The study explores the vertical stratification of microbial diversity and metabolic potential in Earth’s lower atmosphere. Using 16S rRNA sequencing data spanning the planetary boundary layer to the lower stratosphere, we conducted taxonomic profiling and metabolic pathways predictions. The aim was to elucidate microbial community dynamics and their ecological roles under diverse atmospheric conditions. Methods: 51 Publicly available datasets with 3584 samples were retrieved from repositories such as Sequencing Read Archive and European Nucleotide Archive, filtered for studies employing 16S rRNA sequencing. Quality control was performed using FastQC and Trimmomatic, followed by taxonomic classification with Qiime2 and the Silva132 database. Functional pathway predictions were derived using PICRUSt2, and statistical analyses included Kruskal-Wallis tests for diversity comparisons and Mann-Whitney U tests for pathway activity. Results: Microbial diversity decreased with altitude, with the Surface Layer exhibiting the highest Shannon diversity and the significantly decreased in Low Stratosphere. Taxonomic composition shifted along the elevation gradient, with Actinobacteria and Alphaproteobacteria predominant at lower altitudes. In contrast, Bacilli and Gammaproteobacteria became more dominant at higher elevations, though they maintained a notable presence at lower sites as well. Functional analysis revealed altitude-specific adaptations, including significant upregulation of CO2 fixation pathways in the Free Troposphere Transition Layer and secondary metabolite biosynthesis in the lower stratosphere. Discussion: These findings reveal distinct microbial metabolic profiles across atmospheric layers with varying conditions such as oxygen levels, UV radiation, and nutrient availability. While these differences may represent adaptive strategies, they could also reflect source environment characteristics or selective transport processes. The conserved metabolic pathways across altitude layers suggest functional resilience despite taxonomic divergence. These results have implications for astrobiology, providing analogs for microbial life in extraterrestrial environments like Mars or Europa. In summary, this study advances our understanding of aerobiomes’ ecological roles and their potential as models for life detection in extreme environments, bridging atmospheric microbiology with astrobiological exploration.

Five specimens of the rare alpheid shrimp Betaeus levifrons Vinogradov, 1950 were collected from the burrows of the mud-shrimp Upogebia major (De Haan, 1841) in Akkeshi and Usu Bays, along the Pacific coast of Hokkaido, Japan. As B. levifrons has been previously only reported from the Russian coast of the Sea of Japan, the Hokkaido specimens represent the first record of this species from the western Pacific coast as well as a new to the Japanese fauna. Ovigerous females of B. levifrons were recorded for the first time based on specimens. This study provides additional data on this species, including its distribution, colour variation, and DNA sequences of the mitochondrial 16S rRNA and cytochrome c oxidase subunit I barcoding regions. Lastly, we revised the available data on the symbiotic fauna of U. major.

Quantifying snow water equivalent (SWE) with ground-penetrating radar (GPR) in a warming climate is complicated by the incidence and variability of liquid water in snow. Snow surveys conducted during the melt season serve as a valuable analog to conditions under future warming. Here, we determine the variability of wet snowpack properties (relative permittivity and density) to quantify their impact on SWE estimates using GPR. We collected spatially continuous snowpack measurements with 400 MHz GPR in 2012 and 2021 across repeat transects (∼150 km each year) along with spring and summer snow depth and density measurements from snow pits and snow cores. Snow relative permittivity values ranged from 2.06 to 2.62 in 2012 and 2.11 to 5.11 in 2021, resulting in calculated volumetric liquid water content (LWC) between 1.7% and 5.7% in 2012 and 2.1% and 16% in 2021. This variability in snow relative permittivity results in SWE uncertainties of 8% —33%, with more extreme cases reaching 13%—45%. We attribute this uncertainty to spatial and temporal variability in LWC when using GPR to estimate SWE. As snowpacks become wetter with rising atmospheric temperatures, GPR surveys should include in situ relative permittivity measurements to reduce depth and SWE interpretation uncertainties.

We present analyses of bubble number-density (BND) data from the South Pole Ice Core (SPC14) showing warming of ∼7.5°C from the Late Glacial (∼19.5 ka), then relatively stable temperatures during the Holocene (<0.5°C warming), in close agreement with results of independent paleothermometers. The BND data span from ∼160 m just below pore close-off, to ∼1200 m, where bubble loss by clathrate formation is significant. Measurements were made with standard bubble ‘thick’-section techniques and a new application of three-dimensional micro-computed tomography (CT) imagery; the nearly identical results recommend the faster, nondestructive micro-CT. The very high BND at South Pole, typically 800 and 900 bubbles cm−3, reflects the joint effects of the relatively low mean-annual temperature (−49°C) and high accumulation rate (∼7.5 cm w.e. a−1). High BND is physically linked to small grain sizes at pore close-off, which in turn helps explain the near-absence of brittle-ice behavior at the site, contributing to the high quality of the recovered core with implications for siting of future ice cores. The accumulation history, derived from δ15N-N2 firn-column thickness estimates, correlates with the temperature history but varies somewhat more than saturation vapor pressure, suggesting dynamic controls including upstream slope variability.

