ODP806井位氧同位素变化记录中轨道倾斜度和轨道偏心度同时出现     

Mull.  RA 陈玲玲 《海洋地质译丛》1997,(2):72-76

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Cloning of a chub metallothionein cDNA and development of competitive RT-PCR of chub metallothionein mRNA as a potential biomarker of heavy metal exposure   总被引：3，自引：0，他引：3  

Hayes RA  Regondi S  Winter MJ  Butler PJ  Agradi E  Taylor EW  Kevin Chipman J 《Marine environmental research》2004,58(2-5):665-669

Metallothionein has been assayed in a range of aquatic animal tissues as an indicator of metal exposure. We sequenced chub (Leuciscus cephalus) metallothionein cDNA which showed over 90% homology to common carp, goldfish and stone loach and 77% homology to rainbow trout sequences for metallothionein. We then used the extended primer method to develop an accurate quantitative competitive RT-PCR assay for metallothionein mRNA. RT-PCR was used to measure metallothionein mRNA in feral chub from a range of field sites, with different levels of heavy metal pollution, in the West Midlands, UK. Measurements were complemented by analysis of liver and gill metallothionein protein by capillary electrophoresis. There was no significant difference in the metallothionein protein levels between fish of different rivers and there was no evidence of elevation of mRNA at the sites of highest metal exposure. The level of metal exposure (e.g. zinc, nickel and cadmium each ranging between 15 and 28 microg/l ) at the pH (7.5-8.5) of these rivers appears insufficient to elevate hepatic or gill metallothionein in chub. A lack of elevation of hepatic metallothionein mRNA in chub exposed to zinc, copper and manganese for 24 h and 10 days in the laboratory also suggests a non-responsiveness of this species.  相似文献   

Phytoremediation of small-scale oil spills in fresh marsh environments: a mesocosm simulation     

Dowty RA  Shaffer GP  Hester MW  Childers GW  Campo FM  Greene MC 《Marine environmental research》2001,52(3):195-211

Research was conducted to assess the impact of oiling on fresh-marsh plant communities and to test the efficacy of techniques that may be used to enhance the bioremediation of crude oil spills in these environments while minimizing secondary anthropogenic impacts. To emulate field conditions, a mesocosm facility was used that houses 120 mesocosm vessels, each of 200-1 capacity. A five-way factorial treatment arrangement was used that included two substrates (inorganic, organic), two nutrient regimes (fertilized, not fertilized), two aeration levels (substrate aeration, no aeration), three oiling concentrations (0-, 5-, 10-1 m(-2) of South Louisiana Sweet Crude oil), and four vascular plant species (Alternanthera philoxeroides, Panicum hemitomon, Phragmites australis, Sagittaria lancifolia, and an unplanted control). Under the 5- and 10-1 m(-2) oiling concentrations, S. lancifolia displayed a short-term response of increased productivity, whereas P. hemitomon had the highest biomass production and photosynthetic rates at the end of the 18-month experiment. Overall plant growth and productivity, as well as oil degradation, were significantly higher in the inorganic substrate, indicating that biodegradation of oil spills in organic substrates may require a longer time period. Time-released fertilizer also stimulated plant productivity and resulted in higher soil respiratory quotients, suggestive of greater microbial activity, particularly in aerated mesocosms. The amount of oil remaining after 18 months was lowest in aerated and fertilized mesocosms containing either P. hemitomon or S. lancifolia and a substrate of low organic matter content.  相似文献   

Sediment oxygen profiles in a super-oxygenated antarctic lake     

Wharton RA  Meyer MA  McKay CP  Mancinelli RL  Simmons GM 《Limnology and oceanography》1994,39(4):839-853

