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1.
In this study, various amounts of oxygen were added to the anaerobic phase of an anaerobic‐aerobic sequencing batch reactor (SBR) receiving azo dye remazol brilliant violet 5R to mimic the input of oxygen into the anaerobic zones of biological textile wastewater treatment plants. The effect of oxygen on the anaerobic biodegradative capability of the mixed microbial culture for remazol brilliant violet 5R was investigated. To investigate the effect of oxygen on anaerobic azo dye biodegradation, the anaerobic phase of the SBR cultures were exposed to a very low limited amount of oxygen for various air flow rates. Initially, an air flow rate of 20 mL/min was applied, further on the air flow rate in the anaerobic phase was increased up to 40 mL/min. System performance was determined by monitoring chemical oxygen demand, color removal rate, activities of anaerobic (azo reductase) and aerobic enzymes (catechol 2,3‐dioxygenase, catechol 1,2‐dioxygenase). The results of percentage COD reduction at each stage were similar for all runs, giving an overall reduction of 96%. Anaerobic color removal efficiency and azo reductase activity of anaerobic microorganisms were adversely affected by the addition of oxygen. Color removal efficiencies of the anaerobic phases decreased from 80% down to 42 and 38% for the limited oxygen conditions of 20 mL/min and 40 mL/min, respectively. It was observed that the activity of catechol 2,3‐dioxygenase and catechol 1,2‐dioxygenase, involved in breakage of aromatic rings, increased after they are exposed to oxygen limited conditions compared to fully anaerobic conditions. It was also observed that catechol 1,2‐dioxygenase enzyme activity increased by increasing the oxygen level on oxygen limited conditions in the anaerobic zone.  相似文献   

2.
Methods for predicting aquifer sensitivity to contamination typically ignore geochemical factors that affect the occurrence of contaminants such as nitrate. Use of geochemical information offers a simple and accurate method for estimating aquifer sensitivity to nitrate contamination. We developed a classification method in which nitrate-sensitive aquifers have dissolved oxygen concentrations > 1.0 mg/L, Eh values >250 mV, and either reduced iron concentrations < 0.1 mg/L or total iron concentrations < 0.7 mg/L. We tested the method in four Minnesota aquifer systems having different geochemical and hydrologic conditions. A surficial sand aquifer in central Minnesota exhibited geochemical zonation, with a rapid shift from aerobic to anaerobic conditions 5 m below the water table. A fractured bedrock aquifer in east-central Minnesota remained aerobic to depths of 50 m, except in areas where anaerobic ground water discharged upward from an underlying aquifer. A bedrock aquifer in southeast Minnesota exhibited aerobic conditions when overlain by surficial deposits lacking shale, whereas anaerobic conditions occurred under deposits that contained shale. Surficial sand aquifers in northwest Minnesota contained high concentrations of sulfate and were anaerobic throughout their extent. Nitrate-nitrogen was detected at concentrations exceeding 1 mg/L in 135 of 149 samples classified as sensitive. Nitrate was not detected in any of the 109 samples classified as not sensitive. We observed differences between our estimates of sensitivity and existing sensitivity maps, which are based on methods that do not consider aquifer geochemistry. Because dissolved oxygen, reduced iron, and Eh are readily measured in the field, use of geochemistry provides a quick and accurate way of assessing aquifer sensitivity to nitrate contamination.  相似文献   

3.
Heterotropic bacteria can degrade organic substrates utilizing different terminal electron acceptors. The sequence of electron acceptor utilization depends on the energy yield of the individual reaction pathway, which decreases as the redox potential decreases. Due to these differences in energy yield, and an inhibiting activity of oxygen on some enzymatic processes, the simultaneous utilization of oxygen and nitrate as terminal electron acceptors may not occur for many degradation processes, unless the oxygen concentration falls below a given threshold level (about 0.2 mg/l).Two sand column experiments were conducted, with toluene as the carbon source, and showed an apparent simultaneous utilization of oxygen and nitrate as electron acceptors in regions where the oxygen concentration was significantly higher (⩾1.1 mg/l) than the above mentioned threshold concentration. Results from aerobic and anaerobic plate-count analyses showed growth of both aerobes and denitrifiers in the zone of the column where simultaneous utilization of oxygen and nitrate was observed. From these observations, it was postulated that the porous media contained oxygen-free microlocations where the denitrifiers were able to degrade the toluene.To simulate the observed dynamics, a dual biofilm model was implemented. This model formulation assumes that the biofilm is composed of two distinct layers, where the outer layer is colonized by aerobic bacteria and the inner layer by denitrifying bacteria. The thickness of the aerobic layer is such that oxygen is depleted at the boundary of these two layers, resulting in oxygen-free microlocations that allows denitrification to proceed, even though oxygen is still present in the bulk fluid phase. The model simulations compared well to the experimental profiles. Model analyses indicated that changes in physical, chemical, and hydrologic parameters could change the length and location of the zone where at the macroscopic level, oxygen and nitrate are utilized simultaneously. Comparisons of the proposed model to macroscopic modeling approaches showed that a dual biofilm model is able to describe the simultaneous utilization of oxygen and nitrate more accurately.  相似文献   

