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[Display omitted] • Effects of sulfate-reducing bacteria (SRB) on the reducing efficiency (RE) in sulfate-rich systems were investigated. • The optimum temperature (30 °C) and pH (7.0) enhance SRB activity and the increase in salinity inhibits SRB activity. • Multiple grouting times (GTs < 5) improve the RE and stabilize at higher GTs (GTs > 5). • Results provide a reference for the effective utilization of SRB in sulfate-rich systems. The acclimation of sulfate-reducing bacteria (SRB) was performed to improve its adaptation in sulfate-rich systems with high sodium sulfate as a solution for disposing of soil salinization. The effects of pH, temperature, and carbon–sulfur ratio (CSR) on the activity and reduction efficiency (RE) of SRB were analyzed, and the influence of grouting times (GTs) on RE was studied. The impact of different sulfate-rich systems (i.e., sulfate-rich solution and soil) with different salinity on the RE of SRB was investigated. Results show that the optimum temperature and pH for the best activity and RE of SRB were 30°C and 7.0, respectively. The multiple acclimations for SRB significantly improved the activity and RE of SRB at high CSR. The RE of SRB decreased with increasing salinity since high salinity could inhibit SRB activity. The maximum RE of SRB-200 in sulfate-rich soils with 2% salinity is 40%, which may be due to the significant salinity tolerance degree of SRB-200, which is higher than SRB-150 and SRB-175. In addition, the RE of SRB in sodium sulfate solution was higher than that in sulfate-rich soil due to the soil having a complex skeletal structure. The RE of SRB significantly increased after low GTs (<5) and then remained constant after high GTs (>5). The optimal GTs obtained by SRB-150, SRB-175 and SRB-200 were 4, 4 and 5, respectively, corresponding to the final cumulative REs of 37.2%, 45.2% and 55.2%, respectively. The SEM results shows the formation of sulfides verified the reliability of SRB reduction in sulfate-rich systems. All results provide an important reference for the effective utilization of SRB in sulfate-rich systems. [ABSTRACT FROM AUTHOR]

Coastal sediments are a critical domain for carbon sequestration and are profoundly impacted by human activities. Therefore, it is essential to understand the structure and components of benthic autotrophs that play a crucial role in carbon sequestration processes, as well as the influence of anthropogenic activities on their communities. This study utilized an urban estuary, an industrial sea bay, a maricultural sea region, and two mangrove coastlines within the coastal areas of Guangdong Province, China. The micro-benthos in these environments, including prokaryotes and eukaryotes, were identified through high-throughput sequencing of 16S rRNA and 18S rRNA genes. The findings show that the autotrophic composition was altered by the interactions of anthropogenic heavy metals (Cd and Zn) and micro-eukaryotes (protazoa, metazoa, and parasitic organisms). Industrial pollution reduced the abundance of both prokaryotic and eukaryotic autotrophs. Mangroves induced a substantial transformation in the sediment eukaryotic and prokaryotic composition, increasing the proportion of autotrophs, notably sulfur-oxidizing and iron-oxidizing bacteria and microalgae. This alteration suggests an increase in specific sulfur and iron cycling with simultaneous carbon sequestration within mangrove sediments. These results indicate that anthropogenic activities affect sediment carbon sequestration by altering autotrophic assemblages along coastlines, thereby inducing consequential shifts in overall elemental cycling processes. [Display omitted] • Heavy metals (Cu and Zn) determined the benthic prokaryotic autotrophs. • Mangrove sediment enhanced the functional autotrophs of S/Fe-oxidizer and algae. • Industrial coastal sediment inhibited the growth of autotrophs. • The changed of functional autotrophs would finally affect the C, N, S, Fe cycling processes. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) are widespread ocean pollutants and many studies have explored their effects. However, research on MPs combined impact with copper (Cu) on dimethylated sulfur compound production is limited. Dimethyl sulfide (DMS) is an important biogenic sulfur compound related to global temperatures. This study examined the ecotoxicological effects of polyamide 6 MPs and Cu on dimethylsulfoniopropionate (DMSP), DMS, and dimethyl sulfoxide (DMSO) production in Manila clams (Ruditapes philippinarum). Our findings showed that MPs and Cu increased oxidative stress, indicated by higher superoxide anion radical production and malondialdehyde levels while decreasing glutathione contents and increasing superoxide dismutase activities. Additionally, MPs and Cu exposure reduced DMS and dissolved DMSO (DMSO d) concentrations due to decreased grazing. These results contribute to a better understanding of the ecotoxicological effects of MPs/Cu on bivalves and their roles in the organic sulfur cycle, suggesting a need for further research on long-term impacts on them. [Display omitted] • Ecotoxicology effects and dimethylated sulfur yield were assessed under MPs and Cu. • Superoxide dismutase activity increased to defense oxidative stress from MPs/Cu. • R. philippinarum grazing promoted dimethylated sulfur compounds production. • MPs/Cu inhibited dimethyl sulfide yield due to reduced ingestion rates of clams. [ABSTRACT FROM AUTHOR]

Dimethyl sulfide (DMS) is a prevalent volatile organic sulfur compound relevant to the global climate. Ecotoxicological effects of nano- and microplastics (NPs and MPs) on phytoplankton, zooplankton, and bacteria have been investigated by numerous studies. Yet, the influences of NPs/MPs on dimethylated sulfur compounds remains understudied. Herein, we investigated the impacts of polystyrene (PS) NPs/MPs (80 nm, 1 μm, and 10 μm) on zooplankton grazing, chlorophyll a (Chl a) concentration, bacterial community, dimethylsulfoniopropionate (DMSP), and DMS production in the microcosms. Our findings revealed that rotifer grazing increased the production of DMS in the absence of NPs/MPs but did not promote DMS production when exposed to NPs/MPs. The ingestion rates of the rotifer and copepod exposed to NPs/MPs at high concentrations were significantly reduced. NPs/MPs exposure significantly decreased DMS levels in the treatments with rotifers compared to the animal controls. In the bacterial microcosms, smaller NPs/MPs sizes were more detrimental to Chl a concentrations compared to larger sizes. The study revealed a stimulatory effect on Chl a concentrations, DMSP d concentrations, and bacterial abundances when exposed to 10 μm MP with low concentrations. The effects of NPs/MPs on DMS concentrations were both dose- and size-dependent, with NPs showing greater toxicity compared to larger MPs. NPs/MPs led to changes in bacterial community compositions, dependent on both dosage and size. NPs caused a notable decrease in the alpha diversities and richness of bacteria compared to MPs. These results provide insights into the influences of NPs/MPs on food webs, and subsequently organic sulfur compounds cycles. [Display omitted] • High concentrations nano/microplastics inhibited dimethyl sulfide during grazing. • Zooplankton exposed to nano/microplastics did not promote dimethyl sulfide. • Smaller nano/microplastics demonstrated a more detrimental effect on Chl a. • Nanoplastics notably reduced the alpha diversity and richness of bacteria. [ABSTRACT FROM AUTHOR]

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Sulfate-reducing bacteria (SRB) play pivotal roles in the biotransformation of mercury (Hg). However, unrevealed global responses of SRB to Hg have restricted our understanding of details of Hg biotransformation processes. The absence of protein-protein interaction (PPI) network under Hg stimuli has been a bottleneck of proteomic analysis for molecular mechanisms of Hg transformation. This study constructed the first comprehensive PPI network of SRB in response to Hg, encompassing 67 connected nodes, 26 independent nodes, and 121 edges, covering 93% of differentially expressed proteins from both previous studies and this study. The network suggested that proteomic changes of SRB in response to Hg occurred globally, including microbial metabolism in diverse environments, carbon metabolism, nucleic acid metabolism and translation, nucleic acid repair, transport systems, nitrogen metabolism, and methyltransferase activity, partial of which could cover the known knowledge. Antibiotic resistance was the original response revealed by this network, providing insights into of Hg biotransformation mechanisms. This study firstly provided the foundational network for a comprehensive understanding of SRB's responses to Hg, convenient for exploration of potential targets for Hg biotransformation. Furthermore, the network indicated that Hg enhances the metabolic activities and modification pathways of SRB to maintain cellular activities, shedding light on the influences of Hg on the carbon, nitrogen, and sulfur cycles at the cellular level. [Display omitted] • Protein-protein interaction network of SRB response to Hg was constructed and validated. • Hg stimulus influenced SRB's carbon, sulfur, and nitrogen metabolism. • Antibiotic biosynthesis and resistance were correlated with Hg stimulus. [ABSTRACT FROM AUTHOR]

