福建深沪湾不同环境样品中总汞和甲基汞含量的分布     

林方芳  袁东星  刘锡尧  林珊珊  冯丽凤 《台湾海峡》2013,32(3)

测定了福建省泉州深沪湾海水、沉积物和生物体中的总汞含量,测定了沉积物、生物体中的甲基汞含量.海水总汞含量范围是1.16 ～7.29 ng/dm3,平均值为3.32 ng/dm3.沉积物中总汞含量为0.006～0.066 μg/g,甲基汞占总汞的比例为4.7％ ～38.6％,该比例与总汞含量呈负相关关系(r=-0.840,p＜0.05),这可能是因为总汞含量的升高使甲基汞合成反应受到抑制,导致反应速率降低甚至为负,即甲基汞的分解.生物体中总汞含量为0.037 ～0.353 μg/g(干重),甲基汞含量为1.01 ～42.50 ng/g(干重),甲基汞占总汞的比例为1.5％ ～40.4％.甲基汞含量与总汞含量显著相关(r =0.484,p＜0.10);总汞含量与甲基汞占总汞比例略有相关(r=-0.293,p＜0.10);甲基汞含量与其占总汞比例无相关性(r=0.061,p＞0.05).可以推测,生物体中的总汞和甲基汞都是外源性的,不同生物体甲基汞占总汞的比例变化很大.对深沪湾居民进行海产品摄入量评估,以美国EPA规定的甲基汞参考计量0.1 μg/(kg·d)为标准,计算得深沪湾周边居民每周食用3次(600g)湾内的海产品是安全的,不会产生汞中毒.未来还需要测定海水中甲基汞的含量,用以计算生物富集因子,表征不同生物对甲基汞的富集程度;通过测定鱼体中的δ13C、δ15N比值来确定不同鱼类的营养级,进而研究甲基汞的生物累积效应与营养级的关系.  相似文献   

Introduction,preliminary handling,and diseases of grass carp in New Zealand     

D. J. Edwards  P. M. Hine 《新西兰海洋与淡水研究杂志》2013,47(3):441-454

Fry of grass carp, Ctenopharyngodon idella (Val.), were air‐freighted from Hong Kong to New Zealand in October 1971. The fish were at first kept in tanks with a recirculating water supply, where they soon showed symptoms of parasitic infestation and suffered heavy mortality.

Attempts were made to remove parasites with chemotherapeutic treatment. Tripartiella sp., Dactylogyrus ctenopharyngodonis, and Gyrodactylus clenopharyngodontis were eliminated by prolonged bathing of the infected fish with quinine. Chemical treatment failed to eliminate Ichthyophthirius mullifiliis from the body surface and the gills, but the rate of spontaneous recovery of the fish from this disease was accelerated by keeping them in clean, running water. Experiments to remove the cestode Bothriocephalus gowkongensis from the intestine of the fish with tetravalent tin compounds and to control the intermediate host (Cyclops) in the water resulted in the eradiction of the cestode.

When parasitic infestations had been brought under control the fish were transferred to outdoor ponds, where they began to feed on aquatic and terrestrial vegetation and rapidly increased in size.  相似文献   

The physical structures of snow and sea ice in the Arctic section of 150°-180°W during the summer of 2010     

HUANG Wenfeng  LEI Ruibo  ILKKA Matero  LI Qun  WANG Yongxue  LI Zhijun 《海洋学报(英文版)》2013,32(5):57-67

