Iron-Nitrogen Amendment Reduced Perfluoroalkyl Acids' Phyto-Uptake in the Wheat-Soil Ecosystem: Contributions of Dissolved Organic Matters in Soil Solution and Root Extracellular Polymeric Substances.

Understanding the mechanisms underlying perfluoroalkyl acids (PFAAs) translocation, distribution, and accumulation in wheat-soil ecosystems is essential for agricultural soil pollution control and crop ecological risk assessment. This study systematically investigated the translocation of 13 PFAAs under different iron and nitrogen fertilization conditions in a wheat-soil ecosystem. Short-chain PFAAs including PFBA, PFPeA, PFHxA, and PFBS mostly accumulated in soil solution (10.43-55.33%) and soluble extracellular polymeric substances (S-EPS) (11.39-14.77%) by the adsorption to amino- (-NH2) and hydroxyl (-OH) groups in dissolved organic matter (DOM). Other PFAAs with longer carbon chain lengths were mostly distributed on the soil particle surface by hydrophobic actions (74.63-94.24%). Iron-nitrogen amendments triggered (p < 0.05) soil iron-nitrogen cycling, rhizospheric reactive oxygen species fluctuations, and the concentration increases of -NH2 and -OH in the DOM structure. Thus, the accumulation capacity of PFAAs in soil solution and root EPS was increased. In sum, PFAAs' translocation from soil particles to wheat root was synergistically reduced by iron and nitrogen fertilization through increased adsorption of soil particles (p < 0.05) and the retention of soil solution and root EPSs. This study highlights the potential of iron-nitrogen amendments in decreasing the crop ecological risks to PFAAs' pollution.

Global development and future trends of artificial sweetener research based on bibliometrics.

Artificial sweeteners have sparked a heated debate worldwide due to their ambiguous impacts on public and environmental health and food safety and quality. Many studies on artificial sweeteners have been conducted; however, none scientometric studies exist in the field. This study aimed to elaborate on the knowledge creation and development of the field of artificial sweeteners and predict the frontiers of knowledge based on bibliometrics. In particular, this study combined VOSviewer, CiteSpace, and Bibliometrix to visualize the mapping of knowledge production, covered 2389 relevant scientific publications (1945-2022), and systematically analyzed articles and reviews (n = 2101). Scientific publications on artificial sweeteners have been growing at an annual rate of 6.28% and globally attracting 7979 contributors. Susan J. Brown with total publications (TP) of 17, average citation per article (AC) of 36.59, and Hirsch (h)-index of 12 and Robert F. Margolskee (TP = 12; AC = 2046; h-index = 11) were the most influential scholars. This field was clustered into four groups: eco-environment and toxicology, physicochemical mechanisms, public health and risks, and nutrition metabolism. The publications about environmental issues, in particular, "surface water," were most intensive during the last five years (2018-2022). Artificial sweeteners are gaining importance in the monitoring and assessment of environmental and public health. Results of the dual-map overlay showed that the future research frontiers tilt toward molecular biology, immunology, veterinary and animal sciences, and medicine. Findings of this study are conducive to identifying knowledge gaps and future research directions for scholars.

Effects of Escherichia pollution and salinity on nutrient levels in submerged vegetated wetlands: Insights into benthic community stability and metabolisms.

Inner coastal wetland ecosystems are generally eutrophic and are often exposed to both salinity stress and Escherichia coli pollution. However, the effects of these stressors on nutrient-cycling and microbial communities are under-researched. Here, we established a vegetated wetland ecosystem in a saline environment to understand the effects of E. coli pollution on nutrient removal and benthic microorganisms. The results show that E. coli significantly inhibited nutrient removal, especially total nitrogen (TN) and ammonium (78.89-84.98 and 3.45-44.65% were removed from the non-E. coli-treated and the E. coli-treated water, respectively). Compared with non-vegetated systems, archaeal community variations at both compositional and phylogenetic levels were weakened in vegetated systems (p < 0.05). Among all the environmental factors, the ratios of PO43--P to total phosphorus and NO3--N to TN contributed the most to archaeal and bacterial community structural variations, respectively. E. coli pollution affected archaeal community succession more than bacteria (p < 0.05). E. coli also weakened the trophic transferring efficiencies between Cyanobacteria and Myxobacteria (p < 0.05). Metabolically, E. coli inhibited bacterial genetic metabolic pathways but made human infection more likely (p < 0.05). Our findings provide new insights into aquatic ecological conservation and environmental management.

