Using otolith weight to predict the age of <Emphasis Type="Italic">Pennahia macrocephalus</Emphasis> in the mouth of the Beibu Gulf

The relation between otolith weight (OW) and the age of marine fish is studied. A total of 222 individuals of bighead white croaker, Pennahia macrocephalus were sampled seasonally in the mouth of the Beibu Gulf, the South China Sea, in 2007. Since there are no significant differences in sagittal OW between otolith in pairs (P≥0.05), the undamaged left sagittal otolith is used for age determination. The highest correlations among standard length, OW and fish ages are confirmed by linear, exponential and multinomial regression. Results show that sagittal OW overlaps only occasionally among age groups, and to individuals with similar standard length, the older and slower-growing fish has a heavier otolith because of the continued otolith material deposition. There are differences in sagittal OW among different age groups and significant positive linear relationship with age (P<0.05). The age readings can be verified by plotting the sagittal OW versus the standard length for age groups, and the individuals with similar standard length but in different ages can be separated by sagittal OW frequency analysis. Mostly, the predicted ages using the regression between sagittal OW and ages are closed to the observed ages by counting annulus on scale. It indicates that the sagittal OW analysis is a useful technique for validating the accuracy of age determination by annuli counts, especially for individuals of similar size. Furthermore, the technique is applied for Pennahia macrocephalus with discussion in this paper. Supported by the National Natural Science Foundation of China (No. 30771653) and Bureau of Fisheries, Ministry of Agriculture     

Surface sediment diatoms from the western Pacific marginal seas and their correlation to environmental variables

Diatom data of 192 surface sediment samples from the marginal seas in the western Pacific together with modern summer and winter sea surface temperature and salinity data were analyzed.The results of canonical correspondence analysis show that summer sea-surface salinity(SSS) is highly positively correlated with winter SSS and so is summer sea-surface temperature(SST) with winter SST.The correlations between SSSs and SSTs are less positively correlated,which may be due to interactions of regional current pa...     

Formation and evolution of the modem warm current system in the East China Sea and the Yellow Sea since the last deglaciation

To reconstruct the formation and evolution process of the warm current system within the East China Sea (ECS) and the Yellow Sea (YS) since the last deglaciation, the paleoceangraphic records in core DGKS9603, core CSH1 and core YSDPI02, which were retrieved from the mainstream of the Kuroshio Current (KC), the edge of the modem Tsushima Warm Current (TWC) and muddy region under cold waters accreted with the Yellow Sea Warm Current (YSWC) respectively, were synthetically analyzed. The results indicate that the formation and evolution of the modem warm current system in the ECS and the YS has been accompanied by the development of the KC and impulse rising of the sea level since the last deglaciation. The influence of the KC on the Okinawa Trough had enhanced since 16 cal kyr BE and synchronously the modem TWC began to develop with the rising of sea level and finally formed at about 8.5 cal kyr BP. The KC had experienced two weakening process during the Heinrich event 1 and the Younger Drays event from 16 to 8.5 cal kyr BP. The period of 7-6 cal kyr BP was the strongest stage of the KC and the TWC since the last deglaciation. The YSWC has appeared at about 6.4 cal kyr BP. Thus,the warm current system of the ECS and the YS has ultimately formed. The weakness of the KC,indicated by the occurrence of Pulleniatina minimum event (PME) during the period from 5.3 to 2.8 cal kyr BE caused the main stream of the TWC to shift eastward to the Pacific Ocean around about 3 cal kyr BP. The process resulted in the intruding of continent shelf cold water mass with rich nutrients. Synchronously, the strength of the YSWC was relatively weak and the related cold water body was active at the early-mid stage of its appearance against the PME background, which resulted in the quick formation of muddy deposit system in the southeastern YS. The strength of the warm current system in the ECS and the YS has enhanced evidently, and approached to the modern condition gradually since 3 cal kyr BP.     

浅议海上责任保险第三人直接请求权的行使条件

随着海上责任保险第三人权利保护的问题受到人们的日益重视,各国普遍赋予了海上责任保险第三人对保险人的直接请求权,但各国立法基本上未考虑到强制海上责任保险的特殊性,从而没有明确区分自愿海上责任保险中第三人直接请求权与强制海上责任保险中第三人直接请求权不同的权利属性,因而只笼统地对海上责任保险第三人行使直接请求权的条件做出概括性规定,这无法真正实现强制海上责任保险充分维护第三人利益与社会公共利益的立法价值。针对这一立法缺陷,提出应在明确自愿海上责任保险中的第三人直接请求权与强制海上责任保险中的第三人直接请求权具有不同权利属性的前提下,针对这两种不同的海上责任保险规定第三人不同的权利行使条件。     

Comparisons of several evaporation/precipitation datasets for the Bohai Sea based on salinity simulation

Evaporation (E) rate and precipitation (P) rate are two significant meteorological elements required in the ocean baroclinic modeling as external forcings. However, there are some uncertainties in the currently used E/P rates datasets, especially in terms of the data quality. In this study, we collected E/P rates data from ERA-40, NCEP/NCAR Reanalysis, HOAPS for the Bohai Sea and nine routine stations around Laizhou Bay, and made comparisons among them. It was found that the differences in E/P rates between land and sea are remarkable, which was due to the difference in underlying surfaces. Therefore, the traditional way of using E/P rates acquired on land directly at sea is not correct. Since no final conclusion has been reached concerning the net water transport between the Bohai Sea and the Yellow Sea, it is unfeasible to judge the adequacy of the four kinds of data by using the water budget equation. However, the E/P rates at ERA-40 sea points were considered to be the optimal in terms of temporal/spatial coverage and resolution for the hindcast of salinity variation in the Bohai Sea. Besides, using the 3-D hydrodynamic model HAMSOM (HAMburg Shelf Ocean Model), we performed numerical experiments with different E/P datasets and found that the E/P rates at sea points from ERA-40 dataset are better than those from NCEP/NCAR Reanalysis dataset. If NCEP/NCAR Reanalysis E/P rates are to be used, they need to be adjusted and tested prior to simulation so that more close-to-reality salinity values can be reproduced.     