The physical structures of snow and sea ice in the Arctic section of 150°-180°W were observed on the basis of snow-pit, ice-core, and drill-hole measurements from late July to late August 2010. Almost all the investigated floes were first-year ice, except for one located north of Alaska, which was probably multi-year ice transported from north of the Canadian Arctic Archipelago during early summer. The snow covers over all the investigated floes were in the melting phase, with temperatures approaching 0℃ and densities of 295-398 kg/m3 . The snow covers can be divided into two to five layers of different textures, with most cases having a top layer of fresh snow, a round-grain layer in the middle, and slush and/or thin icing layers at the bottom. The first-year sea ice contained about 7%-17% granular ice at the top. There was no granular ice in the lower layers. The interior melting and desalination of sea ice introduced strong stratifications of temperature, salinity, density, and gas and brine volume fractions. The sea ice temperature exhibited linear cooling with depth, while the salinity and the density increased linearly with normalized depth from 0.2 to 0.9 and from 0 to 0.65, respectively. The top layer, especially the freeboard layer, had the lowest salinity and density, and consequently the largest gas content and the smallest brine content. Both the salinity and density in the ice basal layer were highly scattered due to large differences in ice porosity among the samples. The bulk average sea ice temperature, salinity, density, and gas and brine volume fractions were-0.8℃, 1.8, 837 kg/m3 , 9.3% and 10.4%, respectively. The snow cover, sea ice bottom, and sea ice interior show evidences of melting during mid-August in the investigated floe located at about 87°N, 175°W.  相似文献   

Socio-economic aspects of the tiger shark diving industry within the Aliwal Shoal Marine Protected Area,South Africa     

《African Journal of Marine Science》2013,35(2):227-232

Understanding socio-economic aspects of the tiger shark Galeocerdo cuvier diving industry, including information on participant expectations, experiences and expenditure, is necessary for the effective management of the Aliwal Shoal Marine Protected Area on the east coast of South Africa. Between January and December 2007, a total of 2 133 tiger shark dives was conducted by 1 065 divers (95% CI = 946-1 198). Data were collected by means of the administration of a semi-structured survey questionnaire to 197 (18.6%) dive participants. Respondents indicated that the direct value of tiger shark diving to the Aliwal Shoal region was R12 405 274 (95% CI = R10 777 324-14 228 541). A total of 1 000 Monte Carlo simulations was used to estimate confidence intervals. On a ranking from one (poor) to five (excellent), the average participant response to overall quality of dive and standard of dive operator was 4.6 and 4.7 respectively. The majority of divers (98.0%) observed a tiger shark, at an average of four per dive. Although tiger sharks approached to an average distance of 1.6 m from divers, the majority (95.9%) felt safe and enjoyed the experience. The majority of interviewees (88.5%) supported the use of chumming for a closer ‘tiger shark experience’.  相似文献   

Optimisation of underwater visual census and controlled angling methods for monitoring subtidal temperate reef fish communities     

《African Journal of Marine Science》2013,35(3):277-287

Standardised sampling protocols for monitoring fish stocks are essential to assess changes in stock status and provide a means to evaluate the effectiveness of fisheries management measures, such as marine protected areas (MPAs). This study aimed to optimise two standard sampling methods, namely underwater visual census (UVC) and controlled angling, for assessing subtidal reef fish communities. In terms of efficiency, variability and bias, UVC transects were found to be superior to point counts. For controlled angling, an effort of two angler-hours per fishing station provided low catch variability, high catch per unit effort and a representative catch. Whereas UVC provided less variable estimates of relative density, controlled angling provided greater sampling efficiency. It is thus recommended that the two methods be used in conjunction. The optimal sampling protocols identified are suitable for rapid assessments or long-term monitoring of subtidal, temperate reef fish communities.  相似文献   

海洋立管试验支座设计及其对涡激振动影响研究     

李莹  杨新华  郭海燕  李朋 《海洋工程》2013,31(3):31-37

针对大长细比顶张力立管内外流共同作用时涡激振动的试验研究,考虑端部铰接和固接两种边界条件,设计了可施加张力和内流的铰接支座和固接支座,并对两种支座进行数值模拟及受力分析,最后用于深水立管的涡激振动试验。立管模型材料采用6.2 m长铜管,外径20 mm,壁厚1.5 mm,分别支撑在铰接支座和固接支座上,施加不同的顶部张力、外流流速和内流流速。通过在立管表面粘贴光纤光栅应变计获得动态应变数据,分别从动态响应幅值、频率等方面对不同边界条件立管的试验数据进行对比分析,得出在顶张力、内流速相同的情况下,外流速相等时两端铰接立管的振动幅值大于两端固接立管,随着外流速的增加,两端铰接立管比两端固接立管率先发生锁振现象。  相似文献   

