Vertical distribution of phosphorus and P-dissolving/decomposing bacteria in the sediment of Guanting reservoir

In this study, we determined pH, phosphorus content and the number of P-dis- solving/decomposing bacteria in relation to the depth in the sediment of Guanting reservoir in Beijing. The pH value was slightly increased from 8.0 in the surface to 8.5 in the bottle (69 cm in depth) of sediment. The highest P content, 1269 mg/kg, was detected in the 35 cm layer, followed by the 5 cm (993 mg/kg) and 69 cm (580 mg/kg) layers. The number of inorganic P-dissolving bacteria varied from 6(102 to 8(104 and the organic P-discomposing bacteria were from 1.9(103 to 6.3(104 per gram sediment in different depths, which were counted under 28℃ and 20℃ ( pH7.5 and 8.5. The number of P-dissolving/discomposing bacteria was directly correlated to the P content in each layer of sediments. The analysis of P-dissolving/decomposing ability of bacteria showed that some of these bacteria were also capable of accumulating P intracellularly. The intracellular P-accumulation was more efficient at lower temperature; in contrast, the activity of P-dissolving/decomposing was stronger at higher temperature. So the content of dissolved P in water body, or quality of water, could be affected by the change of temperature via the regulation of bacterial activity. On the basis of 16S rDNA sequencing, the 13 efficient P-dis- solving/decomposing bacteria were identified as Bacillus spp., Bacterium sp., Microbacterium sp., Paenibacillus sp. and Pseudomonas sp.     

官厅水库及周边地区地震活动趋势的综合统计预测

利用多种地震统计学分析预测方法，详细分析了官厅水库及周边地区的地震活动情况，和未来50年的地震危险性。综合分析最后认为，未来50年内，官厅水库及周边地区至少应发生一次5.5-6.5级地震和多次5级左右地震的可能性；外国较远地区则具有发生7级以上地震的可能，这里距大坝虽然较远，对大坝的安全可能不会构成真正威胁，但其周边地区可能发生的潜在地震，对水库的可能影响则应引起我们足够的注意及重视。     

北京官厅水库轮虫群落结构与水体富营养化状况

于2007年1-12月对官厅水库上游(北京段)进行调查,利用非生物环境因子对水体的营养状况进行了评价,并通过种类组成、优势种、生物量及多样性指数等指标探讨了轮虫群落结构与水体富营养化的关系.结果表明,官厅水库(北京段)已达到了富营养的水平,在轮虫的种类组成中,10个富营养化的指示种类大部分都有出现,其中螺形龟甲轮虫(Keratella cochlearis)和针簇多肢轮虫(Polyarthra trigla)为优势种;轮虫密度均在1000ind./L以上,生物量在1mg/L以上,轮虫的密度、生物量的季节分布与水温显著正相关(P0.05),水平分布与水体的营养状况显著正相关(P0.05),垂直分布没有明显的规律性;轮虫多样性指数较低,但与水体营养水平显著相关(P0.05).证明轮虫群落结构与水体富营养化之间存在着密切的关系,富营养化是导致轮虫群落结构变化的主要动因.     

Bacterial community in deep subseafloor sediments from the western Pacific "warm pool"

The bacterial community in deep subseafloor sediments at a depth of 230 cm from the western Pacific "warm pool" is studied by construction of 16S rDNA clone library and PCR-RFLP (Restriction Fragment Length Polymorphism) analysis. The results indicate that the bacterial community in these sediments is mainly composed of five groups: α-Proteobacteria, β-Proteobacteria, CFB group (Cytophaga / Flexi-bacteria / Bacteroides), Acidobacteria and gram positive bacteria, with a few genera detected in each group. The most abundant bacteria group is α-Proteobacteria, and the next is β-Proteobacteria. The dominant species in α-and β-Proteobacteria are Sphingomonas paucimobilis and Pseudomonas alca-ligenes respectively. The CFB group is simply composed of members belonging to Flavobacterium. The gram positive bacteria are rich, and mainly consists of the genus Geobacillus. The analysis of bacterial community indicates that organic matter is still abundant in the subseafloor sediments at the depth of 230 cm in the western Pacific "warm pool" . These bacteria in this deep biosphere may play an impor-tant role in the nitrogen cycle of deep sea sediments at "warm pool" .     