This letter to the editor explores the importance of a just transition for waste pickers in the context of the global plastics treaty. It sets out ideas for just transition at the level of production reduction, replacements and substitutes, systems change and waste management.

A key challenge in advancing slushflow management is the limited record of past incidents. Identifying their starting points and enhancing the quality of slushflow documentation are important in order to improve the regional early warning and develop slushflow numerical runout models and susceptibility maps. Here we investigate three major slushflow events at Kistrandfjellet, northern Norway and quantify the differences between registered slushflows in the national rapid mass movement database and the actual events. We use unique image datasets from the events in February 2021, January 2023 and January 2024, and identify slushflow starting points and flow paths. The curvature of the starting point locations is examined to assess how local topography influences slushflow release at the field site. Our mapping reveals 25 slushflows across the three events, whereas only five were registered in the database. For the 2021 event, we found six times as many slushflows as were officially registered. Comparison of our mapped slushflows to modeled drainage pathways and FKB-Vann (the official surface water dataset of Norway), yielded an average overlap of 35%. To improve slushflow management, we recommend establishing a standardized protocol for future data collection.

A clay from Weslatiya that is widely used in Tunisian ceramic production has abundant reserves but generates significant waste, posing environmental concerns if not handled appropriately. This study explores the valorization of this local clay by incorporating ceramic waste (chamotte) and quartz sand to produce eco-friendly materials, in line with sustainability and circular economy principles. X-ray diffraction and scanning electron microscopy analyses reveal that incorporating chamotte at levels exceeding 15% by weight improves the material’s properties. The Young’s modulus of the composite increases to 80 GPa, more than 2.5 times that of the basic clay. Chamotte can replace up to 30% of quartz sand without significantly affecting densification or porosity while preserving structural integrity. This approach offers flexibility in terms of material composition, enhancing performance and promoting sustainability by reusing waste materials for high-performance ceramics in industrial applications.

Bentonite is mined globally for use in commercial and industrial applications. In these applications, smectite content and composition are the paramount factors of the bentonite material and control its properties. As bentonite composition and properties can vary significantly over a large mining district or within a single mine, quality control is required including: mineral composition, especially smectite content; cation exchange capacity (CEC); exchangeable cation composition; and smectite crystallochemical features. Differences in bentonite composition locally or over a spatial area stem from the different geological settings present throughout bentonitization. The study aims were to: (1) determine the layer charge (LC) variation of dioctahedral smectite over the Bavarian mining district and within individual mines in the area; and (2) assess the error in smectite content calculations based on CEC data resulting from the actual range of experimentally determined LC values. This information has been missing in the scientific literature, as previous LC methods were laborious or subject to assumptions, making a comprehensive study over a large spatial area impractical. This study employed the use of the recently developed efficient and precise spectroscopic ‘O-D method’, which enabled the LC measurement of 40 samples from eight mines in the Bavarian bentonite mining district, covering an area of 250 km2, within the North Alpine Foreland Basin. Results showed LC values calibrated against the alkylammonium method (LC (AAM)) generally ranged between 0.29 and 0.30 eq per formula unit (FU), with only 10% of samples showing LC values >0.31 eq/FU. This narrow LC range has positive implications for the accuracy of determining smectite content calculated from CEC data, during routine quality control of Bavarian and other bentonites. The average error of the CEC-based smectite contents resulting from LC variations was, on average, ±3 wt.%.

