珠江三角洲城市群大气微生物优势 种群及时空分异特征   总被引：2，自引：0，他引：2  

郑芷青  谢小保  欧阳友生  王春华  曾海燕  陈仪本 《地理研究》2009,28(3):625-633

用JWL-IIB新型固体撞击式多功能空气微生物采集仪,于2005至2007年,分别在春、夏、秋、冬不同的季节,对珠江三角洲8个城市(广州、深圳、珠海、佛山、江门、东莞、惠州、中山)的四个不同的功能区(交通枢纽、商业区步行街、居民区和工业区)161个样点,进行大气微生物采样、测定与时空分布规律初步研究,拟为珠江三角洲城市环境污染的综合防治和卫生防疫工作提供依据。研究结果表明:珠江三角洲城市群大气微生物真菌的优势种群有:曲霉属(Aspergillus)、青霉属(Penicillium)、枝孢属( Cladosporium)、芽枝霉属(Clodosporium)等,共19属21种,细菌的优势种群有芽孢杆菌属(Bacillus)、葡萄球菌属(Staphylococcus)、微小杆菌属(Exiguobacterium)、链霉菌属(Streptomyces)等,共4属15种。大气微生物含量在珠江三角洲城市群中广州和东莞较高,细菌比真菌含量高;室内较室外高,无绿化地较有绿化地高,大气微生物含量在全年中,春、夏季相对较高。  相似文献   

The significance of microbial processes in hydrogeology and geochemistry   总被引：3，自引：0，他引：3  

Francis H. Chapelle 《Hydrogeology Journal》2000,8(1):41-46

2 (methanogenesis). In aquifers contaminated by anthropogenic contaminants, an excess of available organic carbon often exists, and microbial metabolism is limited by the availability of electron acceptors. In addition to changes in groundwater chemistry, the solid matrix of the aquifer is affected by microbial processes. The production of carbon dioxide and organic acids can lead to increased mineral solubility, which can lead to the development of secondary porosity and permeability. Conversely, microbial production of carbonate, ferrous iron, and sulfide can result in the precipitation of secondary calcite or pyrite cements that reduce primary porosity and permeability in groundwater systems. Received, January 1999/Revised, July 1999, August 1999/Accepted, October 1999  相似文献   

路南石林土壤微生物含量及其对土壤CO2浓度的影响   总被引：5，自引：1，他引：4  

梁福源  宋林华  唐涛  王静 《中国岩溶》2003,22(1):6-11

在植被生长缓慢的季节(1999 年12 月), 对石林地区红壤三个研究点土下20 ～ 60cm 不同深度土壤的温度、pH 、有机质含量、微生物含量和土壤CO2 浓度变化进行了研究。研究表明土壤CO2 浓度和土壤中有机碳含量没有直接的关系, 但是与土壤微生物含量(Mo)、土壤湿度(Mt)和土壤CO2 浓度有很好的相关关系。因此在植被生长缓慢的季节, 土壤微生物对土壤空气CO2 浓度变化的影响要远远大于来源于根系呼吸的比例。   相似文献   

中国海洋生物研究70年   总被引：5，自引：2，他引：3  

孙军  蔡立哲  陈建芳  单秀娟  丁兰平  黄凌风  金显仕  林茂  刘洋  邵宗泽  徐奎栋  王雨  张晓华 《海洋学报》2019,41(10):81-98

随着中国“海洋强国”战略的提出，加快建设海洋类学科的发展成为历史必然，海洋生物是海洋不可分割的一部分，海洋环境和生物相互依存，相互作用，海洋生物研究重要性日益凸显。为纪念中国科学家在海洋生物领域的突出贡献，本文回顾了建国以来中国海洋生物相关的重要研究进展，梳理了中国科学家在海洋生物领域的突出贡献，系统总结并讨论了未来研究方向，抛砖引玉，希望籍此助推中国海洋生物研究的新高潮。  相似文献   

Microbial influence on erosion,grain transport and bedform genesis in sandy substrates under unidirectional flow     