Due to the low C/N and high NO 3 −-N content in tailwater of wastewater treatment plants, the need for further denitrification treatment attracted wide attention. To achieve deep denitrification of tailwater with low C/N and high NO 3 −-N, a novel sulfur-manganese carbonate ore denitrification (SMCD) biological reactor was constructed. The denitrification performance of SMCD reactor was significantly higher than that of sulfur denitrification and manganese carbonate ore denitrification reactors. Across the study, the removal efficiencies of TN and NO 3 −-N were above 90 %, and without NO 2 −-N accumulation in the SMCD reactor. Quantitative results of functional genes showed that SMCD reactor were conducive to realize complete denitrification. Besides, manganese autotrophic denitrification (MAD) process occurred in the SMCD reactor. By analyzing the nitrogen as well as SO 4 2- and Mn(Ⅱ) concentrations along the height, it was found that the conversion between Mn(II) and Mn(IV) was stable during Stage Ⅲ (C/N=1). The microbiota in the SMCD reactor was distinctly different from that in the controls. Thiobacillus , Thermomonas , and an unclassified member in family cvE6 were the dominant members of SMCD reactor. Besides, Thermomonas , Dokdonella , and Simplicispira were identified as potential Mn oxidizers. The SMCD reactor exhibited a significant synergistic denitrification effect by coupling sulfur autotrophic denitrification and MAD process, which provided an effective solution for the deep denitrification of low C/N tailwater. [Display omitted] • SMCD reactor was an efficient carbon self-sufficient system. • MnCO 3 acted as alkaline buffer and provided inorganic carbon source. • Synergistic effects of SAD and MAD process enhanced nitrogen removal. • Mn cycle was formed in SMCD reactor. • Thermomonas , Dokdonella , and Simplicispira were potential Mn oxidizers. [ABSTRACT FROM AUTHOR]

The surface sediments as a repository of pelagic environment changes and microbial community structural succession tend to have a profound effect on global and local nitrogen and sulfur cycling. In this study, analysis of sediment samples collected from the Bohai Sea, Yellow Sea, and north of the East China Seas (BYnECS) revealed longitude, latitude, depth, and chlorophyll had the strongest influence on microbial community structure (p-values < 0.005). A clear distance-decay pattern was exhibited in BYnECS. The result of co-occurrence network modularization implied that the more active pathway in winter was thiosulfate reduction and nitrate reduction, while in summer it was nitrification. The potential functional genes were predicted in microbial communities, and the most dominant genes were assigned to assimilatory sulfur reduction, denitrification, and dissimilatory nitrate reduction. This study innovatively explored the potential relationships between nitrogen and sulfur cycling genes of these three sea regions in the China Sea. [Display omitted] • A clear distance-decay pattern was exhibited in BYnECS. • Spatial heterogeneity had stronger influence than seasonal heterogeneity. • Longitude, latitude, depth and chlorophyll affect microbial structure the most. • Chl-a exhibited positive correlations with AOB and NOB. • Sulfur oxidation genes were closely related to the DN and DNRA genes in both seasons. [ABSTRACT FROM AUTHOR]

Thiosulfate influences the bioreduction and migration transformation of arsenic (As) and iron (Fe) in groundwater environments. The aim of this study was to investigate the impact of microbially-mediated sulfur cycling on the bioreduction and interaction of As and Fe. Microcosm experiments were conducted, including bioreduction of thiosulfate, As(V), and Fe(III) by Citrobacter sp. JH012–1, as well as the influence of thiosulfate input at different initial arsenate concentrations on the bioreduction of As(V) and Fe(III). The results demonstrate that Citrobacter sp. JH012–1 exhibited strong reduction capabilities for thiosulfate, As(V), and Fe(III). Improving thiosulfate level promoted the bioreduction of Fe(III) and As(V). When 0, 0.1, 0.5, and 1 mM thiosulfate were added, Fe(III) was completely reduced within 9 days, 3 days, 1 day, and 0.5 days, simultaneously, 72.8%, 82.2%, 85.5%, and 90.0% of As(V) were reduced, respectively. The products of As(III) binding with sulfide are controlled by the ratio of As-S. When the initial arsenate concentration was 0.025 mM, the addition of thiosulfate resulted in the accumulation of soluble thioarsenite. However, when the initial arsenate level increased to 1 mM, precipitates of orpiment or realgar were formed. In the presence of both arsenic and iron, As(V) significantly inhibits the bioreduction of Fe(III). Under the concentrations of 0, 0.025, and 1 mM As(V), the reduction rates of Fe(III) were 100%, 91%, and 83%, respectively. In this scenario, the sulfide produced by thiosulfate reduction tends to bind with Fe(II) rather than As(III). Therefore, the competition of arsenic-iron and thiosulfate concentration should be considered to study the impact of thiosulfate on arsenic and iron migration and transformation in groundwater. [Display omitted] • Isolation of a bacterium capable of simultaneously reducing arsenate, iron, and thiosulfate. • The input of thiosulfate significantly promoted the bioreduction of arsenate and iron. • The input of thiosulfate induced the precipitation of FeS or arsenic-sulfur compounds. • The ratio of sulfur to arsenic controlled the combination of arsenite and sulfide. [ABSTRACT FROM AUTHOR]

To address sluggish sulfur redox kinetic and the "shuttling behavior" of polysulfides in lithium-sulfur batteries (LSBs), CoS2 hollow nanospheres tightly anchored on three-dimensional (3D) N-doped biological carbon nanofibers skeleton (CoS2/N-CNFs) are successfully designed as highly-efficient sulfur hosts. The carbon nanofibers obtained by carbonization of bacterial cellulose are interweaved with each other, and can provide a firm 3D conductive skeleton for the low-conductive sulfur cathode. And the Ndoping carbon nanofibers skeleton with polar CoS2 can achieve synergetic physical/chemical adsorption of polysulfides and effective catalytic conversion, which are contributed to enhance sulfur redox kinetic and effectively suppress the shuttling effect. Moreover, the skeleton with abundant -OH functional groups achieve strong chemisorption to CoS2, greatly maintaining structural stability during cycling process. Benefitting from the above-mentioned merits, CoS2/N-CNFs@S electrode with high sulfur loading of 74.4% exhibits superior reversible capacity of 497.3 mAh g-1 at 0.2 C after 100 cycles with an improved coulombic efficiency of approximately 100%, and the electrode has excellent cycle life with 73% capacity retention over 300 cycles at 0.5 C. This synthesis strategy makes a leading exploration for the application of biological carbon materials in advanced LSBs. [ABSTRACT FROM AUTHOR]

A combination of electrochemical measurements, H2 volume measurements and surface analysis using Time-of-Flight SecondaryIon Mass Spectrometry (ToF-SIMS) and X-ray Photoelectron Spectroscopy (XPS) was used to investigate the role of the metallic Fe impurities (60 ppm) in high purity (99.9 wt%) magnesium and the effect of sulfur on the hydrogen evolution. The Mg corrosion was studied in NaCl solutions containing dissolved hydrogen sulfide. At OCP and under anodic polarization the hydrogen evolution reaction and the growth of dark corroded areas were significantly inhibited in the presence of H2Saq. ToF-SIMS and XPS analyses showed the presence of sulfur adsorbed on Mg and on Fe segregated at grain boundaries. The observed inhibition of hydrogen evolution at OCP and above is assigned to a poisoning effect by adsorbed S of the H adsorption sites on segregated iron which, in the absence of sulfur, provides catalytic sites for excess HER. The equilibrium Pourbaix diagram for the Mg-Fe-S system including the adsorbed species predicts that S is adsorbed on Mg and Fe in the E-pH conditions of this work, which confirms therole assigned to adsorbed sulfur in the inhibition of excess hydrogen evolution at OCP and under anodic polarization in the presence of H2Saq. [ABSTRACT FROM AUTHOR]