Ferroåkermanite, Ca2FeSi2O7 – a new member of the melilite group, has been found in coarse-grained kirschsteinite-bearing paralava in the Hatrurim Basin outcrop between the Zohar and Halamish Wadies of the Hatrurim Complex in Israel. Ferroåkermanite rarely forms single subhedral light-yellow crystals up to 30–50 μm in size with a prismatic habit. The most common are irregular grains, aggregates and intergrowths with gehlenite or ferroåkermanite crystals with perovskite inclusions. The mineral is transparent, exhibits vitreous lustre and has a distinct cleavage on (001). It is non-fluorescent, brittle and has a conchoidal fracture, a Mohs hardness of ∼4.5–5 and a calculated density of 3.20 g/cm3. Ferroåkermanite is uniaxial (–), ω = 1.652(3) and ε = 1.643(3) (λ = 589 nm), and exhibits a visible pleochroism from light-yellow (ω) to intense yellow (ε). The empirical formula of ferroåkermanite calculated on the basis of 7 O is (Ca1.77Na0.18Sr0.02Ba0.02K0.02)Σ2.01(Fe2+0.68Al0.28Mg0.04)Σ1.00(Si1.93Al0.07)Σ2.00O7. The chemical data obtained confirm the presence of ferroåkermanite–gehlenite solid solution (Fe2+ + Si4+ ↔ 2Al3+) in the studied rock, which was verified by Raman spectroscopy investigation. The crystal structure of the new mineral was refined to R = 0.0617 in the space group P$\overline4$21m with the following unit-cell parameters a = 7.7813(7) Å, c = 5.0114(5) Å, V = 303.43(6) Å3, Z = 2. Ferroåkermanite has a melilite-type structure with layers consisting of (Si2O7)6– disilicate units and (Fe2+O4)6– tetrahedra intercalated by layers formed of eightfold-coordinated Ca atoms. Moreover, the T1 site in the holotype specimen shows a mixed occupancy refined to 0.63(3) Fe2+ and 0.37(3) Al. The presence of rock-forming minerals such as gehlenite or rankinite suggests that the paralava analysed formed under high-temperature conditions, confirming that the new mineral ferroåkermanite is indeed a high-temperature phase. Furthermore, the presence of Fe2+-bearing phases, such as kirschsteinite, ferroåkermanite, chromite, ulvöspinel and bennesherite indicates the reduced conditions.

Effective performance of oil-based drilling fluids (OBFs) in demanding high-temperature environments hinges on the stability of their rheological properties. However, conventional organoclays (OCs) utilized to control these properties often exhibit thermal degradation at elevated temperatures, necessitating the development of more robust alternatives. Therefore, the present study aimed to develop a high-temperature-resistant OC to enhance OBF rheological stability. To address the thermal instability issues of conventional quaternary organo-montmorillonites (OMts), which manifest as interlayer structural collapse and particle aggregation, an innovative dual modification strategy was developed through the synergistic combination of quaternary ammonium intercalation and silane grafting. Montmorillonite (Mnt) was modified with dioctadecyl dimethyl ammonium chloride (1821) and stearyl dimethyl benzyl ammonium chloride (1827) at a mass ratio of 2:1 to yield 1821+1827-OMt, which was subsequently further modified with dodecyl trimethoxy silane (DTMS) to form 1821+1827+DTMS-OMt. Comparison of the properties of 1821+1827-OMt and 1821+1827+DTMS-OMt after high temperatures revealed the following. (1) Thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis and gel volume tests demonstrated that the Si–O–Si bonds in 1821+1827+DTMS-OMt were thermally stable up to ~440°C, and the gel volume of the 1821+1827+DTMS-OMt suspension remained stable at 100 mL following high-temperature aging treatments. (2) X-ray diffraction and elemental analysis revealed that 1821+1827+DTMS-OMt exhibited a larger basal spacing and larger nitrogen content compared with ungrafted 1821+1827-OMt. (3) The suspension containing 1821+1827+DTMS-OMt demonstrated enhanced thermal stability at 260°C, evidenced by its narrower rheological parameter ranges of apparent viscosity (6–12 mPa s), plastic viscosity (5–9 mPa s), and yield point (1–3 Pa), compared with those of the suspension containing 1821+1827-OMt. (4) Optical microscopy demonstrated that 1821+1827+DTMS-OMt exhibited greater resistance to agglomeration at high temperatures than 1821+1827-OMt. The high-temperature-resistant OC developed in this study overcomes the thermal instability of traditional OCs, providing a robust approach for enhancing the efficiency and reliability of oil-based drilling fluids in high-temperature drilling applications.

Here we present the first single-crystal X-ray diffraction analysis of zolenskyite, a chromium-bearing sulfide mineral (FeCr2S4) and newly identified polymorph of daubréelite, discovered in the Muonionalusta meteorite, a well-characterized IVA iron meteorite. Zolenskyite occurs as rare micron-scale grains associated closely with daubréelite and stishovite, within a troilite matrix. Chemical analysis confirms a pure, homogeneous FeCr2S4 composition. The crystal structure was refined in the monoclinic C2/m space group, revealing a framework of face-sharing octahedra, consistent with a cation-deficient NiAs-type structure, distinct from the spinel-type structure of daubréelite. Zolenskyite forms under high-pressure (>7 GPa) and high-temperature (>1000 K) conditions, probably through solid-state transformation from daubréelite during shock events. The serendipitous recognition of zolenskyite emphasizes the value of careful micron-scale mineralogical investigations in revealing transient or metastable phases that record otherwise inaccessible physicochemical conditions. These findings contribute to understanding the thermal and shock history of meteorite parent bodies and the stability of Fe–Cr sulfides in extraterrestrial environments.