Nitrogen addition enhanced Per-fluoroalkyl substances' microbial availability in a wheat soil ecosystem.

Per-fluoroalkyl substances (PFASs) have been widely detected in farmland soils and are understood to pose toxicological threats to soil microbiomes and crop safety. Meanwhile, farmland ecosystems have experienced increasing nitrogen loading caused by soil fertilization. Yet it is still unclear how nitrogen additions affect soil's microbial responses to PFASs. In this study, using a laboratory-based ecological experiment, we assessed the microbial availability of PFASs in soils receiving ammonium, nitrate, and urea nitrogen amendments by quantifying the translocation factors of PFASs from soil particle to soil extracellular polymeric substances (EPS). Our results showed that nitrogen, specifically ammonium, significantly increased the PFASs' microbial availability (p < 0.05). Second, nitrogen fertilization in PFASs-polluted soils decreased the microbial community diversity and stability at the structural, species, and functional levels (p < 0.05). For soil microbial activities, nitrogen enhanced the activity of superoxide dismutase (SOD) while it inhibited the catalase (CAT) and peroxidase (POD) (p < 0.01). Congruently, PFASs, as well as the nitrate and nitrite nitrogen, were shown to be the predominant abiotic drivers regulating the soil fungal succession (p < 0.05), while bacteria were mostly regulated by dissolved organic carbon (DOC) (p < 0.01). Furthermore, we revealed that the nitrogen cycling gene hmp (dominates the transformation from NO to NO3-) was the hub gene integrating the microbially available PFASs and the soil nitrogen cycling processes (p < 0.01), indicating that hmp could be the core regulator affecting the accumulation of PFASs in soil EPS. Our study highlighted that decreasing ammonia's amendments could mitigate China's national initiatives to reduce nitrogen fertilization in farmlands, reduce the PFASs' availability to the soil microbiome, and protect the microbial community stability in soil.

Impacts of iron amendments and per-fluoroalkyl substances' bio-availability to the soil microbiome in wheat ecosystem.

Per-fluoroalkyl substances (PFASs) have become ubiquitous in farmland ecosystems and pose risks to agricultural safety, and iron is often applied to farmland soils to reduce the availability of pollutants. However, the effects of iron amendment on the availability of PFASs in the soil and on the soil microbiome are not well understood. Here, we investigated the responses of wheat soil containing PFASs to iron addition using a 21-day experiment. Our results showed that iron amendment enhanced PFAS availability (p < 0.05) and stimulated superoxide dismutase (SOD) activity in the wheat soil (p < 0.05), but iron amendment decreased the activities of soil catalase (CAT) and peroxidase (POD) (p < 0.05). Soil bacterial community was more structurally stable than fungal community in response to iron addition, while species' pools were more stable in fungi than in bacteria (p < 0.05). Finally, PFPeA's availability in the wheat soil was the most important abiotic factors driving community succession of iron-cycling bacteria (p < 0.05). These results highlighted the potential interactions among PFASs' availability and microbial iron cycling in wheat farmland soil ecosystems and provided guidance in farmland environmental conservation and management.

Perfluoroalkyl acids in the aquatic environment of a fluorine industry-impacted region: Spatiotemporal distribution, partition behavior, source, and risk assessment.