丹江口库区表层沉积物细菌多样性及功能预测分析

湖泊沉积物微生物是水生态系统的重要组成部分,目前关于丹江口库区沉积物细菌群落和功能研究鲜见报道.于2017年5月对丹江口库区内5个典型生态点位表层沉积物进行采集,采用高通量测序技术对表层沉积物细菌群落组成进行研究,结果表明细菌群落主要由变形菌门(Proteobacteria)、绿弯菌门(Chloroflexi)、拟杆菌门(Bacteroidetes)、疣微菌门(Verrucomicrobia)和硝化螺旋菌门(Nitrospirae)等33个门和318个属组成,具有丰富的群落组成.沉积物细菌群落和理化指标冗余分析(RDA)结果表明,pH值、总磷、有机质和铵态氮含量均能显著影响沉积物细菌群落组成.细菌属分类单元与环境因子Spearman相关分析表明,变形菌门中11个属的细菌与环境因子显著相关,为与环境因子显著相关细菌的主要组成(占47.62%).采用细菌群落功能预测软件PICRUSt(Phylogenetic Investigation of Communities by Reconstruction of Unobserved States)对表层沉积物细菌群落进行分析,结果表明沉积物细菌功能主要涉及能量产生和转换、信号转导机制、氨基酸运输和代谢、细胞壁/细胞膜/膜结构的生物合成等24个基因功能家族,表现出功能上的丰富性.基因功能家族预测基因拷贝数表现为台子山宋岗库心渠首黑鸡嘴.     

Seasonal dynamics of a cyanobacteria-dominated microbial community in surface sediments of a shallow,eutrophic lake

The seasonal variation of microbial biomass and activity in the surface sediments (0–10 cm) of the shallow, eutrophic Lake Vallentunasjön was followed during one year. OverwinteringMicrocystis colonies dominated the microbial community during all seasons, constituting 60–90% of the total microbial biomass. Expressed on an areal basis, the benthic biomass was, throughout the year, larger than or similar to the planktonic biomass during the peak of the summer bloom, indicating an ability of the colonies to survive in the sediments for extended periods. Abundance of other, non-photosynthetic bacteria varied in the range 3.0–15.5 · 10¹⁰ cells g^–1 d. w. over the year with minimum values in summer and maximum values in autumn in connection with the sedimentation of theMicrocystis bloom. A substantial part of the non-photosynthetic bacteria, up to circa 40%, was associated with the mucilage of healthyMicrocystis colonies. Bacterial production (³H-thymidine incorporation) appeared to be strongly temperature dependent and less influenced by the seasonal sedimentation pattern. Our data indicate an increasing proportion of non-growing cells in autumn and winter. Biomass-bound phosphorus constituted a significant portion, circa 10%, of the phosphorus content in Lake Vallentunasjön sediments. This pool has normally been overlooked in studies on phosphorus dynamics in lake sediments. Different mechanisms whereby organic phosphorus can be released from the sediments are discussed.     

硝态氮对库区水体藻类和细菌群落的影响

水体富营养化极易引起湖泊水库如藻类水华等水生态系统环境问题。氮素作为初级生产力的限制性生源要素之一,认识其在水华形成过程中潜在作用至关重要。本研究选取胶东半岛低碳高氮水库水体进行模拟实验,通过添加不同剂量硝态氮,探究高硝态氮输入对库区水体藻类和细菌群落结构的影响。结果表明:(1)当硝态氮作为唯一氮源,随着培养时间延长,硝态氮浓度显著下降,亚硝态氮和氨氮浓度逐渐升高,表明微藻和细菌共同作用可能将硝态氮转化为亚硝态氮和氨氮;(2)当硝态氮浓度为6 mg/L时,藻类叶绿素a浓度达到最高值,随着硝态氮浓度升高,叶绿素a浓度则会降低;(3)添加硝态氮后,蓝藻门成为优势藻类,绿藻门次之;变形菌门相对丰度显著升高。研究结果为低碳高氮类水体暴发蓝绿藻水华及有效防控提供理论依据和技术支撑。     

Morphological and molecular analysis of bloom-forming Cyanobacteria in two eutrophic, shallow Mediterranean lakes