Green tide, a typical marine environmental disaster that profoundly influenced the coastal areas, has been occurred consecutively in the South Yellow Sea of China since 2007. Herein, the active microbial community structure and metabolic pathways in Qingdao offshore during an Ulva prolifera green tide were investigated by using metatranscriptomic approach. The dominant active microbial taxa at the outbreak phase were primarily a functional group that can utilize organic matters derived from U. prolifera , such as Lentibacter , Polaribacter and Planktomarina. While the taxa involved in biogeochemical cycles, including Phaeobacter , Pseudomonas and Marinobacterium , dominated the active microbial communities at the decline phase. The expression level of enzymes involved in U. prolifera polysaccharides degradation was significantly higher at the outbreak phase compared to the decline phase. At the same time, the main players Glaciecola and Polarbacter showed similar trends, suggesting that the low competitiveness for nutrients of related microorganisms at this phase made them degrade more U. prolifera polysaccharides to meet their own nutrient needs, thereby accelerating the degradation of U. prolifera. According to KEGG annotation, the biogeochemical pathways including nitrogen cycle, sulfur cycle and methane oxidation altered during the green tide, with thiosulfate oxidation and methane oxidation probably being the crucial pathways at the outbreak and the decline phase respectively. The coupling of sulfide oxidation and denitrification was also observed in this study. Furthermore, the green tide in Qingdao offshore might impact the greenhouse effects induced by CH 4 and N 2 O through influencing the related microbial processes. [Display omitted] • Active microbial community and metabolic pathways varied across phases of green tide. • High gene expression of U. prolifera polysaccharides at the outbreak phase. • Sulfide oxidation and denitrification might couple during the green tide. [ABSTRACT FROM AUTHOR]

Mercury (Hg) contamination is acknowledged as a global issue and has generated concerns globally due to its toxicity and persistence. Tunable surface-active sites (SASs) are one of the key features of efficient BCs for Hg remediation, and detailed documentation of their interactions with metal ions in soil medium is essential to support the applications of functionalized BC for Hg remediation. Although a specific active site exhibits identical behavior during the adsorption process, a systematic documentation of their syntheses and interactions with various metal ions in soil medium is crucial to promote the applications of functionalized biochars in Hg remediation. Hence, we summarized the BC's impact on Hg mobility in soils and discussed the potential mechanisms and role of various SASs of BC for Hg remediation, including oxygen-, nitrogen-, sulfur-, and X (chlorine, bromine, iodine)- functional groups (FGs), surface area, pores and pH. The review also categorized synthesis routes to introduce oxygen, nitrogen, and sulfur to BC surfaces to enhance their Hg adsorptive properties. Last but not the least, the direct mechanisms (e.g., Hg- BC binding) and indirect mechanisms (i.e., BC has a significant impact on the cycling of sulfur and thus the Hg-soil binding) that can be used to explain the adverse effects of BC on plants and microorganisms, as well as other related consequences and risk reduction strategies were highlighted. The future perspective will focus on functional BC for multiple heavy metal remediation and other potential applications; hence, future work should focus on designing intelligent/artificial BC for multiple purposes. [Display omitted] • The governing role of surface-active sites of biochars for Hg remediation in soil is summarized. • Explicate the special effects of numerous functional groups on the remediation behavior of Hg onto biochars. • Abridge and categorize various modification techniques for improving active sites. • Potential impacts of functional biochar amendments to soil are summarized. [ABSTRACT FROM AUTHOR]

Rapid urbanization and mining activities are exacerbating sulfate (SO 4 2-) pollution in surface water, and the information on its sources and transformations is crucial for understanding the sulphur cycle in mining areas. In this study, the SO 4 2- in the surface water of Huaibei mining area were monitored and the main sources of pollution and biogeochemical processes were identified using stable isotopes (δD, δ18O-H 2 O, δ34S-SO 4 2- and δ18O-SO 4 2-) and water chemistry. The results demonstrated the SO 4 2- content in the Huihe River and Linhuan subsidence water area (SWA) is higher than that in other rivers and SWAs, which exceeded the environmental quality standard of surface water. The SO 4 2- content of different rivers and SWAs showed seasonal differences, and the dry season was higher than the wet season. In addition, the SO 4 2- in Tuohe River and Suihe River is primarily caused by urban sewage and agriculture activities, while in Zhonghu and Shuoxihu SWA is mainly contributed by natural evaporate dissolution. Notably, the input of SO 4 2- in the Huihe River and Linhuan SWA caused by mining activities cannot be disregarded. The aerobic environment and isotopic fractionation of surface water indicate that sulfide oxidation is not the major cause of SO 4 2- formation. This work has revealed the multiple sources and transformation mechanisms of SO 4 2-, and provided a reference for the development of comprehensive management and effective remediation strategies of SO 4 2- contamination in surface water around mining areas. • The combination of δ34S-SO 4 2- and δ18O-SO 4 2- and hydrochemistry can accurately trace SO 4 2-. • SO 4 2- in surface water in this area derived from mixed pollution source. • The input of mine drainage is an additional important source of SO 4 2- contribution. • The transformation of SO 4 2- in surface water is relatively conservative. [ABSTRACT FROM AUTHOR]

Weathered oil, that is, tar, forms hotspots of hydrocarbon degradation by complex biota in marine environment. Here, we used marker gene sequencing and metagenomics to characterize the communities of bacteria, archaea and eukaryotes that colonized tar patties and control samples (wood, plastic), collected in the littoral following an offshore spill in the warm, oligotrophic southeastern Mediterranean Sea (SEMS). We show potential aerobic and anaerobic hydrocarbon catabolism niches on tar interior and exterior, linking carbon, sulfur and nitrogen cycles. Alongside aromatics and larger alkanes, short-chain alkanes appear to fuel dominant populations, both the aerobic clade UBA5335 (Macondimonas), anaerobic Syntropharchaeales, and facultative Mycobacteriales. Most key organisms, including the hydrocarbon degraders and cyanobacteria, have the potential to fix dinitrogen, potentially alleviating the nitrogen limitation of hydrocarbon degradation in the SEMS. We highlight the complexity of these tar-associated communities, where bacteria, archaea and eukaryotes co-exist, likely exchanging metabolites and competing for resources and space. [Display omitted] • Metagenomics shows a heterogeneous biota that is associated with tar patties. • Tar patties are hotspots of potential synergistic carbon and nutrient cycling. • Tar degraders may alleviate N limitation by fixing N 2. • Tar hydrocarbons, including short-chain alkanes, may fuel tar-associated microbes. • Micro- and macro-eukaryotes may promote nutrient cycling in tar communities. [ABSTRACT FROM AUTHOR]

Shiga toxin-producing Escherichia coli (E. coli) O157:H7 is recognized as a hazardous microorganism in the environment. Its longer survival might contribute to higher contamination risk. In this study, E. coli O157:H7 survival in estuarine sediments collected from south Hangzhou Bay was investigated. The survival time of E. coli O157:H7 in estuarine sediments increased with the distance to the water-land junction. Sediment pH was the most important factor in regulating E. coli O157:H7 survival in estuarine sediments. In addition, sediment nutrients and texture also played significant roles in the survival of E. coli O157:H7 in the sediments. On the other hand, bacterial diversity as determined by the alpha-diversity index had no significant effect on E. coli O157:H7 survival. However, specific families of bacteria were closely associated with E. coli O157:H7 survival in the sediments. Remarkably, some potential bacterial groups, e.g., the Desulfobacteraceae, Desulfobulbaceae and Desulfarculaceae families, which are mainly involved in the sulfur cycle, showed significant negative correlation with the E. coli O157:H7 survival in the sediments. On the whole, abiotic factors showed greater effects on E. coli O157:H7 survival in the test sediments than the bacterial community. Our findings provide a comprehensive understanding of E. coli O157:H7 survival and regulatory factors in estuarine sediments, establishing foundation for the prevention of pathogen contamination. Image 1 • The survival time of E. coli O157:H7 in estuarine sediments increased with the distance to the water-land junction. • Sediment pH showed an overriding effect on E. coli O157:H7 survival compared to other physicochemical properties. • Sulfate-reducing bacteria negatively correlated with E. coli O157:H7 survival in estuarine sediments. • Physicochemical properties presented a stronger influence on E. coli O157:H7 survival than the bacterial community. This study not only confirms the critical role of pH but also reveals some functional bacteria which is related to E. coli O157:H7 survival in estuarine sediments. [ABSTRACT FROM AUTHOR]