JAMES W. HAGADORN  CONOR MCDOWELL 《Sedimentology》2012,59(3):795-808

Interpreting the physical dynamics of ancient environments requires an understanding of how current‐generated sedimentary structures, such as ripples and dunes, are created. Traditional interpretations of these structures are based on experimental flume studies of unconsolidated quartz sand, in which stepwise increases in flow velocity yield a suite of sedimentary structures analogous to those found in the rock record. Yet cyanobacteria, which were excluded from these studies, are pervasive in wet sandy environments and secrete sufficient extracellular polysaccharides to inhibit grain movement and markedly change the conditions under which sedimentary structures form. Here, the results of flume experiments using cyanobacteria‐inoculated quartz sand are reported which demonstrate that microbes strongly influence the behaviour of unconsolidated sand. In medium sand, thin (ca 0·1 to 0·5 mm thick) microbial communities growing at the sediment–water interface can nearly double the flow velocity required to produce the traditional sequence of ripple→dune→plane‐bed lamination bedforms. In some cases, these thin film‐like microbial communities can inhibit the growth of ripples or dunes entirely, and instead bed shear stresses result in flip‐over and rip‐up structures. Thicker (ca≥1 mm thick) microbial mats mediate terracing of erosional edges; they also, foster transport of multi‐grain aggregates and yield a bedform progression consisting of flip‐overs→roll‐ups→rip‐ups of bound sand.  相似文献   

Long-term effects of gravel-sand mulch thickness on soil microbes and enzyme activities in semi-arid Loess Plateau,Northwest China     

ChengZheng Zhao  YaJun Wang  Yang Qiu  ZhongKui Xie  YuBao Zhang 《寒旱区科学》2021,13(6):510-521

In semi-arid areas of China, gravel and sand mulch is a farming technique with a long history. In this study, a sample survey was conducted on long term gravel sand mulch observational fields in the Northwest Loess Plateau to determine the effects of long term mulch on soil microbial and soil enzyme activities. We found that after long term gravel-sand mulch, compared with bare ground, soil organic matter, alkali nitrogen, conductivity decreased, while pH and soil moisture increased. Urease, saccharase and catalase decreased with increased mulch thickness, while alkaline phosphatase was reversed. The results of Illumina MiSeq sequencing shows that after gravel-sand mulch, the bacterial and fungal community structure was different from bare land, and the diversity was reduced. Compared with bare land, the bacteria Proteobacteria and Acidobacteria abundance increased with increased thickness, and Actinobacteria was opposite. Also, at the fungal genus level, Fusarium abundance was significantly reduced, and Remersonia was significantly increased, compared with bare land. Redundancy analysis (RDA) revealed that soil environmental factors were important drivers of bacterial community changes. Overall, this study revealed some of the reasons for soil degradation after long term gravel-sand mulch. Therefore, it is recommended that the addition of exogenous soil nutrients after long term gravel-sand can help improve soil quality.  相似文献   

Microbial and molecular fossils from the Permian Zoophycos in South China   总被引：1，自引：0，他引：1  

Gong YiMing  Xu Ran  Xie ShuCheng  Huang XianYu  Hu Bin  Qi YongAn  Zhang GuoCheng 《中国科学D辑(英文版)》2007,50(8):1121-1127

The trace fossil Zoophycos was enriched in the lower part of the Guadalupian Maokou Formation of Permian in Laibin, Guangxi of South China, and characterized by observable lamellae within its spreiten. Associated with these lamellae are the prolific coccus- and spirillum-shaped microbe fossils. These microbes morphologically identified are 0.4―3.0 μm in diameter or length. Molecular fossils, including normal alkanes (dominated by C18, without an odd-over-even predominance), acyclic isoprenoids (such as pristane (Pr) and phytane (Ph)), extended tricyclic terpanes, pentacyclic triterpanes, steranes, al-kylcyclohexanes, dibenzothiophenes, benzonaphthothiophenes, benzobisbenzothiophenes, were in-strumentally identified in the wackestone characterized by the occurrence of abundant Zoophycos (composite ichnofabric indices are 4) and crowded microbial fossils. The value of the Pr/Ph ratio is less than 1, indicative of a dysoxic condition. The identification of abundant sulfur compounds (the thio-phene series) related to the contribution of reductive sulfur favors the occurrence of sulphate-reducing bacteria. The association of abundant microbial colonies with microbial molecular fossils within the spreiten suggests that trace fossils Zoophycos would be a multifunctional garden carefully constructed by the Zoophycos-producer, where different microbial colonies were orderly and carefully planted and cultured in different minor lamellae within spreiten. Hence, it is proposed that the Zoophycos-producer symbiosed with microbial colonies on the mutual basis of food supply and the redox conditions.  相似文献   

