密执安湖上空的污染和洁净气团的比较

1976年和1978年夏季,用装有专用仪器的飞机,对平流至密执安湖上空洁净气团和污染气国进行了考察。结果表明,不管污染的严重与否,污染微粒的大小分布呈双峰型。硫酸盐,硝酸盐和微量金属在洁净气团中的浓度较污染气团要低一个量级。而且,其浓度之低可以同世界上偏远地区所测得的浓度相比。在洁净气团内的总光散射率非常接近雷来散射,表明在洁净气团内旋光性量级的微粒含量是很低的。     

微量元素在研究花岗质火成岩成因的应用

虽然微量元素模式用于解释玄武岩系列岩石成因已经有很大进展,但类似的研究在花岗质成分的火成岩上还比较少。通常花岗质熔融体矿物/熔融体稀土元素分配系数等于或大于玄武岩相似矿物的分配系数。因此,在部分熔融和分异作用时花岗岩熔体与残余相容易出现的玄武岩系列比较,这些矿物对稀土元素图谱的影响被夸大。对于K/Rb比值,如果在残余相中既不是钾长石成分,也不是黑云母—金云母成分出现,那么通过分异作用或部分熔融这两个因素,使熔融体K/Rb比值比母岩K/Rb比值减少是困难的。可以得到4个明显不同岩石的成因:(1)太古代云英闪长岩,推测是由太古代拉斑玄武岩在地幔深处部分熔融衍生来的,并留下石榴石加斜方辉石残余物;(2)太古代石英二长岩,推测是在地壳范围内由存在时间短的硬砂岩——泥岩序列部分熔融衍生;(3)塞斑岛英安岩,推测由玄武质母岩通过分异作用形成;(4)南极州罗斯岛粗面岩,推测由玄武岩类母岩分异作用和通过大陆壳组分混染作用形成。     

塞拉利昂太古宙基底中不一致的Rb—Sr和Pb—Pb全岩等时年龄的意义

英国地质科学研究所一个研究队(I.G.S),通过对塞拉利昂北部的野外制图和构造研究,建立了西非克拉通太古宙地层层序,划分出一个较老的利欧尼亚(Leonian)花岗岩—绿岩区,它在利比里亚构造—变质事件结束时形成的,一个花岗岩—绿岩区之前就经受过一次构造—变质事件。在法杜古区,在具有利欧尼亚构造的花岗片麻岩中,得到在统计学上是合理的但不一致的Pb—Pb和Rb—Sr全岩等时年龄分别为2959±50百万年和2753±61百万年(误差2σ)。这些年龄是和塞拉利昂其他地区的利欧尼亚和利比里亚构造放射年龄可对比,可以认为,法杜古区的Rb—Sr全岩等时年龄已受到利比里亚事件的影响。法杜古片麻岩的Pb—Pb全岩等时年龄和一个先前测定的(经重新计算并作部分检查)取自塞拉利昂东南花岗片麻岩中的Rb—Sr全岩等时年龄为2980±80百万年,为利欧尼亚构造—变质事件提供了一个确切的年龄,约2970百万年。利欧尼亚花岗岩类的。~(87)Sr/~(86)Sr初始值和现代单阶段模式U~(238)/Pb~(204)值很难与地幔的值相区分,但并不排除这种可能性,即这些花岗岩类是来自地壳或下部地壳只经历了一个短暂时期的那些母质中。法杜古区花岗片麻岩的2753±61百万年的Rb—Sr全岩等时年龄为塞拉利昂北部的利比里亚事件提供了一个确切的年龄。在野外划分出比利欧尼亚更老的(即老于2970百万年)一套岩石,但还没有测定同位素年龄。     

洋底的深部构造

近年来在苏联,业已对海底地质构造和地貌进行了一些综合的研究,并且已经发表了一些专著。Beloussov和Khain在论述大地构造教科书中专门地研究了海底构造方面的地质和地球物理资料。在本文中,我们使用地质、地震、地电和地磁资料来描述海底构造和岩石圈的一些深部构造带。地质和地球物理证据表明大陆和海洋的地壳构造没有本质的差异,因此,没有根据去划分出一个特殊的海洋地壳类型。(Afanas′yev,Pronin.和其他研究人员提出了相似的观点。)     

