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1.
为获得深海可培养微生物资源,利用2216E培养基,采用涂布平板法从南大西洋热液区沉积物中分离可培养细菌,并通过16S rRNA基因进行分类鉴定.同时测定各菌株产淀粉酶、蛋白酶、果胶酶、木聚糖酶、褐藻酸酶和脂肪酶(三丁酸甘油酯和吐温80)的能力.分离共获得216株菌株,经16S rRNA基因序列比对,共获得71株不同的菌株.其中包括变形菌纲62株、放线菌纲3株、芽孢杆菌纲2株和拟杆菌纲4株,分布于27个属,41个种.酶活检测结果显示,具有淀粉酶、蛋白酶、脂肪酶(底物为三丁酸甘油酯)和脂肪酶(底物为吐温80)的产酶细菌分别为18、14、25、32株,供测细菌中未检出产果胶酶、木聚糖酶和褐藻酸酶的菌株.这些菌株为进一步研究开发提供了深海微生物资源.  相似文献   

2.
姜钊  张卫花 《海洋学报》2022,44(4):104-113
为探索印度洋深海沉积物中纯培养细菌的多样性,本文对采自印度洋12个沉积物样品进行细菌纯培养分离,共获得343株细菌。所有细菌采用16S rRNA 基因进行比对分析,鉴定为4个门:厚壁菌门（Firmicutes）、变形菌门（Proteobacteria）、放线菌门（Actinobacteria）和拟杆菌门（Bacteroidetes）,5个纲,13个目,26个科,39个属下的121个种。分离出的优势类群为链霉菌属（Streptomyces,分离率为16.53%）和芽孢杆菌属（Bacillus,分离率为8.26%）,其中可能有12个潜在的新分类单元。研究结果表明,印度洋深海沉积环境中纯培养细菌资源丰富,潜在新物种较多;其次,分离培养方法与从海洋沉积物中获得的细菌物种多样性直接相关。  相似文献   

3.
采集虾蟹混养池塘沉积物,利用特定饵料培养基,并通过定期增加培养基中饵料添加量的方式,对沉积物中的复合菌进行了6个周期(7d/周期)的富集驯化培养。在COD含量约为1 000mg/L、菌接种量为10%的饵料降解溶液中,后期复合菌在5d内对COD的最大去除率分别达到了64%、70%和88%。在6个周期富集驯化结束后,从复合菌中分离出16株菌,经16S rRNA分析,其中8株属于弧菌属(vibrio sp.),1株属于芽孢杆菌目(Bacillales sp.),2株属于芽孢杆菌属(Bacillus sp.),2株属于交替假单胞菌属(Pseudoalteromonas sp.),1株属于气单胞菌属(Aeromonas sp.),1株属于希瓦氏菌属(Shewanella sp.)。经血平板初步筛选出4株不具潜在致病性的菌,1株属于芽孢杆菌目,1株为巨大芽孢杆菌(Bacillus megaterium),2株为交替假单胞菌,在菌接种量为1.0×10~7cfu/mL的降解溶液中,各株菌在5d内对COD的最大去除率分别达到了40%、40%、56%和46%。将这4株菌按一定比例组合后,在5d内对COD的最大去除率可达到72%。研究表明,经富集驯化后的复合菌及从中分离筛选出的4株不具潜在致病性的细菌及按一定比例重组后的菌在调控养殖环境有机物污染方面都具有潜在应用价值。  相似文献   

4.
从西菲律宾海底4954 m深的沉积物中分离到一批深海细菌,对其中编号为B2、B5、B6的3株细菌进行了生理、光学显微镜和扫描电镜观察,并且进行了分子水平鉴定。菌落呈圆球形,光滑,3株菌均带有颜色, B6菌呈乳白色, B2和 B5菌分别呈现鲜艳的橙色和红色。扫描电镜观察表明 B2和B6呈杆状,但B6菌外面覆有鞘膜, B5菌呈球状。生理实验表明,3株菌温度生长范围在37℃以下,最适生长温度分别为20、28、28℃,属于耐冷菌范畴。pH耐受范围为6~14,最适pH分别为8、8、12。3株细菌16S rRNA基因序列同源性分析表明,它们分属于芽孢杆菌(Bacillus)、节杆菌(Arthrobacter)、蛋白菌(Acinetobacter)3个不同的菌属。  相似文献   

