Stevns Klint Fish Clay (FC-1): Preparation of, and Preliminary Results for, a Candidate Reference Material

The collapse of a section of the cliff at Stevns Klint, Denmark in 1986 provided a unique opportunity to collect about 50 kg of Fish Clay representing the Cretaceous-Tertiary (K-T) boundary layer. In this paper, details of the preparation of this sample are presented, together with preliminary analytical results to support the development of this sample as a reference material, particularly for the determination of iridium and the other platinum-group elements in clays and sediments associated with K-T boundary studies and in other environmental samples collected to study the effects of automobile exhaust catalysts.     

Neue Wege in die Ökotoxikologie: Quantitative Verhaltensmessungen an Fischen als Toxizitätsendpunkt

New Ways to Ecotoxicology: Quantitative Recording of Behaviour of Fish as Toxicity Endpoint The BehavioQuant system will be introduced which uses the integrative whole-organism response by automatized recording and quantifying the spontaneous behaviour of fish and other test organisms. While moving unrestricted within the test chamber, the movements of each single fish are recorded by video imaging, and their traces are digitized numerically by x-/y-coordinates. From the object traces several test parameters are calculated which give information about behavioural changes of the observed fishes. These various parameters are: the average swimming velocity (motility), the average swimming depth below surface, the inconstancy of motility, the frequency of turns, the standard frequency distributions of vertical and horizontal positions (can be used for quantification of a preference for dark or light habitats), and the distance behaviour. A continuously monitoring of up to 16 aquaria is possible. The statistic comparison between treated groups and control groups is done for each test parameter separately. The automatical evaluation of the continuous observation of surface waters results from a comparison of the actual behaviour data to the data of a reference period. Some examples for the applications of the BehavioQuant system will be demonstrated (effects of atrazine), and their results will be discussed. Behavioural changes of a single species can finally cause changes in biocenotic structures and functions. Therefore, it is necessary to include the results of quantitative behaviour measurements in ecotoxicological hazard assessment.     

东川落雪式铜矿的含铜“礁一硅岩组合”与海底喷流热液成矿

从区域地质背景、岩石学、岩石化学、微量元素、氧同位素及稀土元素组成等方面论证东川铜矿含铜“礁—硅岩组合”中的含铜硅质条带—硅质白云岩为海底喷流热水沉积成因；提出了该类层状铜矿的深源含铜富硅混合热液海底喷流—生物富集的沉积成岩成矿模式。并提出东川落雪式层状“马尾丝”铜矿含矿岩系为“含铜礁—硅岩组合”的新观点。     

Effect of the selective feeding ofGalaxias maculatus (Salmoniformes,Galaxiidae) on zooplankton of a South Andes lake

The effect of larval and juvenile predation ofGalaxias maculatus on a natural small-sized zooplankton was studied in a South Andes lake. Field data of zooplankton density and composition were combined with fish gut content analysis during a spring-summer season. Results showed thatGalaxias early stages ingested mostly planktonic preys. A shift was observed in prey electivity: larvae preferred copepod nauplii whereas juveniles preferred cladocerans. Larval predation provokes the failure of the summer cohort of the calanoid copepodBoeckella gracilipes. The effect of juveniles is more undefined, but seems to prevent the reappearance ofCeriodaphnia in the summer plankton.     

版纳勐养保护区鸟类及人为影响分析

切实保护和利用好西双版纳现存热带森林，是急需处理的现实问题。本文通过勐养自然保护区鸟类调查结果，揭示了西双版纳保护区管理现状。多数地区实际上未管理起来，林区居民仍滥用自然资源，对鸟类的猎捕从未停止，有的地方颇为严重；从生物多样性着眼，环境质量在下降。现已管理起来的三岔河保护区，尽管旅游开放后尚存许多问题亟待探索和改进，但鸟类保护状况已明显改善，说明自然保护区旅游在科学管理下才是可行的。就此，本文分析、评价了勐养保护区鸟类受人为影响情况，对自然保护区管理工作提出建议。     

Cavernous weathering in the Capitol Reef Desert,Utah

Tafoni and honeycomb weathering are abundant in sandstones at Capitol Reef National Park. Cavities are particularly common in talus blocks resting on alkali-rich soil, in vertical walls of desert washes, and in sandstones containing calcareous cement. Chemical analyses, X-ray diffraction data, and field observations suggest that salt weathering is the most important cause of disintegration, but dissolution of calcite cement also occurs in calcareous sandstones. Cavernous weathering at Capitol Reef produces cavities similar in appearance to features found in arkose outcrops along the coast of northwest Washington, even though the environmental conditions at these two locations are very different.     

