Vertical variations of the chlorophyll maximum during a red tide in a shallow lagoon

The results of eight sets of repeated observations on the vertical variations of the chlorophyll maximum layer in a shallow lagoon during a red tide show that these were more frequently hydrologically induced, rather than due to active vertical migrations of the red tide-forming organism. These results are discussed and compared to those existing in the literature, with special regard to the role of light and nitrogen in conditioning vertical migrations in red tide-forming dinoflagellates.     

The vertical distribution of zooplankton in the western Irish Sea

Zooplankton diel vertical migration is evident on the mixed isothermal side of the western Irish Sea frontal system but is often influenced by large tides and persistent geostrophic currents. On the stratified side of the front, temperature acts as a controlling factor with most of the zooplankton occurring above the thermocline and carrying out pronounced vertical migration when chlorophyll a levels are low and diffuse. At higher chlorophyll levels, when discrete chlorophyll a maxima form, zooplankton vertical movement may be greatly modified with a large number of species and stages concentrating within these maxima at all times of the diel light cycle.     

Effects of chemical ecological adjustment and control experiment on phytoplankton community in the Aoshan Bay

There is a low nutrient level in the Aoshan Bay. In June 1999, the chemical adjustmentand control experiment was made in the Aoshan Bay. Following tracts investigation was carried out before the experiment and on the 1st, 2nd, 4th, 5th, 6th and 45th day/after the experiment. While the variance of amount of phytoplankton, the replacement of superior species and the species composition of phytoplankton were researched. The results show that the amount of phytoplankton in the Aoshan Bay rises gradually after the experiment. Ceratium macroceros Cleve of pyrophyta was the dominant species before the experiment, its dominant index was 37.7％. Six days after the experiment, its dominant index dropped to 17.6％ . Meanwhile the dominant index of Asterionella japanics Cleve rose from 7.1％ to 39.2％ , it became the first dominant species. Forty-five days after the experiment, the amount of phytoplankton in the Aoshan Bay was 5.15 to 137.32 times more than that in 1997.     

千岛湖蚤状潘垂直分布格局及其季节与昼夜变化

2004年10月至2005年8月，对不同季节千岛湖蚤状潘的垂直分布情况以及昼夜迁移进行了研究。结果表明，蚤状潘在千岛湖分布广泛，春季和夏季蚤状潘主要分布在15-25m水层，而在秋冬季分布相对均匀，从表层到60m水深都有分布；比较了蚤状漫在不同季节的迁移现象，春季和秋季蚤状潘为夜间迁移模式，而在夏季和冬季虽然都存在迁移现象，但不同于常见的三种迁移模式。     

水下智能潜器的神经网络运动控制

本文介绍一种基于神经网络的水下智能潜器的运动控制方法，该方法通过在线学习，融控制与滤波为一体。计算机仿真与水池实验验证表明，该方法的控制与滤波性能良好，对环境的学习与适应能力强。该方法事实上可用于一般动力系统的控制。     

杆状病毒感染越冬亲虾(Penaeus chenesis)的研究——越冬亲虾感染及其垂直传播的可能性

在中国对虾越冬亲虾中检出杆状病毒。经对病虾鳃、前中肠、卵巢组织进行电镜观察，在这些组织中发现大量有囊膜的杆状病毒。病毒粒子大小约为３６７ｎｍ×１２８ｎｍ，核衣壳为３２４ｎｍ×９２ｎｍ。病毒在细胞内不形成包涵体，在核内或在细胞质的发生基质中装配。从病毒的形态特征、感染组织以及典型的发病症状和病理变化，初步认为亲虾感染的病毒与近年广泛报道的造成养殖对虾大规模流行病的主要原因——中国对虾杆状病毒为同一种。卵巢组织也是病毒的主要靶器官之一，亲虾卵巢组织的被感染暗示着该病毒有可能通过生殖细胞而垂直传播     

自主式水下机械手系统研究

本文从水下机械手的总体设计，关节直流电机的驱动和调速，手臂上声纳的水下搜索与跟踪，机械手系统的智能控制和电源等几个方面，介绍了有关自主式水下机械手系统的研究，可为研制自主式水下作业系统提供参考