Summary The Tietê River is an anthropogenically disturbed urban water body polluted by a combination of untreated domestic sewage releasing (carbon, nitrogen and phosphorus pollution) and diffuse pollution that cross São Paulo State in Southeast of Brazil. Along its course, it presents contrasting sites showing elevated levels of nutrients and contaminants (eutrophic sites) and oligotrophic environments, in both water and sediments. In this study, we investigated how pollution influences the taxonomic and functional diversity of microbial communities in the Tietê River watershed, with the aim of understanding their role in pollutant transformation during downstream transport. Four sampling sites along a pollution gradient—from São Paulo city to a relatively pristine area near the river mouth—were evaluated. Results indicated that diversity differences were primarily linked to water quality, with higher diversity observed in less contaminated sites. Heterotrophic metabolism was more prominent in polluted regions, whereas photoautotrophic and lithotrophic microorganisms were more abundant in clean areas. Additionally, genes associated with the metabolism of aromatic compounds and virulence factors were more prevalent in environments with higher anthropogenic influence, suggesting a functional shift geared toward environmental adaptation and bioremediation. We propose that, in areas with high organic matter concentrations, microbial communities tend to adopt an r-strategy lifestyle, characterized by rapid growth and reproduction, while in oligotrophic, less polluted sites, more competitive k-strategists predominate. Although the following hypothesis was not extensively studied, the lower abundance of genes involved in secondary metabolic synthesis in eutrophic sites suggests that pollution may reduce the availability of novel species or traits relevant for biotechnological applications. Additionally, community shifts appear to be influenced by "conditionally rare taxa," which temporarily alter their activity and abundance in response to environmental constraints, playing a critical role in water self-purification processes. Overall, these findings offer new insights into the environmental factors driving self-purification in the Tietê River and shed light on the ecological mechanisms underpinning river resilience.

Context Soil degradation and water scarcity pose critical challenges for vineyard sustainability in semi-arid regions. Objectives This study evaluates the long-term effects of spontaneous cover cropping (CC) on soil health in a rainfed vineyard in central Spain, managed without irrigation or pesticides for over two decades. Methodology By comparing soils under CC and conventional tillage (TILL), we assessed changes in soil physical properties (porosity and water retention), nutrient content, and microbial function up to 30 cm depth. Stepwise regression analysis was used to explore management-driven relationships among CC, soil properties and nutrient dynamics. Results Soils under CC showed significantly higher organic matter content (1.74 ± 0.37% in the topsoil with CC vs. 0.83 ± 0.24% in TILL) and porosity (51.2 ± 2.5% vs. 44.0 ± 1.8% at 10–30 cm depth). Available phosphorus tended to be higher under CC (19.13 ± 0.60 mg/kg in CC vs. 14.13 ± 4.52 mg/kg in TILL), and this trend was further supported by stepwise analysis, which identified P availability as a variable influenced by management practices. Enzymatic activities were consistently elevated under CC, particularly in the topsoil; β-glucosidase (25 ± 9 mU/g) nearly doubled the value observed under tillage. Although soil water availability showed a non-significant trend in the topsoil (10 cm), it was higher in the subsoil (30 cm) under CC (29.0 ± 0.97% vs. 25.1 ± 0.32% in TILL). The stepwise regression analysis supported a management-driven model where CC influence soil organic matter (SOM) and nutrient availability. SOM and soil moisture strongly influenced extractable phosphorus (R² = 0.790, p =0.0047) and mineral nitrogen (R² =0.907, p =0.00018), with moisture at the time of sampling emerging as the dominant driver of nitrogen dynamics. Conclusions The analysis supports a management-driven pathway in which long-term vegetation inputs under CC enhance SOM accumulation. Soil water availability tended to increase in the subsoil under CC, while SOM together with short-term moisture conditions emerged as the main regulators of nutrient dynamics under semi-arid conditions. Implications By aligning ecological processes with practical agronomic outcomes such as nutrient retention and soil structure, these findings offer compelling evidence to support the broader adoption of sustainable ground cover practices in Mediterranean viticulture.

Multi-contaminants in road runoff of a compact city: Characteristics, interactions, and ecological risks.

Laser direct infrared (LDIR) spectroscopy reveals microplastic sorting and risk evolution in a subtropical river-estuary-coastal continuum: Insights on risk assessment.

Mechanical properties and cementation components of particulate tailings after bio-grouting: Insight on calcium carbonate and organic matter content

Carbon cycling across coastal soft sediments: the contribution of macrofaunal communities to seafloor respiration.