对铀矿勘探中所用分析方法的评价

本文的目标是集中研究已为国家和私人实验室实践过了的各种测铀方法。这里讨论的常用测铀方法有:(1)常规的荧光测量法;(2)中子活化分析法、缓发中子计数测量法;(3)X射线光谱法;(4)裂变径迹法;(5)激光激发荧光法;(6)分光光度法;(7)其他方法。这些常规方法中,荧光法和用缓发中子     

Distribution and characteristics of suspended particulate matter in a heavily eutrophic estuary, Tokyo Bay, Japan

Bulk suspended particulate matter (SPM), chlorophyll a (Chl a), ignition loss, particulate organic carbon (POC), organic nitrogen, inorganic phosphorus (PIP), and organic phosphorus were investigated in the heavily eutrophic Arakawa River estuary, Japan. Chl a was high (approximately 35 microg l(-1)) in summer and low (approximately 6.7 microg l(-1)) in winter and autumn. POC from living phytoplankton accounted for approximately 34% and approximately 70% of total POC during low- and high-biomass seasons, respectively. During the low-biomass season, detrital POC distribution was conservative, and less reactive, land-derived materials mainly composed particulate organic materials (POM), but complex mixing of land-derived POM and autochthonous planktonic detritus caused nonconservative detrital POC behavior during the high-biomass season. PIP concentration in SPM decreased with increasing salinity, likely by desorption of soluble orthophosphate (ortho-P). The ortho-P released from SPM, 56% of the ortho-P input from the Arakawa River to the bay, was a significant potential source of biologically available phosphorus causing eutrophication of coastal environments.     

Eutrophication in the Polish coastal zone: the past, present status and future scenarios

In the Baltic Sea eutrophication processes have accelerated in the past 50 years of the 20th century and presently there exists a major ecological problem for this sea. The Polish coastal zone of the southern Baltic Sea is the recipient of riverine inputs from two major sources, namely the Odra and Vistula, as well as a number of smaller rivers along the central coast. Hence, the entire coastal zone remains under severe anthropogenic pressure. The variability of nutrient concentrations, especially the winter nutrient pool in the euphotic zone, summer level of total nitrogen and total phosphorus, together with such eutrophication indicators as water oversaturation with oxygen and the summer oxygen minimum, were analysed in the data time series 1959-2001. The temporal trends were investigated using linear regression and the non-parametric Whirsch test. The future characteristics of the Baltic Sea are discussed taking into account the development of driving forces.     

A simple method to reduce discharge of sewage microorganisms from an Antarctic research station

The majority of coastal Antarctic stations release untreated sewage into the near-shore marine environment. This study examined bacterial reproduction within the temporary sewage-holding tanks of Rothera Research Station (Adelaide Island, Antarctic Peninsula) and monitored sewage pollution in the local marine environment. By continuously flushing the sewage-holding tanks with cold seawater we inhibited microbial reproduction and decreased the numbers of bacteria subsequently released into the sea by >90%. The widespread use of this simple method could significantly reduce the numbers of faecal coliform and other non-native microorganisms introduced into the Antarctic marine environment.     

Chronic effects of tributyltin on the caprellid amphipod Caprella danilevskii

In order to examine the biological effects by TBT exposure, experiments involving the exposure of five levels of TBT concentrations (0, 10, 100, 1000 and 10,000 ngl(-1)) were conducted on the caprellid amphipod Caprella danilevskii, over a generation after hatching. Marked delays in growth and molting during the early developmental stage and maturation were found in both 100 and 1000 ng TBTCl l(-1) concentrations in spite of the sex. All specimens died in 10,000 ng TBTCl l(-1) within 4 days after hatching. Inhibition of maturation and reproduction such as delaying in the achievement of maturity and a decrease in the number of juveniles hatched was apparent in 10 and 100 ng TBTCl l(-1) concentrations. Furthermore, brood loss, and failure in egg formation and hatching were observed as the TBT concentration became higher. No significant changes in sex ratio were seen at any of the TBT exposure levels during hatching and maturation in the present study. This phenomenon was different from a previous study in which the proportion of females was increased with an increase in TBT concentrations in the embryonic exposure experiment. This suggests that sex disturbance is induced during the embryonic stage of the species. A drastic decrease in survival rate was observed at 10 ng TBTCl l(-1) (25%) which corresponds to the mean level in coastal waters. Therefore, the present encountering ambient TBT concentration may influence populations of C. danilevskii in the coastal environment.