The present study investigated the temporal and spatial distributions, partition behaviors, sources, and risks of 14 perfluoroalkyl acids (PFAAs) in the aquatic environment of a fluorine industry-impacted region. The total concentrations of 14 PFAAs (ΣPFAAs) were 118.10-2235.4 ng/L, 40.00-2316.1 ng/g dw, and 6.90-180.5 ng/g dw in dissolved, suspended particle matter (SPM), and sedimentary phases, respectively. The predominant pollutants in the dissolved and SPM phases were perfluoroalkyl carboxylic acids (PFCAs) with carbon chain lengths <9, whereas C13 and C14 PFCAs accounted for a large proportion in the sedimentary phase. The dry season exhibited the highest concentration of ΣPFAAs in the dissolved phase (500.9 ± 350.2 ng/L), while the wet season showed the highest concentrations of ΣPFAAs in the SPM and sedimentary phases (591.6 ± 469.1 ng/g dw and 59.7 ± 35.5 ng/g dw, respectively). Significantly higher concentrations of PFAAs have been found in sewage plant and industrial areas. The concentration of PFAAs in the Xupu water source area (XPS) was slightly higher than that in other water source areas of the Yangtze River, which were either not affected or were less affected by the fluorine industry. The log KD-SPM (distribution coefficient between SPM and water), log KD-SED (distribution coefficient between sediment and water), and log KOC-SED (the organic carbon normalized distribution coefficient) of PFAAs showed significant differences between the wet season and dry season, which may also be affected by carbon chain length. Source identification results showed that industries, wastewater discharge, and nonpoint sources were the main sources of PFAAs in this region. The ecological risk posed by long-chain PFAAs in aquatic organisms cannot be ignored, especially in areas with intensive industrial and agricultural activities. Health risks may exist for local toddlers with long-term exposure to perfluorooctanoic acid (PFOA) through drinking water intake and dermal contact.

Removal of Per-, Poly-fluoroalkyl substances (PFASs) and multi-biosphere community dynamics in a bacteria-algae symbiotic aquatic ecosystem.

The presence of Per-, Poly-fluoroalkyl substances (PFASs) in aquatic ecosystems has drawn broad concerns in the scientific community due to their biological toxicity. However, little has been explored regarding PFASs' removal in phytoplankton-dominated environments. This study aimed to create a simulated bacteria-algae symbiotic ecosystem to observe the potential transportation of PFASs. Mass distributions showed that sand (63-2000 µm), silt & clay (0-63 µm), the phycosphere (>3 µm plankton), and the free-living biosphere (0.22-3 µm plankton) contained 19.00, 7.78, 5.73 and 2.75% PFASs in their total mass, respectively. Significant correlations were observed between carbon chain lengths and removal rates (R2 = 0.822, p < 10-4). Structural equation models revealed potential PFAS transportation pathways, such as water-phycosphere- free-living biosphere-sand-silt&clay, and water-sand-silt&clay (p < 0.05). The presence of PFASs decreased the bacterial density but increased algal density (p < 0.01) in the planktonic environment, and PFASs with longer carbon chain lengths showed a stronger enhancement in microbial community successions (p < 0.05). In algal metabolisms, chlorophyll-a and carotenoids were the key pigments that resisted reactive oxygen species caused by PFASs. PFBA (perfluorobutyric acid) (10.38-14.68%) and PFTeDA (perfluorotetradecanoic acid) (10.33-15.96%) affected bacterial metabolisms in phycosphere the most, while in the free-living biosphere was most effected by PFPeA (perfluorovaleric acid) (13.21-13.99%) and PFDoA (perfluorododecanoic acid) (10.04-10.50%). The results of this study provide new guidance measures for PFAS removal and management in aquatic environments.

Linking microbiomes with per- and poly-fluoroalkyl substances (PFASs) in soil ecosystems: Microbial community assembly, stability, and trophic phylosymbiosis.

