Preliminary study on weathering and pedogenesis of carbonate rock

South China is the largest continuous distribution area of carbonate rock in the world. The origin of the soils over the bedrock carbonate rock has long been a controversial topic. Here further exploration is made by taking five soil profiles as examples, which are developed over the bedrock dolomitite and limestone and morphologically located in upland in karst terrain in the central, west and north Guizhou as well as west Hunan, and proved to be the weathering profiles of carbonate rock by the research results of acid-dissolved extraction experiment of bedrock, mineralogy and trace element geochemistry. Field, mineralogical and trace element geochemical characteristics of weathering and pedogenesis for carbonate rock are discussed in detail. It is pointed out that weathering and pedogenesis of carbonate rock are important pedogenetic mechanisms for soil resources in karst area, providing a basis for further researches on the origin of soils widely overlying bedrock carbonate rocks in South China. Project supported by the National Natural Science Foundation of China (Grant No. 498330003) and National Key Basic Research Project (Grant No. 95pre-39).     

东太平洋铁锰结核区微生物的丰度及其成矿作用研究

１９９４ 年 ４～１１ 月在东太平洋铁锰结核区, 使用 “向阳红 ０９”船, 采集 ３９ 个表层沉积物、１２ 个上覆水和 ７ 个结核样。在现场用平板法测定了异养细菌和铁、锰细菌丰度, 用稀释法（ Ｍ Ｐ Ｎ 法） 测定硫酸还原菌丰度。为了探讨微生物在大洋成矿过程的作用, 在实验室对异养细菌和锰细菌作纯化分离, 并进行了多项生理生化实验, 参照伯杰氏手册第八版鉴定至属。使用分光光度法, 测定锰细菌对锰、铁离子的转化作用, 使用 ｐ Ｈ 计测定了ｐ Ｈ 值的变化, 同时测定了不同培养温度对转化作用的影响。结果表明, 沉积物中异养细菌的数量在 ３×１００～９５×１０３个／ｇ; 锰、铁细菌的数量在１×１００ ～１×１０３ 个／ｇ; 硫酸盐还原细菌的数量分布范围在 ０～４×１０３个／ｇ;在上覆水和结核样中各类细菌的数量均较低,比沉积物样中各类细菌数低 １ 个数量级。在细菌的种群组成方面与近海区相比存在差异, 特别是在革兰氏阳性菌的组成上微球菌占了绝对优势。在成矿作用方面, 锰细菌对锰、铁氧化还原的实验结果表明, 在好氧的条件下, 锰细菌使可溶性的 Ｍ ｎ２＋ 氧化为 Ｍ ｎ４＋ , 其氧化速度与环境温度存在密切关系, 锰细菌对铁的氧化速度比对锰的氧化速度来得快。在     

鲈鱼苗烂鳃、烂尾病病原菌的研究

１９９７年４～５月,对花鲈（Ｌａｔｅｏｌａｂｒａｘｊａｐｏｎｉｃｕｓ）鱼苗期细菌性烂鳃和烂尾病的病原菌进行了研究。从具有明显症状的病鱼的病灶组织分离到２株致病菌Ｃ－１和Ｗ－１,经人工感染及从人工感染发病鱼体再分离的Ｗ－４和Ｗ－５菌株的再感染试验结果表明,所分离的细菌为鲈鱼苗烂尾,烂鳃病的致病菌。经６４项生物学特性,生理生化特征测试结果表明,这４株菌可归为一类,同属于鳗弧菌（Ｖｉｂｒｉｏａｎｇｕｉｌａｒｕｍ）。药敏试验结果表明,痢特灵、ＣＩＮ１００、ＭＥＬ２５、呋喃妥因、氯霉素、磺胺药＋ＴＭＰ和美洛西林等７种药物对病原菌有显著的抑制作用。     

珠江口海水密度的研究

用磁力浮沉子密度测量装置,在１５ ～２５ ℃之间的三个温度下测定了珠江口２０ 个水样的密度。结果表明,测定值皆高于相应条件下国际标准海水状态方程的计算值,在海水盐度范围０．０８～３３ ．４４６ ,密度平均偏差范围为２ ．４ ～５４．０ ×１０ － ３ｋｇ／ｍ３ 。测定密度和计算密度的偏差随盐度的降低而增大,与盐度的变化成直线相关：与（Ｃａ２ ＋ ）／Ｓ、ＳＯ４２ － ／Ｓ比和比碱度之间皆呈指数曲线相关。珠江口水样（Ｃａ２ ＋ ）／Ｃ１ 、ＳＯ４２ － ／Ｃ１ 和比碱度平均值分别超出大洋水平均值１７ ．８ ％ 、８ ．２１ ％ 和１５２ ％ ,其余的Ｎａ ＋ ／Ｃ１、Ｋ＋ ／Ｃ１ 和Ｓｒ２ ＋ ／Ｃ１ 比值与大洋水无明显差别,基本类同。珠江口海水的高碱度、高（Ｃａ２ ＋ ）／Ｃ１ 和高ＳＯ４２ － ／Ｃ１ 是造成其海水密度正偏差的主要因素。经计算机拟合,首次导出了珠江口海水密度的状态方程,该方程计算值与实验值的平均标准偏差为±２．５×１０－ ３ｋｇ／ｍ３ 。     