Multihaem cytochromes c are widespread in nature where they perform numerous roles in diverse anaerobic metabolic pathways. This is achieved in two ways: multihaem cytochromes c display a remarkable diversity of ways to organize multiple hemes within the protein frame; and the hemes possess an intrinsic reactive versatility derived from diverse spin, redox and coordination states. Here we provide a brief survey of multihaem cytochromes c that have been characterized in the context of their metabolic role. The contribution of multihaem cytochromes c to dissimilatory pathways handling metallic minerals, nitrogen compounds, sulfur compounds, organic compounds and phototrophism are described. This aims to set the stage for the further exploration of the vast unknown "cytochromome" that can be anticipated from genomic databases. [ABSTRACT FROM AUTHOR]

Abstract Mangrove forests are highly productive yet vulnerable ecosystems that act as important carbon sinks ("blue carbon"). The objective of this work was to analyze the impact of anthropogenic activities on microbiome structure and functioning. The metagenomic analysis revealed that the taxonomic compositions were grossly similar across all mangrove microbiomes. Remarkably, these microbiomes, along the gradient of anthropogenic impact, showed fluctuations in the relative abundances of bacterial taxa predicted to be involved in sulfur cycling processes. Functions involved in sulfur metabolism, such as APS pathways (associated with sulfate reduction and sulfur oxidation processes) were prevalent across the microbiomes, being sox and dsr AB genes highly expressed on anthropogenically-impacted areas. Apparently, the oil-impacted microbiomes were more affected in taxonomic than in functional terms, as high functional redundancies were noted across them. The microbial gene diversity found was typical for a functional system, even following the previous disturbance. Highlights • Microorganisms from mangrove sediments overcome the disturb caused by anthropogenic activity; • A high functional redundancy on Sulfur cycle was detected; • Microbiome shows the ability to adapt to new conditions created by anthropogenic activities by horizontal gene transfer. [ABSTRACT FROM AUTHOR]

The flow path of a river draining a lowland into the southern Baltic Sea, the Warnow River, was investigated to evaluate its freshwater composition and potential to be a source of dissolved substances for regional coastal waters. A spatial study was conducted in April 2019 to follow the variations from the source to the estuary. A temporal study of the composition, for five years (2017–2021), was carried out at a site just before the river reaches the estuary. Surface water was sampled to analyse major and trace elements, stable (H, C, O, S), and short-lived (Ra) isotopes. The results show that the composition of the Warnow River along the flow path is controlled by a complex interplay between in-situ processes, exchange with the atmosphere, diffuse groundwater, and surface water inlets. On a temporal scale, pH, nutrient, and redox-sensitive trace element concentrations are strongly impacted by pelagic primary production in spring. During summer and autumn, influences occurred due to benthic microbial activity, associated diffusive release from soils/sediments, and surface water inlets. Throughout the investigation period, the Warnow River was a source of isotopically light CO 2 to the atmosphere and DIC to the estuarine waters. The delivered DIC concentrations seemed to vary with season due to changes in biological pelagic and benthic activities. DOC was derived from a mixture of dominated C 3 organic sources and potentially from fertilizers. From concentration-discharge relationships, examples of dilution, mobilization, and chemostasis trends were found. Discharge-controlled seasonal trends were superimposed by system internal processes and the hydrological consequences of the river management. Our analysis thus provides new insights into the controls on the variations of water and solutes in a managed river at the land-sea interface as part of the regional hydrological cycle of a lowland catchment-coastal water system. • Spatial and seasonal investigation of multi-isotope hydrogeochemistry of a river draining into the Baltic Sea • Element sources and internal transformation processes are derived. • Concentration-discharge relationships identify the influence of river management. [ABSTRACT FROM AUTHOR]

Sulfur oxidising bacteria (SOB) are of great importance in the sulfur biogeochemical cycle and removal of undesirable hydrogen sulfide in biogas production. This study evaluated the sulfide oxidising ability of bacteria from different soils using bromocresol purple dye reduction method and spectrophotometry. The study sites were the abattoir, automobile workshop, dumpsite, rhizospheric soil, and sewer disposal sites. Starkey broth was used as a selective culture broth and sodium thiosulfate as an enrichment culture medium, both at pH 8.00. Sulfur ion evaluation was carried out using spectrophotometry at 450 nm wavelength. 16S rRNA sequencing of promising SOB was investigated. The total colony count of sulfur oxidising bacteria able to reduce the bromocresol dye on the sodium thiosulfate agar ranged from 2.00 × 103 cfu/g from the abattoir, dumpsite and sewer disposal sites to 1.50 × 104 cfu/g from the automobile workshop. Paenibacillus ripae and Staphylococcus aureus had the highest sulfur oxidation absorbance of 1.72 and 1.65 with a pH of 5.75 and 5.90 respectively. The pH of the studied bacteria on the sixth day of incubation ranged from 5.69 to 6.03. Bacillus cereus , P. ripae and S. aureus demonstrated most promising potential as sulfur oxidising agents. This work revealed the presence of SOB from different locations with relatively low pH and indicates potential importance of studied bacteria in the removal of hydrogen sulfide in biogas that may not support bio-corrosion. [Display omitted] • The sulfur oxidising bacteria (SOB) are suitable for biological desulfurization. • The SOB moderately reduce pH which makes them unlikely able to corrode bioreactors. • Highest sulfur oxidising bacteria count was recorded from the automobile workshop. • Paenibacillus ripae , Staphylococcus aureus and Bacillus cereus were most prevalent. [ABSTRACT FROM AUTHOR]

This study aims to reveal spatial distribution of hydrogen sulfide and sulfur species in marine sediments in Hiroshima Bay, Japan, by direct analyses using a combination of detection tubes and X-ray absorption fine structure spectroscopy. In summer and autumn, the hydrogen sulfide concentration ranged from <0.1 to 4 mg-S L −1 . In this study, only hydrogen sulfide was observed in autumn and at two stations in summer. In contrast, some earlier studies reported in all seasons in Hiroshima Bay the presence of acid volatile sulfide, which is used as a proxy of sulfide content. The sulfur species in sediments were mainly identified as sulfate, thiosulfate, elemental sulfur, and pyrite. Thiosulfate was a minor component compared to the other sulfur species. The formation of pyrite and sulfur derived from hydrogen sulfide oxidation played an important role in the scavenging of hydrogen sulfide. [ABSTRACT FROM AUTHOR]

The hybrid sulfur cycle has been investigated as a means to produce CO2-free hydrogen efficiently on a large scale through the decomposition of H2SO4 to SO2, O2, and H2O, and then electrochemically oxidizing SO2 back to H2SO4 with the cogeneration of H2. The net effect is the production of hydrogen and oxygen from water. Recently, sulfonated polybenzimidazoles (s-PBI) have been investigated as a replacement for Nafion due to the ability to offer increased process efficiency through the generation of higher acid concentrations at lower potentials. Here, we measure the acid concentrations and individual potential contributions toward the overall operating voltage seen in the SO2-depolarized-electrolyzer. We then determine model parameters necessary to predict voltage losses in a cell over a wide range of operating temperatures, pressures, currents and reactant flow rates. [ABSTRACT FROM AUTHOR]

