Search Results (1,514)

Artificial (technical) snow production is an increasingly common practice in alpine regions, yet little is known about its role in shaping microbial communities at the molecular level. In this study, we combined culture-based methods with high-throughput 16S rRNA gene sequencing and functional trait prediction (FAPROTAX) to investigate bacterial communities across the full technical snowmaking cycle in one of Polish ski resorts. The molecular profiling revealed that technical snow harbors dominant taxa with known cold-adaptation mechanisms, biofilm-forming abilities, and stress tolerance traits (e.g., Brevundimonas, Lapillicoccus, Massilia, with a relative abundance of 2.95, 2.14, 3.38 and 5.61%, respectively). Functional inference revealed a consistent dominance of chemoheterotrophy (up to 38% in relative abundance) and aerobic chemoheterotrophy (up to 36%), with localized enrichment of fermentation (6.9% in cannon filter and 6.5% in sediment) and aromatic compound degradation (3.7% in source waters, 3.8% in cannon filter and 4.6% in sediment). Opportunistic and potentially pathogenic genera (e.g., Acinetobacter, Flavobacterium, Nocardia) persisted in sediments (7.4%, 21.4% and 3.5%) and meltwater (34.9% and 2.31% for the latter two), raising concerns about their environmental reintroduction. Our findings indicate that technical snowmaking systems act as selective environments not only for microbial survival but also for the persistence of molecular traits relevant to environmental resilience and potential pathogenicity. Our study provides a molecular ecological framework for assessing the impacts of snowmaking on alpine ecosystems and underscores the importance of monitoring microbial functions in addition to taxonomic composition. Full article

Due to the rising atmospheric carbon dioxide levels driven by human activity, extensive scientific efforts have been dedicated to developing methods aimed at reducing its concentration in the atmosphere. A novel approach involves using hydrates as a long-lasting reservoir of CO₂ sequestration. This review provides an initial overview of hydrate characteristics, their formation mechanisms, and the experimental techniques commonly employed for their characterization, including X-ray, Raman spectroscopy, cryoSEM, DSC, and molecular dynamic simulation. One of the main challenges in CO₂ sequestration via hydrates is the requirement of high pressures and low temperatures to stabilize CO₂ molecules within the hydrate crystalline cavities. However, deviations from classical temperature-pressure phase diagrams observed in natural and engineered environments can be explained by considering that hydrate stability and formation are primarily governed by chemical potentials, not just temperature and pressure. Activity, which reflects concentration and non-ideal interactions, greatly influences chemical potentials, emphasizing the importance of solution composition, salinity, and additives. In this context the role of promoters and inhibitors in facilitating or hindering hydrate formation is discussed. Furthermore, the review presents an overview of the impact of marine sediments and naturally occurring compounds on CO₂ hydrate formation, along with the sampling methodologies used in sediments to determine the composition of these natural compounds. Special attention is given to the effect and chemical characterization of dissolved organic matter (DOM) in marine aquatic environments. The focus is placed on the key roles of various natural occurring molecules, such as amino acids, protein derivatives, and humic substances, along with the analytical techniques employed for their chemical characterization, highlighting their central importance in the CO₂ gas hydrates formation. Full article

Danube Delta (DD), an ecologically vulnerable site, together with fish populations, which are significant food resources, are largely exposed to heavy metal contamination. This study was developed in the Babina–Cernovca sector of DD in September 2023. Zinc (Zn), and iron (Fe) were identified in water, while copper (Cu), iron (Fe), and manganese (Mn) were in sediments (mud). Proximate composition of the muscle tissues of eight fish species identified in the area was assessed. The muscle was also tested to identify heavy metals contamination. The contamination degree was assessed using bioaccumulation and bioconcentrations factors. The relation between nutritional parameters and metals was tested using bivariate and multivariate analyses. Samples were analyzed by specific laboratory tests, and data were processed using ANOVA, Spearman correlation, Principal Component Analysis (PCA), and hierarchical clustering. S. erythrophthalmus, C. gibelio, and A. alburnus have the highest metal bioaccumulation capacity, exhibiting species-specific accumulation patterns. PCA and clustering analysis reflect the influence of species and environmental factors on heavy metal accumulation in fish tissue. The study integrates the heavy metals content with nutritional parameters in fish muscular tissue, using bivariate and multivariate analysis for assessing fish vulnerability to heavy metals exposure in the Danube River. Full article

