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51.
培育双壳类软体动物幼苗所需的饵料,是指池内培育阶段适合于幼虫和幼苗(壳长一般在1mm以下)的饵料。育苗成功的关键问题之一为是否已经选择到这样的饵料。自40年代找到适宜的饵料生物以后,双壳类幼虫的培养才取得较明显的成效。以往利用过的一些饵料生物巳有文献系统记载。我国贻贝人工育苗是在分离与培养出扁藻以后才获得成功的。随着研究工作的深入以及适应各种不同情况的需要,采用的饵料种类越来越多样化。从生产性育苗特别是多茬育苗考虑,必须因地制宜地筛选出一定种数的饵料,以便在不同培养条件下有机动选择的余地。同一时还应找出适宜的投饵数量,以求取得较好的育苗效果。为此目的,我们于1975-1978年结合生产性育苗的需要进行了一些饵料饲养实验。本文根据实验结果以及多年来生产性育苗的实践,对贻贝育苗的饵料问题进行总结,侧重于不同饵料的饲养效果比较。 相似文献
52.
Study of zooplankton ecology in Zhejiang coastal upwelling system-Zooplankton biomass and abundance of major groups 总被引:1,自引:0,他引:1
He Dehu Yang Guanming Fang Shaojin Shen Weilin Liu Hongbin Gao Aigen Huang Shuxin 《海洋学报(英文版)》1988,7(4):607-620
The studied area is a shallow water area that belongs to the East China Sea continent shelf. The distribution of zooplankton biomass is higher inshore than offshore. The maximum abundance is in the inshore edge of the centre of upwelling, which is the superposed area of the salinity front and temperature front, due to the fact that the mixture of three different waters has brought about a concentration of nutrients. The herbivorous Euphausia, Copepoda and Tunicata are the major groups of the abundant area. Tunicata possess the possibility to compete against other kinds of herbivorous zooplankton. This means that there is negative correlation between the distribution of Tunicata and that of Copepoda and Euphausia. The positions of maximum areas of zooplankton biomass, phytoplankton individual and the concentration of phosphates and chlorophyll-a overlap one another. In the centre of upwelling, zooplankton can not adapt itself to the environment of lower temperature and less oxygen even with rich nutrient 相似文献
53.
A nutrient dynamic model coupled with a 3D physical model has been developed to study the annual cycle of phytoplankton production in the Yellow Sea. The biological model involves interactions between inorganic nitrogen (nitrate and ammonium), phosphate and phytoplankton biomass. The model successfully reproduces the main features of phytoplankton-nutrient variation and dynamics of production. 1. The well-mixed coastal water is characterized by high primary production, as well as high new production. 2. In summer, the convergence of tidal front is an important hydrodynamic process, which contributes to high biomass at frontal areas. 3. The evolution of phytoplankton blooms and thermocline in the central region demonstrate that mixing is a dominant factor to the production in the Yellow Sea. In this simulation, nitrate- and ammonium-based productions are estimated regionally and temporally. The northern Yellow Sea is one of the highly ranked regions in the Yellow Sea for the capability of fixing carbon and nitrogen. The annual averaged f-ratio of 0.37 indicates that regenerated production prevails over the Yellow Sea. The result also shows that phosphate is the major nutrient, limiting phytoplankton growth throughout the year and it can be an indicator to predict the bloom magnitude. Finally, the relative roles of external nutrient sources have been evaluated, and benthic fluxes might play a significant role in compensating 54.6% of new nitrogen for new production consumption. 相似文献
54.
The probability of fractal determination of coastal types based on GIS is preliminarily discussed with China as an example. Finally, some significant conclusions are drawn: (1) The fractal dimension of coastline of the bedrock coast is larger than that of the plain coast on the same scale map; (2) As far as the bedrock coast is concerned, the larger fractal dimension of coastline of the bedrock coast on the same scale map indicates that the bedrock coast is probably not typical; (3) As far as the plain coast is concerned, the smaller fractal dimension of coastline of the plain coast on the same scale map indicates that it is probably the silt plain coast; (4) The different substantial compositions affect the fractal dimensions of coastlines of different coastal types. In general, the coast which lies in the north of the Hangzhou Bay consists of sand mainly, its surface is flat, and it is connected with the coastal plain, its landform is broad shoal, its total change is comparatively homogenous in the tidal dynamic process, and thus, the relatively smaller fractal dimension of coastline results from this. For the bedrock coast, there is more bedrock, the coastline is comparatively smooth and straight, being affected by the faults and ocean dynamic process, which result in the larger fractal dimension. 相似文献
55.
台湾及其邻海的重力特征与构造、地震的关系 总被引:1,自引:0,他引:1
分析认为,在台湾及其邻海的重力场中,具有短波长特征的空间重力异常受地形与海深所制约.玉山的200×10 相似文献
56.
57.
In the present experiments, ethyl methanesulfonate (EMS) is used to treat blue-green alga Spirulina platensis. Results show that the chemical is a very effective mutagen on the species and some genetic changes, including morphological variation, different growth rate and greater resistance to low temperature, have been found, which may offer an efficient method for the strain breeding of Spirulina platensis. 相似文献
58.
Li Yucheng He Ming Professor Dalian University of Technology Dalian Former master student Dalian University of Technology Dalian 《中国海洋工程》1994,(3)
-Based on the extended Morison Equation and model tests, the in-line forces on small square cylinders caused by waves (regular and irregular) and currents are analyzed in detail in this paper. The hydrodynamic coefficient CD and Cu related to KC number and the effect of direction of wave incidence are also given, which can be used in engineering practice. 相似文献
59.
根据聚类方法,对闽南-台湾浅滩渔场变性水团进行划分,本海区共有6个变性水团。讨论各个变性水团在不同季节消长变化规律。 相似文献
60.
考虑底摩擦的波浪折射计算 总被引:2,自引:0,他引:2
本文用考虑底摩擦的折射模式计算了浅水中波高和波向分布。作为一个例子,根据不同的摩擦系数和不同的边界条件计算了一种简单海底地形的折射系数、衰减系数和折射角,所得结果与不考虑底摩擦的折射模式结果进行比较,发展它们之间存在一些差异,表明在浅水中底摩擦对波高有一定影响。 相似文献