Microbiomes are vital in promoting nutrient cycling and plant growth in soil ecosystems. However, microbiomes face adverse effects from multiple persistent pollutants, including per- and poly-fluoroalkyl substances (PFASs). PFASs threaten the fertility and health of soil ecosystems, yet the response of microbial community stability and trophic transfer efficiencies to PFASs is still poorly understood. This study explored the spatial patterns of PFASs in topsoil environments from the West Taihu Lake Basin of China and links their presence to soil microbial community stability at compositional and functional levels. Our results revealed that PFBA (13.87%), PFTrDA (11.63%), PFDoA (11.02%), PFOA (10.99%), and PFOS (10.39%) contributed the most to the spatial occurrence of PFASs. Soil properties, including salinity (14.47%), uniformity (9.68%), dissolved inorganic carbon (8.62%), and clay content (8.18%), affected PFASs distribution the most. In soil microbiomes, eukaryotic taxa had wider niche breadths and stronger community stability than prokaryotes when exposed to PFASs (p < 0.05). The presence of PFBA and PFHpA inhibited the functional stability of archaeal and bacterial communities (p < 0.05). PFBA and PFPeA reduced the structural stability of heterotrophic bacteria and Myxobacteria, respectively (p < 0.05). Based on null modeling, PFPeA significantly regulated the assembly processes of most microbial sub-communities (p < 0.01). The trophic transferring efficiencies of autotrophic bacteria to metazoan organisms were directly stimulated by PFASs (p < 0.05), and the potential trophic transferring efficiencies of methanogenic archaea to protozoa were inhibited by PFASs (p < 0.05). This study highlighted the potential contributions of PFASs to soil microbial community stability and food webs during ecological soil management.

Removal of perfluoroalkyl acids and dynamic succession of biofilm microbial communities in the decomposition process of emergent macrophytes in wetlands.

Perfluoroalkyl acids (PFAAs) are emerging contaminants that pose significant environmental and health concerns. Water-sediment-macrophyte residue systems were established to clarify the removal efficiency of PFAAs, explore possible removal pathways, and profile the dynamic succession of biofilm microbial communities in the decomposition process. These systems were fortified with 12 PFAAs at three concentration levels. Iris pseudacorus and Alisma orientale were selected as the decomposing emergent macrophytes. The removal rates in the treatments with residues of I. pseudacorus (IP) and A. orientale (AO) were 34.4% to 88.9% and 36.5% to 89.9%, respectively, which were higher than those in the control groups (CG) (30.3% to 86.9%), suggesting that decomposition could alter the removal of PFAAs. Sediment made the greatest contributions (preloaded 14.5% to 77.8% of PFAAs in IP, 14.3% to 78.2% in AO, and 27.4% to 71.9% in CG). PFAAs could also be removed by macrophyte residue sorption (0.0190% to 13.0% in IP and 0.016% to 15.6% in AO) and bioaccumulation of residual biofilm (the contributions of biofilm microbes and their extracellular polymeric substances were 0.0110% to 3.93% and 0.918% to 34.4%, respectively, in IP and 0.0141% to 4.65% and 1.49% to 34.1%, respectively, in AO). Significant correlations were observed between sediment/residue adsorption and bioaccumulation of biofilm microbes, and were significantly correlated with perfluoroalkyl chain length (p < 0.05). The dynamic succession of residual biofilm microbial communities was investigated. The largest difference was found at the preliminary stage. The most similar communities were found in AO on day 70 (with specific genera Macellibacteroides and WCHB1-32) and in IP on day 35 (with specific genera Aeromonas and Flavobacterium). This study is useful to understand the removal of PFAAs during the decomposition process, providing further assistance in removing PFAAs during the life cycle of macrophytes in wetlands.

Interactions between dissolved organic matter and perfluoroalkyl acids in natural rivers and lakes: A case study of the northwest of Taihu Lake Basin, China.

Understanding the interactions between dissolved organic matter (DOM) and perfluoroalkyl acids (PFAAs) is essential for predicting the distribution, transport, and fate of PFAAs in aquatic environments. Based on field investigations in the northwest of Taihu Lake Basin combined with laboratory experiments, we obtained DOM and PFAA concentrations as well as compositions and investigated key factors of DOM affecting PFAA variability and capture of PFAAs by DOM. Results indicated that the total concentrations of PFAAs were 73.4-689 ng/L in surface water and that PFAAs were dominated by C3-7 perfluoroalkyl carboxylic acids and perfluorooctane sulfonic acid. The main components of DOM included tyrosine-, fulvic-, and tryptophan-like substances. The Mantel test revealed a significant positive correlation between DOM and PFAAs (P = 0.0001). Fulvic-like substances were identified as the most crucial factors affecting PFAA variability. The laboratory experiments revealed that DOM can spontaneously aggregate into a microgel. Furthermore, 19.1-50.9% of PFAAs, DOM characteristic peaks, and several metals (Ca, Mg, Cu, and Fe) can be removed during aggregation, indicating the capacity of DOM binding organic/inorganic substances. The fulvic-like substances were more effectively removed than the protein-like substances. The distribution coefficients of all PFAAs except perfluorohexanoic acid significantly correlated with their perfluorinated carbon numbers (r = 0.975, p<0.001). Our results provided insights into the interactions between DOM and PFAAs, improving the understanding of the distribution, transport, and fate of PFAAs in aquatic environments.

