys: A computational study validated by interdiffusion experiments

Interstitial alloying is nowadays an important direction for further developments of High Entropy Alloys. In this work, the impact of interstitial carbon on the thermodynamics–kinetics coupling in CoCrFeMnNi-based HEAs is studied through CALPHAD and continuum approaches. First, purely thermodynamic characteristics (phase diagrams and chemical potentials) are calculated. Then purely kinetics properties, i.e., carbon-content dependent mobilities of substitutional elements are modeled, based on experimental data. Consequently, a continuum model is applied to combine these properties in order to simulate interdiffusion in carbon-free/carbon-bearing HEA couples, underlining mutual influence of carbon and matrix elements diffusion on each other. The results are benchmarked against the experimental composition profiles and a very good agreement is observed, specially when carbon effect for all elements is explicitly included. A non-monotonous dependence of the chromium up-hill diffusion on the carbon content is explained by a strong thermodynamic interaction between carbon and chromium elements.

GEMAS: Chemical weathering of silicate parent materials revealed by agricultural soil of Europe

The chemical composition of soil represents to a large extent the primary mineralogy and geochemistry of the source bedrock, the effects of pre- and post-depositional weathering and element mobility, either by leaching or mineral sorting with the addition of secondary products such as clays. Agricultural soil in Europe (0–20 cm, 33 countries, 5.6 million km2) was sampled during the continental-scale soil mapping project (GEochemical Mapping of Agricultural and grazing land Soil - GEMAS). Total element concentrations were determined by wavelength dispersive X-ray fluorescence spectrometry. Bulk content of major elements (SiO2, TiO2, Al2O3, Fe2O3, MgO, CaO, Na2O, K2O, P2O5) in soil has been used to calculate weathering indices such as chemical index of alteration (CIA), reductive and oxidative mafic indices of alteration (MIA), the change in mass balance (τ calculation relative to immobile Nb) for soil derived from silicate bedrocks (granite, gneiss and schist) at the European continental-scale, which are useful tools for evaluating chemical weathering trends.The greatest variation of CIA values is exhibited by soil derived from granite, followed by soil derived from schist. The CIA results show clearly that Ca and Na are removed from agricultural soil (0–20 cm) during soil development. Geographical distribution of weathering indices shows that weak chemical weathering of agricultural soil samples, sourced from gneissic and granitic bedrock, occurs in the Fennoscandian Shield; intermediate chemical weathering in granite, schist and gneiss occurring in the Iberian Peninsula and France, and intense chemical weathering in schist sourced agricultural soil occurring in areas with intense rainfall and moderate temperature (Wales, England, Ireland and western Iberia). In addition, values of CIA and MIA, higher than those for standard rock compositions, suggest more active enrichment/depletion processes during soil formation and subsequent soil weathering/maturation.The range of the elemental mass transfer coefficient τ is wide for agricultural soil derived from gneiss and granite, and narrow for agricultural soil sourced from schist parent rocks. The weathering behaviour of chemical elements, assessed by using the τ mass transport model, suggests an order of susceptibility of K ≈ Na > Al > Fe > Ca > Mg > Ti.Weathering indices and gain-loss mass transfer coefficients, tested on agricultural soil samples, provide an insight to the weathering processes affecting the silicate parent rocks and their impact on soil development at the European scale. This can have further implications for evaluation of soil nutritional conditions and mitigating of soil erosion and deprivation.

How does nickel (Ni) modify two-dimensional black phosphorus to enhance its electrochemical lithium storage performance?

Recently, two-dimensional black phosphorus has shown very high potential for electrochemical lithium storage by virtue of its excellent properties. However, the defects of low electronic conductivity of two-dimensional black phosphorus itself and the tendency of volume expansion during charging and discharging also limit its development in the field of energy storage. In order to achieve better lithium storage performance, two-dimensional black phosphorus modified with Ni element was prepared by solvothermal synthesis in this study, and the high electron mobility of Ni element was used to modify the material. The synthesized material retained the morphology and properties of two-dimensional black phosphorus and its lithium storage performance were enhanced with excellent long cycling and rate performance. It had a first charge/discharge specific capacity of 651.58 mAh g−1 and 963.72 mAh g−1 at a current density of 0.1 A g−1, after which we constructed an approximate model of the material by calculation. The results of the band gap indicated that the conductivity of the material is enhanced, and the results of the lattice constant indicate that the problem of volume expansion of the system is improved. This study lays the foundation for future theoretical and practical applications of two-dimensional black phosphorus.

Pyrite stability and chalcophile element mobility in a hot Eocene forearc of the Pacific Rim Terrane, Vancouver Island, Canada

Pyrite stability and chalcophile element mobility in a hot Eocene forearc of the Pacific Rim Terrane, Vancouver Island, Canada

Features of the development of a unique legume-rhizobium symbiosystem under conditions of metal-induced stress

The development of legume-rhizobium symbiosystems based on the mutant pea genotype SGECdt (Pisum sativum L.) and its wild line SGE grown on a medium supplemented with toxic concentrations of Cd and Co was evaluated under the conditions of a summer greenhouse experiment. Plants were inoculated with a consortium of endomycorrhizal fungus Glomus sp.1Fo, nodule bacteria Rhizobiom leguminosarum bv. viciae and associative ACC-utilizing rhizobacteria Variovorax paradoxus 5C-2. Heavy metals significantly inhibited the growth of uninoculated and inoculated wild line SGE plants compared to SGECdt plants. The content of Cd in the shoots of plants of both genotypes increased in the presence of a toxic concentration of Co, while the latter, on the contrary, decreased. The same effect persisted after inoculation with microorganisms. The introduction of microbes leveled the toxic effect of heavy metals and increased the biomass in both pea genotypes in the absence of the introduction of heavy metals. The microbial consortium also contributed to an increase in the transport of biophilic microelement antagonists to the aerial organs of the pea. In general, based on the results of fractal calculation, despite growth inhibition, the wild line showed higher values of the degree of organization of microelements inside shoots and seeds than the mutant genotype. The stagnation or decrease in the microelement bioconsolidation indices in the homeostasis of shoots of the mutant line can probably be interpreted by the redistribution of the supply of food sources between the partners of the symbiostem, in favor of microsymbionts. An increase in the indicators of the bioconsolidation index in seeds can be considered a positive effect, since the best mobilization of trace elements in their cotyledons, in addition to increasing the germination energy of the offspring, will favorably affect the increase in the adaptive potential of plants.