Compression of clayey sediments not only causes land subsidence but also results in geogenic high fluoride groundwater. The distribution characteristics and enrichment mechanisms of fluoride in alluvial−lacustrine facies clayey sediments in the land subsidence area of Cangzhou Plain, China, were investigated using sample collection, mineralogical research, and hydrogeochemical and isotopic analysis. The results show that F⁻ concentration of groundwater samples ranged from 0.31 to 5.54 mg/L in aquifers. The total fluoride content of clayey sediments ranged from 440 to 792 mg/kg and porewater F⁻ concentration ranged from 0.77 to 4.18 mg/L. Clay minerals containing fine particles, such as muscovite, facilitate the enrichment of fluoride in clayey sediments, resulting in higher total fluoride levels than those in sandy sediments. The clay porewater F⁻ predominantly originated from the dissolution of water-soluble F and the desorption of exchangeable F from sediments. The F⁻ concentration in porewater was further influenced by ionic interactions such as cation exchange. The stable sedimentary environment and intense compression promoted the dissolution of F–bearing minerals and the desorption of adsorbed F in deep clayey sediments. The similar composition feature of δ²H−δ¹⁸O in deep groundwater and clay porewater samples suggests a significant mixing effect. These findings highlight the joint effects of hydrogeochemical and mineralogical processes on F behavior in clayey sediments. Full article

The main aim of this work is to define the limits of detection (LOD) and quantification (LOQ) for polyethylene (PE) particles using a pyrolysis and oxidation-based method, the thermal Rock-Eval^® device, combined with a mathematical extrapolation procedure. The influences of particle size and shape on the thermal degradation of PE polymers are also investigated in this study. Thermal Total HC and Tpeak parameters, recently used to characterize polymer samples, are evaluated as a function of both polymer grain size and shape. Results indicate a LOD for the investigated PE polymers of around 1.7–2 μg in 60 mg of composite sediment (28–33 ppm). A conservative LOQ for the PE samples ranges between 5 and 6 μg (83–100 ppm). The LOQ is on the same order of magnitude for any size or shape of the studied PE polymers. By contrast, the LOD for the PE samples is slightly affected by both the polymer grain size and shape. Results also demonstrate that it is possible to detect PE nanoparticles of 79 nm in size. Finally, this study provides specific Rock-Eval^® parameters, linear regressions, and a mathematical extrapolation procedure that can be used to better quantify very small PE mass contents, including nanoplastics in environmental samples. Full article

Geological modeling is generally based on deterministic models, which provide a single representation of reality. Probabilistic modeling is more appropriate when quantifying or understanding the uncertainty associated with a parameter of interest as it considers several equally probable geological scenarios. The object of this study is to quantify the uncertainty in the estimation of the minerals in the Punta Alegre gypsum deposit, by applying a new method based on the simple normal equation geostatistical simulation technique. The Punta Alegre gypsum deposit is a sedimentary deposit of clastic origin, formed by the complex redeposition of salts, gypsum and other sediments. To carry out this research, 50 equiprobable scenarios were simulated, reproducing overburden, gypsum series (different types of gypsum) and intercalated non-mineral lithologies (limestone and other rocks) in a network of nodes measuring 5 × 5 × 5 m, using a training image, composites and prior probability maps as input data. As a result of scaling the previously simulated geological units, three-dimensional models of volume proportions and estimation error for gypsum were obtained for panels measuring 10 × 10 × 5 m. The quantification of the uncertainty of the gypsum volume, determined by the root mean square error, established that the volume estimation error is small at a global scale (6.51%), given that there is no significant variation when comparing the deterministic model with the gypsum proportion model obtained from the 50 simulated scenarios. Conversely, at the local scale, there is a significant variation in gypsum volume of 42% in the 10 × 10 × 5 m panels with a future impact on recoverable mining resources, given the uncertainty at a local scale, which will cause an increase in mining dilution due to the inclusion of non-mineral lithologies within the extracted mineral that will be sent to the processing plant. On the other hand, it will cause changes in the mining company’s plan in areas where there are panels that were previously accounted for by the deterministic model as minerals and are not actually exploitable. Full article