Per-, poly-fluoroalkyl substances (PFASs) and planktonic microbiomes: Identification of biotic and abiotic regulations in community coalescence and food webs.

The importance of per-, poly-fluoroalkyl substances (PFASs) effects on riverine microbiomes is receiving increased recognition in the environmental sciences. However, few studies have explored how PFASs affect microbiomes across trophic levels, specifically through predator-prey interactions. This study examined the community profiles of planktonic archaea, bacteria, fungi, algae, protozoa, and metazoa in a semi-industrial and agricultural river alongside their interactions with 15 detected PFASs. As abiotic factors, PFASs affected community coalescence more than biogenic substances (p < 0.05). For biotic regulations, sub-communities in rare biospheres (including always rare taxa-ART and critically rare taxa-CRT) contributed to spatial community coalescence more than sub-communities in abundant biospheres (always abundant taxa-AAT and critically abundant taxa-CAT) (p < 0.05). Metazoa-bacteria (Modularity = 1.971) and protozoa-fungi (1.723) were determined to be the most stable predator-prey networks. Based on pathway models, short-chain PFBA (C4) was shown to weaken the trophic transfer efficiencies from heterotrophic bacteria (HB) to heterotrophic flagellates (HF) (p < 0.05). Long-chain PFTeDA (C14) promoted HB to amoeba (p < 0.05), which we postulate is the pathway for PFTeDA to enter the microbial food chain. Our preliminary results elucidated the influence of PFASs on planktonic microbial food webs and highlighted the need to consider protecting and remediating riverine ecosystems containing PFASs.

Ecotoxicological responses and removal of submerged macrophyte Hydrilla verticillate to multiple perfluoroalkyl acid (PFAA) pollutants in aquatic environments.

The ubiquitous existence of perfluoroalkyl acids (PFAAs) in aquatic environments might pose toxic potential to ecosystems. To assess the ecotoxicological responses and removal of submerged macrophyte to multiple PFAA pollutants in aquatic environments, a typical submerged macrophyte, Hydrilla verticillate, was exposed to solutions with 12 typical PFAAs in the present study. The results showed that PFAAs at concentrations higher than 10 µg/L had significantly passive effects on biomass, relative growth rates, chlorophyll contents, and chlorophyll autofluorescence. PFAAs could induce the accumulation of hydrogen peroxide and lipid peroxidation in H. verticillate. Significant upregulation of CAT was observed in treatments with more than 10 µg/L PFAAs (p < 0.05). The results also showed that 13.53-20.01% and 19.73-37.72% of PFAAs could be removed in treatments without plants and with H. verticillate, respectively. The removal rates of PFAAs were significantly correlated with perfluoroalkyl chain length in treatments with H. verticillate. The removal of PFAAs was suggested to be related to the uptake of plant tissues and biosorption of microbiota. Furthermore, the dominant microbiota and biomarkers were identified in water and biofilm. Betaproteobacteriales was the most dominant microbiota at the order level. The presence of PFAAs could significantly increase the relative abundance of Micrococcales, Verrucomicrobiales, Rhizobiales, Sphingomonadales, Roseomonas, Cyanobium_PCC_6307, and Synechococcales. Our results provide scientific basis for evaluating the ecotoxicological responses and removal of submerged macrophytes in response to multiple PFAA pollutants at environmentally relevant levels, thereby providing insights into PFAA management and removal.

Perfluorinated compounds (PFCs) in regional industrial rivers: Interactions between pollution flux and eukaryotic community phylosymbiosis.