抑制涡激振动的螺旋列板设计参数研究   总被引：1，自引：0，他引：1  

沙勇  曹静  张恩勇  周巍伟  陈严飞 《海洋工程》2013,31(1):43-48

基于水池模型实验结果和工程设计经验,结合国内外试验数据,着重分析用于抑制海洋立管涡激振动的螺旋列板几何参数(鳍高和螺距)及覆盖率对立管涡激振动的影响;并对水动力直径和水动力系数的选取对预报涡激振动的影响进行了分析,进而提出了适合于海洋立管工程应用的螺旋列板几何和设计参数选取的建议,为螺旋列板工程应用、海洋立管强度和疲劳设计提供参考。  相似文献   

海洋地质调查设备数据库的智能管理设计     

谭鹰  杨维萍  郑大军  盛堰 《海洋地质前沿》2013,(11):76-78

海洋地质调查设备具有种类多、专业性强等特点,传统的设备管理的方式已经很难适应现代化海洋地质调查设备管理工作的需要。从海洋地质调查设备的智能化管理、提高装备管理工作效率的需求出发,运用现代数据库信息技术、条形码管理技术设计了一套海洋地质调查设备的数据库智能管理方案。该数据库的建立,将有效地管理海洋地质调查设备,充分地发挥海洋地质调查设备的社会效益和经济效益,为促进海洋地质的现代化建设提供有力保障。  相似文献   

Time-Dependent Deformation Behavior of Jiangsu Marine Clay     

L. Miao  J. Zhang  F. Wang  S. L. Houston 《Marine Georesources & Geotechnology》2013,31(2):86-100

In this article, the mechanical behavior of a Jiangsu marine clay was investigated by drained triaxial tests, traixial rheological tests, and one-dimensional compression and swelling tests. A visco-plastic model, the Bingham model combining two yield surfaces model, was proposed to describe the time-dependent deformation behaviors of the marine clay. The governing equation of Biot's consolidation theory for the visco-plastic soil is solved using a finite element code which incorporates the visco-plastic model. Using the finite element method, settlements of a typical embankment on the Lianxu expressway in China are calculated. Settlement calculations using the visco-plastic model are in agreement with the measured settlements in the field. The results demonstrate that the visco-plastic model is appropriate for calculating the visco-plastic deformations of Jiangsu marine clay. Theoretical and experimental studies show that the visco-plastic deformation of Jiangsu marine clay is substantial.  相似文献   

Geotechnical Aspects of Clayey Sediments Off Badagara on the Kerala Coast,India     

Dr. Thomas Mathai  K. N. Rajarama  Satish Kumar  M. Suresh Chandran  M. R. Asoka Kumar 《Marine Georesources & Geotechnology》2013,31(2):180-193

Offshore geotechnical surveys form part of an integrated investigation to rejuvenate a decrepit minor port at Badagara, Kerala on the southwestern coast of India. The sediments typify a fluvio-marine milieu ranging from silty clay, sand, silty sand, sandy silt and clayey silt. Geotechnical and sedimentological studies of shallow cores reveal the geotechnical aspects besides the depositional history of the sediments. Downcore geotechnical variations and regressive coefficients based on their inter-relationships highlight diverse factorial inferences. X-Ray Diffraction data indicate the prominent clay type.

A comparative evaluation of the geotechnical characteristics of clayey sediments off Badagara, with similar studies along various sectors of the Kerala coast, both on land as well as in the near shore, is broadly attempted. Geotechnical studies carried out earlier on the uplifted Cochin marine clays provide comparative data for evaluating the possible variations between present day marine clayey sediments occurring along the Kerala coast and uplifted marine clays which, besides their gross variations in levels with respect to the present sea-level, also obviously relate to a much older depositional environment and provenance during probable Holocene times.  相似文献