4.
Discharge of groundwater from a limestone aquifer through floodplain sediments is associated with a large decrease in the nitrate concentration of the water. Results are presented to show that only a small amount of this reduction is caused by dilution of groundwater by water already present within the floodplain sediments; most of the effect is an active reduction process, most probably biological denitrification. The nitrate reduction process appears to operate independently of surface vegetation type and tends to be focused in specific regions of the floodplain where sediments are anaerobic and carbon-rich. The results suggest that active denitrification can operate throughout the winter, when nitrate concentrations in groundwater are at their highest and that the process remains effective even during periods of maximum run-off. The results show that undrained floodplains can be used as buffer zones to protect surface waters from groundwater polluted with agriculturally derived nitrate.  相似文献   

5.
Due to its oxidation-reduction potential, oxygen occurs in the TTC test for the determination of the dehydrogenase activity as a competitive hydrogen acceptor. At different oxygen concentrations in the solution to be tested and also at varying rates of oxygen depletion, e.g. in activated sludge samples, thus the formazan formation from TTC shows differences. Under similar anaerobic conditions, the test results of the dehydrogenase activity are higher in most cases and show a smaller range of variation than under aerobic conditions. The importance of the oxygen concentration is demonstrated in investigations with activated sludge, anaerobic conditions being set by addition of Na2SO3.  相似文献   

6.
Purification of Wastewaters Containing Azo Dyes This study describes the degradability of the azo dye C.I. Reactive Violet 5 by a continuous flow biological treatment system consisting of three rotating disc reactors. The azo dye was first decolorized in an anaerobic reactor. Decolorization was improved by adding an auxiliary substrate (yeast extract and acetic acid). Although severe operating conditions were experienced due to failures in the temperature and pH-controllers, the reactor recovered quickly and continued to decolorize reliably. The removal of the auxiliary substrate in the anaerobic reactor was not satisfactory, probably due to the copper in the azo dye. Batch experiments showed that copper was removed from the dye molecule and precipitated during the decolorization. In the continuous flow reactor, the copper precipitate on the disc can redissolve due to a pH-gradient in the fixed biomass becoming toxic again for the bacteria. In the following two aerobic reactors, the auxiliary substrate was degraded, but mineralization of the dye metabolites was insufficient. The aromatic amines produced by the anaerobic decolorization are more toxic in the bacterial luminescence test than the azo dye. Therefore, decolorization alone cannot be used to treat colored wastewater. Since the amines can also be produced in anaerobic parts of rivers, the dyes have to be removed in a more efficient way. That is the reason why in further experiments ozonation is being tested to increase the biological degradability of the azo dye for a following aerobic stage. Either ozonation can be used after the two stage treatment of the dye in anaerobic/aerobic reactors or the dye can be oxidized directly, making the addition of auxiliary substrate unnecessary. These configurations are being tested with the goal to degrade the dye with the least ozone consumption.  相似文献   

7.
A demonstration plant for biological heterotrophic water treatment of nitrate polluted groundwater has been operated in Coswig near Dresden since 1989. In this NEBIO tube reactor process the denitrification is achieved in a downstream fluidized bed with continuous regeneration of sintered polystyrene particles as inert carrier material. A nutrient consisting of ethanol and phosphate is dosed in the reactor influent. In the subsequent treatment stages the denitrified water is aerated, filtered through a multilayer and GAC filter, and is finally disinfected with chlorine gas. The influence of changing raw water quality (oxygen content, pH value) on the process performance was examined. Increasing oxygen concentration lowers the nitrate reduction potential and rises the consumptive ratio ΔC/ΔNO3. The technology shows a high removal performance of 270 g NO3 m?3 h?1 in the range of pH 6.2 to pH 7.3 which is typical for natural groundwaters. The degradation of nitrate is increasingly inhibited for pH values beyond 7.6. Nitrite production occurs significantly in high pH ranges. The results lead to further insight in the stoichiometry of heterotrophic denitrification. By expressing the stoichiometric equations for nitrate and oxygen respiration as functions of oxygen and pH value it could be shown that the influent water quality has strong effects on the consumption of ethanol. A kinetic model was developed to predict the reactor performance under changing raw water conditions. A two stage kinetic model was designed, regarding two main effects: biochemical degradation of oxygen, nitrate and ethanol and distribution of active biomass due to hydraulic properties of the tube reactor. This model may be helpful for reactor design for sites of various ground water qualities.  相似文献   

