MBR和CAS工艺污泥在贫营养培养条件下的微生物群落结构研究

采用聚合酶链式-变性梯度凝胶电泳（PCR-DGGE）技术,研究了膜生物反应器（MBR）和传统活性污泥工艺（CAS）反应器中微生物在贫营养条件下的总细菌群落结构.结果表明,在培养过程中,污泥的微生物种群经历了一个比较明显的变化过程,且以CAS污泥微生物种群的变化更为明显,演替过程中既有原始优势种群的消亡,又有新的优势种群...     

First report of microcystin production in Microcystis smithii Komrek and Anagnostidis(Cyanobacteria) from a water bloom in Eastern China

A water bloom sample collected from Lake Dishui in Shanghai was characterized.The morphological identification showed that Micorcystis wesenbergii and Micorcystis smithii were the main component of the bloom.Five strains of M.smithii were successfully isolated.Their 16S rRNA gene sequences based phylogenetic tree showed that the five strains of M.smithii intermixed with strains of other morphospecies in Microcystis.A fragment of mcy gene encoding for microcystin synthetase was detected in one of the five M....     

基于3S技术的呼和浩特市土地利用／覆盖变化研究

本文以呼和浩特市为研究对象,利用遥感（RS技术）、地理信息系统（GIS技术）以及全球定位系统技术（GPS技术）——简称3S技术,对呼和浩特市2000、2004年遥感影像进行了综合技术处理,获得2期土地利用现状图,据此对呼和浩特市土地利用变化幅度及变化速度、土地利用变化程度、土地利用变化空间动态进行了分析,为区域土地资源科学管理及实现区域土地资源可持续利用提供科学依据。     

美军基于模拟仿真的加速腐蚀系统

美军最新开发了全尺寸车辆腐蚀模拟仿真和建模工具,称为加速腐蚀专家模拟器(ACES),它与实际加速腐蚀耐久性试验(ACDT)数据高度相关.该系统引入现有全尺寸车辆3D几何模型,进行综合检测以确定有无故障并报告补救措施;采用了基于腐蚀和涂层失效机理分析的各种人工智能解决方案;使用了由专家、ACDT、实验室试验数据以及现场观...     

Bacterial diversity and distribution in the southeast edge of the Tengger Desert and their correlation with soil enzyme activities

The nature of microbial communities and their relation to enzyme activities in desert soils is a neglected area of investigation. To address this, the bacterial diversity and distribution and soil physico-chemical factors were investigated in the soil crust, the soil beneath the crust and rhizosphere soil at the southeast edge of the Tengger Desert, using the denaturing gradient gel electrophoresis of 16S rRNA genes amplified by the polymerase chain reaction. Phylogenetic analysis of the sequenced DGGE bands revealed a great diversity of bacteria. The Proteobacteria, consisting of the α, β, and γ subdivisions, were clearly the dominant group at all depths and in rhizosphere soil. Analysis of the enzyme activities indicated that the rhizosphere soil of Caragana korshinskii exhibited the highest protease and polyphenol oxidase activities, and in the soil crust there were increased activities of catalase, urease, dehydrogenase and sucrase. The bacterial community abundance closely correlated with soil enzyme activities in different soils. The presence of Cyanobacteria correlated with significant increases in protease, catalase and sucrase in the soil crust, and increased urease in the rhizosphere soil of Artemisia ordosica. The occurrence of Acidobacteria was associated with significant increases in urease, dehydrogenase, and sucrase in the rhizosphere soil of C. korshinski. The presence of γ-Proteobacteria correlated with a significant increase in polyphenol oxidase in the rhizosphere soil of A. ordosica. The study indicated a close relationship between the soil bacterial community and soil enzymes, suggesting the necessity of further investigations into bacterial function in this desert ecosystem.     

连云港海底底泥及青海湖底泥细菌多样性研究

通过对不同盐环境连云港海底底泥和青海湖底泥样品构建细菌16S rRNA克隆文库,对2个环境样品中细菌群落的多样性、丰富度和优势度等进行了比较,并对其群落组成结构进行了分析.结果表明,连云港海底底泥文库的多样性指数Shannon diversity（H）达到3.53,青海湖底泥文库的Shannon diversity（H...     

3S技术在林纸一体化项目生态环境影响评价中的应用

文章以梧州市某林浆纸一体化原料林建设项目为例,借助3S技术分析原料林基地建设对生态环境的影响,探讨3S技术在生态环境影响评价中的应用。     

维管束植物樟树和马尾松叶组织氮、硫含量指示贵阳地区大气氮、硫沉降的空间变化

同时测定了从贵阳市区到农村3个方向采集的樟树叶、马尾松叶、根际土以及苔藓共计296个样品的氮、硫含量,结合苔藓氮、硫含量估算了相应区域大气氮沉降量和SO_2浓度.结果表明樟树叶氮含量(1.01%~2.37%)和马尾松叶氮含量(0.99%~2.42%)在市区最高,往外明显降低,而在较远农村区域(24 km)又出现回升,反映了农村地区大气输入的氮有所增加;叶硫含量变化范围分别为0.16%~0.43%和0.18%~0.32%,均呈现在市区最高,向外逐渐降低的趋势,在距市区最远处(30~36 km)达到最低值,表明市区的生产生活向大气输入了较高的硫.各区域土壤氮、硫含量均无显著差异,将樟树、松树叶氮、硫含量分别与大气氮沉降量和SO_2浓度(由苔藓氮、硫值计算)进行线性回归分析,发现樟树、松树叶氮含量与大气氮沉降量以及樟树、松树叶硫含量与大气SO_2浓度均呈显著正相关(P0.05).研究表明维管束植物樟树与马尾松叶组织氮、硫含量的变化特征能同时很好地指示贵阳区域大气氮、硫沉降的空间变化.     

Featured Collection Introduction: Connectivity of Streams and Wetlands to Downstream Waters

Connectivity is a fundamental but highly dynamic property of watersheds. Variability in the types and degrees of aquatic ecosystem connectivity presents challenges for researchers and managers seeking to accurately quantify its effects on critical hydrologic, biogeochemical, and biological processes. However, protecting natural gradients of connectivity is key to protecting the range of ecosystem services that aquatic ecosystems provide. In this featured collection, we review the available evidence on connections and functions by which streams and wetlands affect the integrity of downstream waters such as large rivers, lakes, reservoirs, and estuaries. The reviews in this collection focus on the types of waters whose protections under the U.S. Clean Water Act have been called into question by U.S. Supreme Court cases. We synthesize 40+ years of research on longitudinal, lateral, and vertical fluxes of energy, material, and biota between aquatic ecosystems included within the Act's frame of reference. Many questions about the roles of streams and wetlands in sustaining downstream water integrity can be answered from currently available literature, and emerging research is rapidly closing data gaps with exciting new insights into aquatic connectivity and function at local, watershed, and regional scales. Synthesis of foundational and emerging research is needed to support science‐based efforts to provide safe, reliable sources of fresh water for present and future generations.     

含酚工业废水处理的探讨

在好氧条件下，以活性污泥为载体固定ＰＳＢ菌体，处理含酚废水，可明显提高去酚能力．通过改变试验条件，使酚的去除率达９５％以上．