Microbial Biomass Dynamics Along a Trophic Gradient at the Atlantic Barrier Reef off Belize (Central America)   总被引：2，自引：0，他引：2  

Gerhard J.  Herndl 《Marine Ecology》1991,12(1):41-51

Abstract. Recent findings indicate that heterotrophic bacteria and not phytoplankton are the most numerous biomass components even in the euphotic zone of oligotrophic, open oceans. In this study it was hypothesized that the microbial biomass components change within a few hundred meters as oligotrophic water flows across the reef and becomes enriched with nutrients. Along a trophic gradient, four stations at the Atlantic Barrier Reef off Belize (Central America) were sampled for microbial biomass components. Phytoplankton biomass (measured as chlorophyll a) ranged from the most oligotrophic station (St. 1) to the most eutrophic station (St. 4) from 6.9–415.5 μg CI"' (assuming a C:chl a ratio of 30): heterotrophic bacterial biomass increased 4-fold (from 10.1–46.4μg C 1^-1), heterotrophic nanoflagellate (HNAN) biomass increased from 4.6-19ug C 1^-1, and cyanobacteria from 0.9-4.5 μg C-1^-1. Production estimates derived from seawater cultures revealed a 5-fold increase in bacterial production from the oligotrophic station (3.7 ug C 1^-1 d^-1) to the eutrophic St. 4 (17.8ug C-1-d1^-1)- Cyanobacterial production rose from 1.1–3.5ug C-1–d^-1 and HNAN production from 0.65-1.13 μg C-1^-1 -d^-1. While cyanobacteria contributed between 13 and 20% to the autotrophic plankton component in the oligotrophic waters, their contribution dropped to about 1 % at the eutrophic stations.  相似文献   

膜-生物反应器与活性污泥工艺处理氨氮废水的微生物特性比较   总被引：1，自引：1，他引：1  

高孟春  杨敏  佘宗莲  金春姬 《中国海洋大学学报(自然科学版)》2005,35(5):830-834

考察了膜-生物反应器（MBR）与活性污泥工艺（CAS）处理无机氨氮废水的对比研究.结果表明,同CAS相比,MBR处于高容积负荷、低污泥负荷的运行状态下,硝化效果较好,除了短期的pH控制故障外,氨氮转化为硝酸盐氮的转化率可达99%.随着运行时间的增加,膜组件的截留作用导致MBR内胞外多聚物的积累,电镜扫描（SEM）不能观察到运行后期微生物的形态变化,然而,CAS中微生物形态变化不大.2个反应器中硝化菌、亚硝化菌和异养菌的变化趋势是一致的,异养菌仅为硝化细菌的万分之一;但与MBR相比, CAS中硝化菌数量少32%,亚硝化菌的数量少35%,异养菌数量少24%.  相似文献   

中国对虾丝状细菌的扫描电镜研究     

杨季芳  吴友吕 《海洋学研究》1992,10(4):56-62

本文应用扫描电镜研究了中国对虾丝状细菌的结构,附着方式及其对对虾的危害和与环境的关系。  相似文献   

Application of Atomic Force Microscopy to Observation of Marine Bacteria   总被引：3，自引：0，他引：3  

Tomohiko Nishino  Eiko Ikemoto  Kazuhiro Kogure 《Journal of Oceanography》2004,60(2):219-225

The atomic force microscopy (AFM) is a recently developed, bench-top instrument that can image the surface structures of biological specimens at high resolution with simultaneous measurement of their size. This paper describes the application of AFM to marine bacteria. Both natural and cultured bacteria were retained on a filter or placed on glass, washed, air-dried and observed by AFM. The instrumental condition, the choice of suitable filter, effect of fixation and filtration, comparison with epifluorescent microscopic (EFM) count, and the size and shape of bacterial cells were investigated. An Isopore filter was best for concentration and subsequent observation because of its surface flatness. Cross section images showed that both rod and coccoid cells were flattened, the former usually having a two-humped shape. Bacterial cells were differentiated from non-living particles based on their cross section shape and size. Bacterial counts by AFM and EFM showed good agreement. Although size measurement is easily done by the instrument, AFM tends to overestimate the size of microspheres. More work is thus needed on the size measurement of living organisms. Because AFM easily provides images of natural bacterial cells at high magnification, it can be used as a new tool to study the fine structures of marine bacteria. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Assessment of the effects of hydrocarbon contamination on the sedimentary bacterial communities and determination of the polar lipid fraction purity: Relevance of intact phospholipid analysis     

Nicolas Mazzella  Josiane Molinet  Agung Dhamar Syakti  Jean-Claude Bertrand  Pierre Doumenq   《Marine Chemistry》2007,103(3-4):304-317

This in situ study reports on the relevance of intact phospholipids as new biomarkers and highlights the limits of the classical fatty acid analysis after the hydrolysis of the polar lipid fraction. The analysis of polar lipid fractions revealed significant contributions of marine macrophytes with either non-phospholipid compounds (sulfoquinovosyl diacylglycerol) or with both non-bacterial phospholipid classes (phosphatidylcholine) and non-bacterial phospholipid molecular species (some molecular species of phosphatidylglycerol). The analysis of intact phospholipids showed also the predominance of gram-negative bacteria in sediments whereas the analysis of fatty acids alone cannot confirm such information. Lastly, as regard to the effects of petroleum hydrocarbons on the sedimentary bacterial communities, we observed a higher degree of saturation of the fatty acyl chains of the phospholipids extracted from sediment exposed to a massive and chronic crude oil contamination. Such a result was interpreted as an adaptive response resulting in higher membrane rigidity of the bacterial communities.  相似文献   

Metabolites from mangrove endophytic fungus Dothiorella sp.     

