Influence of bioturbation by the polychaete Nereis diversicolor on the structure of bacterial communities in oil contaminated coastal sediments

Patterns of change in the structure of bacterial communities monitored by ribosomal intergenic spacer analysis (RISA) in oil contaminated sediments inhabited or not by the marine polychaete Nereis diversicolor were studied during 45 days under laboratory conditions. Results supported by principal component analysis showed a marked response of the bacterial communities to the oil contamination and to the presence of N. diversicolor. Phylogenetic affiliation of specific RISA bands showed that, in the contaminated sediments, the presence of the marine polychaetes favoured the development of bacteria which may play an active role in natural bioremediation processes of oil polluted environments.     

The effect of Prestige oil ingestion on the growth and chemical composition of turbot otoliths

Juvenile turbot (Scophthalmus maximus) were kept in captivity and were fed a prepared food contaminated with five different concentrations of seawater-accommodated fuel oil from 2.4+/-0.35 to 48.2+/-2.2 mg g(-1) food, with a control group receiving uncontaminated food. The growth and survival of individually tagged fish (N=202) were measured after a six-week treatment period. The otolith growth rate was measured and otolith composition was determined before and after the treatments using LA-ICPMS. Fish and otolith growth were negatively affected by the fuel oil treatment, and the response decreased with the level of contamination. Otolith growth and element incorporation peaked at mid level exposures and decreased at the highest level. The otolith elemental composition reflected the presence of some elements in the Prestige fuel that may have been incorporated through the diet into the otolith.     

Polycyclic aromatic hydrocarbons (PAHs) in transplanted Manila clams (Tapes philippinarum) from the Lagoon of Venice as assessed by PAHs/shell weight index: a preliminary study

Variation of polycyclic aromatic hydrocarbons (PAHs) levels was assessed in Tapes philippinarum from the Lagoon of Venice. Clams were transplanted from a polluted area next to Porto Marghera to two rearing areas of the Southern Lagoon. Analyses of PAHs were made in sediments and clams by GC/MS at first sampling and after 30, 60 and 180 days. Principal component analysis was performed to elucidate bioaccumulation and depuration pattern and input sources. Biota-Sediment-Accumulation-Factor (BSAF) was applied to evaluate the PAHs input sources from sediment. Condition index was calculated to compare the seasonal variation of clam tissue to PAHs levels. To propose results not affected by seasonal changes in flesh weight of clams, the approach based on the calculation of PAHs/SW index was applied. From the results, it was concluded that PAHs/SW index is more recommendable to asses temporal variation of PAHs levels in Manila clams.     

Application of biotic indices and relationship with structural and functional features of macrobenthic community in the lagoon of Venice: an example over a long time series of data

In the context of the application of WFD, a scientific debate is growing about the applicability of biotic indices in coastal and transitional waters. In the present work, the question about the discriminating power of different biotic indices and the relationships with the structure and functioning of the macrobenthic community in a transitional environment is discussed. A time series of samples collected during the last 70 years in the lagoon of Venice, reflecting different environmental conditions (a sort of 'pristine state' in 1935, the distrophic crisis in 1988 and subsequent modifications in 1990, the invasion by an alien species and the developing of high impacting fishery in 1999) has been used. The comparison of results obtained by applying different biotic indices, such as AMBI, Bentix and BOPA, shows differences in the discriminating power of indices and a general overestimation of environmental conditions. Discrepancies between environmental status as indicated by biotic indices and the structure and functioning of the benthic community have been highlighted.     

First Late Triassic Record of a Paleoentomofauna from South America(Malargüe Basin,Mendoza Province,Argentina)

<正>Late Middle Triassic to early Late Triassic insects from Argentina have been previously described from the Bermejo and Cuyana Basins where they have been recovered from the Ischichuca-Los Rastros and Potrerillos-Cacheuta Formations,respectively.The insect fauna discussed herein was collected during field studies in 1986/1987 from the Llantenes section(Norian to Rhaetian? Late Triassic),which is situated in the Malargue Basin in southern Mendoza province.The insect remains were found in the upper part of the Llantenes section (Llantenes Formation),which is built up of two coarsening-upwards cycles reflecting a deltaic progradation of a fluvial into a lacustrine environment(lower part),succeeded by repeated progradations into a floodplain-dominated environment(upper part;with finds of insects,conchostracans,fish remains,plant fragments,and drifted logs).The new finds represent the youngest Triassic insect records described from Argentina and even from South America in its entirety.There is only one contemporaneous fossil assemblage in Gondwana:in the Clarence/Moreton Basin(Aberdare Conglomerate;Late Norian)in Australia.The new Triassic insects include an impression of an isolated Mecopterida-like wing(Mendozachorista volkheimeri gen.et sp.nov.; Mendozachoristidae fam.nov.),coleopteran elytra of the Permosynidae(Ademosyne rosenfeldi sp.nov.and Ademosyne llantenesensis sp.nov.)and other isolated body fragments.This new Late Triassic entomofauna from Argentina is of considerable importance in the reconstruction of the biotic recovery of continental environments in Gondwana after the catastrophic mass extinction at the P/T boundary.     