Biofouling and biocorrosion in oil pipelines are serious problems capable of causing expensive, irreparable losses. For a better understanding of biocorrosion processes, several lines of evidence are required, not least experimental considerations that emulate natural conditions inside pipelines. Herein, an omics approach is used to unveil the microbial involvement in the deterioration and electrochemical process on X52 steel with Shewanella (SW), the oil pipeline microbiota (AK), and a mixed culture (AK5), the latter two obtained from a sludge of pig pipeline cleaning in the Gulf of Mexico. Shotgun metagenomics showed diverse communities at species level in pipeline sludge: bacteria up to 112, 34 archaea, 9 fungi, and 23 viruses. In AK the most abundant taxa were Petrotogaceae with Petrotoga (31.16%) and Methanomicrobiaceae (48.51%). In AK5 were Methylobacterium (49%) and Methanomicrobiaceae (19.49%). Concerning fungi and viruses, respectively: Clavariaceae (43.26%), Picciniaceae (35.59), Onygenaceae (3.77%), Siphoviridae (46.8%), Myoviridae (33.50%), Podoviridae (7.36%) in AK5. Proteomics revealed 32,284 proteins in AK, 13,664 in AK5, and 7 in SW. Expressed proteins were oxidoreductases, lyases, nitrogenases, metalloproteases, and hydrolases associated with the biocorrosion process, for instance, electron transport, sulfur oxidation, nitrate reduction, biofilm formation, and oxygen reduction. In addition to the functional annotation of metagenomes in KEGG pathways, through the Multigenomic Entropy Based Score (MEBS) the metabolic functions were evaluated explaining the relation to energy transfer processes of the biogeochemical cycles. The sludge was analyzed by X-ray diffraction (XRD), X-ray fluorescence (XRF), and Mössbauer spectroscopy suggesting the microbiota involvement in the biofouling and biocorrosion processes. Regarding the electrochemical assessments, scanning electron microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX) coupled to SEM, AK, AK5, and SW biofilms on X52 steel behaved differently. Three electrochemical mechanisms of biocorrosion are proposed. [Display omitted] • Bacteria, archaea, fungi, and viruses in biofouled marine oil pipeline were unveiled. • Oxidoreductases, nitrogenases and metalloproteases expressed during biocorrosion. • Microbiota's electrochemical behavior is involved in oil pipeline biocorrosion. • Sludge chemical features are linked up microbiota to the pipeline biofouling process. [ABSTRACT FROM AUTHOR]

Biological corrosion of sewers and sewage treatment plants constitutes a serious problem and its effects result in the loss of billions of dollars a year. It is generally acknowledged that corrosion of concrete caused by microorganisms is associated with their production of sulphuric acid as the main metabolic product. The activity of the bacteria leads to the formation of the sulphur cycle in the system, and consequently to the formation of sulphuric acid, whose presence causes corrosion of concrete. Moreover, the presence of other organisms, such as nitrifying bacteria, fungi and organic acids also contributes to the degradation of the concrete. This article discusses the mechanism caused by biogenic inorganic acids. [ABSTRACT FROM AUTHOR]

The cycling of sulfur (S), iron (Fe) and phosphorus (P) in sediments and pore water can impact the water quality of overlying water. In a heavily polluted river estuary (Yantai, China), vertical profiles of fluxes of dissolved sulfide, Fe 2+ and dissolved reactive phosphorus (DRP) in sediment pore water were investigated by the Diffusive Gradients in Thin films technique (DGT). Vertical fluxes of S, Fe, P in intertidal sediment showed the availability of DRP increased while the sulfide decreased with depth in surface sediment, indicating that sulfide accumulation could enhance P release in anoxic sediment. In sites with contrasting salinity, the relative dominance of iron and sulfate reduction was different, with iron reduction dominant over sulfate reduction in the upper sediment at an intertidal site but the reverse true in a freshwater site, with the other process dominating at depth in each case. Phosphate release was largely controlled by iron reduction. [ABSTRACT FROM AUTHOR]

Despite the effort to control SO 2 emission, sulfate is still one of the major inorganic components of PM 2.5 in urban area. Moreover, there is still a lack of understanding of the sulfate formation mechanism via SO 2 oxidation under various ambient conditions. In this study, we focus on sulfate formation during a haze pollution episode in the spring/summertime of 2016 in Seoul Metropolitan Area (SMA). During the pollution episode, PM 2.5 mass concentration exceeded over 60 μg m−3, and sulfate accounted for about 25% of the total PM 2.5 mass concentration. A sharp increase of sulfur oxidation ratio (SOR) values along with aerosol liquid water content (AWC) under humid conditions could be ascribed to an apparent contribution of aqueous-phase oxidation of SO 2 of sulfate formation during the pollution period. Comparisons of SOR values with four representative oxidants for the aqueous-phase oxidation (i.e., NO 2 , H 2 O 2 , O 3 , and TMIs) indicated that TMIs concentration, especially for Mn (II), showed the best positive correlation. Furthermore, for calculating the sulfate production rate, the contribution of TMIs concentration was found to be dominant within the pH range in SMA (2.1–3.0), which was determined by the chemical composition and derived AWC. These results imply that not only the SO 2 emission but also other chemical components (e.g., TMI and nitrate) would play a critical combined role in sulfate formation under urban haze condition. [Display omitted] • Aqueous-phase formation of sulfate occurred importantly during the haze in SMA. • The oxidation by TMIs is the most significant for sulfate formation. • Within the pH ranges in SMA (2.1–3.0), TMIs are the most contributing oxidants. [ABSTRACT FROM AUTHOR]

With the development of technology over the past twenty years’ human kind has solved most of its biggest problems that were considered unsolved before. Unfortunately, though, the consequences of this industrial and technological development affect to a great extend the major factor of life, the environment. The aim of this article is to begin with a theoretical review of the importance of the cycles for humans and to analyze the way we intervene in them and what will the consequences (long or short term) be for our lives. Furthermore, we explain phenomena like acidification, particle and photochemical cloud and how they affect our health. Moreover, we quote the substances and chemical reactions that are produced by human activity and penetrate in the cycles creating the above phenomena. We also mention especially in Greece, how human activity has changed its environment through years and we compare it with other countries from different backgrounds. [ABSTRACT FROM AUTHOR]

The colourless mat covering organically enriched sediments underlying an intensive salmon farm in Estero Pichicolo, southern Chile, was surveyed by combined 454 PyroTag and conventional Sanger sequencing of 16S/18S ribosomal RNA genes for Bacteria and Eukarya . The mat was dominated by the sulphide-oxidizing bacteria (SOB) Candidatus Isobeggiatoa, Candidatus Parabeggiatoa and Arcobacter . By order of their abundances, sulphate-reducing bacteria (SRB) were represented by diverse deltaproteobacterial Desulfobacteraceae , but also within Desulfobulbaceae , Desulfuromonadaceae and Desulfovibrionaceae . The eukaryotic PyroTags were dominated by polychaetes, copepods and nematodes, however, ciliated protozoans were highly abundant in microscopy observations, and were represented by the genera Condylostoma , Loxophyllum and Peritromus . Finally, the abundant Sulfurimonas / Sulfurovum also suggest the occurrence of zero-valence sulphur oxidation, probably derived from Beggiatoaceae as a result of bacteriovorus infaunal activity or generated as free S 0 by the Arcobacter bacteria. The survey suggests an intense and complex sulphur cycle within the surface of salmon-farm impacted sediments. [ABSTRACT FROM AUTHOR]

In assessing the soil corrosion activity on the pipeline locations caused by a combination of factors, the severity of microbiological indicators (number of sulfur cycle bacteria) was determined. Soils microbiological testing revealed the absence of sulfate-reducing bacteria and detected thiobacteria in different concentrations. Severity assessment of the soils biocorrosion activity allowed to identify a sufficiently high level of soil samples having a moderately corrosive activity. Correlation between soils biocorrosion activity criterion index and quantitative content thiobacteria of the soil was identified. The results suggest that thiobacteria play an important role in the corrosion development in underground metal pipelines and use the findings in validation preventive trends. [ABSTRACT FROM AUTHOR]

