调查锚在海缆路由调查中的应用

介绍了海底调查锚的结构和用调查锚进行海缆路由调查的方法。通过实例 ,分析了不同底质情况下的实测结果。     

GPS坐标向国家坐标转换的三维分离回归法

三维分离回归法是一种简单、有效、实用的转换方法,该方法可有效地克服病态矩阵问题。同时,为切实、有效地提高三维分离回归法的转换精度,计算时引入了三向尺度因子,使得三维转换参数由传统的7个变为现在的9个。详细介绍了三维分离回归法的基本原理、转换过程及转换实例。     

Study of Water Motion at the Dissolved Oxygen Minimum Layer and Local Oxygen Consumption Rate from the Lagrangian Viewpoint

By using the Euler-Lagrangian method, we examine water movements within the layer of minimum oxygen concentration and estimate local oxygen consumption rates for 15 regions of the global ocean. To do this, a number of labeled particles (which represent water parcels) are deployed at the center of a grid with 15 depth levels and tracked backward in time for 50 years in a three-dimensional velocity field. We assume that a particle picks up oxygen when it encounters the point of maximum oxygen concentration along the 50 years segment of its path. We introduce a contribution rate from waters distributed throughout the global ocean to the oxygen concentration of a local layer under consideration. Water parcels which are assumed to pick up oxygen within the oxygen minimum layer of an oceanic region under consideration make a very small contribution to the overall oxygen concentration of this layer. In addition, these parcels move out of the layer and water parcels from the upper layers take their place. The averaged Lagrangian local oxygen consumption rate is 0.033 ml/l/yr for the depth of the oxygen minimum layer, 0.20 ml/l/yr at 100 m depth (euphotic layer), 0.043 ml/l/yr for layers from 150 m to 800 m depth and 0.012 ml/l/yr for deep layers from 800 m to 3000 m. The present Lagrangian numerical experiment produces a maximum difference between observed and calculated concentrations of oxygen and, therefore, a maximum oxygen consumption rate. Although the present method has an ambiguity as to how oxygen is picked up, we nevertheless were able to identify regions in which the water parcels pick up oxygen of maximum concentration. We found that the South Equatorial Current (SEC) transports oxygen of higher concentration to the middle latitude regions of both the North Atlantic and the North Pacific across the equator.     

Comparative ecophysiology of active zoobenthic filter feeding, essence of current knowledge

The present contribution gives an overview of current knowledge of a comprehensive and steadily growing research field. The first section deals with water pumping and particle retention mechanisms in ciliary and muscular filter feeders. The second section examines the biological filter pumps in order to assess adaptation to the environment. Filter-feeding benthic invertebrates have evolved filter pumps to solve common basic problems. This has led to a large degree of similarity between otherwise distant standing species, which makes comparative studies interesting and important. The present review of zoobenthic filter feeding aims at accentuating such recognition.     

Nature of the connection between the Northern and Southern Zechstein Basins across the Mid North Sea High

The seismic expression of a salt-filled channel which cuts across the Mid North Sea High in Quadrant 37 is described, with features interpreted as being produced by salt-edge dissolution forming both eastern and western margins of the channel. The apparent half-graben nature of the channel is shown to be only superficial, and due to complex faulting associated with, but not defining, its western margin. The shallower faulting here is a Mesozoic to early Tertiary growth fault related to local dissolution of Zechstein salt. The dissolution effect appears in turn to have been localized by the presence of a deeper fault that was already downthrown to the east in Zechstein times, when it seems to have limited the eastward progradation of Zechstein shelf carbonates and anhydrites, and had probably ceased to move significantly before the onset of the Late Cimmerian erosional phase. The origin of this arcuate fault is tentatively ascribed to subsidence around a granite batholith. Zechstein salt originally spread some distance to the east and west of the channel; it was dissolved from the edges inwards, mainly before the Late Cretaceous, giving rise to a thicker Mesozoic sequence on parts of the flanks of the channel than in the middle. Besides providing an interesting structural case history, the features described have implications regarding Zechstein sedimentation, reservoir potential, the tectonic history of the North Sea, and the nature of the Mid North Sea High itself.     