Beryl crystals from hydrothermal veins in the Colombian emerald mining district, were examined to understand their growth and dissolution processes. Chemical analysis reveals minor substitution of Al by Na, Mg and the colouring elements V, Cr and Fe. Growth features include characteristic indentations on (0001) and a ridge-and-valley structure on the second-order prism, which is also observed on rare conical growth faces. Zoning is the primary internal growth feature, investigated in cross sections parallel to the main growth directions, the a- and c-axes of beryl. All crystals show sector zoning, with enrichment of Na and Mg in the c-sector, whereas Al and most of the trace elements measured are concentrated in the a-sector. H2O and CO2 molecules in the crystal structure were identified by infrared spectroscopy. Two types of H2O are present, with the H–H vector aligned (type I) and perpendicular (type II) to the c-axis, with H2O II predominant in the c-sector. CO2 is present in both sectors, decreasing from core to rim, and is higher in the a-sector. Variable sector boundaries suggest irregular changes in the growth rate in the two growth directions. The substitution (VIMg+channelNa)c-sector = (VIAl+channel□)a-sector creates a pattern of stripes, originating at the steps of the sector boundaries. Etch pits as a result of dissolution are arranged in chains, typically forming etching channels, but the overall amount of dissolution is minor. The arrangement of the etch pits indicates that they formed on dislocation bundles, which originate at the sector boundaries. The observations indicate rapid crystallisation with skeletal growth in [0001] is responsible for the distribution of elements in sectors, and are consistent with a closed-system behaviour in the veins.

Electrum dendrites and associated minerals from the Ametistovoe Au–Ag epithermal deposit (Kamchatka) were investigated by optical and electron microscopy, X-ray computed tomography, electron microprobe and electron back-scattered diffraction techniques. Electrum forms dendrites up to 1 mm in size within sphalerite, or, rarely, within galena and chalcopyrite and random particles within quartz. The electrum has a very homogeneous composition (fineness 603 to 615) which correlates neither with the host mineral nor with the electrum morphology. X-ray computed microtomography showed electrum dendrites are 2-dimensional and consist of an acicular ‘trunk’ hosting numerous ‘branches’. 3-dimensional and ‘bush-like’ dendrites are rare. Angles between ‘trunk’ and ‘branches’ are usually 90° and less commonly, 60° suggesting twinning along (100) and (111) planes, respectively. Electron back-scattered diffraction showed the dendrites are single crystals with no defects detected, whereas electrum within quartz has a mosaic texture with low pattern quality. A model proposed for the observed phenomena includes: (1) growth of single-crystal electrum dendrites within silica gel; (2) overgrowth of dendrites by sphalerite crystals; (3) recrystallisation of the opaline silica to crystalline quartz which resulted in destruction of electrum dendrites located within silica and preservation of those hosted by sphalerite. This model proposes crystallisation of electrum dendrites from a hydrothermal solution and implies a critical role for amorphous silica gel as a precursor for dendrite formation.

The endosymbiotic association between the diatom Hemiaulus and the cyanobacterium Richelia was first observed in the Sea of Marmara in July 2021. The spatial distribution of the host diatom Hemiaulus spp. and the endosymbiont cyanobacterium Richelia intracellularis was investigated along with available physicochemical parameters. Three species of the Hemiaulus genus (H. hauckii, H. membranaceus, and H. sinensis) were morphologically identified in the study area. Hemiaulus hauckii and H. sinensis reached up to 128 × 103 cells L−1 and 38 × 103 cells L−1, respectively, while H. membranaceus was rarely observed. Each Hemiaulus cell contained one Richelia trichome, which had heterocysts at both ends. The surface water temperatures and salinity varied between 23.2°C and 28.5°C, 21.4 and 23.5, respectively. Dissolved oxygen levels ranged from 6.2 to 7.6 mg L−1, while chlorophyll-a concentrations were between 0.3 and 6.8 µg L−1. Nutrient concentrations varied between 0.05 and 0.18 μM for NO3 + NO2–N, 0.04–0.24 μM for NH4–N, 0.02–0.39 μM for PO4–P, and 0.18–1.42 μM for SiO2–Si. This study reveals that the Hemiaulus–Richelia symbiosis may promote the proliferation of diatom populations and may play an important role in nutrient dynamics in nitrogen-limiting environments and in the overall functioning of the marine ecosystem.