An anomalous warm weather event in the Antarctic McMurdo Dry Valleys on 18 March 2022 created an opportunity to characterize soil biota communities most sensitive to freeze-thaw stress. This event caused unseasonal melt within Taylor Valley, activating stream water and microbial mats around Canada Stream. Liquid water availability in this polar desert is a driver of soil biota distribution and activity. Because climate change impacts hydrological regimes, we aimed to determine the effect on soil communities. We sampled soils identified from this event that experienced thaw, nearby hyper-arid areas, and wetted areas that did not experience thaw to compare soil bacterial and invertebrate communities. Areas that exhibited evidence of freeze-thaw supported the highest live and dead nematode counts and were composed of soil taxa from hyper-arid landscapes and wetted areas. They received water inputs from snowpacks, hyporheic water, or glacial melt, contributing to community differences associated with organic matter and salinity gradients. Inundated soils had higher organic matter and lower conductivity (p < .02) and hosted the most diverse microbial and invertebrate communities on average. Our findings suggest that as liquid water becomes more available under predicted climate change, soil communities adapted to the hyper-arid landscape will shift toward diverse, wetted soil communities.

Evaluating petroleum contamination risk and implementing remedial measures in agricultural soil rely on indicators such as soil metal(loid)s and microbiome alterations. However, the response of these indicators to petroleum contamination remains under-investigated. The present study investigated the soil physicochemical features, metal(loid)s, microbial communities and networks, and phospholipid fatty acids (PLFAs) community structures in soil samples collected from long-(LC) and short-term (SC) petroleum-contaminated oil fields. The results showed that petroleum contamination increased the levels of soil total petroleum hydrocarbon, carbon, nitrogen, sulfur, phosphorus, calcium, copper, manganese, lead, and zinc, and decreased soil pH, microbial biomass, bacterial and fungal diversity. Petroleum led to a rise in the abundances of soil Proteobacteria, Ascomycota, Oleibacter, and Fusarium. Network analyses showed that the number of network links (Control vs. SC, LC = 1181 vs. 700, 1021), nodes (Control vs. SC, LC = 90 vs. 71, 83) and average degree (Control vs. SC, LC = 26.244 vs. 19.718, 24.602) recovered as the duration of contamination increased. Petroleum contamination also reduced the concentration of soil PLFAs, especially bacterial. These results demonstrate that brief exposure to high levels of petroleum contamination alters the physicochemical characteristics of the soil as well as the composition of soil metal(loid)s and microorganisms, leading to a less diverse soil microbial network that is more susceptible to damage. Future research should focus on the culturable microbiome of soil under petroleum contamination to provide a theoretical basis for further remediation. (c) 2025 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

Lead (Pb), a prevalent heavy metal contaminant in aquatic environments, has complex effects on the gut microbiome function of aquatic animals. In this study, metagenomic analysis of Bufo gargarizans tadpoles was carried out following Pb exposure. Moreover, histological analysis was performed on the intestines. The results showed that Pb exposure induced histological damage to the intestinal epithelium. Significant differences in microbial abundance and function were detected in the 200 mu g/L Pb group compared to the control group. Specifically, an increase in Bosea and Klebsiella was noted at 200 mu g/L Pb, which potentially could induce inflammation in tadpoles. Notably, the decrease in the abundance of glycoside hydrolases subsequent to exposure to 200 mu g/L Pb is likely to attenuate carbohydrate metabolism. Furthermore, increased fluoroquinolone-related antibiotic resistance genes (ARGs), phenolic-related ARGs, and iron uptake systems following 200 mu g/L Pb exposure might heighten the disease risk for tadpoles. These discoveries augment our comprehension of the influences of Pb on the intestinal well-being of amphibians and offer valuable insights for further assessment of the ecological risks that Pb poses to amphibians.

The environmental prevalence of the tire wear-derived emerging pollutant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q) has increasingly raised public concern. However, knowledge of the adverse effects of 6PPD-Q on soil fauna is scarce. In this study, we elucidated its impact on soil fauna, specifically on the earthworm Eisenia fetida. Our investigation encompassed phenotypic, multi-omics, and microbiota analyses to assess earthworm responses to a gradient of 6PPD-Q contamination (10, 100, 1000, and 5000 mu g/kg dw soil). Post-28-day exposure, 6PPD-Q was found to bioaccumulate in earthworms, triggering reactive oxygen species production and consequent oxidative damage to coelomic and intestinal tissues. Transcriptomic and metabolomic profiling revealed several physiological perturbations, including inflammation, immune dysfunction, metabolic imbalances, and genetic toxicity. Moreover, 6PPD-Q perturbed the intestinal microbiota, with high dosages significantly suppressing microbial functions linked to metabolism and information processing (P < 0.05). These alterations were accompanied by increased mortality and weight loss in the earthworms. Specifically, at an environmental concentration of 6PPD-Q (1000 mu g/kg), we observed a substantial reduction in survival rate and physiological disruptions. This study provides important insights into the environmental hazards of 6PPD-Q to soil biota and reveals the underlying toxicological mechanisms, underscoring the need for further research to mitigate its ecological footprint.

