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21.
水稻土中五氯酚的降解转化动态及其对微生物群落的影响 总被引:1,自引:0,他引:1
采用室内培养实验,研究厌氧条件下水稻土中五氯酚(Pentachlorophenol,PCP)的还原转化与微生物群落组成变化。结果表明,室内培养实验条件下,PCP在水稻土样品中降解比较迅速,在反应17 d时,实验添加的PCP能够完全被还原转化。高通量测序结果显示PCP的添加明显改变了水稻土壤的微生物群落结构,其微生物多样性显著下降,在PCP降解完之后逐渐恢复。原始土壤以及添加PCP的土壤样品中其优势微生物主要分布在变形菌门(Proteobacteria)。PCP添加刺激了水稻土中伯克氏菌科(Burkholderiaceae)、丛毛单胞菌科(Comamonadaceae)、地杆菌科(Geobacteraceae)、红环菌科(Rhodocyclaceae)和假单胞菌科(Pseudomonadaceae)等脱氯相关的微生物菌群繁殖,成为PCP降解过程中的优势菌群,有利于PCP还原降解。本研究结果可为水稻土中有机氯农药污染物的微生物降解脱毒提供理论依据。 相似文献
22.
Gu B Watson DB Wu L Phillips DH White DC Zhou J 《Environmental monitoring and assessment》2002,77(3):293-309
Zero-valent iron (Fe0)-based permeable reactive barriertreatment has been generating great interest for passivegroundwater remediation, yet few studies have paid particularattention to the microbial activity and characteristics withinand in the vicinity of the Fe0-barrier matrix. The presentstudy was undertaken to evaluate the microbial population andcommunity composition in the reducing zone of influence byFe0 corrosion in the barrier at the Oak Ridge Y-12 Plantsite. Both phospholipid fatty acids and DNA analyses were usedto determine the total microbial population and microbialfunctional groups, including sulfate-reducing bacteria,denitrifying bacteria, and methanogens, in groundwater andsoil/iron core samples. A diverse microbial community wasidentified in the strongly reducing Fe0 environment despitea relatively high pH condition within the Fe0 barrier (up topH 10). In comparison with those found in the backgroundsoil/groundwater samples, the enhanced microbial populationranged from 1 to 3 orders of magnitude and appeared to increase from upgradient of the barrier to downgradient soil. Inaddition, microbial community composition appeared to change overtime, and the bacterial types of microorganismsincreased consistently as the barrier aged. DNA analysisindicated the presence of sulfate-reducing and denitrifyingbacteria in the barrier and its surrounding soil. However, theactivity of methanogens was found to be relatively low,presumably as a result of the competition by sulfate/metal-reducing bacteria and denitrifying bacteria because of the unlimited availability of sulfate and nitrate in the site groundwater. Results of this study provide evidenceof a diverse microbial population within and in the vicinity ofthe iron barrier, although the important roles of microbial activity, either beneficially or detrimentally, on the longevityand enduring efficiency of the Fe0 barriers are yet to be evaluated. 相似文献
23.
Selecting Socio-Economic Metrics for Watershed Management 总被引:1,自引:0,他引:1
The selection of social and economic metrics to document baseline conditions and analyze the dynamic relationships between
ecosystems and human communities are important decisions for scientists, managers, and watershed citizens. A large variety
of social and economic data is available but these have limited use without theoretical frameworks. In this paper, several
frameworks for reviewing social-ecosystem relations are offered, namely social sanctions, sense of place, civic structure,
and cultural differences. Underlying all of these frameworks are attitudes, beliefs, values, and norms that affect which questions
are asked and which indicators are chosen. Much work and significant challenges remain in developing a standard set of spatially
based socio-economic metrics for watershed management. 相似文献
24.
通过对2014—2016年湖体水质中氮素质量浓度分析,结合出入湖总氮浓度、水量、湖体水生生态等影响因素,发现太湖水体中总氮浓度呈现逐年下降的趋势,各监测点位总氮为0.530 mg/L~5.51 mg/L,时空分布不均,差异明显。时间上,总氮浓度表现为春季最高,夏季和秋季最低,且月均值变化曲线呈现出规律的正弦函数波形。空间上,总氮浓度大致表现出由西部湖区向东部湖区递减的趋势,呈现西部湖区﹥北部湖区﹥南部湖区﹥湖心区﹥东部湖区。要改善湖体水质,不仅要切断污染源,而且要加强水生生态功能修复。 相似文献
25.
Stin OC Carnahan A Singh R Powell J Furuno JP Dorsey A Silbergeld E Williams HN Morris JG 《Environmental monitoring and assessment》2003,81(1-3):327-336
Molecular methods, including DNA probes, were used to identify and enumerate pathogenic Vibrio species in the Chesapeake Bay; our data indicated that Vibrio vulnificus exhibits seasonal fluctuations in number. Our work included a characterization of total microbial communities from the Bay; development of microarrays that identify and quantify the diversity of those communities; and observation of temporal changes in those communities. To identify members of the microbial community, we amplified the 16S rDNA gene from community DNA isolated from a biofilm sample collected from the Chesapeake Bay in February, 2000. The resultant 75 sequences were 95% or more similar to 7 species including two recently described Shewanella species, baltica and frigidimarina, that have not been previously isolated from the Chesapeake. When the genera of bacteria from biofilm after culturing are compared to those detected by subcloning amplified 16S fragments from community DNA, the cultured sample exhibited a strong bias. In oysters collected in February, the most common bacteria were previously unknown. Based on our 16S findings, we are developing microarrays to detect these and other microbial species in these estuarine communities. The microarrays will detect each species using four distinct loci, with the multiple loci serving as an internal control. The accuracy of the microarray will be measured using sentinel species such as Aeromonas species, Escherichia coli, and Vibrio vulnificus. Using microarrays, it should be possible to determine the annual fluctuations of bacterial species (culturable and non-culturable, pathogenic and non-pathogenic). The data may be applied to understanding patterns of environmental change; assessing the health of the Bay; and evaluating the risk of human illness associated with exposure to and ingestion of water and shellfish. 相似文献
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