Cladoceran stratigraphy in two shallow brackish lakes with special reference to changes in salinity, macrophyte abundance and fish predation

Sub-fossils of Cladocera and Foraminifera were used to reconstruct changes since 1870 in the trophic dynamics of two brackish lakes, Glombak and Han Vejle, located in the Vejlerne nature reserve, Denmark, a site of international conservation importance. After creation of the lakes in the mid-1870s following land reclamation, the two lakes have developed quite differently; today Glombak is turbid, while Han Vejle is clear. In both lakes, stratigraphic changes in the assemblages of foraminifers and cladocerans indicate an abrupt shift from marine to brackish conditions at the end of the 19th century, coinciding with land reclamation. However, the composition of the fossil invertebrate assemblages in the 20th century implies differences in the exposure to salinity, in fish predation and in habitat diversity. In Glombak, the cladoceran record suggests relatively saline conditions in the first quarter of the last century and high macrophyte abundance followed by lower salinities and subsequently a major decrease in macrophyte abundance and an increase in fish predation during the past ca. 40 years. By contrast, in Han Vejle low salinity, high abundance of macrophytes and only minor changes in fish predation seem to have prevailed throughout most of the 20th century. The results are consistent with recent contemporary data, the few historical records, as well as with trends in the records of diatoms and macrofossils. This study highlights the potential of using crustacean remains as indicators of long-term changes in the trophic dynamics of brackish lakes.     

A new two-way nesting technique for ocean modeling based on the smoothed semi-prognostic method

A new two-way nesting technique is presented for a multiple nested-grid ocean modeling system. The new technique uses the smoothed semi-prognostic (SSP) method to exchange information between the different subcomponents of the nested-grid system. Four versions of the new nesting technique are described, together with conventional one-way nesting. The performance of the different nesting techniques is compared, using two independent nested-grid modeling systems, one for the Scotian Shelf of the northwest Atlantic Ocean and the other for the Meso-American Barrier Reef System of the northwestern Caribbean Sea. Nesting using the semi-prognostic method is shown to effectively prevent unrealistic drift of the inner model, while use of the SSP method avoids unnecessary damping of small scales on the inner model grid. Comparison of the annual-mean flow field with the near-surface currents determined by Fratantoni (in J Geophys Res 106:2977–2996, 2001) from observed trajectories of near-surface drifters demonstrates the overall superiority of the nesting technique based on the SSP method.     

浙江桐庐冷坞二叠纪生物礁的发育模式

礁体底部具脉状层理的潮坪相碎屑沉积,礁体内部藻叠层岩夹层的存在,及礁体上部为煤系地层覆盖等都表明冷坞生物礁是一个典型的二叠纪岸礁;海绵骨架岩的存在表明它是个骨架型岸礁。     

南京玄武湖鱼类暴发性死亡原因分析

南京玄武湖近年来死鱼事件频发，对该湖水生生态系统的长期监测结果表明，湖水富营养化和沉积物污染十分严重；但生态毒理学研究表明，湖水和沉积物等对鱼类尚未见有急性毒性作用．根据玄武湖鱼类死亡症状，从玄武湖鱼体上分离到一种致病力极强的鱼类病原菌──嗜水气单胞菌（Aeromonashydrophila），研究了该病原菌的致病特性，并系统地分析了水质主要污染指标、水体富营养化、藻类种群动态、沉积物污染及其氧化还原层（Eh，＋200mV）等多种因素对玄武湖鱼类暴发性死亡的发生和流行的影响．研究结果表明，近年来玄武湖频频发生的暴发性死鱼多系病原菌感染鱼体引起的鱼类暴发性出血病（鱼类环境病）所致，而该湖水体长期处于严重富营养和有机污染状态以及年久未清的沉积物等是这种“鱼类环境病”的诱发因素．