Saline fresh water interface structure in Mahanadi delta region, Orissa, India   总被引：1，自引：0，他引：1  

I. Radhakrishna 《Environmental Geology》2001,40(3):369-380

 Saline/fresh water interface structure is one of the most important and basic hydrogeological parameter that needs to be estimated for studies related to coastal zone management, well-field design and understanding saline water intrusion mechanism/processes. The success and stability of a groundwater structure in a coastal region depend upon an accurate estimate of interface structure between saline and fresh water zones, aquifer-aquiclude boundaries and their lateral continuities and the interstitial water qualities of aquifers. Self-potential and resistivity logs provide a reasonably good basis for such estimates and for sustainable development of fresh groundwater resources. The interface depth structure for the Mahanadi delta region, as obtained and interpreted through self-potential and resistivity logs, provides a fairly clear picture of the regional extensions and boundaries of aquifers, aquicludes and interstitial water quality patterns. Aquifers in the northern sector of the basin and within the framework of Birupa and Mahanadi are characterized by an interface depth range that varies between 40 and 280 m below ground level (bgl) with brackish water on the top underlain by freshwater aquifers. The aquifers in the southern sector within the framework of Khatjori/Devi and Koyakhai/Daya/Kushbhadra/Bhargavi are characterized by an interface depth range that varies from 10 to 120 m with freshwater aquifers near the surface underlain by saline, brackish water aquifers. The inversion of these major fluid systems appears to have taken place over a narrow zone between Mahanadi and Khatjori tributaries, possibly over a wide subsurface ridge with separate basin characteristics. Received: 29 November 1999 · Accepted: 2 May 2000  相似文献   

Similarities in the behaviour of Chernobyl derived Ru-103, Ru-106 and Cs-137 in two freshwater lakes     

J. Hilton  W. Davison  J. Hamilton-Taylor  M. Kelly  F. R. Livens  E. Rigg  D. L. Singleton 《Aquatic Sciences - Research Across Boundaries》1994,56(2):133-144

Measurements of the concentrations of Ru-103 and Ru-106 in the water column and sediments of two productive temperate lakes were made during an eight month period following the Chernobyl accident. Ru-103 accumulation in the sediments began simultaneously with that of Cs-134 and a constant ratio (approx. 2.0 on a decay corrected basis) of Ru-103/Cs-137 was observed in surface waters and sediments throughout the measurement period. The ratio is not statistically different from that reported for atmospheric input and for epilimnetic water. The results suggest that the processes of removal of radioactive ruthenium and caesium from the mixed water column to the sediments are the same.Enhancement of Cs, compared with Ru, in the isolated bottom waters of one of the lakes in the summer months provided evidence for Cs release from the sediments during a period of hypolimnetic anoxia.  相似文献   

几种海洋生物体内硒含量的测定   总被引：4，自引：1，他引：4  

毛文君  管华诗 《海洋湖沼通报》1995,(4):28-32

本文用石墨炉原子吸收光谱法直接测定几种海洋生物体内的硒含量。本方法的最低检出限为３０ｐｇ，变异系数低于５．９％，回收率９４％－９９％。测定发现；褐藻含硒量比红藻和绿藻低，紫贻贝和海湾扇贝的外套膜中硒含量远远高于肌肉组织。  相似文献   

蚌、鱼养殖模式对水体富营养化控制作用的研究   总被引：11，自引：0，他引：11  

张根芳  邓闽中  方爱萍 《中国海洋大学学报(自然科学版)》2005,35(3):491-495

为了探索控制水体富营养化的新方法．在5～9月长江中下游地区水体富营养的发展期，通过野外规模性试验，即水体吊养珍珠蚌并搭养少量鱼类，然后定期测定4个主要富营养化指标，观察水生生物种群和数量。结果表明，养蚌育珠并搭养适量鱼类可以使20～40cm的水层形成附着丝状藻类、原生动物、腔肠动物、多孔动物和苔藓动物等多种附着生物，使N，P，COD和BOD5含量分别下降67．3％，73．2％，38．1％和15．5％，起到了明显控制富营养化的作用，同时还能收获珍珠、蚌肉和贝壳等产品。比其他控制方法具有更好的实际应用性。  相似文献   