Perfluorinated compounds (PFCs) pose serious threats to aquatic ecosystems, especially their microbial communities. However, little is known about the phylosymbiosis of aquatic fungal and viridiplantae communities in response to PFC accumulation. We quantified the distribution of 14 PFCs in rivers and found that PFBA was dominant in the transition from water to sediment. High through-put sequencing revealed that phyla Ascomycota, Basidiomycota, Anthophyta, and Chlorophyta were the predominant in eukaryotic community. The effects of PFCs on spatial community coalescence at taxonomic and phylogenetic levels (p < 0.05) were revealed. Fungal community coalescence triggered the spatial assembly of fungal and viridiplantae communities in riverine environments (p < 0.05). Null modeling indicated that PFBA, PFTrDA and PFOS, etc, mediated phylogenetic assembly (p < 0.05) and stochastic processes (86.67-100%) maintain phylogenetic turnover in the fungal community. Meanwhile, variable selection (27.78-54.44%) explained the viridiplantae community assemblage. Finally, we identified fungal genera Hannaella, Naganishia, Purpureocillium and Stachybotrys as indicators for PFC pollution (p < 0.001). These results help explain the effects of PFCs on riverine ecological remediation.

Removal potential of multiple perfluoroalkyl acids (PFAAs) by submerged macrophytes in aquatic environments: Tolerance of Vallisneria natans and PFAA removal in submerged macrophyte-microbiota systems.

Perfluoroalkyl acids (PFAAs) have emerged as a global concern in aquatic environment remediation due to their abundance, persistence, bioaccumulation, and toxicity. To comprehensively understand the removal potential of multiple PFAAs by submerged macrophytes in aquatic environments, systematic investigations into the tolerance of the typical submerged macrophyte Vallisneria natans to 12 typical PFAAs and the removal capacity to PFAAs in V. natans-microbiota systems were carried out. Results showed that although PFAAs could induce the accumulation of hydrogen peroxide and malondialdehyde, V. natans was overall resistant to multiple PFAAs with natural concentrations. Catalase is one of the main strategies of V. natans to alleviate PFAA stress. Microbiota can remove 18.10-30.84% of the PFAAs from the water column. 24.35-73.45% of PFAAs were removed from water in V. natans-microbiota systems. The uptake of plant tissues and the bioaccumulation of microbiota were proposed as the main removal processes. The removal rates were significantly correlated with the perfluorinated carbon atoms numbers (p < 0.05). PFAAs and V. natans increased the relative abundance of Betaproteobacteria, Nostocales, Microscillaceae, Sphingobacteriales, SBR1031, Chlamydiales, Phycisphaerae, Caldilineales, Rhodobacterales, and Verrucomicrobiales. The present study suggested that V. natans can be a potential species to remove multiple PFAAs in aquatic environments, and further providing insights into the PFAAs' remediation.

Distribution, sources, and dietetic-related health risk assessment of perfluoroalkyl acids (PFAAs) in the agricultural environment of an industrial-agricultural interaction region (IAIR), Changshu, East China.

The exploration of the distribution and dietetic-related health risks of perfluoroalkyl acids (PFAAs) in industrial-agricultural interaction regions (IAIRs) is of significant importance, due to the transfer of many PFAA-related factories to developing countries with intensive agricultural activities. In the present study, based on the local diet, edible parts of rice, vegetables, fish, and their corresponding soils and irrigation/aquaculture water were investigated in a typical Chinese city (Changshu). The concentrations of total perfluoroalkyl acids (ΣPFAAs) in the edible parts of rice /vegetables and fish tissues ranged from 26.69 to 37.09 ng/g dw, 12.93 to 40.77 ng/g dw, and 13.27 to 29.82 ng/g ww, with perfluorohexanoic acid (PFPeA) and perfluorooctane sulfonic acid (PFOS) as the most dominant compounds. The PFAA concentrations in the corresponding rice soils, vegetable soils, irrigation water, and aquaculture water ranged from 11.99 to 26.33 ng/g dw, 14.06 to 36.19 ng/g dw, 141.36 to 297.00 ng/L, and 179.23 to 235.82 ng/L, respectively. Biota-sediment accumulation factor (BSAF) values for the plant-soil system were far greater than those for bioaccumulation factor (BAF) values for the plant-irrigation water system. PFAAs were more inclined to accumulate in the gills of fish as determined by their highest BAF values. Correlation analysis showed that PFAAs in root vegetables had a stronger correlation with those in soil compared with those in irrigation water. Source analysis showed that emissions from fluoride industries, textiles, and food industries may be the dominant sources of PFAAs in agricultural environments. The estimated dietary intake (EDI) for the selected diet was lower than that for rice/vegetables but was higher than that found in fish. Toddlers (2-5 years) had the highest exposure risk, and rural residents were more exposed to PFAAs than urban residents under the selected diet.