闽中、闽东渔场扁舵鲣的资源生物学

本文以1981～1984年4～9月累计18个月在闵中、闵东渔场开展中上层鱼类资源开发性探捕调查的材料,报道了扁舵鲣的生态分布、群体结构和生活史主要特征。鱼群先后于4～7月由南而北进入本渔场,数量分布以5月为多;栖息的最适温、盐度分别为23.5～25.5℃和33～34;渔获群体由0～V龄组成;性成熟的最小年龄为Ⅰ龄,最小叉长271～280mm;生长参数L_∞=484.44mm,W_∞=2050.76g,K=0.5109,t_0=0.3598;瞬时自然死亡率为0.8937,开发比率为0.2138,属于轻度利用的鱼类资源,尚有较大的开发潜力。     

基于基因组survey的横带髭鲷(Hapalogenys analis)微卫星位点筛选与特征分析

探究横带髭鲷(Hapalogenysanalis)的种质资源情况以及群体的遗传多样性和遗传结构,对于其增养殖实践尤为重要。微卫星分子标记在研究物种种质情况及遗传信息方面有很大优势。采用基因组survey测序方法开发横带髭鲷微卫星位点,结果表明,横带髭鲷基因组大小为543Mb;微卫星位点丰富,共检测到280 378个完美型微卫星位点,相对丰度为415.17个/Mb。二核苷酸重复是最丰富的微卫星类型(56.05%),其次为单核苷酸(29.20%)、三核苷酸(10.28%)、四核苷酸(2.99%)、五核苷酸(1.03%)、六核苷酸(0.45%)重复,短序列重复类型占95.53%。重复单元中A/T, TG/CA为优势重复单元,分别占总微卫星位点数的22.37%和21.98%;10次重复和6次重复的微卫星位点数量最多,占横带髭鲷基因组微卫星总数的14.60%和12.46%。利用筛选出的20对多态性微卫星位点扩增一个供试群体进行群体遗传学检测。结果表明,各位点等位基因数从5到13不等,均值为8.75个;平均观测杂合度(Ho)和期望杂合度(He)分别为0.808和0.863;多态信息含量(PIC)均...     

Gradation affects basic mechanical characteristics of Chinese calcareous sand as airport subgrade of reefs

Abstract

Construction of the reefs in the South China Sea is a significant foundation to the secure stability and economic development of China. The construction of an airport runway is necessary for this realization. The calcareous sand is the main primary material in the runway construction. A certain type of calcareous sand near a certain reef of the South China Sea was studied in this paper. To investigate this specific calcareous sand, quartz sand was used as a reference for comparison. Microscopic 3-D imaging, compression and triaxial tests were conducted to test the micro, squeezing and shear properties. The effect mechanism of gradation on the calcareous sand’s compressibility and shear characteristics are discussed from a mesoscopic viewpoint using 3-D morphology. Calcareous sand particles are multiangular and flatter in comparison with quartz sand. The larger the particle sizes are, the more different the two sands’ morphologies are. The compressibility of calcareous sand is greater, and the effect of the coarse fraction (5–1?mm) content in the gradation plays the most significant role in this feature. When the coarse particles’ content is less than 25% and the mass ratio of the middle and fine particles (M) is constant, there is the worst coarse fraction content causing the calcareous sand to be most likely compressed. The worst coarse fraction content decreases with the increase in M, and an empirical formula is proposed. When the gradation, relative density and confining pressure are the same, the peak shear stress and strain of calcareous sand are all at a high level. The effect of confining pressure is manifested in calcareous sand. The shear strength and dilation of calcareous sand are also most affected by the medium coarse fraction (5–0.25?mm) content.     

基于拉格朗日拟序结构的吕宋海峡表层水交换研究

黑潮通过吕宋海峡入侵南海呈现明显的瞬态特征。以往的研究通常将黑潮在吕宋海峡附近的流态分为几种不同类型。本文基于表层地转流计算得到的有限时间李雅普诺夫指数场（FTLE）,展示了拉格朗日视角下的吕宋海峡上层水交换特征。从FTLE场提取的拉格朗日拟序结构（LCSs）很好地识别了吕宋海峡附近的典型流态和旋涡活动。此外,这些LCSs还揭示了吕宋海峡周围复杂的输运路径和流体域,这些特征得到了卫星跟踪浮标轨迹的验证,且从流速场中是无法直接识别的。FTLE场显示,吕宋海峡附近表层水体的输运形态主要可分为四类。其中,黑潮直接向北流动的“跨越”形态和顺时针旋转的“流套”形态的发生频次明显高于直接进入南海的黑潮分支“渗入”形态和南海水流出至太平洋的“外流”形态。本文还进一步分析了黑潮在吕宋海峡处的涡旋脱落事件,突出强调了LCSs在评估涡旋输运方面的重要性。反气旋涡旋的脱落个例表明,这些涡旋主要源自黑潮“流套”,涡旋脱落之前可有效地俘获黑潮水。LCS所指示的输运通道信息有助于预测最终被反气旋涡所挟卷水体在上游的位置。而在气旋涡的形成过程中,LCS的分布特征表明,大部分气旋涡并未与黑潮水的输运路径相连通。因此,气旋涡对从太平洋到南海的上层水交换的贡献较小。