Distribution of seabirds in the northern Gulf of Mexico in relation to mesoscale features: initial observations   总被引：1，自引：0，他引：1  

Ribic  Christine A.; Davis  Randall; Hess  Nancy; Peake  Dwight 《ICES Journal of Marine Science》1997,54(4):545-551

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Quantitative assessment of intertidal blue mussel (Mytilus edulis L.) stocks: combined methods of remote sensing, field investigation and sampling   总被引：3，自引：0，他引：3  

Marc Herlyn 《Journal of Sea Research》2005,53(4):243-253

The aim of this investigation was to develop appropriate methods for quantitative assessment of blue mussel beds. Combined methods of remote sensing, ground truth investigation and sampling in the field were applied to mature and young intertidal mussel beds. Three variables were measured to obtain reliable quantitative estimates of biomass and abundance: the total area covered by a bed; the cover, i.e. the area of mussel-covered patches in relation to the total mussel bed area; and the proportion, i.e. the area covered by mussels within the patches in relation to the total area of mussel patches. Cover and proportion of intertidal blue mussel beds were measured in the field by the transection method. Aerial photographs enabled the total area of the beds to be determined and large-scale surveys of mussel beds to be carried out synchronously. By examining large-scale aerial photographs it was possible also to determine the cover by remote sensing. The proportion could not be derived from aerial photographs, even from pictures at the largest scale tested during this investigation (scale 1:2500). By statistical methods it was estimated that 12 sub-samples (each covering 177 cm²) from mature beds, and 12 sub-samples (each covering 38 cm²) from young beds are needed to obtain reliable data on biomass and abundance.  相似文献   

Simultaneous Sv and TS measurements on Young-of-the-Year (YOY) freshwater fish using three frequencies     

Guillard  J; Lebourges-Dhaussy  A; Brehmer  P 《ICES Journal of Marine Science》2004,61(2):267-273

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贻贝外套膜富硒液的研究     

毛文君  管华诗  李八方 《中国海洋大学学报(自然科学版)》1995,(Z1)

提出以贻贝的外套膜为主要原料，通过多种酶水解及其它工艺处理，研制出贻贝外套膜富硒液。分析表明，提取液富含天然有机硒、锌、铁、铜、锰微量元素及丰富的维吐素Ａ、维生素Ｅ、必需氨基酸等多种天然营养物质。  相似文献   

Accumulation and depuration of pectenotoxins in brown crab Cancer pagurus     

LI Zhaoxin 《中国海洋湖沼学报》2009,27(2)

Pectenotoxins (PTXs) are a group of marine algal toxins. In this study, the accumulation and depuration of pectenotoxins in brown crab Cancer pagurus were investigated. Crabs were fed with toxic blue mussels Mytilus edulis for 21 days and then depurated for 42 days. Toxins were extracted with methanol from the digestive glands of contaminated crabs, uncontaminated crabs (control group) and from blue mussels for comparison. Extracts were analyzed by liquid chromatograph coupled with tandem mass spectrometry (LC-MS-MS). The concentrations of PTX-2, PTX-2 SA, 7-epi-PTX-2 SA, and PTX-12 were analyzed in two batches of toxic blue mussels and the crabs. A one-compartment model was applied to describe the depuration of PTXs. The half-life of PTXs was estimated to be 6-7.5 days. After depuration for 42 days, the amount of PTXs measured in the crab digestive glands was less than 1 μg/kg.  相似文献   

Length-weight relationships for six freshwater fish species in Iran   总被引：2，自引：0，他引：2  

M. S. HEYDARNEJAD 《中国海洋湖沼学报》2009,27(1):61-62

The aim of this study is to report the length-weight relationship parameters (a and b) for some economically important fish species from Iranian freshwaters. The length-weight relationships (LWR) are calculated for six freshwater fish species collected during 2006 and 2007 in Iran. The values of the exponent b in the LWR (W=aLb) vary between 2.985 and 3.543. The LWR with high correlation coefficient (r2) is significant for all the species. These parameters are of great importance to evaluate the relative condition of populations, biology, species management and their fisheries and stock assessment. The application of the length-weight relationships presented here should be limited to the observed length ranges.  相似文献