Over the past decades, mangrove ecosystem has been polluted by plastic debris and microplastics (MPs) due to anthropogenic activities. Yet, little information is available on the composition and functional diversity of microbial communities on the surface of MPs in this ecosystem. The present study aims to investigate the bacterial communities growing on the surface of polyethylene microplastics (PE-MPs) in water, surface sediments and at the water-sediment interface (WSI) of mangrove ecosystems. Obtained results showed distinct variations in the taxonomic composition of bacterial communities among water, surface sediments and PE-MPs exposed to the different sites in mangrove ecosystems. For PE-MPs deployed to water, the dominant phyla were Proteobacteria and Bacteroidetes, accounting for 89.2% of the total abundance, while a relatively high proportion of Proteobacteria (85.6 ± 8.4%) was found for PE-MPs in sediments. For PE-MPs at the WSI, the top five phyla were Proteobacteria, Bacteroidetes, Planctomycetes, Actinobacteria and Firmicutes. Relatively abundant microorganisms on PE-MPs at the WSI were mainly due to tidal ebb and flood increasing interactions of sediment bacteria and PE-MPs. Functional annotation of prokaryotic taxa (FAPROTAX) analysis demonstrated that the ecological functions of microbial communities inhabiting PE-MPs were exposure site-dependent. Bacteria living on PE-MPs in water and at the WSI mainly participated in carbon and nitrogen cycle process, whereas PE-MPs in sediments enriched bacteria responsible for sulphur cycle. These results presented here highlight the importance of the exposure sites to MPs-associated bacteria in mangrove ecosystems. [Display omitted] • Distinct microbes were found among water, sediments and PE-MPs exposed to the different sites in mangrove ecosystems. • Tide-induced resuspension favoured bacterial colonization of PE-MPs at the water-sediment interface. • Microbially-driven functions of PE-MPs varied as a function of exposure sites. [ABSTRACT FROM AUTHOR]

Abstract: The diversity of sulfate-reducing prokaryotes (SRPs) and sulfur-oxidizing prokaryotes (SOPs) in freshwater lake ecosystems was investigated by cloning and sequencing of the aprA gene, which encodes for a key enzyme in dissimilatory sulfate reduction and sulfur oxidation. To understand their diversity better, the spatial distribution of aprA genes was investigated in sediments collected from six geographically distant lakes in Antarctica and Japan, including a hypersaline lake for comparison. The microbial community compositions of freshwater sediments and a hypersaline sediment showed notable differences. The clones affiliated with Desulfobacteraceae and Desulfobulbaceae were frequently detected in all freshwater lake sediments. The SOP community was mainly composed of four major phylogenetic groups. One of them formed a monophyletic cluster with a sulfur-oxidizing betaproteobacterium, Sulfuricella denitrificans, but the others were not assigned to specific genera. In addition, the AprA sequences, which were not clearly affiliated to either SRP or SOP lineages, dominated the libraries from four freshwater lake sediments. The results showed the wide distribution of some sulfur-cycle prokaryotes across geographical distances and supported the idea that metabolic flexibility is an important feature for SRP survival in low-sulfate environments. [Copyright &y& Elsevier]

The article presents a culture-independent analysis of the bacterial assemblages in the sediments of a lugworm Arenicola marina L. bioturbated mesocosm using a molecular RNA-gene based approach. It constructs clone libraries for four spatial locations including deep yeast layer (DYL), mid sand (MS), new casts (NC), and old casts (OC). It analysed 495 clones which were grouped into 159 phylotypes. It conducts phylogenetic comparison of the sites with respect to evolutionary distance. It reveals differences in species composition between but not within the two groupings, DYL and MS and NC and OC.

Abstract: At the Nakabusa hot spring, Japan, dense olive-green microbial mats develop in regions where the slightly alkaline, sulfidic effluent has cooled to 65°C. The microbial community of such mats was analyzed by focusing on the diversity, as well as the in situ distribution and function of bacteria involved in sulfur cycling. Analyses of 16S rRNA and functional genes (aprA, pufM) suggested the importance of three thermophilic bacterial groups: aerobic chemolithotrophic sulfide-oxidizing species of the genus Sulfurihydrogenibium (Aquificae), anaerobic sulfate-reducing species of the genera Thermodesulfobacterium/Thermodesulfatator, and filamentous anoxygenic photosynthetic species of the genus Chloroflexus. A new oligonucleotide probe specific for Sulfurihydrogenibium was designed and optimized for catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH). In situ hybridizations of thin mat sections showed a heterogeneous vertical distribution of Sulfurihydrogenibium and Chloroflexus. Sulfurihydrogenibium dominated near the mat surface (50% of the total mat biovolume), while Chloroflexus dominated in deeper layers (up to 64% of the total mat biovolume). Physiological experiments monitoring in vitro changes of sulfide concentration indicated slight sulfide production by sulfate-reducing bacteria under anoxic-dark conditions, sulfide consumption by photosynthetic bacteria under anoxic-light conditions and strong sulfide oxidation by chemolithotrophic members of Aquificae under oxic-dark condition. We therefore propose that Sulfurihydrogenibium spp. act as highly efficient scavengers of oxygen from the spring water, thus creating a favorable, anoxic environment for Chloroflexus and Thermodesulfobacterium/Thermodesulfatator in deeper layers. [Copyright &y& Elsevier]

Significant links exist between the sulfur cycle, sulfur geochemistry of sedimentary systems, and ore deposits over the course of Earth history. A picture emerges of an Archean and Paleoproterozoic stage of the sulfur cycle that has much lower levels of sulfate (<200 µM), carries a signal of mass-independent sulfur, and preserves evidence for temporal and spatial heterogeneity that reflects lower amounts of sulfur cycling than today. A second stage of ocean chemistry in the Paleoproterozoic, with higher atmospheric oxygen and oceanic sulfate at low millimolar levels, follows this stage. The isotopic record in sedimentary rocks and in sulfide-bearing ore deposits suggests abundant pyrite burial and implies a missing 34S-depleted pool that may have been lost via deep ocean deposition and possibly subduction. Proterozoic ocean chemistry appears to be quite complex. The surface waters of the Proterozoic oceans are believed to have been oxygenated, but geologic evidence from ore deposits and sedimentary rocks supports coexistence of significant anoxic, intermediate water and deep-water pools in the Mesoproterozoic. This stage in ocean chemistry ends with the second major global oxidation event in the latest Neoproterozoic (~600 Ma). This event started the transition to more oxygenated intermediate and deep waters, and higher but variable oceanic sulfate concentrations. The event set the scene for the formation in the Phanerozoic of the first significant MVT deposits and possibly is reflected in changes in other sedimentary rock-hosted base metal sulfide deposits. [ABSTRACT FROM AUTHOR]

The article discusses various reports published within the issue, including one on the evolution of Earth's sulfur cycle and its importance in defining the metallogenic history of several base metal-rich deposit types, one on the long-term relationships between manganese ores and evolving seawater chemistry, and another on a description of four metallogenci periods.

The article presents a study which determines the influence on biogeochemical dynamics and molecular-level speciation of soil sulfur. It cites that main component of the global biogeochemical sulfur cycle is soil environment. The soil environment acts as source and sink of several sulfur species and mediates oxidation state changes. The study uses elemental analysis and X-ray absorption near-edge structure (XANES) to investigate the long-term influences anthropogenically mediated transitions coming from natural to managed ecosystems.

Airborne bacteria may absorb the substance from the atmospheric particles and play a role in biogeochemical cycling. However, these studies focused on a few culturable bacteria and the samples were usually collected from one site. The metabolic potential of a majority of airborne bacteria on a regional scale and their driving factors remain unknown. In this study, we collected particulates with aerodynamic diameter ≤2.5 μm (PM 2.5) from 8 cities that represent different regions across China and analyzed the samples via high-throughput sequencing of 16S rRNA genes, quantitative polymerase chain reaction (qPCR) analysis, and functional database prediction. Based on the FAPROTAX database, 326 (80.69%), 191 (47.28%) and 45 (11.14%) bacterial genera are possible to conduct the pathways of carbon, nitrogen, and sulfur cycles, respectively. The pathway analysis indicated that airborne bacteria may lead to the decrease in organic carbon while the increase in ammonium and sulfate in PM 2.5 samples, all of which are the important components of PM 2.5. Among the 19 environmental factors studied including air pollutants, meteorological factors, and geographical conditions, PM 2.5 concentration manifested the strongest correlations with the functional genes for the transformation of ammonium and sulfate. Moreover, the PM 2.5 concentration rather than the sampling site will drive the distribution of functional genera. Thus, a bi-directional relationship between PM 2.5 and bacterial metabolism is suggested. Our findings shed light on the potential bacterial pathway for the biogeochemical cycling in the atmosphere and the important role of PM 2.5 , offering a new perspective for atmospheric ecology and pollution control. [Display omitted] • Airborne bacteria can conduct carbon, nitrogen, and sulfur cycles in Chinese cities. • The bacterial carbon cycle was conducive to the degradation of organic carbon. • Bacterial nitrogen and sulfur cycles contributed to ammonium and sulfate formation. • PM 2.5 will drive the bacterial metabolisms in carbon, nitrogen, and sulfur cycles. [ABSTRACT FROM AUTHOR]