太湖梅梁湾藻类生态模拟与蓝藻水华治理对策分析

根据目前对太湖梅梁湖生态环境的认知,建立该湖区藻类生态动力学模型进行生态模拟,基于模拟结果对太湖富营养化中最严重的蓝藻水华治理与污染物排放控制和清淤工程进行了分析。结果显示;太湖污染物排放达标将极大改善富营养水平;但应结合经济分析和效益分析,通过组合各类污染物控制总量来达到最优治理效果,模拟分析表明,单一清淤工程对于富营养化中蓝藻水华治理意义有限。     

内蒙古呼伦湖表层沉积物的矿物组成和沉积速率

呼伦湖表层沉积物的取样和分析表明,沉积物主要由碎屑矿物和自生碳酸盐矿物组成。碳酸盐含量为10％—18％。碳酸盐沉积作用与湖水的较高含盐量和碳酸盐过饱和度有关。湖泊中心HL8号柱样的~(210)Pb测定结果是,10cm以上平均沉积速率0.25cm/a,10—12cm为0.05cm/a。60年代开始随湖泊水位上涨沉积物输入量迅速加大。     

基于改进LM-GN算法的磁性目标定位方法研究

利用三轴磁传感器阵列对水下磁性目标进行定位是典型的非线性最小二乘优化问题,传统高斯– 牛顿（GN）法和列文伯格–马夸尔特（LM）算法在求解该问题时具有初值敏感性问题。通过引入信赖域搜索技术,对 LM 算法进行改进,并基于改进的 LM 算法实现磁性目标定位,又通过设置判断阈值来评估迭代点与最优解的距离,提出一种结合改进 LM 算法和高斯–牛顿法特点的改进 LM-GN 算法,既降低了算法对初始值的依赖性,又提高了运行效率。仿真实验结果表明：该方法可以克服现有方法中受初始值影响较大的问题,对目标特征参数的估计更精确,且收敛速度快,具有一定的实际应用价值。     

Application of an optical nitrate profiler to high- and low-turbidity coastal shelf waters

Here, we report the results of high-resolution nitrate measurements using an optical nitrate profiler(in situ ultraviolet spectrophotometer, ISUS) along transect across a high-turbidity shelf(East China Sea) and a lowturbidity shelf(Chukchi Sea). The ISUS-measured nitrate concentrations closely reproduced the results measured by conventional bottle methods in low-turbidity waters. However, for high-turbidity waters of the East China Sea(salinity<30), a correction factor of 1.19 was required t...     

Application of chemometric methods to analyze the distribution and chemical fraction patterns of metals in sediment from a metropolitan river

Rivers in metropolitan areas are often highly polluted with materials that pose a threat to a large number of residents. Human influences lead to contaminants in metropolitan rivers having more complex sources than those in rural rivers. This complexity results in contamination that is unstable and rapidly changing. Here, the contents and chemical fractionation patterns of eleven toxic elements (As, Cd, Co, Cu, Cr, Mn, Ni, Pb, Zn, Y, and Hg) were evaluated in 13 samples collected from along the Beiyunhe River in Beijing, China. The results revealed that the metal contents were unevenly distributed along the river, with higher levels being observed in the downriver sites and the rendezvous sites. Additionally, more than 80% of the metals were found to be in the residual phase. The organic and sulfide phases were the most important extractable phases of most metals, with Ni, Co, Cu, and Cr primarily being associated with these phases and As, Cd, and Zn having a strong association with the iron/manganese oxide and hydroxide phases. Additionally, Mn was associated with the exchangeable and carbonate phases, with the lowest concentrations being observed in the organic and sulfide phases. Conversely, the metal exchangeable and carbonate phases were uniformly distributed throughout the river. Analysis of the metal sources revealed that particles input from the atmosphere comprised a considerable amount of the metals in the Beiyunhe River. However, these metals likely do not enter the sediment via atmospheric deposition directly, but rather through rainwater runoff into the river. The methods used in the present study will be useful in other studies that require analysis of complex data.