西枝江流域浮游植物群落结构特征与主要环境因子的关系研究

于2012年枯水期、丰水期与平水期(2、8、11月)在西枝江全流域开展浮游植物群落的种类组成、密度和生物多样性指数研究,并分析环境因子与浮游植物群落之间的关系.结果表明,西枝江流域共检出浮游植物6门98种,其中卵形隐藻(Cryptomonas ovata)为流域全年常见种,西枝江流域浮游植物种类数由上游至下游逐渐增加,且支流淡水河浮游植物种类和数量高于干流;西枝江流域水体浮游植物群落密度变化范围为2.2×104~6.72×106cell·L~(-1);Shannon-Weaver多样性指数、Pielou均匀度指数、Margalef丰富度指数评价结果表明,西枝江流域部分点位浮游植物群落生物多样性受到一定程度的损害.西枝江流域平水期总氮浓度显著高于枯水期、丰水期(p0.05);西枝江干流总磷全年差异不明显(p0.05),支流淡水河总磷在枯水期显著高于丰水期、平水期(p0.05).氮磷含量空间分布特征为淡水河高于西枝江下游高于西枝江中游,西枝江上游水质最优,且浮游植物指示种的演替与流域内水质变化情况相吻合;RDA分析结果表明,氮磷营养盐、T以及CODMn是西枝江流域浮游植物群落结构的重要影响因子.     

高通量测序研究酒精废水治理中厌氧活性污泥的微生物菌群

厌氧消化是治理酒精生产废水的主要技术,本实验基于Illumina Mi Seq高通量测序研究了厌氧活性污泥的微生物菌群,在属(genus)水平上分析了污泥中细菌和古菌的种类和相对丰度,探讨了细菌和古菌的功能.结果表明:高温厌氧活性污泥(TAS)中相对丰度≥1.0%的细菌属有10个,包括Coprothermobacter、Longilinea、Levilinea等,它们的主要功能是分解蛋白质、代谢碳水化合物生成有机酸、乙酸氧化、硫酸盐还原.中温厌氧活性污泥(MAS)中相对丰度≥1.0%的细菌属有21个,包括Acinetobacter、Succinibibrio、Meniscus、Longilinea等,它们的主要功能是代谢碳水化合物生成有机酸、脂肪酸和有机酸氧化、分解结构顽固化合物.TAS中古菌属主要是产甲烷古菌Methanosaeta、Methanobacterium和Methanothermbacter,它们的相对丰度分别为57.72%,28.35%和9.90%.MAS中古菌属主要是产甲烷古菌Methanobacterium、Methanosarcina、Methanosaeta和Methanosphaera,它们的相对丰度分别为33.21%、23.70%、16.63%和11.77%.高通量测序研究充分展示了厌氧活性污泥的微生物菌群,可为阐释酒精废水治理中厌氧消化技术的生物机制及其技术改良提供参考.     

石墨烯修饰电极微生物燃料电池及其抗菌性研究进展

基于石墨烯具有优异的物理化学特性,石墨烯修饰电极能有效提升微生物燃料电池(Microbial Fuel Cell,简称MFC)产电性能并降低制备成本,而成为MFC研究发展的重要方向.本文系统介绍了石墨烯及石墨烯复合材料修饰阳极和阴极MFC、石墨烯材料的抗菌性等方面的研究进展,提出深入探讨石墨烯修饰电极与MFC微生物的相互作用关系,协调MFC石墨烯修饰电极抗菌性及强化产电是今后石墨烯电极MFC研究的重要内容.     

基于PLFA法分析亚硝氮、硝氮和氨氮对厌氧微生物细菌群落的影响

利用磷脂脂肪酸(PLFA)技术研究了亚硝氮、硝氮和氨氮在不同浓度水平下对中温厌氧颗粒污泥中厌氧细菌群落结构的影响.结果表明,高浓度亚硝氮(360 mg·L-1,以N计)、硝氮(300 mg·L-1,以N计)和氨氮(3000 mg·L-1,以N计)使系统COD去除率分别下降至3.49%、10.85%和71.53%,并使污泥表面主要细菌由杆菌变为球状菌;亚硝氮和硝氮引起厌氧细菌和革兰氏阳性菌的含量下降,氨氮引起革兰氏阴性菌的含量下降;PLFA香农-威尔多样性指数随着亚硝氮和硝氮浓度的升高从1.12分别下降至0.96和1.03,氨氮对PLFA香农-威尔多样性指数无明显影响.     

基于流体分离污泥的异质性:微生物活性和群落结构

生物流化床处理系统中的剩余污泥如果能够被识别为老化的污泥和高活性的污泥,并通过某一种物理方法加以原位分离,则有可能提高生物处理的效率.本文以构造流体力场实现基于比重分布不同污泥组分的分离,得到聚结型污泥与离散型污泥,考察了两种污泥在胞外聚合物、微生物活性和微生物群落结构方面的差异,并与降解活性相关联,以证明异质性的存在.研究发现:活性污泥这种异质性的存在归因于离散型污泥中的胞外聚合物含量高,亲水性更强,比重更小;聚结型污泥在基质利用效率、比耗氧速率方面优于离散型污泥;在废水生物处理系统的污泥中,聚结型污泥较离散型污泥具有微生物群落结构分布上的优势,种群丰度更高.研究结果证明了聚结型污泥和离散型污泥内部菌胶团存在着功能上的差异,前者是应该被保留的活性组分,后者应该作为剩余污泥加以分离排出.     