8.
A simplified suspended growth integrated system with an anaerobic zone in front of the aerobic one was used for the development of the bacterium Acinetobacter for phosphorus removal. The pilot plant experimental equipment was built at the Prague municipal works. The tests were carried out on a comparative basis, the control system was operated as a completely mixed activated sludge process. In the integrated system a to phosphate removal of 80 to 86% was achieved only in a biological way. In the control system, there was no development of Acinetobacter and the biological phosphate removal was only 5%. To rise it to the extent comparative with the integrated system, high doses of ferric chloride for a simultaneous precipitation of phosphate were required. The results obtained showed that the strictly biological process in the integrated system could meet normal practice requirements, even though it is not able to compete with the simultaneous phosphate precipitation using high coagulant dosages as for as the attainable efficiency and higher values of the sludge index are concerned.  相似文献   

9.
氧化还原条件对红枫湖沉积物磷释放影响的微尺度分析   总被引：7，自引：0，他引：7  
选取贵州红枫湖为研究对象,在实验室条件下模拟了自然、好氧和厌氧条件下沉积物内源磷的释放过程,联合应用微电极技术和沉积物磷形态分析对沉积物—水界面开展了微尺度观测与研究.结果表明,厌氧条件下红枫湖沉积物总磷含量显著降低,且主要是NaOH提取态磷(NaOH-P)和残渣态磷(rest-P)含量降低所致,厌氧条件下沉积物孔隙水中磷酸盐浓度明显升高,而好氧条件下沉积物孔隙水磷酸盐浓度显著降低,反映厌氧条件显著促进了红枫湖沉积物磷释放.厌氧条件下沉积物内部溶解氧浓度下降、硫还原活动增强可能是导致NaOH-P释放的主要原因.O_2浓度的降低加速了沉积物还原作用并产生大量H2S,进而与二价铁离子形成硫化亚铁沉淀,最终导致NaOH-P(Fe-P)释放到孔隙水中.好氧条件向厌氧条件的转换可通过改变沉积物内部pH值分布和微生物活动促使rest-P释放:厌氧条件下,厌氧微生物不仅可以消耗硫酸根产生H_2S,导致pH值降低,还可消耗有机质,将有机磷转变为无机磷.上述研究结果表明,沉积物—水界面氧化还原环境可影响沉积物氧渗透深度、pH值分布、微生物活动、硫循环以及有机质降解过程,进而控制沉积物磷的形态转化与释放.联合应用微电极技术和沉积物磷形态分析对湖泊沉积物—水界面开展微尺度观测研究是揭示沉积物内源磷释放机制与控制因素的有效途径.  相似文献   

10.
A model framework is presented for simulating nitrogen and carbon cycling at the sediment–water interface, and predicting oxygen consumption by oxidation reactions inside the sediments. Based on conservation of mass and invoking simplifying assumptions, a coupled system of diffusive–reactive partial differential equations is formulated for two-layer conceptual model of aerobic–anaerobic sediments. Oxidation reactions are modeled as first-order rate processes and nitrate is assumed to be consumed entirely in the anoxic portion of the sediments. The sediments are delineated into a thin oxygenated surface layer whose thickness is equal to the oxygen penetration depth, and a lower, but much thicker anoxic layer. The sediments are separated from the overlying water column by a relatively thin boundary layer through which mass transfer is diffusion controlled. Transient solutions are derived using the method of Laplace transform and Green’s function, which relate pore-water concentrations of the constituents to their concentrations in the bulk water and to the flux of decomposable settling organic matter. Steady-state pore-water concentrations are also obtained including expressions for the extent of methane saturation zone and methane gas flux. A relationship relating the sediment oxygen demand (SOD) to bulk water oxygen is derived using the two-film concept, which in combination with the depth-integrated solutions forms the basis for predicting the extent of oxygen penetration in the sediment. Iterative procedure and simplification thereof are proposed to estimate the extent of methane saturation zone and thickness of the aerobic layer as functions of time. Sensitivity of steady-state solutions to key parameters illustrates sediment processes interactions and synergistic effects. Simulations indicate that for a relatively thin diffusive boundary layer, d, oxygen uptake is limited by biochemical processes inside the sediments, whereas for a thick boundary layer oxygen transfer through the diffusive boundary layer is limiting. The results show an almost linear relationship between steady-state sediment oxygen demand and bulk water oxygen. For small d methane and nitrogen fluxes are sediment controlled, whereas for large d they are controlled by diffusional transfer through the boundary layer. It is shown that the two-layer model solution converges to the one-layer model (anaerobic layer) solution as the thickness of the oxygenated layer approaches zero, and that the transient solutions approach asymptotically their corresponding steady-state solutions.  相似文献   