基于多维决策分析的海湾海岸带主体功能区划技术研究

文章根据海岸带区域特征,剖析了主体功能区划内涵,遵循基于生态系统管理以及海陆统筹等原则,构建了基于多维决策分析的海湾海岸带主体功能区划技术方法,包括海湾海岸带主体功能区划原则、技术框架和分析方法。     

非结构网格空气质量模式对东亚强沙尘暴的初步模拟研究

基于中国科学院大气物理研究所自主研发的嵌套网格空气质量数值预报模式(NAQPMS)和英国帝国理工学院应用计算与建模小组(AMCG)研制的有限元流体模式(Fluidity),构建了非结构网格沙尘传输模式(Fluidity-Dust),并模拟再现了2010年3月19~22日东亚强沙尘暴整个暴发、演变的三维立体动态过程,从整体上对这次沙尘事件有了全新的直观认识和了解。通过利用FY-2D卫星沙尘反演资料及MODIS(Moderate Resolution Imaging Spectroradiometer)卫星反演的气溶胶光学厚度(AOD)资料,可对模拟结果进行整体上对比验证;同时,利用中国9个城市站点的PM10(空气动力学当量直径小于等于10μm的颗粒物,即可吸入颗粒物)地面观测资料以及日本多个站点的激光雷达资料,逐一对比分析了不同地区PM10的时空分布以及沙尘传输经过时的垂直分布情况;并与NAQPMS模式的沙尘模拟结果进行了模式间的对比分析。对比结果均表明:该模式具有较好的模拟能力,能很好地模拟再现整个沙尘暴过程,为今后进一步运用自适应变网格技术以实现对沙尘暴的高精度追踪模拟奠定了基础。不同模式比较是量化模拟不确定性的重要方法。以往沙尘输送模式比较研究表明:起沙量模拟的不确定性是沙尘暴数值模拟的最大不确定来源。本文通过两个具有相同起沙方案的模式对同一沙尘事件的模拟,发现不同的平流方案以及不同的沉降计算也会对沙尘过程模拟产生重要影响。     

推断解释薄板重力异常的特征曲线法

根据理论模型对剩余异常进行直接推断解释的问题,在于选择模型的大小和密度差,以使它的重力效应尽可能地与剩余异常图形吻合.这基本上是一种实行曲线或曲面拟合的方法,然而,它绝不是一种简单的方法.由于即使用公式来描述最简单模型的位场都过于繁杂,因此,给任何一种直接拟合法都带来了困难.为了说明曲线直接拟合方法的困难,让我们来研究一个经常用来表示岩脉或矿脉的模型.一般认为,岩脉或矿脉是一种宽度远小于其长度的地质体,通常用薄板模型来表示这种地质体,其图形如图1所示.因为重力效应有可能比其他类型的位场观测结果对这种地质体的走向长度更为敏感,所     

土壤水可用性田间测定界限值与实验室测定值特征的比较

土壤选择过程为了围绕广泛分布的土壤结构、物理、化学性质建立数据库,所有符合某一标准的发表的、未发表的数字都被采集、总结、表格化。这篇文献回顾是根据250个研究人员的调查写成的,这250人正引导着包括不同作物下土壤水含量的田间测定在内的研究工作。在文献研究期间,调查表被送到参加上述研究工作的研究人员那里,同时也送到州和联邦研究所研究土壤物理、土壤水分控制的专家手中。调查表设计成能够统一符合下述研究标准的格式:①生长在所研究范围内的土壤上的作物已经经受了严重的水分亏缺;②在经受水分亏缺期间,通过根系层的土壤水含量已经阶段性地测量过;③水量测定地点能够精确定位。     

美国五个州加强中学地理教学的情况

地理学的发展有赖于中小学地理教学水平的提高。