5.
青岛潮间带沉积物可培养厌氧细菌多样性的研究   总被引：1，自引：1，他引：0  
为了验证设计的简易厌氧培养方法,作者以青岛潮间带沉积物为研究对象,采用5种培养基,从青岛潮间带沉积物共分离获得138株厌氧细菌。16S r DNA序列分析表明,这些细菌分属3个门15个属32个种,其中γ-变形菌纲64株18个种,在种类上处于优势地位;此外还包括δ-变形菌纲(δ-Proteobacteria)16株2个种,ε-变形菌纲4株1个种,拟杆菌门(Bacteroidetes)29株8个种,梭杆菌门(Fusobacteria)25株3个种。在属水平上,弧菌属(Vibrio)、Marinifilum属、泥杆菌属(Ilyobacter)、脱硫弧菌属(Desulfovibrio)、希瓦氏菌属(Shewanella)在数量上占优势。此外,有26株8种细菌(占总菌株数的18.84%)与已知菌的同源性介于89.38%~94.22%,为潜在的海洋细菌新科或新属,表明此简易厌氧菌培养方法在获得新菌方面具有较大优势。另外,研究结果还表明,不同培养基对特定的类群具有选择性:2216E培养基对γ-变形菌纲分离培养效率较高;SPG培养基在获得新菌方面具有优势(占新菌数62.5%),且这些新菌大多属于拟杆菌门和梭杆菌门,其中SPG-1培养基对于分离硫酸盐还原菌和难培养的ε-变形菌纲细菌具有优势,SPG-4培养基对分离硝酸盐还原菌具有优势。  相似文献   

6.
针对长江口10个站位样品,采用HM培养基和ZMCA培养基分离培养耐(嗜)盐菌,通过PCR方法获取156株细菌的16S rDNA序列。其中,由HM培养基分离获得136株菌株,可划分为33个分类单元(OUT),分属α-变形菌纲(Alphaproteobacteria)、γ-变形菌纲(Gammaproteobacteria)和厚壁菌门(Firmicutes)的芽孢杆菌纲(Bacilli)3个类群,其中γ-变形菌纲为优势耐(嗜)盐细菌;靠近海岸的站点M5-1,N6-2和M4-1耐(嗜)盐细菌均属于厚壁菌门,而远离海岸的站点耐(嗜)盐细菌均属于变形菌门。以ZMCA培养基分离获得的20株菌株分属α-变形菌纲和放线菌纲(Actinobacteria),可划分为10个OTU。由HM培养基分离获得的菌株中,70.5%属于耐盐菌,29.5%属于中度嗜盐菌;由ZMCA培养基分离获得的菌株均为耐盐菌。HM培养基分离得到的136株细菌的硝酸盐和亚硝酸盐还原性分析表明,亚硝酸盐还原菌数量仅为硝酸盐还原菌的1/3左右。  相似文献   

7.
海草植株共附生大量具有合成植物激素、促进植物营养物质吸收和拮抗病原菌作用的促生菌,对海草的健康生长具有重要作用。本研究利用固氮、溶磷培养基从海南省新村湾泰来草(Thalassia hemperichii)和海菖蒲(Enhalus acoroides)植株中获得细菌131株,分布于36属61种,其中芽孢杆菌属(Bacillus)为优势属。通过可培养细菌的多样性分析发现,从泰来草分离获得细菌的OTU(Operational Taxonomic Unit)数目、Chao和Shannon指数均高于海菖蒲,其具有更高的细菌多样性;而三种培养基中,应用PSM培养基获得的细菌的多样性最低。另外,对包括17株溶磷菌和12株固氮菌在内的61株菌进行促生特性分析,结果显示菌株L-2以C_2H_4计的固氮酶活性达14.27nmol/(h·m L),有3株菌溶磷活性在29.91～44.86 mg/L之间,6株菌产铁载体能力很强,8株菌氨化能力很强,10株菌吲哚乙酸(IAA)产量在50μg/m L以上。基于促生能力的综合分析,我们筛选出5株具有较强促生潜能的菌株,16S rRNA鉴定结果显示其中2株为芽孢杆菌(Bacillus sp.),1株克雷伯氏菌(Klebsiella sp.),1株拉乌尔菌(Raoultella sp.)和1株Breoghania sp.。它们适合进一步开发研制为微生物菌剂,可应用于促进移植海草生长发育和退化海草床生态保护修复中。  相似文献   