Microbial denitrification is a main source of nitrous oxide (N 2 O) emissions which have strong greenhouse effect and destroy stratospheric ozone. Though the importance of sulfide driven chemoautotrophic denitrification has been recognized, its contribution to N 2 O emissions in nature remains elusive. We built up long-term sulfide-added microcosms with sediments from two freshwater lakes. Chemistry analysis confirmed sulfide could drive nitrate respiration in long term. N 2 O accumulated to over 1.5% of nitrate load in both microcosms after long-term sulfide addition, which was up to 12.9 times higher than N 2 O accumulation without sulfide addition. Metagenomes were extracted and sequenced during microcosm incubations. 16 S rRNA genes of Thiobacillus and Defluviimonas were gradually enriched. The nitric oxide reductase with c-type cytochromes as electron donors (cNorB) increased in abundance, while the nitric oxide reductase receiving electrons from quinols (qNorB) decreased in abundance. cnorB genes similar to Thiobacillus were enriched in both microcosms. In parallel, enrichment was observed for enzymes involved in sulfur oxidation, which supplied electrons to nitrate respiration, and enzymes involved in Calvin Cycle, which sustained autotrophic cell growth, implying the coupling relationship between carbon, nitrogen and sulfur cycling processes. Our results suggested sulfur pollution considerably increased N 2 O emissions in natural environments. • N2O accumulation was up to 12.9 times higher after long-term sulfide input. • N2O production was associated more with c-type cytochrome nitric oxide reductases. • cnorB genes similar to Thiobacillus were enriched in both microcosms. • Sulfur oxidation supplied electrons to nitrate respiration. • Microbes sustained autotrophic growth through the Calvin cycle. [ABSTRACT FROM AUTHOR]

Natural processes and human activities exert important impacts on elemental cycling in coastal sediments, which has not been well documented. Sediments in the Bohai Sea and North Yellow Sea were investigated to assess the impacts of the Yellow River inputs and/or anthropogenic perturbations on diagenesis of iron and sulfur. Labile iron (0.5 M HCl-extractable iron) in the sediments is low due to iron-poor nature of source materials. Dynamic regimes and low availability of labile organic carbon (OC) result in relatively low sulfide contents in deltaic sediments. However, low but continuous supply of labile OC exported from an anthropogenically impacted bay could substantially elevate sulfide burial in sediments near the bay. Neither offshore oil exploitations nor frequent algal blooms in the seas have detectable influences on iron and sulfur diagenesis in the sediments. The sediments are capable of quickly consuming porewater sulfide by reaction with reactive iron under the current conditions. [Display omitted] • Availability of labile organic carbon is driving factor of sulfate reduction. • Labile iron is low in the sediment due to iron-poor nature of source materials. • Human perturbations have no significant impact on sulfur and iron diagenesis. • The Yellow River estuary exerts important influences on sulfur cycling. [ABSTRACT FROM AUTHOR]

Dimethylated sulfur compounds play an important role in global sulfur cycle. We investigated the seasonality of dimethylsulfoniopropionate (DMSP), dimethylsulfoxide (DMSO), dimethylsulfide (DMS) and associated processes in two north China marginal seas during 2014 and 2016. High concentrations of DMS, DMSP and DMSO occurred in summer/spring, while the lowest were observed in winter. This clear seasonality was primarily driven by biomass abundance and phytoplankton communities, reflected in chlorophyll a concentrations and the composition/ratios of diatoms and dinoflagellates. The spring maximum was attributed to the annual occurrence of algal bloom. The sea-to-air fluxes of DMS also varied largely between seasons, with an average of 8.84, 11.87, 10.50 and 2.14 μmol m−2 day−1 in spring, summer, autumn and winter, respectively. Given the seasonal uncertainty of sea-to-air flux, the seasonality or situations where specific blooms occur regularly should be considered for accurate estimation of annual global DMS emission. • Strong seasonality driven by biomass abundance and phytoplankton communities were observed for dimethylated sulfur compounds. • Annual occurrence of algal bloom lead to the spring maximum of sulfur compounds in north China marginal seas. • Sea-to-air flux of DMS varied largely between seasons and influences the estimation of annual emissions. [ABSTRACT FROM AUTHOR]

The anaerobic hypersaline sediments of an ephemeral pond from the S'Avall solar salterns constituted an excellent study system because of their easy accessibility, as well as the analogy of their microbial assemblages with some known deep-sea hypersaline anaerobic brines. By means of shotgun metagenomics and 16S rRNA gene amplicon sequencing, the microbial composition of the sediment was shown to be stable in time and space. The communities were formed by prokaryote representatives with a clear inferred anaerobic metabolism, mainly related to the methane, sulfur and nitrate cycles. The most conspicuous finding was the inverted nature of the vertical stratification. Contrarily to what could be expected, a methanogenic archaeal metabolism was found to dominate in the upper layers, whereas Bacteria with fermentative and anaerobic respiration metabolisms increased with depth. We could demonstrate the methanogenic nature of the members of candidate lineages DHVE2 and MSBL1, which were present in high abundance in this system, and described, for the first time, viruses infecting these lineages. Members of the putatively active aerobic genera Salinibacter and Halorubrum were detected especially in the deepest layers for which we hypothesize that either oxygen could be sporadically available, or they could perform anaerobic metabolisms. We also report a novel repertoire of virus species thriving in these sediments, which had special relevance because of their lysogenic lifestyles. [ABSTRACT FROM AUTHOR]

• Ore petrography and EPMA studies reveal chalcopyrite disease in Fe2+ rich sphalerite at Biskhan and Jangeldehri. • The absence of chalcopyrite disease in Fe2+ poor sphalerite at Ghisi is due to variable conditions of the reduced hydrothermal fluid, and different depth of mineralization. • The significant and wider variation of δ 34S VCDT of sulfide from three VHMS deposit of Betul Belt suggestive of multiple sources. • Different depth S reduction leads to different assemblages of mineralization (Zn–Cu–Pb to Zn–Cu). This work provides an overview of the geological, petrological, and geochemical data available on the three volcanic-hosted massive sulfides (VHMS) deposits (Ghisi, Biskhan, and Jangaldehri) in Betul Belt, Central Indian Tectonic Zone. Sulfur isotope geochemistry was used for the first time from the Betul Belt to constrain the source of sulfur for a better understanding of the ore genesis process. Mineralization is hosted in a felsic dominant bimodal volcano-sedimentary sequence associated with syn-genetic hydrothermal alteration, i.e., intense Mg–Ca alteration (actinolite-tremolite-anthophyllite) and Al–Fe alteration zone (gahnite-garnet-biotite-staurolite) followed by regional metamorphism. Field observations, drill core logging, and petrography studies reveal different modes of mineralization, i.e., dissemination, stringers, and semi-massive sulfides vein, comprises of chalcopyrite, sphalerite, pyrite, galena with lesser pyrrhotite, are paragenetically distinct in three deposits. The petrography, SEM-EPMA studies show the presence of chalcopyrite disease in Fe-rich sphalerite at Biskhan and Jangaldehri in the east and absence of the same texture at Ghisi in the west. This difference reveals the variable physio-chemical nature of the hydrothermal fluid and partial melting of sulfides during subsequent metamorphism. Cu–Fe mineralization was deposited from high-temperature hydrothermal fluids with less sulfur activity at Biskhan-Jangaldehri. Later Zn–Cu–Pb mineralization was formed from lower temperature hydrothermal fluids with higher sulfur activity. The δ 34S values of sulfides (sphalerite, chalcopyrite, and pyrite) from three deposits show a wide range of sulfur values (δ 34S) from −12.87 to + 19.31‰ (n = 27), consistent with heterogeneous sourcing of S, probably combining magmatic source along with the reduction of seawater sulfate. Variation in the sulfur isotopic compositions of sulfide was the result of dilution and cooling of the metalliferous fluid at different stages after interaction with meteoric, seawater and hydrothermal fluids, which caused the deposition of base metal sulfides. Sulfides from Ghisi in the west display both +ve and −ve values (−12.88 to + 0.38‰; n = 10), suggest sulfur predominantly derived by thermochemical reduction of seawater sulfate with minor input of magmatic sulfur reduction lead to polymetallic Zn–Cu–Pb mineralization. The gradual increasing in the δ 34S values (more + ve values +18.65 to +19.31‰; n = 8) from west to east at Biskhan and Jangaldehri (+ 5.01 to + 8.3‰, n = 9) may be due to involvement of both the leaching of igneous basement rocks and chemical process of seawater sulfates by thermochemical reduction (TSR) from deep water levels lead to Zn–Cu mineralization. This δ 34S variation occurs in three deposits of the Betul Belt due to modifications of the primary mineralization during subsequent stages of ore formation and metamorphism, indicating a complex fluid evolution history for VHMS deposits in Betul Belt, Central India, where S derived from a heterogeneous source by multiple geological processes. This situation is more akin to many established VHMS deposits of ancient and modern submarine hydrothermal systems. [ABSTRACT FROM AUTHOR]

