Environmental Research最新文献

The spatial patterns of dissolved organic matter (DOM) in the Three Gorges Reservoir (TGR) are highly heterogeneous, yet how land use regulates these patterns across different spatial scales remains poorly understood. In this study, we characterized DOM composition and optical properties in the mainstem and representative tributaries of the TGR. After rigorous False Discovery Rate (FDR) correction, most bulk DOM optical properties did not show statistically significant differences between the two systems, suggesting a macroscopic homogenization. Model selection based on the Akaike Information Criterion corrected for small sample sizes (AICc), however, revealed distinct scale-dependent associations: the mainstem DOM was optimally explained by broader-scale land use (500 m buffer), whereas the tributary DOM was highly sensitive to local-scale land use (100 m buffer). In the tributaries, agricultural runoff strongly enhanced DOM aromaticity, whereas urban impervious surfaces reduced it. This macroscopic homogenization is likely driven by the massive water volume and longer hydraulic retention time of the mainstem, which buffer and dilute these localized inputs. Collectively, these findings demonstrate that hydrological mixing drives macroscopic homogenization while land-use control remains highly scale-dependent. This dual perspective provides a scientific basis for developing zone-specific pollution control measures tailored to different spatial scales in the TGR region.

Triboelectrification converts mechanical contact and separation into interfacial charge, yet whether mineral-derived triboelectric electrons can sustain microbial growth and metabolism remains unclear. Here, we report a mechanically powered autotrophic pathway in which mineral-mediated triboelectrification converts mechanical energy into an extracellular electron supply. Within the α-Fe₂O₃-Rhodopseudomonas palustris biohybrid, triboelectrically generated electrons were routed through cell-envelope redox conduits into respiratory metabolism, thereby converting interfacial charge into cellular energy and reducing power. This bioenergetic conversion coupled inorganic carbon fixation to nitrate respiration, sustaining autotrophic growth and lycopene biosynthesis in the dark without conventional chemical electron donors. Its compatibility with distinct mechanical inputs, electroactive microorganisms, and terminal electron acceptors demonstrates the broad adaptability of this energy-coupling pathway, whereas mineral-dependent performance identifies interfacial charge generation as an important control on microbial electron supply. These findings identify mineral-solid triboelectric contact as a distinct interfacial route linking mechanical energy to microbial carbon and nitrogen transformations, highlighting its potential relevance to biogeochemical processes in energy-limited environments.

Karst caves represent important yet understudied components of the global carbon cycle, where microbial dark carbon fixation contributes substantially to subterranean carbon sequestration. However, how habitat heterogeneity regulates autotrophic microbial communities and how CO₂ concentration impacts on their carbon fixation performance remains poorly understood. Here, we investigated autotrophic microbiomes across weathered rocks of cave wall and sediment along the cave passage, as well as the overlying-soil, in Luohandu Cave, a typical karst ecosystem in southwestern China, by integrating community profiling, ecological network analysis, and microcosm validation experiments. Functional prediction based on 16S rRNA gene sequencing identified six carbon fixation pathways, among which the Calvin-Benson-Bassham (CBB) cycle, Wood-Ljungdahl pathway, and 3-hydroxypropionate bicycle exhibited marked variation across the three habitats. High-throughput sequencing of the cbbL gene further revealed pronounced habitat-specific community structures: overlying soils exhibited the highest diversity and enrichments of Mesorhizobium, Variovorax, and Bradyrhizobium, whereas sediments were dominated by Pseudonocardia. cbbL communities were significantly influenced by total organic carbon, total nitrogen, pH, Ca²⁺, and Mg²⁺. Co-occurrence network analysis revealed highly modular interaction structures with predominant positive links among nodes and a limited number of keystone taxa. Microcosm incubations under a CO₂ gradient further demonstrated a nonlinear response of microbial carbon fixation, with both the microbial inorganic carbon incorporation rate (1.29 mg C kg^-1·d^-1) and cbbL abundance (1.77 × 10⁶ copies g^-1) peaking at 2000 ppm CO₂. Collectively, these findings establish an ecological framework that links habitat heterogeneity, autotrophic community structure, microbial interactions, and carbon fixation function, thereby providing mechanistic insights into microbial contributions to carbon sequestration in karst cave ecosystems.