The efficacy and environmental effects of using metal-organic frameworks (MOFs) for the remediation of arsenic (As)-contaminated soil, a significant global problem, remain unclear. This study evaluated MIL-88A(Fe) and MIL101(Fe) coupled with ramie (Boehmeria nivea L.) for As-contaminated soil remediation. A soil incubation experiment revealed that 10,000 mg kg-1 MIL-88A(Fe) and MIL-101(Fe) reduced As bioavailability by 77.1 % and 65.0 %, respectively, and increased residual As fractions by 8 % and 7 % through Fe-As co-precipitation and adsorption. Divergent environmental effects emerged, which were probably due to differences in the framework structures and organic ligands: MIL-88A(Fe) improved soil urease activity and bacterial diversity, whereas MIL101(Fe) induced acidification (decreasing soil pH by 25 %) and salinity stress (elevating soil electrical conductivity (EC) by 946 %). A pot experiment showed that 1000 mg kg-1 MOFs enhanced ramie biomass via As immobilization, whereas 5000 mg kg-1 MIL-101(Fe) suppressed growth because exposure to the MOF caused root damage. The MOFs enriched Pseudomonas (As-oxidizing) and suppressed Dokdonella (pathogenic), enhancing plant resilience. Notably, 100 mg kg-1 MIL-101(Fe) increased As translocation to stems (14.8 %) and leaves (27.6 %). Hydroponic analyses showed that 50-200 mg L-1 MIL-101(Fe) mitigated As-induced chlorophyll degradation (elevating Soil and plant analyzer development (SPAD) by 12.8 %-28.3 %), whereas 500 and 1000 mg L-1 induced oxidative stress (reducing SPAD by 4.2 %-10.7 %). This study provides valuable insights into using Fe-based MOFs in soil remediation and highlights their beneficial and harmful effects.

Understanding how land cover and seasonal variations influence soil microbial communities and nutrient cycling is crucial for sustainable land management in tropical forests. However, such investigations are limited in Madagascar's tropical ecosystems. This study investigated the impacts of land cover types and seasonal variations on soil properties and microbial communities in the tropical forest region of Andasibe, Madagascar. Soil samples were collected from four land cover types-tree fallow (TSA), shrub fallow (SSA), eucalyptus forest (EUC), and degraded land (TM)-across three seasonal periods: the dry season, the start of the rainy season, and the end of the rainy season. Both land cover and sampling season affected soil pH and available P, whereas total nitrogen, soil organic carbon, and the C/N ratio were affected only by land cover. The soil organic carbon and total nitrogen concentrations were greater in TM. NextSeq sequencing of the 16S rRNA gene and ITS regions of the nuclear rRNA operon revealed distinct microbial community compositions across land covers, with greater diversity in the TSA and SSA. Bacteria are more sensitive to seasonal changes than are fungi, with phosphate-solubilizing (gcd) and phosphate-mineralizing (phoD) genes being more abundant in the rainy season, emphasizing the role of microbes in nutrient availability under different climatic conditions. Principal component analysis highlighted SSA as a hotspot for microbial activity, reinforcing the potential of shrub ecosystems in soil restoration. These findings reveal strong land cover and seasonal effects on soil microbial functions, with implications for nutrient cycling, ecosystem resilience, and sustainable land management in tropical forest landscapes.

Global warming has led to permafrost thawing in mid-latitude alpine regions, resulting in greater availability of carbon (C) and nutrients in soils. However, how these changes will impact the functional genetic potential of permafrost soil microbiomes, and subsequently, how they will influence the microbially mediated feedback of mountain soils under climate change remains unknown. To help answer this question, we conducted a permafrost thawing experiment on the north-facing slope near the summit of Muot da Barba Peider (2979 m above sea level) in the Swiss Alps. Specifically, we transplanted permafrost soils from a depth of 160 cm to the active-layer topsoils (0-18 cm) and incubated the soils in situ for three years. Using shotgun metagenomics, we found that transplantation significantly altered the gene structure of the permafrost microbiome, with changes occurring in the short term (< one year) and remaining stable over time. Transplanted soils exhibited an enhanced functional genetic potential, particularly for genes related to Information storage and processing, Cellular processes and signaling and Metabolism functions, which suggests increased cellular processes and metabolism. Carbohydrate-active enzymes involved in the degradation of both labile (such as starch) and recalcitrant (such as lignin) C substrates were enriched in transplanted soils, indicating an enhanced C-degradation potential. Nitrogen (N)-cycling genes related to the degradation and synthesis of N compounds, denitrification, assimilation and dissimilatory nitrate reduction were overrepresented in the transplanted soil, pointing to enhanced N assimilation and transformation potential. Our study elucidates how the permafrost microbiome may functionally respond to warming in the European Alps. This research complements observations from Tibetan and Arctic regions, improving our understanding of functional changes in thawing permafrost globally.