New data on mobility of transuranium elements in sediments of the Yenisei River

The inflow of transuranium elements to the Yenisei River was previously associated with the production of weapons-grade plutonium at the Mining-and-Chemical Combine (MCC, Zheleznogorsk, Russia), but the source of transuranium elements in the River today is fabrication of MOX fuel that started recently at the MCC. The current study presents results of sequential chemical extraction of radionuclides from sediment samples collected in 2014 and 2020 in two areas near the MCC discharge site and compares these results with the data obtained previously by sequential extraction of sediments collected during 1999–2007. Over the study period, the strength of binding of 137Cs and 60Co in the Yenisei River sediments was high (up to 100%) and remained so, while the percentages of 241Am and 152Eu in residual solids after sequential extraction increased considerably and the percentage of 239,240Pu in residual solids decreased in samples from all study areas. In samples collected at the position located close to the MCC discharge site, the percentages of the strongly bound 241Am and 152Eu as well as 239,240Pu were lower than in the samples from the other positions. The study demonstrated an enormous increase in 239,240Pu activity concentration in the top sediment layers collected at all positions in 2020 relative to 2014. In the same period, as literature data suggest, 239,240Pu activity concentrations also increased in aquatic organisms of the Yenisei River, which can be indicative of the growing potential bioavailability of plutonium in the aquatic ecosystem, which could be caused by the presence of the mobile form of plutonium in the routine discharges from the MCC.

Downregulation of transposable elements extends lifespan in Caenorhabditis elegans

Mobility of transposable elements (TEs) frequently leads to insertional mutations in functional DNA regions. In the potentially immortal germline, TEs are effectively suppressed by the Piwi-piRNA pathway. However, in the genomes of ageing somatic cells lacking the effects of the pathway, TEs become increasingly mobile during the adult lifespan, and their activity is associated with genomic instability. Whether the progressively increasing mobilization of TEs is a cause or a consequence of ageing remains a fundamental problem in biology. Here we show that in the nematode Caenorhabditis elegans, the downregulation of active TE families extends lifespan. Ectopic activation of Piwi proteins in the soma also promotes longevity. Furthermore, DNA N6-adenine methylation at TE stretches gradually rises with age, and this epigenetic modification elevates their transcription as the animal ages. These results indicate that TEs represent a novel genetic determinant of ageing, and that N6-adenine methylation plays a pivotal role in ageing control.

Impure CO2 storage reactions of sandstone, mudstone and carbonate cemented cores: Experimental CO2 SO2 NOX O2 reaction metal mobilisation and fate

CO2 geological storage can be part of the solution to reduce carbon emissions to the atmosphere. An understanding of the geochemical processes occurring during CO2 storage is needed to reduce risk. Drill cores from a low salinity reservoir site proposed for CO2 storage, and the overlying and underlying formations, were characterised for minerals by QEMSCAN, total metals and porosity. Elements including Li, Ba, Sr, K, Mg, V, Zn, REE, Fe, Pb, P, and S were relatively elevated in the Moolayember Formation underlying the reservoir. Synchrotron XFM showed the main host of Mn was siderite, with Rb in K-feldspar, Zn and Cu in sphalerite and chalcopyrite, and As in pyrite in coal pores associated with coal laminations. Drill cores are reacted at reservoir conditions with synthetic formation water and an impure CO2 stream composition of CO2-SOx-NOx-O2 expected to be injected at the site. Elements released were dependant on mineral content, with quartz rich reservoir, lower Precipice Sandstone core reactions resulting in dissolution of trace carbonates, alteration of sulphides and monazite, and variable elevated dissolved Pb, and U. Dissolved Co, Ni, Ca, Zn, Li, Rb, and U were released at relatively elevated concentrations from the mudstone. For carbonate cemented upper Precipice Sandstone or Moolayember Formation core strong dissolution of calcite and ankerite, with corrosion of siderite, Fe-rich chlorite, and sulphides or monazite were observed after reaction. Dissolved elements including Ca, Mg, Mn, Sr, and Ba increased in experiments from the reaction of calcite, siderite, and ankerite. Generally dissolved Fe, Pb, Cr, Cu, Co etc. increased from dissolution, and subsequently decreased in concentration with adsorption and precipitation processes. The fast mobilisation of elements including Fe and Pb are consistent with the release of metals from carbonate dissolution and desorption. The presence of O2 and NOX in the gas stream results in Fe-(oxyhydr)oxide precipitation especially where Fe has been rapidly mobilised from dissolution of siderite and Fe-chlorite. This acts as a sink for Fe and provides new adsorption sites for sequestering a proportion of the trace metals. These processes are applicable to other CO2 storage sites and potential leakage indicators in overlying drinking water aquifers. The findings are also more broadly applicable to subsurface energy storage such as compressed air renewable energy storage, CO2 enhanced recovery, geothermal, natural gas or hydrogen storage.