Bacteria-Induced Cementation Process in Loose Sand Medium

Several conventional methods for treatment of soil are available for engineers. The most widely used method includes solution/grout, but they alter the ground pH level and could be toxic. In order to avoid the potential environmental harms and make use of naturally occurring microorganisms, biological methods to improve the engineering properties of soils have been intensely studied. This article presents the results of a research project in which Sporosarcina pasteurii (formerly known as Bacillus pasteurii) was used to induce biological cementation in loose sand medium. The bacteria was injected into sand, which led to the development of cementation (calcium carbonate crystal) between sand grains. The calcification was observed using a scanning electron microscope (SEM).     

Genetic discrimination for three gynogenetic clones of silver carp Hypophthalmichthys molitrix , based on restriction endonuclease analysis of Nd5-Nd6 region of mitochondrial DNA

Three artificial gynogenetic clones of silver carp were produced for the analysis of restriction enzyme digestion patterns of ND5-ND6 region from mtDNA of the clones. It is revealed that all intraclonal individuals shared completely the same digestion patterns but among interclonal individuals did not. The three clones were mixed and cultured in a pond together for two years, and restriction endonuclease digestion patterns of ND5–ND6 were used as genetic markers to assess the growth performance of each clone. Project supported by the National Natural Science Foundation of China (No. 39830300).     

华南珊瑚礁的海岸生物地貌过程

海岸生物地貌学研究海岸带生物过程和动力-沉积-地貌过程之间的双向相互作用，是海岸生态系统响应和反馈全球变化的重要机制，被列为全球变化核心项目海岸带陆海相互作用研究的重点内容。20世纪90年代以来对华南珊瑚礁热带生物海岸生物地貌过程的调查研究显示：①造礁石珊瑚的高生长率和珊瑚礁高堆积速率是珊瑚礁生物地貌过程的物质基础；②珊瑚礁海岸地貌结构分带性和生物地貌类型和动力地貌类型叠加并共存；③潮汐水位严格控制珊瑚礁群落分布格局并形成重要的生物地貌界限；④珊瑚礁海岸生物地貌过程有利于消除或减缓海平面上升的浸淹效应；⑤珊瑚礁海岸不断加剧的人类活动干扰和生态破坏导致生物地貌功能削弱和海岸资源环境恶化。急需加强珊瑚礁管理和保护。     

A Comparison Among Assemblages in Areas Invaded by Caulerpa taxifolia and C. racemosa on a Subtidal Mediterranean Rocky Bottom

Abstract.  This study compares the structure of Mediterranean macroalgal assemblages invaded by Caulerpa taxifolia and C. racemosa . Assemblages in areas colonized by the two algae and in reference areas were sampled and analyzed for 2 years. Significant differences were recorded both between reference and invaded areas and between areas invaded by different Caulerpa species. Macroalgal assemblages colonized by C. racemosa were more separated from references than those colonized by C. taxifolia . Differences between assemblages colonized by C. racemosa and the others decreased during the alga's period of vegetative rest and increased at the last sampling date. While erect and turf species showed similar patterns in invaded areas, covers of encrusting algae were lower in C. racemosa areas than in C. taxifolia areas.     

Numerical Simulation of Biological Impact Caused by Direct Injection of Carbon Dioxide in the Ocean

The direct injection of CO₂ in the deep ocean is a promising way to mitigate global warming. One of the uncertainties in this method, however, is its impact on marine organisms in the near field before CO₂ is diluted widely in the ocean. Since field experiments cost enormously, computational simulations are expected to show detailed information on the dilution process near injection points and its impact on marine organisms. In general, the LC50 concept is widely applied for testing the acute impact of a toxic agent on organisms. As a biological impact model we therefore consider mortality, which reflects recent laboratory experiments on zooplankton at various concentrations of CO₂. Here we regard the sigmoid-transformed mortality as a linear function of time in the logarithmic scale, and not just of the concentration of CO₂ in the logarithmic scale. This model was installed in a computational simulation code for the reconstruction of small-scale ocean turbulence. The results suggest that the biological effect is not significant when the ship speed is 4 knots and CO₂ is injected at 0.1 ton/sec in the form of a spray through 100 nozzles provided vertically on a pipe at 10 m intervals. It is therefore considered that the moving-ship method is effective for direct CO₂ injection. This revised version was published online in July 2006 with corrections to the Cover Date.     

Sinularia属短指软珊瑚化学成分及生理活性的研究概况

已进行化学成分研究的Sinularia属短指软珊瑚有42个种，主要化学成分有萜类、甾醇类、含氮化合物和一些长链脂肪酸、酯、醇类等。其中一些化学成分结构新颖，具有较好的生理活性。综述了国内外有关该属短指软珊瑚化学成分及生理活性的研究概况。     

眼斑拟石首鱼早期幼鱼的饲料试验

本文报道用 1 .92万尾平均体重为 1 .4 2 g 尾的眼斑拟石首鱼 (Sciaenopsocelle tus)早期幼鱼 ,在 5个海上浮式网箱中分两个阶段用粉末型配合饲料与传统的鲜活饲料进行饲养效果对比试验 .试验期间表层海水温度范围 2 2 .9～ 30 .0℃ ,表层海水比重范围 1 .0 1 55～ 1 .0 2 0 1 .试验结果如下 :对照组 (喂鲜活饲料组 )和各试验组 (喂粉末型配合饲料组 )全长和体重、体长和体重、全长和体长关系式的差异都不大 ,对照组和试验组实验鱼的平均肥满度分别为 1 .4 8、1 .51 g cm3.粉末型配合饲料组鱼的平均成活率为 81 .5% ,全长平均增长率为 73.2 % ,体长平均增长率 79.6 % ,平均增重量为 2 7.5g 尾 ,平均增重率为 52 6 .9% ,总投饲量为 336 .2 6kg ,饲料系数的平均值为1 .0 7.鲜活饲料组鱼的平均成活率为 87.2 % ,全长平均增长率为 57.0 % ,体长平均增长率为 6 1 .4 % ,平均增重量为 1 9.0 g 尾 ,平均增重率为 377.6 % ,总投饲量为1 1 54.2 8kg ,平均饲料系数为 5.1 6 .粉末型配合饲料养殖效果的综合生物学评定值为 2 38% ( >1 0 0 % ) ,表明其养殖效果优于鲜活饲料     

分子遗传标记技术在双壳贝类研究中的应用

分子遗传标记是随着分子生物学技术的发展而出现的遗传学标记技术,它突破了形态和细胞水平上遗传标记的局限性,发挥着独特的优势.分子遗传标记目前已出现了几十种,本文主要介绍了同工酶、RFLP、SSR、RAPD这几种常用的分子遗传标记方法在双壳贝类的分类学、遗传多样性研究、遗传育种研究、病理学研究等方面的应用.通过本文可以看出,分子遗传标记多应用在分类学、遗传多样性、遗传育种方面,涉及的种类较广,但主要集中于珠母贝和牡蛎的研究上.