南半球冰川形成早于北半球

不久前．人们还认为北半球冰川化开始于距今1100万年至500万年前．但这一观点受到与其相矛盾的证据的挑战．其中包括关于4160万年前超过南极洲存储容量的全球冰川体积的估计数字。Edgar等人利用来自赤道大西洋的海洋沉积物记录．对认为当时两个半球都存在大型冰层的假设进行了验证。他们关于冰层体积的估计值可以很容易按照南极洲的存储容量得到解释．     

福建罗源湾海洋生态环境研究

依据2004年的调查资料与历史资料对比,分析了罗源湾海区多年来水质、水域的养殖力(营养盐、叶绿素a和初级生产力)以及浮游植物多样性的变化,并采用潜在生态危害指数法对其生态危害程度进行评价.结果表明,罗源湾水体中的无机氮和活性磷酸盐超过二类水质标准,沉积物中除Hg、Cd污染较为严重外,其它重金属的生态危害很小.此外,还对罗源湾表层沉积物微量元素进行了调查研究.     

苏州河底泥重金属形态分析

Nine elements （As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn） in sediment samples at 7 sites （Site 1-7） from Suzhou Creek in Shanghai were analyzed with the Community Bareau of Reference （BCR） （sequential extraction （SE）） protocol and simultaneously extracted metals （SEM）/acid volatile sulfide （AVS） procedure to assess the metal bioavailability and toxicology in this area. The results showed that the BCR extraction can be utilized as an additional tool with the AVS method for assessing the potential bioavailability and toxicity of metals in sediments. Pollution from S5 （Site 5） was more severe than from other sites, especially Pb, Cu and Zn. Among all the sites, more than 80% of the total concentration of Fe existed in the residual fraction, As, Cr, Mn also dominated in the residual fraction （more than 50%）. While Cd, Ni and Zn （more than 35%） were mainly in the non-stable phase. Cu had a strong affinity with oxidizable phase and Pb varied from site to site. The SEM/AVS ratio was less than one in these sediments and results implied that the majority of Zn and Ni （〉 40%） were bound to AVS. In contrast, Pb, Cu and Cd were little bound to AVS due to their low ration of SEM-Pb, Cu, Cd to corresponding total concentration and relatively high Dorewater concentration.     

Study on Sorption of Monocrotophos and Parathion—methyl on Yellow River‘s Sediments

A study on the sorption of monocrotophos and parathion-methyl on Yellow River‘s sediments was performed.The influence of some factors,such as pH value and ionic strength,on the sorption was investigated and first order kinetics mode for the sorption of monocrophos was shown.Freundlich isotherm was suggested as the most appropriate type for monocrophos an parathion-methyl.But the sorption isotherms of monocrotophos and parathion-methyl are also in conformity with Langmuir equation.Both partition and adsorption occur to the sorption of monocrophos to Yellow River‘s sediments.but partition is the predominant for that of parathionmethyl.     

星云湖水体及表层沉积物中磷的空间分布特征及差异性分析

通过现场调查和实验室分析方法对星云湖水体及表层沉积物各形态磷的空间分布特征及差异性进行分析.结果表明,星云湖表层水体各形态磷在空间上表现出明显的分异性,磷的浓度总体呈现从北向南逐渐升高的趋势.而底层水体各形态磷空间差异较小,全湖无明显变化趋势.表层沉积物中总磷以无机磷为主,占总磷的64.61%～90.79%,呈现从北向南逐渐递减的趋势,有机磷含量相对较低.无机磷中各形态磷的含量由高到低依次是Ca-P>Fe/Al-P>NH4Cl-P.     

5000年前的鞋子什么样?

据德国媒体报道,考古学家们在博登湖湖滨发现一只出自公元前2900年前的鞋子。鞋号36意义等同冰人奥茨身上衣物据报道,这只鞋子用树皮编织,大小相当于现在的鞋号36号(据查适合脚长23厘米的     

Bacterial and archaeal communities in the surface sediment from the northern slope of the South China Sea

Microbial diversity of sediments from the northern slope of the South China Sea was studied by constructing bacterial and archaeal 16S rRNA gene clone libraries. Fourteen bacterial phylogenetic groups were detected, including Gammaproteo-bacteria, Deltaproteobacteria, Planctomycetes, Alphaproteobacteria, Firmicutes, Bacteroidetes, Actinobacteria, Chloroflexi, Acidobacteria, Betaproteobacteria, Nitrospirae, candidate divisions OP8 and OP11, and an unknown group. Gammaproteobacteria was the predominant group in bacterial libraries with the percentage ranging from 31.8% to 63.2%. However, archaeal libraries had relatively lower diversity, with most clones belonging to marine archaeal group I uncultured Crenarchaeota. In addition, two novel euryarchaeal clones were detected not to match any culture-dependent or -independent isolates. Compared with other gas hydrate-rich ecosystems and different areas of the South China Sea, a distinct microbial community was revealed in this study.     

“大不整合面”之谜

“大不整合面“是一个世界范围的地层特征,指大陆结晶基岩与较年轻的浅层海洋沉积物之间的一个分界线。偶尔．如在本期封面所示的在Toroweap Overlook这个地方所拍摄的“大峡谷”那样,它会暴露在地球表面上,产生戏剧化的效果。自从这个术语在1869年被创造出来之后．     

长江口及其邻近海域表层沉积物中锑的地球化学特征与环境风险评价研究

锑是一个可长距离输送的全球性有毒元素,但锑在河口不同环境要素中的迁移、转化以及其地球化学行为特征最近才引起国际社会的关注。为了揭示锑元素在长江口及其邻近海域的富集程度、物质来源及其潜在生态环境影响,本次研究以长江口及邻近海域29. 5°～32. 5°N,121°～124. 5°E区域内表层沉积物样品为研究对象,基于沉积物全样Al、Ca、Si、Ni等主量元素,以及Cd、Cr、Cu、Pb、Sb、Sr、Zn等微量元素的含量检测分析,并采用地积累指数和潜在生态风险指数展开了锑元素在研究海域表层沉积物中累积程度和潜在生态风险。研究结果表明研究区内表层沉积物中的锑含量范围为0. 44～4. 41μg/g,平均值为1. 15μg/g;已达到了偏中度污染水平,并且具有着较高的潜在生态风险,尤其是在长江入海口南支与杭州湾内锑元素具有很高的潜在生态风险。通过主成分分析方法认为锑元素的主要物质来源为长江径流输入以及人为活动输入。     

X射线荧光光谱法测定沉积物中重金属

以大庆市贴不贴纳污湿地为例,研究纳污湿地沉积物重金属污染.在用X射线荧光光谱法测定纳污湿地沉积物中重金属时,为检测实验分析的可靠性,随机抽取了12个样品做5次重复实验,其中:Cd、Hg、Cr、Zn的相对标准偏差均小于5%;Cu和Pb的相对标准偏差均小于10%;Cr和Ni的相对偏差均小于20%.结果表明,X射线荧光法测定样品,不需对固体样品进行消化处理,操作简便,可以同时测定多种元素,效率较高,而且是一种非破坏性的分析方法,样品可重复利用.