XU Qingyan  WANG Jianfeng  HUANG Yaojian  ZHENG Zhonghui  SONG Siyang  ZHANG Yongmin  SU Wenjin 《海洋学报(英文版)》2004,23(3):541-547

Mangroves are special woody plant communities in the intertidal zone of tropical and subtropical coasts. They prove to be a natural microorganisms and new metabolites storage. In the study of mangrove endophytic fungi metabolites, four new compounds, Compounds 1, 2, 3 and 4, as well as a known octaketide, cytosporone B (5), are isolated from an endophytic fungus, Dothiorella sp., HTF3. They all show cytotoxic activities. The elucidation of these structures is mainly based on 1D/2D NMR and ESI-MS spectral analyses.  相似文献   

秋季东、黄海异养细菌(Heterotrophic Bacteria)的分布特点   总被引：27，自引：1，他引：27  

赵三军  肖天  岳海东 《海洋与湖沼》2003,34(3):295-305

2000年10-11月,乘"北斗号"考察船进行秋季"东、黄海生态系统动力学与生物资源可持续利用"大面调查,研究秋季东、黄海异养细菌的分布.结果表明,异养细菌在黄海和东海的丰度分别在(2.37-13.33)×108 cell/L和(3.05-13.62)×108 cell/L之间.细菌丰度最高值出现在长江口附近,且断面E和断面F各站位的细菌丰度明显高于其他断面.异养细菌丰度大小以长江口为中心向外海依次递减.东、黄海水体异养细菌生物量分别在244.45-1812.90mgC/m2和100.60-940.87mgC/m2之间.东、黄海异养细菌丰度无显著差异,但是东海海域水体异养细菌生物量高于黄海海域.异养细菌空间分布与浮游植物叶绿素在东海有一定的相关性,黄海异养细菌与硝酸盐浓度的相关性极显著.  相似文献   

Biological Responses to Seasonally Varying Fluxes of Organic Matter to the Ocean Floor: A Review   总被引：8，自引：0，他引：8  

Andrew J. Gooday 《Journal of Oceanography》2002,58(2):305-332

Deep-sea benthic ecosystems are sustained largely by organic matter settling from the euphotic zone. These fluxes usually have a more or less well-defined seasonal component, often with two peaks, one in spring/early summer, the other later in the year. Long time-series datasets suggest that inter-annual variability in the intensity, timing and composition of flux maxima is normal. The settling material may form a deposit of “phytodetritus” on the deep-seafloor. These deposits, which are most common in temperate and high latitude regions, particularly the North Atlantic, evoke a response by the benthic biota. Much of our knowledge of these responses comes from a few time-series programmes, which suggest that the nature of the response varies in different oceanographic settings. In particular, there are contrasts between seasonal processes in oligotrophic, central oceanic areas and those along eutrophic continental margins. In the former, it is mainly “small organisms” (bacteria and protozoans) that respond to pulsed inputs. Initial responses are biochemical (e.g. secretion of bacterial exoenzymes) and any biomass increases are time lagged. Increased metabolic activity of small organisms probably leads to seasonal fluctuations in sediment community oxygen consumption, reported mainly in the North Pacific. Metazoan meiofauna are generally less responsive than protozoans (foraminifera), although seasonal increases in abundance and body size have been reported. Measurable population responses by macrofauna and megafauna are less common and confined largely to continental margins. In addition, seasonally synchronised reproduction and larval settlement occur in some larger animals, again mainly in continental margin settings. Although seasonal benthic responses to pulsed food inputs are apparently widespread on the ocean floor, they are not ubiquitous. Most deep-sea species are not seasonal breeders and there are probably large areas, particularly at abyssal depths, where biological process rates are fairly uniform over time. As with other aspects of deep-sea ecology, temporal processes cannot be encapsulated by a single paradigm. Further long time-series studies are needed to understand better the nature and extent of seasonality in deep-sea benthic ecosystems. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

海绵共栖细菌抗菌活性及其群体感应信号的研究     

郭秀春  郑立  崔志松  杨佰娟  田黎  王小如 《海洋学报(英文版)》2010,29(5):135-143

利用平板涂布法从南海海绵生物样品中分离海绵共栖细菌,以枯草芽孢杆菌、金黄色葡萄球菌、大肠杆菌及酿酒酵母作为实验用指示菌对海绵共栖细菌进行了抗菌活性筛选。利用气相质谱联用仪(GC-MS)建立了群体感应信号分子酰基高丝氨酸内酯类化合物(AHLs)的检测方法,分析了活性菌株粗提液中信号分子的产生及种类。同时采用16S rDNA同源性和系统发育分析对活性菌株进行种属鉴定和系统发生学研究。结果表明,在分离到的94株海绵共栖细菌中18株(占19.1%)细菌具有抗菌活性。通过GC-MS检测确定大多数活性菌株都含有AHLs,因此提出了海绵共栖细菌抗菌活性与群体感应之间可能存在必然联系的推测。通过细菌分类鉴定,结果显示具有抗菌活性的细菌大部分属于芽孢杆菌属(Bacillus)。  相似文献   

鱼类消化道细菌及其作用研究Ⅱ.鲻鱼     

周宗澄  叶德赞  倪纯治  刘文华 《台湾海峡》1997,(1)

本文报道了从鲻鱼消化道分离的好气性异养细菌数量为（1．5×108±0．4×108～6.4×108±2.0×108）个／g，共分离220株细菌。其种群组成为弧菌、气单胞菌、不动细菌、假单胞菌、微球菌、黄杆菌、葡萄糖细菌、纤维单胞菌、节细菌和棒状杆菌。测定其生化特性，表明该类菌对有机质的分解能力比较强，这些特性有利于鱼类对营养物质的消化和吸收，并进一步促进其生长和发育。  相似文献