11.
Diisopropanolamine Biodegradation Potential at Sour Gas Plants   总被引：1，自引：0，他引：1  
The potential for aerobic and anaerobic biodegradation of a sour gas treatment chemical, diisopropanolamine (DIPA), was studied using contaminated aquifer materials from three sour gas treatment sites in western Canada. DIPA was found to be readily consumed under aerobic conditions at 8°C and 28°C in shake flask cultures incubated with aquifer material from each of the sites, and this removal was characterized by first-order kinetics. In addition, DIPA biodegradation was found to occur under nitrate-, Min(IV)., and Fe(III)-reducing conditions at 28°C, and in some cases at 8°C, in laboratory microcosms, DIPA loss corresponded to consumption of nitrate, and production of Mn(II) and Fe(II) in viable microcosms compared to corresponding sterile controls. A threshold DIPA concentration near 40 mg/L was observed in the anaerobic microcosms. This report provides the first evidence that DIPA is biodegraded under anaerobic conditions, and our data suggest that biodegradation may contribute to DIPA attenuation under aerobic and anaerobic conditions in aquifers contaminated with this sour gas treatment chemical.  相似文献   

12.
This study reports the performance of a combined anaerobic–aerobic packed‐bed reactor that can be used to treat domestic sewage. Initially, a bench‐scale reactor was operated in three experimental phases. In the first phase, the anaerobic reactor was operated with an average organic matter removal efficiency of 77% for a hydraulic retention time (HRT) of 10 h. In the second phase, the reactor was operated with an anaerobic stage followed by an aerobic zone, resulting in a mean value of 91% efficiency. In the third and final phase, the anaerobic–aerobic reactor was operated with recirculation of the effluent of the reactor through the anaerobic zone. The system yielded mean total nitrogen removal percentages of 65 and 75% for recycle ratios (r) of 0.5 and 1.5, respectively, and the chemical oxygen demand (COD) removal efficiencies were higher than 90%. When the pilot‐scale reactor was operated with an HRT of 12 h and r values of 1.5 and 3.0, its performance was similar to that observed in the bench‐scale unit (92% COD removal for r = 3.0). However, the nitrogen removal was lower (55% N removal for r = 3.0) due to problems with the hydrodynamics in the aerobic zone. The anaerobic–aerobic fixed‐bed reactor with recirculation of the liquid phase allows for concomitant carbon and nitrogen removal without adding an exogenous source of electron donors and without requiring any additional alkalinity supplementation.  相似文献   

13.
Investigations of geology, hydrogeology, and ground water chemistry in the aquifer downgradient from Sjoelund Landfill, Denmark, formed the basis for an evaluation of natural attenuation as a remediation technology for phenoxy acid herbicides at the site. Concentrations of phenoxy acids were up to 65 μg/L in the ground water, primarily 4-chlor-2-methylphenoxypropionic acid (MCPP) and 2,4-dichlorophenoxypropionic acid (dichlorprop). Mass removal of the phenoxy acids was shown within 50 to 100 m of the landfill by calculation of contaminant fluxes passing transects at three distances. There was accordance between increasing oxygen concentrations and decreasing phenoxy acid concentrations with distance from the landfill, indicating that aerobic degradation was a major mass removal process. Presence of high concentrations of putative anaerobic phenoxy acid metabolites suggested that anaerobic degradation was also occurring. Laboratory degradation experiments using sediment and ground water from the aquifer supported aerobic and anaerobic degradability of MCPP at the site. It was concluded that natural attenuation may be applicable as a remedy for the phenoxy acids at the Sjoelund Landfill site, although uncertainties related to calculations of chloride and phenoxy acid fluxes at a complex site and identification of specific in situ indicators were encountered. Thus, there is a pronounced need for development and broader experience with evaluation tools for natural attenuation of phenoxy acids, such as specific metabolites, changes in enantiomeric fractions, compound-specific stable carbon isotope ratios, or microbial fingerprints.  相似文献   