Under climate change, the frequency of extreme rainfall events is increasing. However, how rainfall-runoff duration shapes water quality dynamics and microbial ecological processes in drinking water reservoirs remains poorly understood. Using Jinpen Reservoir as a case study, this study investigated ecological responses to contrasting short- and long-duration rainfall-runoff events by integrating water quality monitoring, microbial community analysis, community assembly assessment, and functional potential prediction. Short-duration rainfall-runoff resulted in rapid pulse inputs of allochthonous nutrients and organic matter, leading to transient deterioration of water quality. In contrast, long-duration continuous rainfall-runoff promoted enhanced water renewal and vertical mixing, coinciding with improved water quality conditions during the later stage of the event. Microbial communities exhibited distinct response patterns under contrasting rainfall-runoff regimes. Short-duration rainfall-runoff induced transient microbial community fluctuations and maintained higher community evenness, whereas long-duration rainfall-runoff was linked to persistent microbial community reorganization, altered microbial association networks, increased community richness, a higher proportion of specialist taxa, and stronger environmental filtering signals. Redundancy analysis (RDA) and Mantel tests revealed that nitrogen, phosphorus, dissolved organic carbon (DOC), CODMn, and turbidity were key environmental factors associated with microbial community variation. PICRUSt2-based functional prediction further indicated that long-duration rainfall-runoff was linked to enhanced predicted microbial functional potential, particularly for nitrogen cycling-related functional pathways. Overall, this study reveals that rainfall-runoff events with different durations correspond to distinct ecological response modes, with prolonged disturbances associated with stronger environmental coupling and microbial community reorganization. These findings advance our understanding of reservoir microbial responses under changing precipitation regimes and provide scientific insights for adaptive management of drinking water reservoirs under climate change.

Recently, per- and polyfluoroalkyl substances (PFAS) pollution has gradually shifted from a pattern dominated by traditional long-chain PFAS to a more complex situation where both short-chain and long-chain PFAS coexist. This poses significant challenges to conventional adsorbents such as activated carbon (AC) and ion exchange resins, whose adsorption performance is strongly influenced by PFAS chain length, adsorbent surface chemistry, and multiple interactions. Herein, we designed and prepared aminated polyurethane (PU) sponge materials by introducing alkylamines with different carbon-chain lengths, denoted as PPU-C₂, PPU-C₆, and PPU-C₁₄ according to the carbon-chain lengths of the grafted alkylamines, thereby constructing interfaces with progressively tuned hydrophilic-hydrophobic characteristics. The resulting material exhibited chain-length-dependent adsorption preferences toward perfluoroalkyl carboxylic acid (PFCA) of different chain lengths. Specifically, PPU-C₂ achieved a removal efficiency of 72% for ultra-short-chain trifluoroacetic acid (TFA) with a maximum adsorption capacity of 596 mg g^-1, whereas PPU-C₆ exhibited the highest adsorption capacity toward perfluorohexanoic acid (PFHxA) (829.2 mg g^-1) with a removal efficiency of 89%. In contrast, PPU-C₁₄ showed superior affinity toward long-chain perfluorononanoic acid (PFNA), achieving a removal efficiency of 96% and a maximum adsorption capacity of 848.2 mg g^-1. Experimental and theoretical results supported a chain-length-dependent matching relationship between PFCA molecular structure and local interfacial polarity. Appreciable PFCA adsorption performance was also retained in natural water samples. The material also exhibited good reusability. This study highlights the role of interfacial hydrophilic-hydrophobic regulation in governing chain-length-dependent PFCA adsorption and provides a basis for designing adsorbents with tunable affinity toward PFCA of different chain lengths.