We investigated the diversity of Cyanobacteria by microscopic observation and sequencing of cyanobacterial-specific amplified 16S rRNA genes in the water column of two shallow, eutrophic lakes (Doirani and Kastoria, northern Greece) during summer blooms. Previous phytoplankton studies in these lakes have shown that prolonged cyanobacterial blooms can occur, which are dominated by known toxic species, as well as other less known, co-occurring species. A total of 118 clones were sequenced which were grouped in 23 Cyanobacteria and 11 chloroplast-like phylotypes. Phylogenetic analysis revealed that each library included several unique phylotypes, as well as members of all common bloom-forming Cyanobacteria. Most of the phylotypes belonged to the genera Microcystis, Anabaena, Aphanizomenon, Cylindrospermopsis-Raphidiopsis group, Limnothrix and Planktothrix, comprising most of the diversity previously recognized by morphological observations in cyanobacterial morphospecies in these lakes. In addition, novel phylotypes belonging to the Chroococcales were recognized in both lakes. The structure of the cyanobacterial communities of the lakes were very similar, as revealed by the diversity index H (2.06 and 2.01 for L. Doirani and Kastoria, respectively) and LIBSHUFF analysis (XY₁₂P-value = 0.122 and YX₁₂P-value = 0.536), due to occurrence of groups of common phylotypes. This study gives an example for successful cyanobacterial bloom analysis by the combination of morphological and phylogenetic methods useful for monitoring cyanobacteria and water quality in freshwaters.     

Study on the endogenous phosphorus load of sediments in Miyun reservoir

Based on the research into the physical-chemical properties and distribution of sediments and the characteristics of pore water in sediments of Miyun reservoir, the release flux of the total phosphorus (TP) from sediments is estimated by simulating deposit environment of reservoir bottom in laboratory. They are 0.018 mg·cm-2·d-1 and 0.821 mg·cm-2·d-1 at 2℃ and 8℃ respectively. The gross TP released in a year is 11.34t. As a contrast, the pore water diffusion simulation method is used to measure gross TP released and gains 11.56t. The two results are relatively close and prove that experiment simulation has some reliability. On the basis of experiments, some conclusions can be drawn: (1) Endogenous phosphorus from sediments accounts for 27.9 percent of the TP entering the reservoir, and it cannot be ignored; and (2) increasing temperature is helpful to TP releasing from sediments.     

-座富营养化水库—福建山仔水库夏季热分层期间浮游植物垂向分布

对福建省水温分层型富营养化山仔水库夏季大坝断面垂向水体的物理化学参数进行了监测分析,并应用荧光分析法结合显微镜细胞计数法,对垂向分层水体和沉积物中的浮游植物生物量、群落组成及丰度进行了分析.结果表明,水库的水温分层能够引起水化学指标的分层.夏季大坝断面水体中的浮游植物以蓝藻门微囊藻属占绝对优势,垂向分布表现为表层的浮游植物细胞数量高于底层,温跃层以下细胞数急剧减少,水温分层可能决定着浮游植物的垂向分布,底泥中的浮游植物将为水体的水华提供"种源".     

岱海水体及沉积物细菌多样性及群落组成特征

采用高通量测序技术,研究了内蒙古岱海流域入湖河流、湖水及沉积物细菌多样性及群落组成.结果显示,细菌多样性从高到低依次为：沉积物>河流>湖泊.聚类分析表明入湖河流、湖水和沉积物细菌群落可分为明显不同的3支,说明这3种生境中细菌群落结构有较大差异.物种注释结果表明,河流中优势细菌菌群为髌骨细菌(Patescibacteria)、变形菌门(Proteobacteria)、拟杆菌门(Bacteroidetes)和放线菌门(Actinobacteria);湖水中优势细菌菌群为放线菌门(Actinobacteria);而沉积物中优势细菌菌群为变形菌门和绿弯菌门(Chloroflexi).典范对应分析及Monte Carlo检验表明,电导率和悬浮物含量对水体中(河流与湖泊)细菌群落影响显著,二者共解释了细菌群落变化的86.5%;而冗余分析及Monte Carlo检验表明,泥深、磁化率和总有机碳对沉积物中细菌群落影响显著,三者共解释了细菌群落变化的47.9%.近30年来,岱海地区气候变化和人类活动导致湖水咸化,沉积物碳氮指标显著增长.岱海水体及沉积物细菌多样性及群落组成的差异及其主要驱动因...     