Perennially ice-covered lakes are found in the McMurdo Dry Valleys of southern Victoria Land, Antarctica. In contrast to temperate lakes that have diurnal photic periods, antarctic (and arctic) lakes have a yearly photic period. An unusual feature of the antarctic lakes is the occurrence of O2 at supersaturated levels in certain portions of the water column. Here we report the first sediment O2 profiles obtained using a microelectrode from a perennially ice-covered antarctic lake. Sediment cores collected in January and October 1987 from Lake Hoare in Taylor Valley show oxygenation down to 15, and in some cases, 25 cm. The oxygenation of sediments several centimeters below the sediment-water interface is atypical for lake sediments and may be characteristic of perennially ice-covered lakes. There is a significant difference between the observed January and October sediment O2 profiles. Several explanations may account for the difference, including seasonality. A time-dependent model is presented which tests the feasibility of a seasonal cycle resulting from the long photoperiod and benthic primary production in sediments overlain by a highly oxygenated water column.  相似文献   

Regional trends in crude birth,death, and natural increase rates in Russia and the USSR: 1897-1989     

Lewis RA  Rowland RH 《Post-Soviet geography》1995,36(10):617-643

"This paper establishes and discusses briefly regional patterns and trends in crude birth, death, and natural increase rates in Russia and the USSR from the turn of the century to 1989. The study is based on a comparable regional framework and placed in the context of the demographic transition theory. It discusses sources, collection, and quality of data, as well as necessary estimating procedures. An attempt also is made to examine briefly regional age-standardized rates."  相似文献   

院士风采之三——陈梦熊院士     

詹庚申 《地质学刊》2006,30(4):253-253

著名水文地质学家，浙江上虞人。1942年毕业于昆明西南联大地质系。同年人中央地质调查所，1949年离所。1991年当选为中国科学院地学部学部委员。历任地矿部水文地质工程地局副总工程师、地矿部教授级高级工程师、高级顾问、国土资源部咨询研究中心咨询委员。  相似文献   

地县级MICAPS系统二次开发     

高明华  孙志于蔺波 詹红霞 《沙漠与绿洲气象(新疆气象)》2005,28(1):41-42

1开发背景 随着MICAPS系统的广泛使用，9210工程下发的各类MICAPS资料迅速增加，面对庞大的气象卫星广播资料(每天的资料接近1G)，筛选本地可用的资料，最大限度地利用现有资料，提高看图效率，简化、优化MICAPS系统显得尤为重要。优化、完善、本地化MICAPS系统已经成为新疆预报员需要解决的首要问题。因此，我们对原MICAPS系统进行了仔细的研究，  相似文献   

微量物质对海洋的大气输入     

Duce  RA 李诗明 《气象科技》1997,(1):9-19

在过去的十年中，显而易见，大气是许多自然物质和污染物从大陆输送到海洋的重要途径。这些物质的大气输入对海洋生物过程和海洋化学循环有正或负的影响。例如：很明显，大气是许多区域的重要营养成分如铁，氮等的重要输送途径。在本报告中，我们评价了这些地区的期的数据，发展向海洋的微量元素，矿物气溶胶，含氮物质合成有机物的大气通量的全球范围的估算值；比较了这些物质通过大气和河流输入的海洋比率。  相似文献   

工业矿物在特种玻璃生产中的应用     

Bolger  R 詹庚申 《江苏地矿信息》1997,22(1):9-10

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遥感综合信息在宁芜地区找矿预测中的应用     

詹雅婷 《地质与勘探》2016,52(6):1087-1094

为了研究宁芜北段火山岩盆的矿产资源潜力及空间分布,本文以Landsat8中分辨率遥感数据及Pleiades1高分辨率遥感数据为数据源,综合运用目视解译法和多种遥感图像增强技术,结合区域成矿地质背景,对研究区进行了遥感影像解译,提取了与预测矿种密切相关的线、环、色、带、块遥感五要素。通过分析遥感五要素矿产地质特征与矿产点分布关系表明,研究区内的铁铜硫金矿床及星罗棋布的矿点大部分位于构造岩浆成矿亚带中,受区内北东向、东西向、北西向及其它断裂纵横交叉形成的断裂网格及火山机构控制,大多分布在数条断裂带交汇位置,另有一些分布在断裂带与环形构造的交汇处附近。基于主要的矿点受区内断裂网格及火山机构控制,遥感图像的综合地质信息特征与找矿目标紧密相联,说明了基于遥感图像的综合信息可以作为找矿预测的标志。  相似文献