Microplastics (MPs) serve as substrates for bacterial colonization, facilitating pathogen transport in aquatic environments. Therefore, this study investigated the attachment of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) to five MP polymers and evaluated the effects of pH, temperature, hydrodynamic conditions, natural organic matter (NOM), and salinity using polypropylene (PP)-MPs. PP-MPs supported the highest bacterial attachment efficiencies due to their hydrophobicity (water contact angle  = 98.4°) and weak negative surface charge (zeta potential = -16.6 mV). Bacterial attachment decreased as pH increased (4.5-8.6) because of increased electrostatic repulsion. Increasing temperature (20 to 35 °C) decreased E. coli attachment, possibly through reduced curli production and increased motility, whereas it increased S. aureus attachment, which may be attributed to enhanced EPS production and surface hydrophobicity. Under varying hydrodynamic conditions, E. coli attachment peaked at 150 rpm, whereas S. aureus attachment remained high under both static and high-mixing conditions. Increasing NOM concentrations suppressed E. coli attachment through enhanced electrostatic repulsion but increased S. aureus attachment owing to the charge heterogeneity of its cell envelope. Elevated NaCl concentrations promoted bacterial attachment by screening electrostatic repulsion, consistent with the extended Derjaguin-Landau-Verwey-Overbeek theory, although this effect was less pronounced for S. aureus due to its high attachment. E. coli attachment decreased from 79.72% in sterilized water to 17.10% in lake water and 4.87% in WWTP effluent, whereas S. aureus retained high attachment efficiencies of 78.26% and 90.14%, respectively. These findings highlight how environmental conditions and species-specific traits collectively govern MP-associated bacterial attachment.

Anaerobic digestion (AD) represents a mature and extensively adopted technique to dispose organic waste, yet ammonia toxicity remains a major bottleneck for stable AD operation. For activating methanogenesis-related enzymes, regulating the microbial community structure, and optimizing the reaction efficiency of AD process, supplementation of trace elements has been validated as an effective approach to counteract ammonia inhibition. However, mechanisms of how different trace elements modulate the biosynthesis and release of N-acyl homoserine lactones (AHLs), as well as the subsequent relieving ammonia inhibition are still unknown. Therefore, the current study investigated the effects of different trace elements on the secretion of AHLs under ammonia stress. The results showed that optimal concentrations of Fe, Co and Ni could enhance the secretion of AHLs, mainly N-butyryl-_DL-homoserine lactone (C4-HSL) and N-hexanoyl-_L-homoserine lactone (C6-HSL), and adjust microbial social behaviors under high ammonia levels. In addition, microbial community changes (enriched Bacteroidetes_vadinHA17, Syntrophomonas and Methanosarcina) were closely associated with increased methane production and stimulated AHLs accumulation by trace elements. Furthermore, increased AHLs signals correlated with intercellular communication could regulate critical genes transcription (glk, pgk, and yhdR) and enzymes synthesis (glucokinase, acetate kinase, and Coenzyme-B sulfoethylthiotransferase) to alleviate ammonia inhibition during the whole AD process. Trace elements could serve for multiple enzymes, which could be beneficial for AHL secreting hydrolytic-acidogenic consortia. The current study could provide primary insights for applying trace elements to relieve ammonia stress via AHLs regulation.

Green synthesis has emerged as a sustainable and mechanistically versatile strategy for fabricating nanomaterials with tunable physicochemical and interfacial properties for advanced sensing applications. Unlike conventional synthesis routes that depend on toxic chemicals, harsh reaction conditions, and post-synthetic functionalization, green synthesis integrates nanoparticle formation, stabilization, defect generation, and surface engineering within a biomolecule-rich environment. Biological entities such as plant extracts, microorganisms, proteins, polysaccharides, flavonoids, and polyphenols act as reducing and capping agents, producing intrinsically functionalized nanostructures with enhanced biocompatibility and sensing performance. Recent studies demonstrate that biomolecule-mediated synthesis strongly influences nucleation kinetics, morphology evolution, defect chemistry, electronic structure, plasmonic behaviour, and interfacial charge transfer, which collectively govern sensitivity, selectivity, and signal amplification in sensing systems. This Review critically discusses the mechanistic foundations of green nanoparticle synthesis and their use in electrochemical, fluorescence, colorimetric, SERS, and photoelectrochemical sensing platforms. Emphasis is placed on morphology engineering, defect-mediated electronic modulation, biomolecular corona formation, heterojunction design, and nano-bio interface engineering. Current challenges related to reproducibility, scalability, and mechanistic understanding are also highlighted, alongside future opportunities involving AI-assisted synthesis optimization and sustainable next-generation sensing architectures.