Seismically induced slope instabilities and the corresponding treatments: the case of a road in the Wenchuan earthquake hit region

On May 12, 2008, a magnitude 8.0 earthquake hit Wenchuan County, Sichuan Province resulted in great loss of life and properties. Besides, abundant landslides and slope failures were triggered in the most seriously hit areas and caused disastrous damages to infrastructures and public facilities. Moreover, abundant unstable slopes caused by the quake have the potential to cause damages for a considerable long period of time. The variety of these slopes and the corresponding treatments are connected with the topographical and geological conditions of the sites. It is decided to document and identify some of these major slope instabilities caused by the earthquake and their treatments. The paper shows the condition of a road in Dujiangyan through in situ explorations. The case history showed significant implications to the reconstruction of the quake-hit regions and future disaster prevention and management works.     

现今绝对板块运动

根据热点假设,热点对于中间层是固定的.相对热点的板块运动叫做绝对板块运动.绝对板块运动模型可以通过反演火山链传播的速率和走向数据以确定相对板块运动在角速度空间的原点来得到.利用一组近来(0～7.8 Ma)全球分布的热点的迁移速率和走向数据,结合板块运动模型NNR-NUVEL1A,已研制出一个叫做APM2的现今绝对板块运动模型.按照该模型,太平洋板块围绕60.063°S、102.210°E处的极以(0.833 0°±0.013 3°)/Ma的速率运动,非洲板块围绕46.849°N、44.372°W的极以(0.101 5°±0.013 4°)/Ma的速率运动,南极板块的运动则以46.871°N、146.942°E为极,速率为(0.084 6°±0.017 7°)/Ma,欧亚板块的运动更慢,极为27.291°N、171.925°W,速率为(0.065 5°±0.020 6°)/Ma.这一模型表明,岩石圈相对深部地幔有一个以49.423°S、90.625°E为极,速率为(0.198 3°±0.013 5°)/Ma的净旋转.表明太平洋热点同印度-大西洋热点不一致,显示太平洋热点的运动也不一致.为了分析和比较,还给出了仅用全球分布的热点的走向数据和仅用印度-大西洋热点的走向数据得到的板块绝对运动的角速度.     

黄海南部黄鲫(Setipinna taty)资源利用分析

以2005-2006年江苏省帆式张网渔获资料为基础,分析研究了黄海南部黄鲫资源的时空分布、群体组成结构以及产卵群体生物学特征.结果表明,黄海南部黄鲫主要利用渔期为春季3-5月、冬季1月或12月.春季高产渔区主要分布在大沙渔场的西南部和吕泗渔场的东部,冬季和秋季高产渔区相对靠近或较春季高产渔区偏东.黄鲫高产渔区的分布无明显季节变化特征.黄鲫渔获群体主要由体长70-110mm、体重0-15g的个体组成,产卵群体的平均体重范围为8.7-12.0g.与1981-2000年的研究结果相比,黄鲫个体小型化越趋显著,当前利用个体偏小.     

南海西缘断裂带右行走滑的地球动力学机制

南海西缘断裂带,北端始于17°30'N附近的海南岛南部,往南延伸止于北西走向的卢帕尔断裂,南北延伸长度约达1 600 km,十分壮观(见图1)。该断裂带除了其名称和延伸长度在不同研究者的文章中各有所不同[1—4]之外,其名称和作用至少在20世纪80年代初已得到广泛的应用,早已成习惯,如在《亚洲地质》[5]一书和杨树康等[1]、陈国达[4]等许多著名科学家的论著中不断地得到了应用。该断裂带的构造地位和作用得到地学界的普遍重视,到目前为止地学界基本上认为它就是印支亚板块与南海亚板块之间的区域性边界断裂。     

台风作用下淤泥质海岸动力地貌响应

基于200509号麦莎台风(近似百年一遇)作用前后杭州湾北岸龙泉-南竹港实测的海岸地形和水文资料,利用分形技术、冲刷深度和闭合水深等相关概念分析淤泥质海岸的剖面变化、岸线进退以及地形冲淤,进而探讨海岸响应台风作用的动力地貌行为.结果表明:1)台风作用前后的海岸动力地貌过程表现为水下类似沙坝的堆积体削平、凹处填洼,水下平台发育锯齿或较小的坝--槽,海岸剖面的分维数降低,剖面坡度处于平缓;2)麦莎台风对海床的整体冲淤幅度不大,这可能是由于研究区大潮讯的增水致使波浪对海床的塑造能力减弱以及码头的遮蔽作用造成;3)台风作用对海岸的冲刷深度约为0.8 m,闭合水深为9.5 m,近岸-1 m邻近区成为海岸响应台风作用最敏感的地带;泥沙主要在0 m到闭合水深区间的海床发生纵、横向运移.