The lunar surface soil (regolith) represents a potential substrate for crop cultivation in future extraterrestrial bases. However, the absence of indigenous microbial activity severely limits nutrient availability in lunar soil. In this study, the effects of three commercial microbial fertilizers on improving simulated lunar soil and promoting lettuce (Lactuca sativa L.) growth were experimentally evaluated. The results showed that microbial fertilizers significantly increased the contents of available nutrients (N, P, and K) and organic matter in simulated lunar soil, thereby enhancing lettuce growth and biomass accumulation. Compared with the treatment without adding microbial fertilizer application (CK), the aboveground and belowground fresh weights of lettuce increased by up to 91.61% and 89.08%, respectively, under the microbial fertilizer MLQ treatment. In addition, microbial fertilizer treatment increased nutrient accumulation and photosynthetic pigment contents in lettuce, alleviated oxidative stress by improving antioxidant system performance, and consequently enhanced lettuce quality. High-throughput sequencing analysis further revealed that the dominant bacterial genera under these conditions were Bacillus, Glutamicibacter, Acetobacter, Enterococcus, and Microbacterium, while the dominant fungal genera included Saccharomyces, Pichia, and Trigonopsis. These findings provide theoretical support for the development of functional microbial fertilizers tailored for simulating lunar soil.

Rapid methods for the quantification of ingested nano-and microplastics in marine fish by imaging flow cytometry.

Enhancing 1O2 pathway via ultrasound-coupled iron-carbon activated persulfate for improving sludge dehydration and reducing antibiotics mutagenicity.

Electrokinetic mobilization of PFAS in soils: Linking head group and chain length to remediation efficiency.

Methodological advancements in soil erosion: a meta-analysis of organic matter content and erosion in the Mediterranean region

Effects of land use changes on soil organic matter content and speciation in volcanic soils of southern Chile

Improved estimation of soil organic matter content in the Yellow River delta using spectral data optimization and environmental variables integration

Physiological and transcriptomic responses of a harmful algal bloom-causing dinoflagellate Karenia mikimotoi to multiple environmental factors.

Technical and economic feasibility of composting recalcitrant olive oil industry wastes for the production of organic amendments and bio-based fertilisers.

Mechanisms of phosphorus release from coastal sediments driven by organic matter enrichment at high nitrogen concentrations.

Monoculture and mixed sowing are common practices for restoring degraded alpine meadow grasslands. To investigate the effects of different sowing patterns on soil bacterial community characteristics in alpine artificial grasslands, this study examined a 20-year-old established artificial grassland, systematically analyzing plant community attributes, soil physicochemical properties, and the diversity and functional structure of soil bacterial communities under various monoculture and mixed-sowing treatments. The results showed that: (1) Mixed-sowing treatments significantly improved soil physicochemical properties and plant community characteristics. The P4 (Elymus nutans + Poa pratensis + Festuca sinensis + Poa crymophila) mixed-sowing treatment notably enhanced vegetation performance and soil conditions. Compared with the monoculture P1 (Elymus nutans) treatment, aboveground biomass (AGB) and soil organic matter (SOM) content increased by 57.23% and 68.25%, respectively, indicating that perennial grass mixtures improve soil water and nutrient retention, thereby promoting plant growth. (2) Microbiome analysis revealed that mixed sowing significantly optimized the structure of rhizosphere bacterial communities. Operational Taxonomic Units (OTUs), which represent sequence-based taxonomic units and their abundance information, were most abundant in the P4 mixed-sowing treatment, reaching a total of 5685 OTUs. In terms of bacterial diversity indices, the OTU richness, Ace index, and Chao1 index in the P4 mixed-sowing treatment were 26.12%, 25.81%, and 24.34% higher, respectively, than those in the monoculture P1 treatment, with all differences being statistically significant (p < 0.05). (3) Mantel test and redundancy analysis (RDA) revealed that soil electrical conductivity (SEC) and pH were negatively correlated with bacterial diversity indices, while soil organic matter (SOM) was identified as the key environmental driver shaping bacterial community assembly. In summary, appropriate grass mixtures effectively enhance “plant–soil–microbe” interactions, leading to improved soil fertility and optimized bacterial communities, representing a viable strategy for long-term ecological restoration and sustainability of alpine artificial grassland ecosystems. The P4 treatment—comprising a four-species mixture of Elymus nutans, Poa pratensis, Poa crymophila, and Festuca sinensis—achieved the best overall performance.