Per-, poly-fluoroalkyl substances (PFASs) pollution in benthic riverine ecosystem: Integrating microbial community coalescence and biogeochemistry with sediment distribution.

Per-, Poly-fluoroalkyl substances (PFASs) accumulation in benthic environments is mainly determined by material mixing and represents a significant challenge to river remediation. However, less attention has been paid to the effects of sediment distribution on PFASs accumulation, and how PFASs influence microbial community coalescence and biogeochemical processes. In order to identify correlations between PFASs distribution and benthic microbial community functions, we conducted a field study and quantified the ecological constrains of material transportation on benthic microorganisms. Perfluorohexanoic acid (PFHxA) contributed most to the taxonomic heterogeneity of both archaeal (12.199%) and bacterial (13.675%) communities. Genera Methanoregula (R2 = 0.292) and Bacillus (R2 = 0.791) were identified as indicators that respond to PFASs. Phylogenetic null modeling indicated that deterministic processes (50.0-82.2%) dominated in spatial assembly of archaea, while stochasticity (94.4-97.8%) dominated in bacteria. Furthermore, spatial mixing of PFASs influenced broadly in nitrogen cycling of archaeal genomes, and phosphorus mineralization of bacterial genomes (p < 0.05). Overall, we quantified the effect of PFASs on community assembly and highlighted the constrains of PFASs influence on benthic geochemical potentials, which may provide new insights into riverine remediation.

Planktonic microbial responses to perfluorinated compound (PFC) pollution: Integrating PFC distributions with community coalescence and metabolism.

The presence of perfluorinated compound (PFC) contamination in riverine ecosystems represents a novel challenge for environmental remediation. However, little attention has been paid to how PFCs affect planktonic microbial community coalescence. Here, the spatial profiles of fourteen PFCs and their contributions to community assembly were determined using field sampling in a natural river confluence. Overall, PFPeA (perfluorovaleric acid), PFBS (perfluorobutylsulfonate), PFHpA (perfluoroheptanoic acid) and PFHxA (perfluorohexanoic acid) were identified as important indicators of PFC pollution, accounting for the majority of the spatial heterogeneity in PFC pollution. PFPeA (perfluorovaleric acid) (9.39%) and PFTrDA (perfluorotridecanoate acid) (8.61%) contributed more to microbial taxonomic spatial heterogeneity than did other factors, such as pH, dissolved oxygen and velocity. PFOA (pentadecafluorooctanoic acid) (R2 = 0.353) and PFBS (R2 = 0.297) drove turnover in archaeal communities within river sections (transversely), while PFHpA (R2 = 0.251) and PFOS (perfluorooctane sulphonate) (R2 = 0.105) drove turnover in bacterial communities transversely and longitudinally, respectively. Phylogenetic null modeling suggested that archaeal (68.89-83.33%) community assembly was dominated by stochastic processes, and was balanced by PFHxA (R2 = 0.349) and PFOA (R2 = 0.290). Furthermore, PFOS inhibited the biosynthesis of several key amino acids in archaea, and PFBA enhanced the potential for bacterial infections in humans (p < 0.05), threatening water quality. In sum, this study provides new insights into riverine ecological risk management.

Removal of perfluoroalkyl acids (PFAAs) in constructed wetlands: Considerable contributions of submerged macrophytes and the microbial community.