8.
以龙须菜为唯一的营养源对深海沉积物进行富集和筛选,获得一个可降解龙须菜(Gracilaria lemaneiformis)、紫菜(Porphyra umbilicalis)和海带(Laminaria japonica)产生还原性寡糖的菌群.通过16S rRNA序列及16S rRNA-RFLP分析对该菌群中的细菌多样性进行了研究.结果表明,降解菌群中的细菌组成主要为弧菌属(Vibrio,8株)、火色杆菌属(Flammeovirga,7株)和希瓦氏菌属(Shewanella,5株),其中希瓦氏菌属和火色杆菌属的细菌在菌群中的丰度较高.采用龙须菜为唯一营养源的筛选培养基对菌群中的细菌进行分离,获得4株具有琼胶酶活力的细菌,包括2株火色杆菌属和2株希瓦氏菌属细菌.培养和未培养的结果均表明火色杆菌和希瓦氏菌这2个属为所研究的深海沉积物主要的龙须菜降解菌.对原始降解菌群和所分离的关键菌株进行了龙须菜酶解产糖能力的比较,结果发现菌群中的弧菌属菌株虽然自身没有酶解龙须菜的能力,但可能可以协助关键菌株,提高菌群对龙须菜的降解效率.因此本研究中所获得的菌群和菌株有望在琼胶寡糖的绿色生产中得到广泛应用.  相似文献   

9.
为了解九孔鲍鲍鱼脱板期养殖环境中细菌的多样性,分离培养了脱板病发生期养殖环境(包括附着基上和养殖池水中)细菌32株,并用限制性片段长度多态性分析和16S rDNA序列分析法对其进行了分子鉴定,构建了系统进化树.结果表明,所分离的细菌分为3大类群9个属,分别是:γ-变形菌纲(γ-Proterbacteria)的交替假单胞菌属(Pseudoalteromonas)、Cobetia属、盐单胞菌属(Hlomonas)、弧菌属(Vibrio)和海单胞菌属(Marinomonas);厚壁菌门(Firmicutes)的盐水球菌属(Salinicoccus)、动球菌属(Planococcus)和芽孢杆菌属(Bacillus);还有拟杆菌门(Bacteroidetes)的Tenacibaculum属.这些细菌大多与GenBank库中分离自发病的水产养殖生物的细菌最相似.这说明从该养殖环境中分离培养出的细菌和水产养殖病害间存在着一定的关系.  相似文献   

10.
为研究南太平洋环流区底层海水可培养细菌的多样性,通过IODP 329航次获得了该区域7个站点的底层海水样品,利用传统的分离培养法获得菌株后,进行16SrDNA测序及系统发生分析。结果表明,从南太平洋环流区7个站点的底层水中分离出174株深海细菌,这些菌株属于4个门,30个属,78个种。其中γ-变形菌纲(γ-Proteobacteria)有143株,在数量和种类方面均占主导地位;α-变形菌纲(α-Proteobacteria)7株,β-变形菌纲(β-Proteobacteria)2株,厚壁菌门(Firmicutes)11株,放线菌门(Actinobacteria)6株,拟杆菌门(Bacteroidetes)5株。优势属有假交替单胞菌属(Pseudoalteromonas)、交替单胞菌属(Alteromonas)、弧菌属(Vibrio)、盐单胞菌属(Halomonas)等10个属;优势种有居珊瑚假交替单胞杆菌(Pseudoalteromonas paragorgicola)、子午盐单胞菌(Halomonas meridiana)、坎氏弧菌(Vibrio campbellii)、西班牙交替单胞菌(Alteromonas hispanica)、河豚毒素假交替单胞菌(Pseudoalteromonas tetraodonis)、琼氏不动杆菌(Acinetobacter junii)等12个。在7个站点中,位于环流边缘的U1371站点分离出的菌株数量明显多于其他站点,且是7个站点中唯一1个包含了分离出的所有6个门类的站点,多样性最高;而U1369和U1370站点都只分离出γ-变形菌纲1个门类。此外,9株细菌可能为海洋细菌新属或新种。  相似文献   

11.
Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding.  相似文献   

12.
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.  相似文献   

13.
This study tests the hypothesis that the in situ void ratio of surficial marine sediments may be predicted from shear wave velocity-depth data with a reliability equal to that of other methods currently available. Shear wave velocity is fundamentally controlled by the number of grain-to-grain contacts per unit volume of material and by the effective stress across those contacts. In this study, three previously established empirical formulae are used to predict void ratio from velocity-depth data. Field data were acquired along a transect off the northern Californian coast across which water depth increased from 35 to 70 m and seafloor sediment type varied from sand to silty-sand, respectively. A towed seafloor sled device was used to collect shear wave refraction data, and a marked, systematic decrease in velocity was observed along the line, ranging from 35-70 m/s for the coarse, near-shore material to 25-40 m/s for the finer, offshore deposits. Void ratios predicted from these velocities were compared with data measured directly from box-core samples. Of the formulae used for prediction, two agree remarkably well with the control data. Both predicted and control values increase from 0.6-0.8 for the sandy material to 1.1-1.5 for the silty-sand. Thus, this study does not disprove the hypothesis set and demonstrates the potential of field shear wave velocity-depth data as a means of delineating spatial variation in void ratio for surficial marine sediments in a remote, nondestructive manner.  相似文献   