The environmental fate of nickel (Ni) is dictated by its interaction with organic matter (OM), yet the specific roles of OM source and molecular size remain unclear. This study investigated the binding characteristics of Ni with size-fractionated dissolved OM (DOM) from the water column and alkaline-extractable OM (AEOM) from sediments in a tropical wetland. Using ultrafiltration and spectroscopy, we found that sedimentary AEOM was predominantly high-molecular-weight (HMW) and terrestrial compounds, whereas aquatic DOM was dominated by low-molecular-weight (LMW), microbial-derived compounds. Counterintuitively, the highest Ni binding affinity (NiBA) for both DOM and AEOM occurred in the smallest-molecular-weight fraction (<0.3 kDa). Predictive models confirmed this divergence: the model for the more chemically homogeneous AEOM was highly predictive (r = 0.89), while the model for the complex DOM was less robust (r = 0.70). Our findings demonstrate that LMW fractions are hotspots for Ni binding, challenging the common assumption that larger molecules are more reactive. We conclude that biogeochemical processing in sediments creates an OM pool that is chemically distinct and more predictable than that in the overlying water. This distinction is critical for accurately assessing Ni mobility and ecological risk in aquatic systems. Full article

This study addresses critical knowledge gaps in adobe construction by systematically investigating soil mineralogy–additive effectiveness relationships and developing dual-additive optimization strategies for flood sediment valorization. Four Thai soil types—Nakhon Pathom (NPT), Sisaket (SSK), Uttaradit (UTT), and September 2024 Chiang Rai flood sediment (CRI)—were characterized using XRD and EDS analyses. Twelve adobe formulations incorporating rice husk (3.45%) and graduated bentonite concentrations (5–15%) were evaluated for mechanical and thermal properties. UTT soil with balanced mineralogy (42.1% SiO₂, 40.4% Al₂O₃) achieved optimal mechanical performance (3.12 ± 0.11 MPa compressive strength), while CRI demonstrated superior thermal insulation (0.200 ± 0.009 W/m·K). Rice husk systematically enhanced compressive strength across all soils (13.6–82.5% improvement) while reducing thermal conductivity to 0.211–0.278 W/m·K. Dual-additive optimization of CRI enabled application-specific customization: rice husk alone maximized strength (1.34 ± 0.09 MPa), while bentonite combinations optimized thermal performance (0.199 ± 0.015 W/m·K). Microstructural analysis revealed distinct reinforcement mechanisms and matrix densification effects. This research establishes predictive frameworks for material selection based on soil composition, demonstrates viable flood waste valorization pathways, and supports Thailand’s Bio-Circular-Green economic framework through sustainable construction material development. Full article

Hydrothermal vents, widely occurring along middle-ocean ridges and volcanic arcs, have been well-studied in vent-associated microbiology, mineralogy, and geochemistry. However, there are rarely investigations regarding the detailed microbial community in the hydrothermal vent-influenced sediment. To explore hydrothermal activities on microbial diversity at the Carlsberg Ridge in the northwestern Indian Ocean, four sediment cores were sampled from the near-vent fields to distant vent sedimentary fields in the Tianxiu hydrothermal field, and the microbial community compositions were analyzed. The sediment microorganisms closest to the hydrothermal vent were primarily composed of Acidimicrobiia, Gammaproteobacteria, Anaerolineae, and Planctomycetes. The microbial communities at the depth containing extensive signals of hydrothermal activity consisted mainly of Dehalococcoidia, Aerophoria, Anaerolineae, and Gammaproteobacteria. No significant differences in microbial composition were observed between the two weak hydrothermal sediment cores, primarily composed of Nitrososphaeria, Gammaproteobacteria, Alphaproteobacteria, and Acidimicrobiia. Moreover, heterogeneous selection substantially impacted the bacterial community assembly in near-vent sediments other than stochasticity. Multivariate statistical analysis identified that environmental fluctuations accounted for 55.59% of the community variation, with hydrothermal inputs (such as Fe, Pb, Cu, and Zn) being the primary factors shaping the construction of hydrothermal sediment microbial communities. These results enhance understanding of the response of deep-sea sediments to hydrothermal activity. Full article