Reviews on Ancient Halophilic Microbes in Halite Fluid in Clusions     

Wang Jiuyi  Liu Chenglin 《地球科学进展》2016,31(12):1220-1227

Fluid inclusions trapped in ancient evaporites can contain a community of halophilic prokaryotes and eukaryotes that inhabited the surface brines from which the minerals formed. Entombed in the fluid inclusions in evaporites, some of these halophilic microbes remain viable for at least tens of thousands of years and possibly for hundreds of millions of years, even under high salinity, low oxygen, high radiation, low nutrient concentration. This review presents the scientific history of discovery, isolation, and culture of ancient halophilic microbes in halite fluid inclusions. We elucidated the controversy associated with the ancient halophilic microbes between geologists and geomicrobiologists. Major concerns and future perspectives on halophiles research were proposed. We emphasized that lithofacies analysis and depositional environment determination on evaporites are prerequisites before any microbiological survey, and rigorous biological protocol must be obeyed at all retrieval procedures for ancient microorganisms. We suggested that future study related to ancient halophilic microbes should focus on other evaporites such as gypsum, glauberite, and trona, characterize and identify older halophiles; clarify metabolic mechanism for longevity of ancient microorganisms.  相似文献   

Deposit Feeding and Sediment:     

Rainer M. W.  Amon Gerhard J.  Herndl 《Marine Ecology》1991,12(2):175-184

Abstract. The feeding of the epibenthic deposit-feeder Holothuria tubulosa GMELIN and its influence on sediment metabolism was investigated from February 1988 to February 1989. Water samples, specimens of H. tubulosa , and samples of freshly egested feces were taken by SCUBA diving in a 5 m deep seagrass bed at the Island of Ischia in the Gulf of Naples (Italy). Particulate organic carbon (POC), particulate organic nitrogen (PON), total particulate carbohydrates (PCHO), and bacterial biomass exhibited higher values in the foregut than in the surrounding sediment. Even the freshly egested feces were richer in the organic components than the sediment. The percentage of growing bacterial cells increased from 4.1 % in the sediment to 12.2 % in the foregut and declined to 11.6 % in the hindgut and 6.2 % in freshly egested feces.
On an annual average, absorption efficiency was highest for bacteria (x = 71%); for PON we calculated a mean absorption efficiency of 20.9%, for PCHO 19.5%. It was estimated that bacterial biomass supplied between 4 and 25 % of the respiratory carbon demand of H. tubulosa. We present evidence that the feeding activity of H. tubulosa stabilizes the bacterial community in the sediment. Furthermore, our data indicate that H. tubulosa reacts quickly to changing conditions, such as sedimented phytoplankton blooms.  相似文献   

国际五城市空气微生物概况     

陈皓文  宋庆云 《海洋科学进展》1993,(1)

对瓦尔帕莱索、彭塔阿雷纳斯、坎帕纳、新加坡和青岛的港口等空气微生物作了监测。这五个城市空气中的海洋性微生物及陆源性微生物数量(CFU/m~3)按大小次序排列均为:坎帕纳>青岛>瓦尔帕莱索>彭塔阿雷纳斯>新加坡。对空气微生物数量与气温、风速和相对湿度的关系作了初步比较分析后,认为适宜的气温及较大幅度的相对湿度有利于空气中微生物的增加:大风速、低相对湿度或高气温不利于空气中海洋性微生物的增加,本结果反映有关城市间空气污染的差异,坎帕纳的空气状况较差,对所得菌株作了初步分类,其中以不动杆菌较多,次为欧文氏菌等。  相似文献