乌鲁木齐10号泉水体细菌群落对地震的响应

以无震时期细菌群落及水文化学元素信息为背景,阐明有感地震时的泉水细菌群落映震特征． 2010年12月——2011年4月,乌鲁木齐周边先后发生了MS3.1和MS3.6两次有感地震．本文采用末端限制性片段长度多态性法(T-RFLP)分析了该时间段内乌鲁木齐10号泉中细菌群落结构、多样性、稳定性、优势类群及特殊类群变化特征．结果表明,水文地球化学指标对有感地震不敏感,泉水细菌群落结构稳定,地震对其优势类群及多样性影响均不显著,但无震时期部分类群（以82,170, 176, 462 bp为代表）在前后两次地震中丰度变化趋势相似,即震前有小幅上升,震后1——12天内出现极大值,之后丰度逐渐恢复至较低水平,且表现出与震级、震中距具有一定相关性．这表明部分泉水细菌对有感地震映震灵敏．      

Vertical variations and associated ecological function of bacterial communities from Sphagnum to underlying sediments in Dajiuhu Peatland

To investigate vertical changes of bacterial communities from living plants to the associated sediments and bacterial biogeochemical roles in peatland ecosystem,samples of different part of individual Sphagnum palustre and the different layers of the underlying sediments were collected from Dajiuhu Peatland in central China.All samples were subject to 16S rRNA gene clone libraries and quantitative PCR analysis.Even though bacteria vary in abundance at the same order of magnitude in all samples,they show great profile difference in composition from the top part of S.palustre to the low layer of the sediments.Cyanobacteria and alpha-Proteobacteria dominate at the top part whereas Acidobacteria at the middle part of S.palustre.Alpha-Proteobacteria and Acidobacteria are the dominant phyla at the bottom part of S.palustre and in the surface peat sediment.In contrast,bacterial communities in the subsurface sediments are dominated by Acidobacteria.These profile distributions of different bacterial communities are closely related to their ecological functions in the peatland ecosystem.Specifically,most Cyanobacteria were observed at the top green part of S.palustre,a horizon where the active photosynthesis of the moss occurs,which infers their endosymbiosis.In contrast,Acidobacteria,dominant in the subsurface sediments,are able to decompose the specific compounds on the cell wall of Sphagnum moss and thus might play an important role in the formation of the peatland,including the acidic condition.Methane oxidizing process might have been underestimated in Sphagnum peatland due to the identification of Methylocystaceae in all parts of the moss investigated here.The vertical difference in bacterial composition and bacterial ecological functions presented here sheds light on the understanding of biogeochemical processes,in particular the CH4 flux,in peat ecosystems.     

山东某新建水库浮游藻类的群落结构特征及其环境驱动因子

基于山东某新建水库中2014年4月-2017年12月的浮游藻类和水质监测结果,研究了藻类群落结构特征,采用非度量多维尺度分析了各年份不同季节藻类群落结构的相似性,利用冗余分析探究了藻类群落结构和环境因子的关系.结果表明：尖针杆藻（Synedra acus）、湖泊伪鱼腥藻（Pseudanabaena limnetica）和小球藻（Chlorella vulgaris）为此水库的主要优势藻种.水库藻类群落结构的季节演替不稳定,冬、春季多以硅藻和绿藻占优势,不同年份夏、秋季藻类结构差异较大,蓝藻和硅藻在夏、秋季存在一定的竞争优势.该水库于2013年底开始启用,由于水体环境的波动,藻类群落结构有所变化,整体上是由蓝藻-绿藻-硅藻向硅藻-绿藻-蓝藻变化.水库浮游藻类生长主要受到氮盐和高锰酸盐指数影响,但不同年份的主要环境影响因子存在一定差异.     

青藏高原湖泊沉积物与水体细菌群落共发生网络和群落构建过程差异解析

研究高原湖泊沉积物和水体细菌群落结构的差异对于水生态治理与保护具有重要的科学意义。本文选取青藏高原中东部共19个湖泊为研究对象,采集沉积物和水体样本,使用高通量测序技术和统计分析,解析湖泊沉积物和水体细菌群落结构、空间分布特征、共发生网络模式、群落构建过程的差异及其原因。研究结果表明沉积物细菌群落alpha多样性指数(Chao1指数、Shannon多样性指数、Faith’s系统发育指数和Pielou均匀度指数)均显著高于水体细菌群落。沉积物和水体细菌的优势门均为Proteobacteria(相对丰度为45.33%和41.77%),而水体细菌群落结构具有较强的空间异质性。主坐标分析和相似性分析结果表明沉积物和水体中细菌群落结构差异极显著,海拔和纬度分别是青藏高原湖泊沉积物和水体细菌群落结构变化最显著的驱动因子。沉积物和水体细菌群落均具有明显的距离衰减模式,而沉积物细菌比水体细菌群落在空间上的周转率小。采样湖泊沉积物细菌群落共发生网络复杂度和稳定性高于水体细菌。沉积物和水体细菌群落的平均归一化随机率值分别为0.24和0.72,表明确定性过程在沉积物细菌群落构建的过程中起到了重要的作用,而水...     

