扬子地台前寒武纪－寒武纪界线地层的微体植物化石群

前寒武纪一寒武纪界线地层在扬子地台发育良好、分布广泛,并有包括微体植物群、海藻、瓶形原生物、具硬体动物及‘澄江动物群’等化石的发现。因而,扬子地台成为研究前寒武纪－寒武纪界线生物地层的代表地区之一。基于对扬子地台前寒武纪－寒武纪界线地层已知微体植物化石记录的回顾和论定,总结概括了下寒武统微体植物化石组合：寒武系最底部硅质磷块岩中的Ｍｉｃｒｈｙｓｔｒｉｄｉｕｍ－Ｐａｒａｃｙｍａｔｉｏｓｐｈａｅｒａ－Ｍｅｇａｔｈｒｉｘ组合和较高层位页岩的Ｓｋｉａｇｉａ－Ａｎｎｕｌｕｍ－Ａｒｃｈａｅｏｄｉｓｃｉｎａ组合。它们分别与Ａｎａｂａｒｉｔｅｓ－Ｃｉｒｃｏｔｈｅｃａ－Ｐｒｏｔｏｈｅｒｔｚｉｎａ小壳动物化石带和Ｐａｒａｂａｄｉｅｌｌａ及Ｅｏｒｅｄｌｉｃｈｉａ三叶虫带相对应。与东欧地台疑源类生物地层相对照,扬子地台Ｍｉｃｒｈｙｓｔｒｉｄｉｕｍ－Ｐａｒａｃｙｍａｔｉｏｓｐｈａｅｒａ－Ｍｅｇａｔｈｒｉｘ组合的纵向分布大体和东欧地台Ａｓｔｅｒｉｄｉｕｍｔｏｒｎａｔｕｍ－Ｃｏｍａｓｐｈａｅｒｉｄｉｕｍｖｅｌｖｅｔｕｍ组合带相一致,而以上两地台的化石组合产出层位可能都略高于纽芬兰东部剖面,依据Ｐｈｙｃｏｄｅｓｐｅｄｕｍ所厘定的寒武系底界?     

冀西北长城纪宣龙式铁矿层中微体植物化石的发现及其意义

本文研究的是笔者等在冀西北长城系串岭沟组宣龙式铁矿层中发现的微体植物化石,这些化石都保存在铁质叠层石(肾状赤铁矿)和铁质核形石(鲕状赤铁矿)的基本层中。微化石以丝状体为主,部分为球状体。归属于原核生物蓝藻门颤藻科的两个属和色球藻科的一个属。化石层同位素年龄约在1800—1757Ma。这些化石与北美冈弗林特组微化石比较,既有些相似,又有些区别。该化石的发现为研究铁矿的成因,指示沉积环境及层位对比都很有意义。     

下扬子区大隆组的底界

<正> 下扬子区大隆组化石丰富、牙形刺动物群以 Neogondolella subcarinata-N.chang-xingensis组合为特征,与长兴组一致;而菊石动物群既有长兴阶的Pseudotirolites,Ple-uronodoceras,Tapashanites分子,又有吴家坪阶的 Anderssonceras,Konglingites分子。郭佩霞同志协助笔者对江苏南京湖山、团山、安徽铜陵杨桃山、南陵丫山、泾县晏公     

观赏石奇葩——化石雨花石

雨花石历来以五彩缤纷的色彩、千姿百态的纹理以及人们赋予的丰富文化内涵为世人称颂。 雨花石品种很多，有矿物娄玛瑙、蛋白石、玉髓、水晶，岩石娄硅质岩、砂岩、石灰岩、大理岩、火成岩，以及古生物化石等。其中化石雨花石为地质历史时期保存在地层里的生物遗体、遗迹，主要来源于古长江流域两岸山体，经长期风化、破碎、搬逗、磨蚀而成。其浑圆度高，有的已玛瑙矿化，色彩花纹美丽，被视为佳品．     

华夏龙谱(38)--寐龙(Mei long Xu et Norell,2004)

2004年10月,中国科学院的徐星和美国自然历史博物馆的马克·诺瑞尔(Mark A.Norell)共同报道了一项新发现———辽宁省北票市早白垩世义县组地层中的伤齿龙科恐龙新物种骨骼化石,第一次让人们看到了恐龙的睡眠姿势。这只长53 cm的小型食肉恐龙保存极为完整,整体形态看上去很像一只大鸟,有着小小的头骨,长长的后肢。其后肢蜷缩于身下,头埋在一个前肢下面,这与现代鸟类的睡眠状态非常相似。徐星认为,这只恐龙的体态和睡眠状态都与现代鸟类相似,团着身体睡觉,减少了表面积,有利于抵御体温下降。诺瑞尔则指出,该恐龙可能是在它熟睡时,附近的火…     

Temporal and dimensional distribution of sulfate-reducing bacteria （SRB） groups and quantity in the sediments of Lake Erhai