14.
The gel-permeation chromatography system with multicomponent detection of organic carbon, organic nitrogen, organic halogen, and UV/vis absorption measurement is shown to be a useful tool for characterization of industrial wastewaters and wastewater treatment processes. The proposed system was used to investigate biologically treated wastewater from chemical industry, whereby one branch stream was identified to be the main source of persistent halogenated organics. Various treatment processes of pulp mill wastewater were also evaluated revealing that precipitation with aluminium is very effective for the removal of the high molecular fraction whereas the biological treatment is generally less selective. In the biological treatment of tannery wastewaters, it has been shown that the aerobic treatment, in contrast to anaerobic step, causes evident alterations of the composition of the polar DOC fraction. The nitrogen containing compounds are also better decomposed in the aerobic step compared to the anaerobic one.  相似文献   

15.
湖泊生态系统产甲烷与甲烷氧化微生物研究进展   总被引：3，自引：1，他引：2  
唐千  薛校风  王惠  邢鹏 《湖泊科学》2018,30(3):597-610
湖泊生态系统是重要的大气甲烷来源,其甲烷释放量占全球自然生态系统的40%.产甲烷和甲烷氧化微生物在湖泊甲烷生产和消耗过程中发挥关键作用.本文综述了近期有关湖泊生态系统甲烷产生与氧化过程的研究进展,重点介绍产甲烷与甲烷氧化微生物在湖泊中的分布特征、代谢途径以及调控机制.现有研究表明,湖泊中甲烷的生成不仅仅依靠赋存于沉积物和水体厌氧层的产甲烷古菌,还可能来自有氧环境中其他产甲烷微生物的代谢作用.湖泊中的甲烷在脱离水体逸散至大气之前,被甲烷氧化微生物利用,转化成二氧化碳和小分子有机化合物(如甲醇、甲醛和甲酸等).除了传统依赖氧气作为电子受体的好氧氧化过程外,新近研究还揭示了多种厌氧甲烷氧化过程,包括依赖还原硫酸盐、硝酸盐和亚硝酸盐以及Fe~(3+)/Mn~(4+)等金属离子的甲烷氧化过程.文献综合分析表明,反硝化型厌氧甲烷氧化过程主要发生在淡水湖泊中,而硫酸盐还原型主要发生在高盐度或者高碱度湖泊中.水体温度、溶解氧浓度可以显著影响产甲烷与甲烷氧化微生物的丰度与群落结构,其他湖泊环境条件,如盐度、pH和有机质类型等都可能改变产甲烷与甲烷氧化微生物的分布和代谢活性.不同湖泊类型的比较研究,有助于全面掌握影响湖泊产甲烷与甲烷氧化微生物的时空分布与代谢特征的主导因素.  相似文献   

16.
A field study of oxygen-enhanced biodegradation was carried out in a sandy iron-rich ground water system contaminated with gasoline hydrocarbons. Prior to the oxygen study, intrinsic microbial biodegradation in the contaminant plume had depleted dissolved oxygen and created anaerobic conditions. An oxygen diffusion system made of silicone polymer tubing was installed in an injection well within an oxygen delivery zone containing coarse highly permeable sand. During the study, this system delivered high dissolved oxygen (DO) levels (39 mg/L) to the ground water within a part of the plume. The ground water was sampled at a series of monitors in the test zone downgradient of the delivery well to determine the effect of oxygen on dissolved BTEX, ground water geochemistry, and microbially mediated biodegradation processes. The DO levels and Eh increased markedly at distances up to 2.3 m (7.5 feet) downgradient. Potential biofouling and iron precipitation effects did not clog the well screens or porous medium. The increased dissolved oxygen enhanced the population of aerobes while the activity of anaerobic sulfate-reducing bacteria and methanogens decreased. Based on concentration changes, the estimated total rate of BTEX biodegradation rose from 872 mg/day before enhancement to 2530 mg/day after 60 days of oxygen delivery. Increased oxygen flux to the test area could account for aerobic biodegradation of 1835 mg/day of the BTEX. The estimated rates of anaerobic biodegradation processes decreased based on the flux of sulfate, iron (II), and methane. Two contaminants in the plume, benzene and ethylbenzene, are not biodegraded as readily as toluene or xylenes under anaerobic conditions. Following oxygen enhancement, however, the benzene and ethylbenzene concentrations decreased about 98%, as did toluene and total xylenes.  相似文献   