与微囊藻胞外多糖降解相关的微生物菌群分析

从铜绿微囊藻培养液中提取胞外多糖,化学分析显示其为含8.3%蛋白质的酸性杂多糖.以胞外多糖为碳源接种自然水体的菌群进行富集培养,分析胞外多糖的微生物降解过程及降解菌的组成.结果表明,接种太湖水华期微生物富集菌群后,多糖立即开始被降解,大约在18d后多糖降解过程显著减慢,37d后仍有一部分多糖未能被降解.这些结果说明在自然界中微囊藻胞外多糖是可以被微生物降解的.比较不同水体的菌群对多糖的降解能力后显示,降解菌群只存在于微囊藻水华暴发的阶段.变性梯度凝胶电泳(DGGE)结果显示在整个降解过程中,降解菌群的组成未发生显著变化.对DGGE条带中的DNA片段进行序列分析和系统发育分析表明降解菌群包含以下几类:鞘氨醇单胞菌属(Sphingomonas)3个,褐螺菌属(Phaeospirillum)1个,假单胞菌属(Pseudomonas)1个,红环菌科(Rhodoeyclaceae)1个,Hylemonella(无译名)1个,分枝杆菌属(Mycobacterium)1个.     

新疆博斯腾湖浮游细菌丰度对富营养化及咸化的响应

本文以地处干旱地区我国最大的内陆淡水湖——博斯腾湖为研究对象,于2010年6月,在博斯腾湖大小湖区共选取23个采样点,采用表面荧光显微镜直接计数法( FDC)研究了水体中浮游细菌丰度的空间分布规律及其与环境因子的关系.结果表明:博斯腾湖水体中总氮(TN)浓度在0.26-1.45 mg/L之间变动(均值0.91 mg/L...     

Chemical forms of heavy metal contaminants in sediments of Miyun reservoir

The chemical forms, spatial distribution and sources of As, Hg, Cd, Pb and Zn in sediments of the Miyun reservoir were studied. The results of sequential extraction demonstrate that most of As, Pb and Zn were bound to the residual fraction, Hg was associated with the sulfide fraction while Cd was associated with the carbonate fraction and the residual fraction. On the vertical profiles the concentrations of the heavy metals in total and each fractions mostly decreased with increasing depths in sediments, suggesting that the heavy metals input from the upstream watershed increases yearly. Summation of the residual fraction, the sulfide fraction and the carbonate fraction accounts for 60.03%―85.60% of the total heavy metal contents in the sediments, which represent the geochemical background values of the elements and relate closely to soil erosion. Results of the main factor analysis show that most sediments of the reservoir come from the upstream soil erosion, the point source pollution and domestic waste. Moreover, the microbial activities taking place on the sediment-water interface are also one of the major factors to cause the increasing content of the organic matter fraction and the iron-manganese oxide fraction. Environmental change of the reservoir water could make the removability of the heavy metals increase, leading to the increase of their concentrations in pore water in sediments, and imperiling water quality of the reservoir.     

青藏高原东北部湖泊细菌群落结构特征季节性差异及驱动机制

微生物是湖泊生态系统重要的有机组分。了解不同时期青藏高原湖泊细菌群落特征、环境驱动因子及其群落构建过程的差异,对高原湖泊水生态管理具有重要的指导意义。分别于2020年6和12月采集青藏高原东北部5个湖泊水样,基于高通量测序技术、统计分析和模型分析,解析高原湖泊群在非冰封期和冰封期细菌群落结构、环境驱动因子和中性过程、确定性过程以及随机性过程在细菌群落构建过程的贡献。结果表明：（1）非冰封期湖泊细菌群落的Chao1丰度指数、Simpson和Shannon多样性指数低于冰封期,Spearman相关性分析结果表明非冰封期细菌群落的Chao1丰度指数和多样性指数与水温和海拔显著相关,而冰封期细菌群落的Chao1指数和多样性指数与总氮显著相关;（2）水体细菌群落的优势门均为变形菌门（Proteobacteria）,非冰封期细菌中拟杆菌门（Bacteroidetes）、放线菌门（Actinobacteria）和厚壁菌门（Firmicutes）的平均相对丰度明显高于冰封期。另外,主坐标分析和相似性分析结果表明非冰封期和冰封期的细菌群落组成差异极显著;（3）冗余分析结果表明不同时期湖泊群细菌群落结构的...