This study compared bacterial diversity and putative functionality between two saline lagoons, La Muerte and Salineta, in the Monegros desert ecosystem. Amplicon sequencing analysis revealed distinct taxonomic and functional patterns between the lagoons. Pseudomonadota dominated both systems, averaging 31.0% in La Muerte and 47.4% in Salineta, reflecting their well-documented osmotic stress tolerance. However, significant compositional differences were observed: Cyanobacteriota comprised 18.4% of La Muerte communities but remained below 1% in Salineta, while Bacteroidota showed higher abundance in La Muerte (16.6%) compared to Salineta (6.7%). Principal coordinate analysis demonstrated strong community differentiation between lagoons (Bray–Curtis dissimilarity p < 0.05). Functional profiling revealed contrasting metabolic capabilities: La Muerte communities showed enhanced autotrophic carbon fixation pathways (especially the Calvin–Benson cycle) and nitrogen cycling processes, while Salineta exhibited stronger denitrification signatures indicative of anoxic conditions. Carbohydrate indices suggested different organic matter quality and polymer composition between lagoons. La Muerte demonstrated significantly elevated stress response mechanisms compared to Salineta, which can be attributed to its ephemeral, shallow, and high evaporation rates that collectively generate more severe osmotic, thermal, and oxidative stress conditions for the sediment microbiota. These findings demonstrate that site-specific environmental factors, including hydroperiod variability and salinity dynamics, strongly influence microbial community structure and metabolic potential in saline wetland ecosystems. Full article

In this paper, an innovative method consisting of the construction of an artificial dune reinforced with a composite made by combining sand and seagrass wrack is presented. The performance of this reinforced dune is compared with sand-only dunes, built at the same time, through data collected during 17 field campaigns (covering a period of one year) carried out with an unmanned aerial vehicle (UAV), whose images allow digital elevation models (DEMs) to be built. The results show that, in the medium term, while the sand-only dunes lose much of their volume (up to 25% of the refilled sediment), the reinforced dune only reduces its volume by around 1.4%. In addition, the cross-shore and longitudinal profiles extracted from the DEMs of the dunes indicate that sand-only dunes greatly reduce the elevation of their crests, while the profile of the reinforced dune remains almost unchanged. This suggests that the addition of seagrass wrack can greatly contribute to increasing the resilience of restored dunes and the time between re-fillings, therefore reducing beach protection costs. However, as the results are based on a single wrack–sand dune and have not been replicated, they should be treated with caution. At the same time, this work illustrates how UAVs can acquire the data needed to map coastal restoration works in a fast and economical way. Full article

In this review paper, we briefly discuss the occurrence of oil spills and their behavior under natural sea conditions and clean-up methods, as well as their environmental and economic impacts. We discuss methodologies for oil spill modeling used to predict the fate of a spill under dynamic physical and chemical processes. Weathering processes such as evaporation, emulsification, spreading, dissolution, dispersion, biodegradation, and sedimentation are considered within easy-to-use modeling frameworks. We present simple models based on the principles of thermodynamics, mass transfer, and kinetics that under certain conditions can predict oil thickness, volume, area, composition, and the distribution of toxic compounds in water and air over time for various types of oil and their products. Modeling approaches for underwater oil jets, including applications related to the 2010 BP oil spill in the Gulf of Mexico, are reviewed. The influence of sea surface velocity and wind speed on oil spill mapping, spill location, oil spill trajectory over time, areas affected by light, medium, and heavy oil, and comparisons between satellite images and model predictions are demonstrated. Finally, we introduce several recently published articles on more recent oil spill incidents and the application of predictive models in different regions. We also discuss the challenges, advantages, and disadvantages of various models and offer recommendations at the end of the paper. Full article

The presence and accumulation of microplastics (MPs) in riverine waters have been widely documented. The sustained operation of cascade reservoirs has altered the retention characteristics of MPs in the Han River basin. In this study, the composition, sources, and ecological risks of MPs in the water column and sediments of the Han River mainstream across different periods were investigated. Results showed that the MP abundances in the water column and sediments were higher during the flood season than in the non-flood season. Additionally, MPs in the water column exhibited an increasing trend along the operational sequence of cascade reservoirs. During the flood season, polyamide (PA), polyethylene (PE), and polypropylene (PP) were the dominant MP types in the water column, while polycarbonate (PC) and PP prevailed in sediments. In the non-flood season, polyethylene terephthalate (PET) was the dominant MP type in the water column, whereas PC and PET dominated in sediments. Overall, the distribution characteristics of MPs conformed to the “upstream input-reservoir accumulation-downstream output” pattern. The pollution risk of MPs in both the water column and sediments ranged from low to moderate. These findings provide a basis for exploring the impacts of cascade reservoir operation on the characteristics of MP in water and sediments. Future research will focus on migration mechanisms of MP under the joint operation of cascade reservoirs. Full article

