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21.
凡纳滨对虾咸淡水养殖系统内细菌群落组成的PCR-DGGE分析 总被引:16,自引:0,他引:16
采用PCR(polym erase chain reaction)-DGGE(denaturing grad ient gel electrophoresis)及传统的微生物培养方法对凡纳滨对虾Litopenaeus vannam ei咸淡水养殖系统内各种环境的细菌群落组成进行了比较研究。传统的微生物培养计数表明,从海湾水、养殖池水到对虾粪样,细菌和弧菌的数量表现出依次增加的趋势,粪样及肠壁中弧菌的数量高出外界水环境1—4个数量级。相对于外界水环境,粪样中有很高的芽孢杆菌孢子含量,但是肠壁定植细菌中不存在芽孢杆菌(孢子)。PCR-DGGE及聚类分析结果表明,从海湾沿岸、养殖池、对虾粪便到对虾肠壁,细菌群落的多样性由高到低,无论是在哪种环境,群落的优势种都十分明显,且只有2—4种。来自同一环境各样品间的细菌群落组成非常相似,来自不同环境的样品,其细菌群落组成差别较大。聚类图上各簇的排列顺序反映了样品在取样空间分布上的毗邻次序和它们的相似程度。 相似文献
22.
台湾海峡金色小沙丁鱼幼鱼索饵群体研究 总被引:2,自引:1,他引:2
本文研究了台湾海峡南部和北部的金色小沙丁鱼当年生幼鱼计数性状和量度性状特征差异,并结合其生物学特性、产卵场、洄游及海区环境特征进行综合分析。结果表明,台湾海峡南部和北部的索饵幼鱼仍属于同一地方种群:闽南-台湾浅滩语地方种群。根据其索饵洄游特点,可分为台湾海峡南部和北部两个索饵群体. 相似文献
23.
俄国鱼类行为与感觉研究(Ⅰ) 总被引:6,自引:1,他引:6
本文简述俄国鱼类行为及感觉系统研究的发展,概述了在洄游及基本行为类型研究结果,鱼在水流中行为,其水动力学特征及游泳速度、温度选择、与个体生理状态相关的鱼行为,以及鱼类行为遗传研究。 相似文献
24.
Fish growth and the relation between growth and environmental conditions offer a good opportunity for measuring alkaline and earthy ions in fish otoliths.The analytical method must involve high sensitivity when attempting to discriminate between fish growth and environmental conditions.The aim of this paper is to propose a chromatographic method, with low detection limits, as a new approach in determining some important micronutrients present in sea water and fish otoliths.The work samples are: coastal, off-shore and sediment waters and fish otoliths (Engraulis encrasicholus, Mullus barbatus, Umbrina cirrhosa, Sciaena umbra, Pagellus erythrinus) in the Adriatic Sea and the Canal of Sicily.The analytical method includes an IONPAC CS12A chromatographic column and a 18 mM methanesulfonic acid eluent.The detection limit readings obtained with this method, for one E. encrasicholus fish otolith, weighing 2.6 mg are equal or inferior to 0.1 μg/L for lithium (Li), 59 μg/L for sodium (Na), 46 μg/L for ammonium (NH4), 23 μg/L for potassium (K), 13 μg/L for magnesium (Mg), 88 μg/L for manganese (Mn), 2.567 μg/L for calcium (Ca) and 13 μg/L for strontium (Sr).The HPIC method minimizes overlaps such as Na on Li, and NH4 in seawater and Ca on Mg and Sr in fish otolith. These elements are an essential constituent present in otoliths when describing the relation between growth and environmental conditions.Good separation among analytes is achieved within 16 min. 相似文献
25.
26.
Natalia V. Zhukova 《Ocean Science Journal》2005,40(3):34-42
Variation in the microbial biomass and community structure found in sediment of heavily polluted bays and the adjacent unpolluted
areas were examined using phospholipid fatty acid analysis. Total microbial biomass and microbial community structure were
responding to environmental determinants, sediment grain size, depth of sediment, and pollution due to petroleum hydrocarbons.
The marker fatty acids of microeukaryotes and prokaryotes - aerobic, anaerobic, and sulfate-reducing bacteria -were detected
in sediments of the areas studied. Analysis of the fatty acid profiles revealed wide variations in the community structure
in sediments, depending on the extent of pollution, sediment depth, and sediment grain size. The abundance of specific bacterial
fatty acids points to the dominance of prokaryotic organisms, whose composition differed among the stations. Fatty acid distributions
in sediments suggest the high contribution of aerobic bacteria. Sediments of polluted sites were significantly enriched with
anaerobic bacteria in comparison with clean areas. The contribution of this bacterial group increased with the depth of sediments.
