Heavy metals in marine sediments of Taranto Gulf (Ionian Sea, Southern Italy)   总被引：5，自引：0，他引：5  

Alessandro Buccolieri  Giovanni Buccolieri  Nicola Cardellicchio  Angelo Dell'Atti  Antonella Di Leo  Antonella Maci 《Marine Chemistry》2006,99(1-4):227

Al, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Ti and Zn concentrations have been determined in surface sediment samples collected in the Taranto Gulf (Ionian Sea, Southern Italy) in order to evaluate their levels and spatial distribution in this important area of the Mediterranean Sea. For various metals, the geoaccumulation index has been calculated as a criterion to assess if their concentrations represent contamination levels or can be considered as background levels. The results show that metals concentrations in sediments can be considered near the background levels found in the Mediterranean Sea.Analytical results have been elaborated by using a Geographical Information System (GIS) software to show metals accumulation areas. Using multivariate statistical analysis, we evaluate the possibility to distinguish the sampling stations, in relation to their geographical position. Results have showed metals distribution in the Taranto Gulf is principally influenced by industrial and urban wastes, located mostly in the northern coastal area of the Ionian Sea. Rivers in the Basilicata region and prevailing anticlockwise marine currents are further factors influencing metal accumulation in sediments.  相似文献   

Coastal geomorphic evolution at the Denglou Cape, the Leizhou Peninsula     

Wang Lirong  Zhao Huanting  Song Chaojing  Yuan Jiayi  Yu Hongbing 《海洋学报(英文版)》2002,21(4):597-611

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅＤｅｎｇｌｏｕＣａｐｅ ,ｉｎｔｈｅｓｏｕｔｈｗｅｓｔｏｆｔｈｅＬｅｉｚｈｏｕＰｅｎｉｎｓｕｌａ ,ｉｓａｔｔｈｅｎｏｒｔｈｍａｒｇｉｎｏｆｔｒｏｐｉｃａｌｚｏｎｅ .ＳｅｖｅｒａｌｒｅｓｅａｒｃｈｅｓａｎｄｃａｒｔｏｇｒａｐｈｉｅｓｏｆｔｈｅｒｅｇｉｏｎａｌｇｅｏｍｏｒｐｈｏｌｏｇｙａｎｄＱｕａｔｅｒ ｎａｒｙｇｅｏｌｏｇｙ ,ｗｈｉｃｈｗｅｒｅｃａｒｒｉｅｄｏｕｔｉｎｔｈｅｐａｓｔ,ａｌｌｉｎｃｌｕｄｅｔｈｉｓａｒｅａ (ＭＧＬ ,ＳＣＳＩＯ ,ＣＡＳ ,1 978;ＧＰＣＳＧＲＣＺＴ…  相似文献   

Comparison of Drags on Fish Cages of Different Shapes   总被引：1，自引：0，他引：1  

詹杰民 苏炜李毓湘  贾晓平黄武林 《中国海洋工程》2006,20(3):457-471

1 .Introduction Commercial fishfarming in net cages is becoming widespread around the world as an importantsource of food.In PRChina ,mostfishfarmingtakes placeincalmcoastal areas .Fishcages work wellat these sites becausethe environmental forces are usua…  相似文献   

边坡整体稳定的可靠性分析方法   总被引：8，自引：0，他引：8  

韩玉芳  刘德辅  董胜 《海岸工程》2001,20(4):7-14

边坡整体滑动稳定性的可靠性分析是建立在土体具有的抗力大于荷载效应的概率基础上进行设计和校验的。在条分法的基础上推导出了进行边坡稳定可靠性分析的统一极限状态方程 ,将土的容重γ、内摩擦角φ、粘聚力 c作为随机变量 ,当其为非正态分布时 ,进行当量正态化 ,考虑变量相关的情况 ,用简化相关法对随机变量进行统计分析 ,并以 Bishop圆弧滑动法为例 ,用 JC法求解边坡的可靠性指标及失效概率 ,给出计算安全系数和可靠性指标的算法程序。并就影响可靠性指标的因素如抗剪强度指标、变量分布形式、土性参数的变异性等进行了讨论。  相似文献   

盐度对双棘黄姑鱼仔鱼活力及仔稚鱼生长的影响   总被引：8，自引：0，他引：8  

林向阳  刘伟斌  叶金聪 《台湾海峡》2005,24(3):351-355

分别用不同盐度梯度海水对双棘黄姑鱼仔鱼进行饲养试验。结果表明：盐度为17．0．22．0、27．0．31．0～33．0的4个试验组仔鱼的不投饵存活系数分别为5．38、7.35、6.46、6．18；各盐度组仔稚鱼的生长速度没有显著差异（P〉0．05），各组仔鱼经25d的培养，其平均全长为18．8～19．2mm；盐度22．0及27．0的海水中仔稚鱼呈较高的存活率，各盐度组的平均存活率为36、0％、48．5％、46．7％和39．2％．  相似文献   

中国西部地区基于经验模型的土壤水分反演     

马浩  江涛  蔡玉林 《测绘科学》2008,(Z1)