ABSTRACT This study evaluates the influence of hydrothermal carbonization (HTC) conditions on the chemical composition and quality of sugarcane bagasse-based hydrochars, with potential relevance for agricultural applications. A limitation in current literature is the lack of detailed assessments of HTC operating conditions when organic matter quality is the primary focus. Sugarcane bagasse was subjected to HTC using a combined 3² × 2¹ experimental design, varying reaction time (10, 12, and 14 h), temperature (180, 190, and 200 °C), and reaction medium (H₂O and HNO₃ 0.1 mol L⁻1). Hydrochar yield, organic matter (OM), total organic carbon (TOC), and atomic ratios (H/C and O/C) were determined. Structural and chemical features were evaluated by FTIR and SEM, while Py-GC/MS was applied to investigate molecular composition, with emphasis on compounds associated with plant growth. Principal component analysis (PCA) was used to correlate chemical profiles with hydrochar quality. Hydrochars produced in acidic medium exhibited lower yields but higher OM and TOC contents compared to those obtained in water, indicating enhanced carbon concentration. FTIR results suggested progressive biomass carbonisation, whereas SEM revealed marked surface modifications, including fibre grooving, reduced interstitial material, and increased surface area under more severe HTC conditions. Py-GC/MS revealed distinct chemical profiles, with higher concentrations of bioactive compounds in acid-assisted treatments. PCA indicated that reaction medium and temperature were the dominant factors controlling organic matter transformation, followed by residence time. Overall, HTC conditions strongly influenced hydrochar chemical quality, and samples A/200/12 and A/200/14 exhibited the most favourable combination of quality-related chemical indicators.

Global agriculture faces a critical paradox: the need to increase food production while drastically reducing its environmental impact. The Brazilian sugarcane-energy industry, responsible for over 40% of global ethanol production, exemplifies this dilemma by generating over 200 billion liters annually of vinasse, an effluent with high pollution potential. Anaerobic digestion stands out as a technology with high potential to transform this environmental liability into a circular bioeconomy asset. Anaerobic digestion is a mature and highly efficient technology, removing up to 87.6% of Chemical Oxygen Demand (COD) and yielding methane of 243 NmL CH4 g CODr−1 (69% of the theoretical value). The resulting digestate, or biodigested vinasse, acts as a high-value biofertilizer, significantly improving organic matter content, soil physical structure, microbial activity and diversity, while reducing greenhouse gas emissions by at least 48% compared to the application of raw vinasse. This practice aligns with multiple Sustainable Development Goals (SDGs), including SDG 2 (Zero Hunger and Sustainable Agriculture), SDG 7 (Affordable and Clean Energy), SDG 12 (Responsible Consumption and Production), SDG 13 (Climate Action), and SDG 15 (Life on Land). The valorization of vinasse through biodigestion is an essential and urgent strategy for the sustainability of the sugarcane-energy sector, promoting resource use efficiency, reducing chemical inputs, and contributing to global climate change mitigation goals.

The growing accumulation of coal beneficiation waste represents a significant environmental and technological challenge while simultaneously creating opportunities for the resource recovery within circular economy frameworks. This study presents the development and process-oriented evaluation of an environmentally safe technology for converting coal beneficiation waste into potassium humate, with the simultaneous recovery of molybdenum compounds via alkaline extraction. The proposed solution is designed to improve resource efficiency, reduce the volume of waste directed to landfilling, and generate a high value-added product for agricultural and technological applications. The process flow includes preliminary characterization and preparation of the waste, determination of moisture, ash, and organic matter content, and the separation of metal-bearing fractions. Alkaline extraction was carried out using potassium hydroxide under controlled temperature and reaction time conditions, followed by purification and concentration of the humate solution. The process management strategy focuses on optimizing key technological parameters, including alkali concentration, solid-to-liquid ratio, temperature, and reaction time, to maximize humate yield while preserving functional groups responsible for biological activity. Comprehensive physicochemical, thermal, and mineralogical analyses confirmed the stability of the aluminosilicate matrix and the suitability of the material for alkaline processing without adverse structural degradation. Biological tests using oat (Avena sativa) demonstrated that potassium humate derived from coal beneficiation waste exhibits higher growth-stimulating effectiveness than a conventional commercial humate. Economic analysis revealed a strong correlation between humic acid content and added value, confirming the feasibility of transforming coal beneficiation waste from an environmental burden into a valuable secondary resource.