Concentration-based assessments may overlook changes in dissolved organic carbon (DOC) inventory when lake water volume varies seasonally. Here, we combined MODIS observations, an XGBoost retrieval model, and lake water storage (WSC) to reconstruct DOC concentration (DOCc) and DOC storage (DOCs) over 100 consecutive seasons from spring 2000 to winter 2024 across the analyzed open-water domain of Lake Taihu. The model was developed from 411 satellite-in situ matchups and achieved an R² of 0.69 and an RMSE of 0.61 mg/L on the held-out validation dataset. DOCc exhibited a distinct bimodal seasonal cycle, with higher values in spring and autumn and lower values in summer and winter, whereas DOCs remained relatively high from spring through autumn and declined markedly in winter. Log-scale accounting partitioned DOCs variability into DOCc (44.7%) and WSC (56.0%) variance terms, together with a -2.1% covariance term and a 1.4% residual, showing that the DOCc and WSC terms were of comparable magnitude. Long-term changes were also season dependent: DOCc showed net declines from 2000 to 2024 in spring and summer but no robust monotonic trend in any season, whereas autumn DOCs showed the clearest positive long-term tendency in the baseline analysis, with a slope of 121.55 t C/yr. The runoff proxy also covaried consistently with WSC in spring and winter. Overall, DOCc and DOCs captured complementary but non-equivalent aspects of lake carbon dynamics, demonstrating that seasonal water-volume variability is integral to DOC inventory estimates and can yield patterns not evident from concentration alone.

Continuous wastewater effluent discharge sustains pronounced redox heterogeneity in the hyporheic zone (HZ), with consequences for dissolved organic matter (DOM) transformation and sediment biogeochemistry. However, the ecological pathways linking redox-dependent DOM transformation to multitrophic organization and coupled nitrogen (N) and sulfur (S) cycling remain poorly understood. We integrated fluorescence and molecular DOM characterization, bacterial and eukaryotic community profiling, metagenomics, ecological network analysis, and structural equation modeling across oxic and anoxic zones. The summed relative contribution of protein-like fluorescence did not differ significantly between zones, while tyrosine-like fluorescence was 31% higher in the oxic zone and the median tryptophan/tyrosine ratio was 52% higher under anoxia. FT-ICR MS analysis showed that formulas positively associated with HIX had higher O/C ratios and a median NOSC of 0.35, whereas negatively associated formulas had a median NOSC of -0.90, linking optical humification to molecular carbon oxidation characteristics. Bacterial genera exhibited broader estimated niche breadths than eukaryotic genera, with median Levins' B values of 7.19 and 5.86, respectively. Under oxic conditions, DOM was associated with basal communities within a connected sequence of bacterial, protozoan, and metazoan associations. Bacterial and algal communities were primarily associated with N and S cycling potentials, respectively. Under anoxia, significant DOM associations with basal groups and the bacteria-to-protozoa association were not detected, while both cycling potentials shifted toward bacteria-centered regulation. N and S cycling potentials remained strongly coordinated, while modeled network robustness was 20.5% lower under anoxia. These findings reveal that redox-associated DOM reorganization shifts multitrophic regulation of coupled N and S cycling, thus providing a framework for integrating DOM composition and multitrophic organization when assessing aquatic interfaces exposed to sustained organic matter loading and redox heterogeneity.