This study investigates the role of arbuscular mycorrhizal fungi (AMF) in the metabolism of hexabromocyclododecane (HBCD) and its ecological effects in contaminated environments. We focused on the symbiotic relationships between Iris pseudacorus L. and AMF (Rhizophagus irregularis) under HBCD exposure. Our results show that HBCD induces oxidative damage, which hinders plant growth. However, AMF significantly enhance the plant's antioxidant defenses, reducing oxidative damage and supporting better growth of I. pseudacorus. HBCD biodegradation patterns showed beta- > gamma- > alpha-HBCD, with AMF playing a key role in stabilizing rhizosphere microbial communities, particularly promoting Proteobacteria and potential bacterial degraders like Aeromonas and Trichococcus, which contributed to HBCD removal. Additionally, AMF appear to upregulate genes such as cypD_E, GST, dehH, dehA, dehM, Em3.8.1.2, and ligB, which are involved in debromination and hydroxylation reactions. This research highlights AMF's potential to enhance the phytoremediation of HBCD, providing valuable insights for environmental remediation strategies.

Background and AimsMicroorganisms are essential for carbon and nitrogen cycling in the active layer of permafrost regions, but the distribution and controlling factors of microbial functional genes across different land cover types and soil depths remain poorly understood. This gap hinders accurate predictions of carbon and nitrogen cycling dynamics under climate change. This study aims to explore how land cover type and soil depth influence microbial functional gene distribution in the Qinghai-Tibet Plateau's permafrost regions.MethodsSoil samples (0-50 cm) were collected from alpine wet meadows, alpine meadows, and alpine steppes. We analyzed the samples for physicochemical properties, microbial amplicon sequencing, and metagenomic sequencing. Correlation analyses were conducted between microbial community structure, functional genes, and environmental factors to identify the drivers of microbial carbon and nitrogen cycling.ResultsBacterial richness was 6.03% lower in steppe soils compared to wet meadow soils. Steppe soils exhibited the highest aerobic respiration potential, while deeper wet meadow soils had enhanced anaerobic carbon fixation potential and a higher abundance of carbon decomposition-related genes. Nitrogen assimilation was highest in steppe surface soils, whereas denitrification and ammonification were greatest in wet meadow soils. Carbon cycling potential was influenced by total soil carbon, nitrogen, phosphorus, and belowground biomass, while nitrogen cycling was driven by belowground biomass, soil moisture, and pH.ConclusionOur findings underscore the role of environmental factors in microbial functional gene distribution, providing new insights for modeling carbon and nitrogen cycling in alpine permafrost ecosystems under climate change.

Tire wear particles (TWPs) attract attention because of their harmful impact on the soil ecosystem. Nevertheless, there is limited understanding regarding how aging affects the toxicity of TWPs to soil microorganisms. Herein, a microcosm experiment was performed to compare the toxicity of pristine and UV-aged TWPs on the soil microbial community. After 28 days operation, more holes and cracks appeared on the surface of the UV-aged TWPs compared with the pristine TWPs. The diversity and community structure of soil microorganisms changed under the pristine and UV-aged TWPs exposure, with the UV-aged TWPs significantly altered nirK-type soil denitrifying bacteria. Streptomyces played an important role in connecting the nirK-type bacterial community and promoting the denitrification process under the UV-aged TWPs exposure. The soil microorganisms further promoted the membrane transport of metabolites to resist the toxic effects of UV-aged TWPs by up-regulating the ATP-binding cassette (ABC) transporters, which consumed lots of energy and led to interference in energy metabolism. Furthermore, UV-aged TWPs further stimulated the accumulation of reactive oxygen species (ROS), stimulated the soil microorganisms to secrete more extracellular polymers substances (EPS) and activated the antioxidant defense system against oxidative damage caused by UV-aged TWPs, however, the activation of SOS response in turn increased the risk of antibiotic resistance genes (ARGs) transmission.