生物质炭对邻苯二甲酸二丁酯污染土壤微生物群落结构多样性的影响

在邻苯二甲酸二丁酯(DBP)污染的不同类型土壤(有机质含量低的新垦红壤、有机质含量高的熟化红壤)中添加不同种类(稻草炭、毛竹炭)以及不同用量(0%、0.5%和2%)的生物质炭,温室种植上海青并在56 d后采集土样,采用磷脂脂肪酸法(PLFA)考察了土壤类型、生物质炭种类以及用量对土壤微生物群落结构多样性的影响.结果表明:对细菌、真菌及微生物总PLFA这三者的含量而言,熟化红壤显著(p0.05)高于新垦红壤,熟化红壤中添加2%稻草炭使其显著(p0.05)增加,新垦红壤中添加毛竹炭使其显著(p0.05)降低.新垦红壤中添加2%稻草炭对革兰氏阴性菌/革兰氏阳性菌比值的增加效果最显著(p0.05),添加2%毛竹炭对土壤微生物群落Shannon指数的降低效果最显著(p0.05).添加2%稻草炭对DBP污染土壤中微生物压力指数降低效果最显著(p0.05).生物质炭对熟化红壤中真菌/细菌、革兰氏阴性菌/革兰氏阳性菌及微生物群落Shannon指数均无显著影响.PCA分析表明,土壤有机质含量以及生物质炭的种类和用量均会对土壤微生物群落结构产生一定影响,且生物质炭的影响与土壤有机质含量密切相关.     

硝酸盐浓度对微生物燃料电池阳极产电性能的影响

采用以假单胞菌Pseudomonas sp.C27为阳极优势菌属的微生物燃料电池(MFC)为研究对象,重点考察了进水中的硝酸盐浓度对于MFC系统产电及污染物去除的影响.实验结果表明,硝酸盐对于MFC的库仑效率(CE)影响较大,当硝酸盐浓度为250 mg·L~(-1)时,其电压下降段库仑效率仅为0.17%,而阳极未加入硝酸盐时,库仑效率为9.3%.当阳极初始硝酸盐浓度由0 mg·L~(-1)增加到250 mg·L~(-1)时,系统的传荷内阻由16.3Ω下降至11.2Ω,输出电压经短暂的电压下降后迅速回升至稳定,其稳定阶段输出电压与未受抑制阶段基本持平,最大输出功率可达到120 m W·m~(-2)左右.当硝酸盐浓度大于300 mg·L~(-1)时,硝酸盐对阳极微生物产电活性造成不可逆的抑制作用,系统产电能力大幅度下降且无法恢复至未受抑制阶段.可见,阳极生物反硝化过程对阳极生物产电具有电子竞争作用,过高的硝酸盐浓度会造成阳极生物膜产电性能降低甚至完全丧失.     

Effects of Pond Draining on Biodiversity and Water Quality of Farm Ponds

Farm ponds have high conservation value because they contribute significantly to regional biodiversity and ecosystem services. In Japan pond draining is a traditional management method that is widely believed to improve water quality and eradicate invasive fish. In addition, fishing by means of pond draining has significant cultural value for local people, serving as a social event. However, there is a widespread belief that pond draining reduces freshwater biodiversity through the extirpation of aquatic animals, but scientific evaluation of the effectiveness of pond draining is lacking. We conducted a large‐scale field study to evaluate the effects of pond draining on invasive animal control, water quality, and aquatic biodiversity relative to different pond‐management practices, pond physicochemistry, and surrounding land use. The results of boosted regression‐tree models and analyses of similarity showed that pond draining had little effect on invasive fish control, water quality, or aquatic biodiversity. Draining even facilitated the colonization of farm ponds by invasive red swamp crayfish (Procambarus clarkii), which in turn may have detrimental effects on the biodiversity and water quality of farm ponds. Our results highlight the need for reconsidering current pond management and developing management plans with respect to multifunctionality of such ponds. Efectos del Drenado de Estanques sobre la Biodiversidad y la Calidad del Agua en Estanques de Cultivo     

Testing Hypotheses of Bird Extinctions at Rio Palenque,Ecuador, with Informal Species Lists

Abstract: Informally gathered species lists are a potential source of data for conservation biology, but most remain unused because of questions of reliability and statistical issues. We applied two alternative analytical methods (contingency tests and occupancy modeling) to a 35‐year data set (1973–2007) to test hypotheses about local bird extinction. We compiled data from bird lists collected by expert amateurs and professional scientists in a 2‐km² fragment of lowland tropical forest in coastal Ecuador. We tested the effects of the following on local extinction: trophic level, sociality, foraging specialization, light tolerance, geographical range area, and biogeographic source. First we assessed extinction on the basis of the number of years in which a species was not detected on the site and used contingency tests with each factor to compare the frequency of expected and observed extinction events among different species categories. Then we defined four multiyear periods that reflected different stages of deforestation and isolation of the study site and used occupancy modeling to test extinction hypotheses singly and in combination. Both types of analyses supported the biogeographic source hypothesis and the species‐range hypothesis as causes of extinction; however, occupancy modeling indicated the model incorporating all factors except foraging specialization best fit the data.