Integrated aquaculture, centered around polyculture involving multiple species, is a typical practice for the sustainable development of the aquaculture industry, capable of enhancing resource utilization efficiency, environmental stability, and overall productivity through establishing symbiotic interactions among species. This study employed multi-amplicon high-throughput sequencing to assess the ecological impacts of two polyculture methods involving river crabs on sediment bacteria, fungi, and protists. One method involved polyculturing river crabs with mandarin fish, silver carp, and the stone moroko (SPC), and the other involved polyculturing river crabs with only mandarin fish and silver carp (SMC). The results showed that, compared to the SMC group, the SPC group remarkably increased the Chao1 index of bacterial communities in pond sediment and decreased the Pielou_J index of protists. The relative abundances of all fungal phyla and most dominant bacterial and protistan phyla (top 10 in relative abundance) in the SPC group were considerably different from those in the SMC group. In the co-occurrence networks of bacterial, fungal, and protistan communities, the numbers of edges and nodes were higher in the SPC group than in the SMC group, and the habitat niche breadth of bacterial community was also notably increased in the SPC group. The levels of total carbon (TC), total nitrogen (TN), and phosphates within pond sediment in the SPC group were obviously lower than those in the SMC group, and were significantly correlated with the microbial communities, with TC being identified as the primary contributor driving changes in the microbial communities. All the findings collectively demonstrate that the polyculture of river crabs with mandarin fish, silver carp, and the stone moroko enhances the stability of bacterial, fungal, and protistan communities in sediment and enhances resource utilization efficiency in aquaculture, thereby preventing the environmental risks associated with excessive nutrient accumulation in sediment. Polyculture systems integrating river crabs with mandarin fish, silver carp, and the stone moroko represent a sustainable aquaculture model with significant ecological benefits. Full article

As the residual products of severe chemical weathering, bauxite deposits serve both as essential economic Al-Fe resources and geochemical archives that reveal information about the parent rocks’ composition, paleoenvironments and paleoclimates, and the tectonic settings responsible for their genesis. The well-developed Early Paleocene bauxite deposits of the Salt Range, Pakistan, provide an opportunity for deciphering their ore genesis and parental affinities. The deposits occur as lenticular bodies and are typically composed of three consecutive stratigraphic facies from base to top: (1) massive dark-red facies (L-1), (2) composite conglomeratic–pisolitic facies (L-2), and (3) Kaolinite-rich clayey facies (L-3). Results from optical microscopy, X-ray powder diffraction (XRPD), and scanning electron microscopy with Energy-Dispersive X-Ray Spectroscopy (SEM-EDS) reveal that facies L-1 contains kaolinite, hematite, and goethite as major minerals, with minor amounts of muscovite, quartz, anatase, and rutile. In contrast, facies L-2 primarily consists of kaolinite, boehmite, hematite, gibbsite, goethite, alunite/natroalunite, and zaherite, with anatase, rutile, and quartz as minor constituents. L-3 is dominated by kaolinite, quartz, and anatase, while hematite and goethite exist in minor concentrations. Geochemical analysis reveals elevated concentrations of ${\mathrm{Al}}_2$${\mathrm{O}}_3$, ${\mathrm{Fe}}_2$${\mathrm{O}}_3$, ${\mathrm{SiO}}_2$, and ${\mathrm{TiO}}_2$. Trace elements, including Th, U, Ga, Y, Zr, Nb, Hf, V, and Cr, exhibit a positive trend across all sections when normalized to Upper Continental Crust (UCC) values. Field observations and analytical data suggest a polygenetic origin of these deposits. L-1 suggests in situ lateritization of some sort of precursor materials, with enrichment in stable and ultra-stable heavy minerals such as zircon, tourmaline, rutile, and monazite. This facies is mineralogically mature with bauxitic components, but lacks the typical bauxitic textures. In contrast, L-2 is texturally and mineralogically mature, characterized by various-sized pisoids and ooids within a microgranular-to-microclastic matrix. The L-3 mineralogy and texture suggest that the conditions were still favorable for bauxite formation. However, the ongoing tectonic activities and wet–dry climate cycles post-depositionally disrupted the bauxitization process. The accumulation of highly stable detrital minerals, such as zircon, rutile, tourmaline, and monazite, indicates prolonged weathering and multiple cycles of sedimentary reworking. These deposits have parental affinity with acidic-to-intermediate/-argillaceous rocks, resulting from the weathering of sediments derived from UCC sources, including cratonic sandstone and shale. Full article