14.
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors.  相似文献   

15.
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake.  相似文献   

16.
Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ～ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream.  相似文献   

17.
Current trends of development of satellite derived bathymetry (SDB) models rely on applying calibration techniques including analytical approaches, neuro-fuzzy systems, regression optimization and others. In most of the cases, the SDB models are calibrated and verified for test sites, that provide favorable conditions for the remote derivation of bathymetry such as high water clarity, homogenous bottom type, low amount of sediment in the water and other factors. In this paper, a novel 3-dimensional geographical weighted regression (3GWR) SDB technique is presented, it binds together methods already presented in other studies, the geographically weighted local regression (GWR) model, with depth dependent inverse optimization. The proposed SDB model was calibrated and verified on a relatively difficult test site of the South Baltic near-shore areas with the use of multispectral observations acquired by a recently launched Sentinel-2 satellite observation system. By conducted experiments, it was shown that the proposed SDB model is capable of obtaining satisfactory results of RMSE ranging from 0.88 to 1.23[m] depending on the observation and can derive bathymetry for depths up to 12m. It was also shown, that the proposed approach may be used operationally, for instance, in the continuous assessment of temporal bathymetry changes, for areas important in the context of ensuring local maritime safety.  相似文献   

18.
As a part of the environmental impact assessment studies, geotechnical properties of sediments were determined in the Central Indian Basin. The undrained shear strength and index properties of the siliceous sediments were determined on 20 box cores of uniform dimension collected from various locations in five preselected sites. The maximum core length encountered was 41 cm and most of the sediments were siliceous oozes consisting of radiolarian or diatomaceous tests. The shear strength measurements revealed that surface sediments deposited in recent times (0-10 cm) have a shear strength of 0-1 kPa; this value increases with depth, reaching 10 kPa at 40 cm deep. Older sediments have greater strength because of compaction. Water content varies in the wide range of 312-577% and decreases with depth. The clay minerals such as smectite and illite are dominant and show some control over water content. Wet density, specific gravity, and porosity do not indicate any notable variation with depth, thereby indicating a uniform, slow rate of sedimentation. The average porosity of sediments is 90.2%, specific gravity 2.18, and wet bulk density 1.12 g/cm 3 . Sediments exhibit medium to high plasticity characteristics, with the average plasticity index varying between 105% and 136%. Preliminary studies on postdisturbance samples showed an increase in natural water content and a decrease in undrained shear strength of sediments in the top 10- to 15-cm layer.  相似文献   

19.
海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。  相似文献   

20.
Several major improvements to an existing method for calibrating satellite altimeters using tide gauge data are described. The calibration is in the sense of monitoring and correcting temporal drift in the altimetric time series, which is essential in efforts to use the altimetric data for especially demanding applications. Examples include the determination of the rate of change of global mean sea level and the study of the relatively subtle, but climatically important, decadal variations in basin scale sea levels. The improvements are to the method described by Mitchum (1998a), and the modifications are of two basic types. First, since the method depends on the cancellation of true ocean signals by differencing the altimetric data from the tide gauge sea level time series, improvements are made that produce a more complete removal of the ocean signals that comprise the noise for the altimetric drift estimation problem. Second, a major error source in the tide gauge data, namely land motion, is explicitly addressed and corrections are developed that incorporate space-based geodetic data (continuous GPS and DORIS measurements). The long-term solution, having such geodetic measurements available at all the tide gauges, is not yet a reality, so an interim solution is developed. The improved method is applied to the TOPEX altimetric data. The Side A data (August 1992?February 1999) are found to have a linear drift component of 0.55 + / 0.39 mm/yr, but there is also a significant quadratic component to the drift that is presently unexplained. The TOPEX Side B altimeter is estimated to be biased by 7.0 + / 0.7 mm relative to the Side A altimeter based on an analysis of the first 350 days of Side B data.  相似文献   

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