Aquaculture-related trace metals in sediments and lobsters and relevance to environmental monitoring program ratings for near-field effects

The study was undertaken to assess the marine environmental effects from feed and waste associated with aquaculture activities. Metal compositions of sediment, lobster, and feed were used to evaluate the extent of detectable effects at 0 m (under the cage) and 50 m distance. Sediments that were collected under the cages and were characterised as hypoxic or anoxic, showed elevated levels of Cu, Zn, organic carbon, and % <63 microm particles, and low Mn and Fe. At 50 m there was a major reduction in waste chemical impact. Using lobster, a bioindicator species, as a tool for detecting near-field impacts, showed accumulations of high Cu associated with active aquaculture sites. Chemical compositions and metal ratios normalised with organic carbon, were used to assess the sediment conditions associated with environmental monitoring program ratings (EMP--normal, hypoxic, and anoxic). Principal component analysis (PCA) was used to explore chemical data at all sites for differentiating normal, hypoxic and anoxic sediment conditions. Selected variables (Cu, Zn, Fe, Mn, organic carbon, and particles <63 microm) were sufficient for the PCA approach with >90% explainable variance of first two components. The groupings based on PCA and cluster analysis were similar to EMP classifications with some exceptions of mis-identification by EMP. The sediment chemistry components were valid indicators for evaluating marine environmental conditions and for assessing aquaculture operating sites. The developed techniques, using chemical variables in combination with EMP and the statistical approach should be useful to predict the effects of aquaculture practices and the suitability of aquaculture operations.     

登山技术在岩质开挖边坡分析和岩崩治理中的应用

在加利福尼亚有近3000英里的公路上,已有岩崩现象的报导。由于交通通道变得越来越受到限制,因此,现存岩质挖方边坡的加固也就变得更加重要了。一般情况下,这些加固场地都位于从路面上去检测通道受到限制的地区。本文讨论了登山技术在帮助工程地质学家进行岩质边坡近距离调查中的应用。通过地面上拥有倾斜航空照片的专家组的无线电指导,攀登绳上的工程地质学家就能够收集到关于斜坡的重要资料。控制边坡稳定性的平面特征就可以直接被观察和测量,不连续面间距的变化,水的存在以及结构面产状也能够直接测量。路面上的调查组拍摄登山组所安装的观标,就可以准确地确定边坡上的关键控制点的位置。本文强调了通过安全的、有控制的登山技术,将岩石力学运用于岩石边坡开挖设计和岩崩治理之中。     

国际矿物学协会新矿物及矿物命名委员会关于矿物命名的程序和原则（1997年）

1引言国际矿物学协会新矿物及矿物命名委员会(简称CNMMN)是由各有关国家矿物学团体指定的代表组成的,目的在于控制新矿物的引入和矿物命名的合理性,自1959年成立以来,其工作得到了国际矿物学界广泛的支持。CNMMN不希望将一套严格的规则强加于矿物学界,而是提供一套具有连续性的原则,以便于为新矿物的确认和矿物命名法的应用提供一个合理的、一致性的方法。现在所提出的原则可能会十分合理地应用于绝大多数情况,但是,总会不可避免地出现一些例外,如文中多次强调的,每项建议必须根据其具体情况进行判断。2新矿物2.1有关新矿物种…     

东营第三系凹陷中央断裂带的演化机制探讨

中央断裂带位于中国东部东营凹陷中部,发育有厚达７００ｍ的第三系碎屑岩。主要勘探目的层是第三系的沙河街组地层。影响中央断裂带的主要地质力学因素有三个方面：（１）脊部塌陷机制：由东营凹陷北部的埕南大断裂（犁式张性断裂）所控制的凹陷中部地堑型断裂;（２）塑性物质上隆机制：中央断裂带深部存在盐体上隆;（３）右旋张扭机制。这些机制在时间上不是弧立的,而是相互作用的。区域构造、沉积作用和右旋张扭应力控制了脊部     

An experimental investigation of nitrogen gas produced during denitrification

In situ denitrification relies on indigenous microorganisms to reduce nitrate to N(2) gas. However, when initial nitrate concentrations are large, produced gas volumes also can be very large, potentially resulting in reduced water saturation and hydraulic conductivity in the treatment zone. In this study, we investigated the fate of N(2) and other gases produced during denitrification in a laboratory flow cell containing packed sediment. Denitrifying activity was stimulated by additions of nitrate and ethanol. Microbial activity was monitored by measuring nitrate, nitrite, and ethanol concentrations; gas saturations were measured during the experiment using a gamma imaging system. Biomass was measured using phospholipid fatty acid analysis of sediment samples. Bioenergetic calculations calibrated to measured nitrate consumed and biomass produced predicted that 1.2 L N(2) gas/L water should have been produced following the addition of 100 mM nitrate. However, the maximum measured gas saturation was only 23%, indicating substantial gas loss from the sediment pack. Temporal gamma images and visual observations confirm that small gas bubbles formed in the sediment pack coalesced into larger bubbles and migrated upward through gas-filled channels to the sediment pack surface. Although gas saturations increased, there was no significant change in sediment pack hydraulic conductivity. These results suggest that in permeable reactive barriers used for in situ denitrification, gas production will not necessarily lead to unlimited gas accumulation in the pore space and that the effects of gas production on water saturation and hydraulic conductivity may be relatively minor.