The purpose of the thesis is to analyze the temporal and dimensional distribution of sulfate-reducing bacteria （SRB） groups and quantity in Lake Erhai. In April and September 2005, two sediment cores were collected from Lake Erhai. SRB groups were analyzed by PCR with six-groups primers designed according to the specific 16SrDNA sequence. FISH （fluorescence in-situ hybridization） was established with the oligonucleotide probe （SRB385） and utilized to analyze SRB quantity in the sediments. The results showed that in the sediments of Lake Erhai four SRB groups were detected except Desulfobacterium and Desulfobacter, meanwhile Desulfovibrio-Desulfomicrobium were detected only in autumn; different SRB groups had different temporal and dimensional distribution, and each group in autumn is distributed more widely than in spring; FISH used to count SRB in the sediments of fresh lake was set up successfully; the analysis of correlation between the sediment＇s depth and SRB quantity had statistical meaning （P〈0.05） . The result showed that SRB quantity showed a decreasing trend with increasing depth. Through the analysis of randomized block designed analysis of variance, the difference in SRB quantity between spring and autumn also had statistical meaning （P〈0.001）, which revealed SRB quantity in autumn was larger than in spring; the result of FISH showed that there were some SRB in the deeper sediments in which no above-mentioned six SRB groups were detected by PCR. SRB groups in the sediments of Lake Erhai were rich, and the quantities of SRB groups in autumn were larger than in spring; possibly there were uncultivable SRB groups in the sediments of Lake Erhai.     

Geochemistry of porewater and sulfate-reducing bacteria in sediment cores from the Chianan Plain, Taiwan

High concentrations of arsenic and humic substances in groundwater from the southwestern coastal plain of Taiwan were well known for their probable relationships with black-foot disease. In order to realize the relationships between the concentrations of humic substances and arsenic in this area, 24 well water samples were analyzed. After filtered through 0.45 μm glass fiber membrane in the field, samples were kept in the dark at 4℃ and then separated into six fractions with varying range of molecular weight （〈0.5, 0.5-1, 1-5, 5-10, 10-50 and 〉50 k Da） by ultrafiltration apparatus （Molecular/Por Stirred Cell system） in the lab. Concentrations of humic substances were measured by fluorescence spectrometer （HITACHI F-2000, ex=370, em=445） and arsenic by FIAS-AA （Perkin Elmer AAnalyst 100, FIAS-400）. On average, only 6.2% of the total arsenic in water existed in the fraction of 〉0.5 k Da. and the others were complexed with humic substances （including humic acid and fulvic acid）. The results demonstrated a distinct positive correlation between the concentrations of humic substances and arsenic.     

Synergistic effect of combining sulfate reducing bacteria and zerovalent iron permeable reactive barriers on the treatment of groundwater rich in uranium, sulfate and heavy metals

Uranium processing and mining activities that generate many contaminants, such as high concentrations of U （VI）, sulfate and heavy metals （Zn, Cu, Ni, etc）, may pose a serious threat to the groundwater resources. In recent years, considerable research has been conducted respectively on two kinds of permeable reactive barriers （PRB）, including zerovalent iron （ZVI） and sulfate reducing bacteria （SRB）, for in-situ removal of these pollutants from groundwater. However, little investigation has been carried out on the potential benefits of bioaugmenting ZVI barriers to enhance the elimination of the pollutants by combining ZVI with SRB systems. The main goal of this study was to conduct batch and column experiments to determine whether the combination of SRB and ZVI can function synergistically and accelerate the rate of pollutant removal. The results of anaerobic batch experiments demonstrated that although the integrated ZVI/PRB system itself has no ability to reduce and remove sulfate directly, SRB can utilize hydrogen gas produced during the slow process of ZVI corrosion as an electron donor to raise biomass yields significantly and accelerate reductive sulfate removal. In particular, ferrous cations produced as the byproduct of ZVI corrosion process reacted with hydrogen sulfide from sulfate reduction and formed iron-bearing sulfide precipitates, which can stimulate the growth of SRB and promote sulfate removal activity by eliminating the biotoxicity of hydrogen sulfide. It was also shown that secondary mineral products （pyrite/ferrous sulfide） formed as a consequence of microbial sulfate reduction and ZVI corrosion process can enhance the microbial precipitation of soluble U （VI） as insoluble uraninite（uranium dioxide）.     

Characterization of microbial communities associated with African desert dust and their implications for human and ecosystem health

Desert winds aerosolize several billion tons of soil-derived dust each year, including concentrated seasonal pulses from Africa and Asia. Huge dust events create an atmospheric bridge over continents and oceans, and eject a large pulse of soil-associated microorganisms into the atmosphere. These dust events might therefore have a role in expanding the biogeographical range of some microorganisms by facilitating rare long-distance dispersal events. The goal of this study is to characterize the microbes associated with African dust events and determine if they pose a risk to humans or downwind ecosystems. Air samples were collected by vacuum filtration in a source region （Mali, West Africa） during dust events and plated on R2A media to culture microorganisms. These organisms were compared to those in similar samples collected in the Caribbean during Saharan/Sahelian dust events. A high-volume liquid impinger is currently being tested in Barbados, collecting aerosol samples during African dust events. Over 100 bacteria and fungi （19 genera of bacteria and three genera of fungi） have been characterized from source region dust events.     

南极菌Pseudoalteromonas sp．S-15-13产胞外多糖的研究及其分子鉴定

本文对影响南极细菌S-15-13生长和胞外多糖产量的主要环境因子进行了研究,同时采用16S rDNA序列分析及系统发育分析方法对其进行了分子鉴定。结果表明：菌株S-15-13最佳产糖条件为：培养时间,56h；培养温度,8℃；碳源,1．0%葡萄糖；NaCl浓度,3．0%；pH,6．0-7．0。16S rDNA序列分析和系统发育分析表明,菌株S-15-13属于假交替单胞菌属(Pseudoaltero- monas)。