Microbial mercury (Hg) methylation transforms inorganic mercury to neurotoxic methylmercury (MeHg) mainly in aquatic anoxic environments. Sampling challenges in marine ecosystems, particularly in submarine canyons, leads to a lack of knowledge about the Hg methylating microbia in marine sediments. A previous study showed an enrichment of mercury species in sediments from the Capbreton Canyon where both geochemical parameters and microbial activities constrained the net MeHg production. In order to characterize Hg-methylating microbial communities from coastal to deeper sediments, we analysed the diversity of microorganisms' (16S rDNA-based sequencing) and Hg methylators (hgcA based cloning and sequencing). Both, 16S rDNA and hgcA gene analysis demonstrated that the putative Hg-methylating prokaryotes were likely within the Deltaproteobacteria, dominated by sulfur-compounds based reducing bacteria (mainly sulfate reducers). Additionally, others clades were also identified as carrying HgcA gene, such as, Chloroflexi, Spirochaetes, Elusimicrobia, PVC superphylum (Plantomycetes, Verrucomicrobia and Chlamydiae) and Euryarchaea. Nevertheless, 61% of the hgcA sequences were not assigned to specific clade, indicating that further studies are needed to understand the implication of new microorganisms carrying hgcA in the Hg methylation in marine environments. These first results suggest that sulfur cycle drives the Hg-methylation in marine ecosystem. Image 1 • Environmental parameters (e.g. %MeHg and [HgII]) explained the microbial community distribution according to their location in the Capbreton Canyon. • Global diversity showed dominance of Deltaproteobacteria known to include the major known Hg-methylators. • Identification of Procaryotes carrying hgcA involved in the methylation of mercury in submarine canyon sediments. • The methylation of mercury is mainly drived by the sulfur-compounds reduction. • More than 50% of Procaryotes carrying hgcA were unknown; novel Hg-methylators must still be discovered in oceans. [ABSTRACT FROM AUTHOR]

Distributions and variations of biogenic sulfur compounds including dimethylsulfide (DMS), dissolved and total dimethylsulfoniopropionate (DMSPd and DMSPt) and acrylic acid (AA) were investigated in coastal waters off Qingdao, China during the late-bloom and after-bloom periods of the Ulva prolifera bloom of 2015. DMSPd, DMS and AA concentrations after the bloom were significantly higher than during the late-bloom, but DMSPt concentrations in surface waters began to decrease. High concentrations of these compounds in the surface layer were associated with the bloom, with the exception of increased concentrations of DMSPt in the middle layer as decaying U. prolifera debris settled. The sea-to-air fluxes of DMS were estimated to be 18.08 and 24.24 μmol m−2 d−1 during the late-bloom and after-bloom, and about three times higher than the reported average fluxes of the Yellow Sea, which highlighted the impacts of U. prolifera blooms on DMS emissions. • High concentrations of DMSP, DMS and AA were released by the Ulva prolifera bloom. • DMSPd, DMS and AA concentrations after the bloom were higher than during the bloom. • High values of DMSPd, DMS and AA emerged in surface waters except DMSPt. • The sea-to-air flux of DMS was three times higher than that of the Yellow Sea. [ABSTRACT FROM AUTHOR]

Mangroves in the Northwest Coast of South America are contaminated with heavy metals due to wastewater discharges from industries, affecting the biota from this environment. However, bacteria proliferate in these harsh environmental conditions becoming possible sentinel of these contaminations. In this study, bacterial community composition was analyzed by throughput sequencing of the 16S rRNA gene from polluted and pristine mangrove sediments affected by marked differences in heavy metal concentrations. Core bacteria were dominated by Proteobacteria, Firmicutes, and Bacteroidetes phyla, with strong differences between sites at class and genus levels, correlated with metal levels. Increment of abundance on specific OTUs were associated with either elevated or decreased concentrations of metals and with the sulfur cycle. The abundance of Sulfurovum lithotrophicum, Leptolinea tardivitalis, Desulfococcus multivorans and Aminobacterium colombiense increases when metals rise. On contrary , Bacillus stamsii, Nioella nitrareducens and Clostridiisalibacter paucivorans abundance increases when metal levels are reduced. We propose these OTUs as bacterial sentinels, whose abundance can help monitor the restoration programs of contaminated mangrove sediments in the future. • Bacteria community on pristine mangroves (PH) is different from one with high levels of metals (GYE). • Fluctuations in metal levels in GYE affected the composition of the bacterial community. • While Bacillus sp. Decreases its abundance, Desulfococcus sp. is favored within GYE. • The abundance of Romboutsia sp. and Sunxiuqinia in GYE would not be related to metal levels. Capsule: Unveiling specific bacterial taxa to be proposed as environmental sentinels for mangrove sediment pollution. [ABSTRACT FROM AUTHOR]

• We study the impacts of bacteria on the occurrence of algal blooms in the lake. • Time delay is considered for nutrient recycling and growth of bacterial population. • The system exhibits chaotic dynamics for increasing the values of time delay. • We draw Poincare map and compute maximum Lyapunov exponent to confirm chaos. • We perform a global sensitivity analysis to identify the important parameters. Bacteria associated with oceanic algal blooms are acknowledged to play important roles in carbon, nitrogen, and sulfur cycling. They influence the climate, mediate primary production, participate in biogeochemical cycles, and maintain ecological balance. A greater insight on the control of the interactions between microalgae and other microorganisms, particularly bacteria, would be helpful in exploring the role of bacteria on algal blooms in lakes. The present study is to investigate the effects of bacteria on the occurrence of algal blooms in lakes. We propose a nonlinear mathematical model by taking into account interactions among nutrients, algae, detritus and bacteria in a lake. We assume that bacteria enhance the growth of algal biomass through remineralization only. Equilibria are analyzed for feasibility and stability, substantiated via numerical simulations. Increase in uptake rate of nutrients by algae and bacteria death rate generates transcritical bifurcations. We perform a global sensitivity analysis to identify the important parameters of the model having a significant impact on the densities of algae and bacteria in the lake. Our findings show that massive algal production might occur in the presence of bacteria, and microalgae-bacteria interactions can be beneficial to the massive production of microalgae. Further, the effect of time delays involved in the bacterial decomposition conversion of detritus into nutrients is studied. Chaotic oscillations may arise via equilibrium destabilization on increasing the values of the time lag. To support chaos occurrence, the Poincaré map is drawn and the Lyapunov exponents are also computed. The findings, critically important for lake restoration, indicate that hypoxia in the lake can be prevented if detritus removal is performed on a regular basis, at time intervals smaller than the critical threshold in the delay with which detritus is decomposed into nutrients. [ABSTRACT FROM AUTHOR]