17.
The tannery industry influences the gross domestic product/economic activity of any country, but the uncontrolled release of tannery effluents causes environmental degradation and increases health risks to human. The reason for the toxicity of tannery effluents is the presence of high concentrations of organic and inorganic chemicals used in the production of leather goods. Untreated or partially treated effluents discharged into surface water results in an increase in both chemical and biological oxygen demand as well as in an increase in the levels of total suspended solids, dissolved solids, and toxic metals in environmental bodies, especially in soil, water bodies, and water sediments. Various treatment techniques, such as physicochemical, biological, and advanced oxidation methods, which include chemical precipitation, electrocoagulation, aerobic or anaerobic treatment, wetland construction, and Fenton, electro-Fenton, and photo-Fenton processes are also described. This review also discusses the technical appropriateness and economic feasibility of reducing the effluent pollution load and solid waste emanating from the tannery industry. Considering the enhanced health risks in the tannery waste treatment and management regime, some green and advanced technologies should be explored. A sustainable green technology that avoids the use of toxic chemicals in the tanning process is seen well for ecological health.  相似文献   

18.
好氧和厌氧条件对霞浦湖沉积物-水界面氮磷交换的影响   总被引：59，自引：4，他引：55  
在实验室控制条件下,研究了日本霞浦湾和湖心区底泥中形态氮磷,在好氧和厌氧条件下水土界面交换量变化及差异,结果表明;好氧条件下,ＮＯ＾－３－Ｎ,ＮＯ＾－２－Ｎ,ＮＨ＾＋４,－Ｎ,和ＰＯ＾３－４－Ｐ均有释放作用产生,量值多数较小,ＤＴＮ和ＤＴＰ则净释放作用接近零;厌氧条件下,ＮＯ＾－３－Ｎ和ＮＯ＾－２－Ｎ呈负释放状态,ＮＨ＾＋４－Ｎ和ＰＯ＾３－４－Ｐ的释放速率是好氧条件下的２－８倍。  相似文献   

19.
In a batch experiment with activated sludge from a large-scale plant the hydrolytical and biochemical degradation of dimethylformamide (DMF) and its reaction product dimethylamine (DMA) and the conversion connected with this under aerobic and anaerobic conditions is investigated. Parallel to the hydrolysis of DMF the biochemical degradation of DMA occurs. The extensive conversion of these substrates is followed by the nitrification of the ammoniumions formed, and under subsequent anaerobic conditions with methanol as the carbon source also denitrification can be achieved. If the oxygen supply of the activated sludge is insufficient, however, also DMA can be used as a carbon source for denitrification, ammonium-ions being released from DMA in addition. In the batch experiment the elimination rates referred to nitrogen were 7 … 14 mg/g · h for DMF, 0.8 … 1.7 mg/g · h for DMA, 0.3 … 0.6 mg/g · h for NH and 0.4 to 1.3 mg/g · h for nitrate in the presence of methanol. DMF and DMA are obviously not suitable as the only carbon source for denitrification.  相似文献   

20.
内陆水体好氧甲烷氧化过程研究进展   总被引：1，自引：0，他引：1  
秦宇  黄璜  李哲  鲁伦慧  汤琼  苏友恒  李欣芮 《湖泊科学》2021,33(4):1004-1017
内陆水体是全球碳循环的关键组成部分,是大气中甲烷(CH_4)的重要来源,每年从内陆淡水与自然湿地排放进入大气的CH4约为185～357 Tg/a.通常,内陆水体中CH_4主要由分布于水层底部的厌氧区或沉积层内的产甲烷菌介导产生,其向水层表面传输的过程中易被甲烷氧化菌所氧化.甲烷氧化菌可分为好氧甲烷氧化菌和厌氧甲烷氧化菌,有氧条件下,由好氧甲烷氧化菌介导的好氧甲烷氧化过程是水体中甲烷氧化过程的主要形式,湖泊底部产生的CH_4总量中约有99%可以被上覆水体中的好氧甲烷氧化过程所消耗.本文收集文献综合分析阐明,好氧甲烷氧化过程是由水环境因子、水文条件以及不同内陆水体的生态系统特征共同调控,同时也表现在了好氧甲烷氧化菌的生境偏好上.复杂的调控过程构建了内陆水体向大气输送CH_4的动态平衡,并最终反映在内陆水体对全球CH_4循环、碳循环作出的贡献上.  相似文献   

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