地表土壤水分含量的时空分布信息是十分重要的,常常作为水文模型、气候模型、生态模型的输入参数,同时,也是干旱预报、农作物估产等工作的重要指标。被动微波遥感是监测土壤含水量最有效的手段之一。相比红外与可见光,它具有波长长,穿透能力强的优势。相比主动微波雷达,被动微波辐射计具有监测面积大、周期短,受粗糙度影响小,对土壤水分更为敏感,算法更为成熟的优势。目前,已研究出许多反演土壤水分的方法.本课题的主要内容是借助AMSR-E土壤水分影像数据、MODIS归一化植被指数(NDVI)影像数据和MODIS分类影像数据,利用ENVI软件进行遥感图像数据处理,运用统计分析方法建立NDVI与土壤水分的经验模型,研究中国西部地区稀疏植被覆盖区土壤水分的反演。  相似文献   

Main Controlling Factors on Hydrocarbon Accumulation and Distribution in Marine Sedimentary Sequences in South China     

蔡立国  周雁  白振瑞 《中国地质大学学报(英文版)》2008,19(6):645-655

Multiple source rock assemblages were deposited in the sedimentary provinces in South China in geologic history,and some of them were destructed by and some survived against multiple tectonic movements.Therefore,multiple sources,mixed sources,and uneven distribution of sources occurred in the marine sedimentary basins in South China during the late stage of hydrocarbon pooling.Epidiagenesis of the marine carbonate reservoirs and its modification to reservoir poroperm characteristics determined the formation and the scale of natural gas pools.The exploration practices show that the large to medium gas fields mainly occur in areas with high-quality reservoirs.Detailed study of the paleo-oil accumulations and typical oil and gas reservoirs reveals that the basins experienced multiphase superimposition and modification,leading to the distribution of the Paleozoic paleo-oil accumulations and bitumen in the peripheral areas.The phenomenon that oil and gas production concentrates in the Sichuan basin indicates that the overall sealing conditions of a basin determine the oil/gas potentials and the scale of oil and gas production.This is a critical factor controlling the accumulation and distribution of gas in the marine sequences in South China.The early oil and gas pools in the Yangtze platform left billions of bitumen in the peripheral areas due to the destruction of seals.Since the Himalayan,"late-generation and late-accumulation" gas pools represented by the gas pools in the Sichuan (四川) basin were formed in the marine sedimentary sequences in South China as a result of the change of the sealing conditions.Current gas discoveries appear to be "paleo-generation and paleo-accumulation" gas pools but actually are "late-generation and late-accumulation" gas pools.These patterns of hydrocarbon pooling clearly depict themselves in western Sichuan basin and Weiyuan (威远)gas field.It is revealed that the gas pools in the Sichuan basin were mainly formed as a result of hydrocarbon phase change (thermal cracking of oil to gas),miscible migration,and dynamic equilibration since the Himalayan.A large number of gas pools were formed in the Himalayan and the gas pools in the marine sequences are characterized by late pooling; this kind of gas fields/pools are controlled by:(1) effectiveness of modification and superimposition of the marine basins,(2) effectiveness of the source rocks,(3) effectiveness of the overall preservation conditions,and (4) effectiveness of plays.  相似文献   

低渗透储层水平井—直井联合布井极限注采井距研究     

侯晓春  陆程  蔡文  郑兴范 《现代地质》2008,22(1)

低渗透储层水平井—直井联合布井技术具有广泛的应用前景,其布井方式至关重要。首先利用劈分流场的方法直观地给出常规储层水平井—直井联合布井的产能评价方法;然后针对低渗透储层的渗流特点,在考虑启动压力梯度条件下建立新的井网渗流物理模型并求解得到产能评价公式;最后经分析计算给出启动压力梯度影响的面积井网极限注采井距关系曲线。研究结果为低渗透储层部署水平井—直井联合井网提供理论依据。  相似文献   

汞元素的石油地质意义     

李广之  袁子艳  庄原  江浩 《物探与化探》2008,32(2):143-146,185

油气中都含有汞元素组分,汞的物理化学性质决定其可以从油气藏中向上垂向运移,根据采样介质类型及样品预处理的手段不同,地表中汞的分析方法可分为壤气、热释汞及土壤总汞分析方法。壤气汞、热释汞及土壤总汞指标都有着很好的示油气意义,同时也有着示断裂带的地质意义。  相似文献   

我国西部特殊景观区化探方法研究进展   总被引：5，自引：2，他引：3  

张必敏 《物探与化探》2008,32(5):473-476

西部特殊景观区的化探方法研究一直是中国化探界的一个研究热点和难点.在岩石出露、水系发育地区可以沿用传统的水系沉积物化探方法,但在覆盖景观区,常规化探方法效果并不理想.目前,谢学锦和王学求所提出的深穿透地球化学方法,经过一系列的实验研究,证明其能在覆盖区达到快速有效地圈定战略靶区的作用,具有广泛的应用前景.要做好西部特殊景观区的化探工作,化探科研人员必需采取新方法、新思路,继续系统地开展化探方法技术研究,通过不懈的努力最终找到一套适合中国西部特殊景观区特别是覆盖区的行之有效的化探方法.  相似文献