Anaerobic bacteria were predominantly present in muddy sediments, as evidenced from the fatty acid profiles. Relatively high
concentrations of marker fatty acids of sulfate-reducing bacteria were associated with organic pollution in this site. Specific
fatty acids of microeukaryotes were more abundant in surface sediments than in deeper sediment layers. Among the microeukaryotes,
diatoms were an important component. Significant amounts of bacterial biomass, the predominance of bacterial biomarker fatty
acids with abundance of anaerobic and sulfate-reducing bacteria are indicative of a prokaryotic consortium responsive to organic
pollution. 相似文献
27.
Ana P. Mucha M. Teresa S. D. Vasconcelos Adriano A. Bordalo 《Estuarine, Coastal and Shelf Science》2004,59(4):663
Vertical distribution (0–15 cm) of the macrobenthic community and its relationships to natural sediment characteristics and trace metal contents and bioavailability were studied at five locations in the lower Douro estuary, Portugal. An analysis of vertical metal distribution, for the interpretation of anthropogenic impact on the estuarine sediments, was also investigated. Sediment characterisation included organic matter, grain size, metals (Al, Fe, Cu, Pb, Cr, Ni, Cd, Zn and Mn), acid volatile sulphide (AVS) and simultaneously extracted metals (SEM). The macrobenthic community had low diversity (14 species), was dominated by small size opportunists and seemed to be controlled mainly by natural factors such as grain size distribution, Al and Fe contents and sediment depth. The vertically heterogeneous distribution of macrobenthic community appears to affect redox status of the sediments and consequently metal bioavailability. Despite anthropogenic contamination in terms of Zn, Cu, Pb, Cr and Ni having already been detected in the north bank, the analysis of vertical distribution was essential for the identification of current anthropogenic contamination in terms of Zn, Pb and Cd in the south bank. 相似文献
28.
Mussel Periostracum from Deep-Sea Redox Communities as a Microbial Habitat: 3. Secondary Inhabitants
Abstract. Vacated microborings in periostracum of live mussels of the Florida Escarpment redox community (depth of 3266 m) become a habitat for a prolific secondary microbiota consisting of a variety of prokaryotic and a few eukaryotic organisms. Periostracum surface is also colonized by diverse microorganisms, dominated by presumed chemolithotrophic bacteria with stacks of intracellular lamellae. Unlike sheltered microflora within borings, the surface community is heavily grazed upon by numerous archaeogastropods and ciliates. 相似文献
29.
Abstract. Aquatina lake is a brackish basin, connected with the Adriatic Sea along the mast of Apulia (Italy), with a mean salinity of 26%. The abundance and biomass of fifteen polychaete species were recorded by monthly samples in a pilot area of the lake from February 1989 to February 1990. Naineris laevigata was dominant, both in number of individuals and biomass. During 1990, obstruction of freshwater inflow to the lake caused an increase in salinity up to 4O%, followed by some changes in the polychaete community. Noromasrus hiericeus became dominant, and the abundances of the other species decreased except for Naineris laevipru . Salinity assumed normal values after three months, but community responded slowly becauie the massive presence of N. latericeus inhibited the recovery of other species. An abiotic disturbance, followed by a biotic disturbance, altered the structure of the polychaete community. 相似文献
30.
五种植物提取液的抗鱼病菌和抗鱼病毒效应(英文) 总被引:1,自引:0,他引:1
本文旨在探索用廉价的野生植物防治鱼病。所用的植物有牛繁缕(Stellaria aqu-atica),双花凤仙(Impatiens biflora),夜来香(Oenothera biennis),艾草(Artem-isia vulgaris)和忍冬(Lonicera japonica)。用作试验的鱼病菌共13种(18个菌株),分属于气单孢菌属、假单孢菌属、爱德华氏菌属、耶尔森氏菌属、弧菌属。所用的鱼病毒为传染性胰脏坏死病毒IPNV,传染性造血组织坏死病毒IHNV。上述病原微生物均获自美国马里兰大学微生物系。实验结果表明,五种植物提取液均有不同程度的抗鱼病菌作用,其中以牛繁缕的抗菌谱最广,作用力最强。忍冬、艾草、牛繁缕有抗鱼病毒作用。其中以忍冬的效果最好,它能抑制IPNV和IHNV。而艾草和牛繁缕只能抑制IHNV。 相似文献