The broad application of perfluoroalkyl acids (PFAAs) has attracted global concern regarding their adverse environmental effects. The possible removal processes of PFAAs in constructed wetlands were excavated and quantified using two typical submerged macrophytes (rooted Potamogeton wrightii and rootless Ceratophyllum demersum). Our results showed that 33.59-88.99% of PFAAs could be removed via not only sediment sorption or phytoextraction but also by the bioaccumulation of microbiota. The sediment acts as a vital sink for PFAAs, preloading 23.51-50.09% and 16.65-52.18% of PFAAs in treatments with P. wrightii (Pw1) and C. demersum (Cd1), respectively. C. demersum showed a better capacity to accumulate PFAAs (0.91-32.03%) than P. wrightii (<10%). Considerable PFAAs were observed to be distributed in microbes, underlining the non-negligible role of microbiota in bioaccumulating PFAAs. The contributions of planktonic microbes, biofilm microbes, and extracellular polymeric substances in biofilms were 0.39-20.96%, 0.03-7.95%, and 0.39-14.15% in Pw1 and 0.23-15.68%, 0.01-15.68%, and 0.53-26.77% in Cd1, respectively. The adsorption/uptake was significantly correlated with the perfluoroalkyl chain length (p<0.05), except for the uptake of biofilms in C. demersum. Furthermore, PFAAs and submerged macrophytes could decrease the richness of microbiota but increase the relative abundance of some strains in Betaproteobacteriales, Sphingomonadales, and Cytophagales. Our results were helpful for understanding the removal processes of PFAAs in constructed wetlands and their linkages with PFAA properties, thus further providing insight into the management and removal of emerging organic contaminants.

Benthic prokaryotic microbial community assembly and biogeochemical potentials in E. coli - Stressed aquatic ecosystems during plant decomposition.

Benthic microbes play a crucial role in maintaining the biogeochemical balance of aquatic ecosystems especially the material cycling during plant decomposition. However, those systems in agricultural area are always threatened by agricultural run-off containing a mass of typical pathogenic invader- Escherichia coli. It is therefore vital to clarify the turnover, assembly, and geochemical functions of the E. coli invaded benthic prokaryotic microbial community during plant decomposition. During the decaying process, the key filtering factors of benthic community assembly were NH4+-N (P < 0.001), NO2--N (P < 0.01), and Organic-N (P < 0.05). The E. coli colonized significantly in sediments (P < 0.001) and drove the turnover of the bacterial community (P = 0.001), which enhanced archaeal dominance in the benthic microbial network. E. coli also triggered niche structural variations. The biomass (%) of benthic nutrient cycling genera including Dechloromonas, Pseudomonas, Bacteroides, Candidatus_Methanofastidiosum, and Desulfomicrobium (P < 0.05) was altered by E. coli stress. The structural equation model illustrated that E. coli critically affected the benthic microbial geochemical functions in multiple pathways (P < 0.05). Our results provide new insights into benthic prokaryotic microbial community assembly and nutrient cycling and management under pollution stress.

Effects of Escherichia coli pollution on decomposition of aquatic plants: Variation due to microbial community composition and the release and cycling of nutrients.

Determination of the effects of Escherichia coli (E. coli) pollution on agricultural pond ecosystems with vegetation at different life stages is essential for the protection of ecological functions. However, no comprehensive study has yet shown the responses of epiphytic microbial communities to E. coli invasion during plant decay. Thus, this study was conducted to clarify variation in the decay of the following aquatic plants-Myriophyllum aquaticum, Nymphaea tetragona and Phragmites australis after E. coli pollution. Exogenous E. coli especially shifted the epiphytic microbial composition and distribution of P. australis. Stronger effects of E. coli on the archaeal community (edges/nodes = 0.818 < 1, modularity = 0.654; lower clustered structure, 0.389) were found than on the bacterial community (edges/nodes = 1.538 > 1, modularity = 1.291 > 0.654; higher clustered, 0.593). During plant decomposition, E. coli weakened methanogenesis by regulating the network of core genera Methanobacterium and Methanospirillum (spearman, P < 0.05), stimulated the accumulation of organic matters in water (P < 0.05). Similarly, nitrification and denitrification increased and decreased through network regulation in relative biomass of genera Devosia and Desulfovibrio (P < 0.05), respectively. The results provided theoretical supports for eutrophication management in pond ecosystems threatened by E. coli pollution.