Seasonal and annual variations of marine sinking particulate flux during 1993~1996 in the central South China Sea

A total of 67 samples from the upper and lower sediment traps in the central South China Sea were analyzed, which were collected during 1993~1996. It is indicated that the distribution of stable isotope values, surface primary productivity, fluxes of total particulate matter, carbonate, biogenic opal, organic carbon, planktonic foraminiferal species and their total amount exhibit obviously seasonal and annual fluctuations. High values of the fluxes occurred in the prevailing periods of the northeastern and southwestern monsoons, and the low values occurred during the periods between the two monsoons. The fluxes of some planktonic foraminiferal species (Globigerinoides sacculifer, G. ruber, Globigerinita glutinata, Neogloboquadrina dutertrei) and their percentages also exhibit two prominent peaks during the prevailing periods of the northeastern and southwestern monsoons respectively, while those of Globigerina bulloides, Globorotalia menardii and Pulleniatina obliquiloculata only exhibit one peak in the prevailing periods of the northeastern monsoon. In addition, fluxes and percentages of Globigerinoides sacculifer and Globorotalia menardii as well as the fluxes of carbonate and total amount of planktonic foraminifera decrease gradually from 1993 to 1996, and those of Globigerina bulloides, Globigerinita glutinata and biogenic opal increase gradually from 1993 to 1996. The fluxes of carbonate and organic carbon in the upper trap are higher than those in the lower one. The study indicates that the seasonal and annual variations of the sediment fluxes and planktonic foraminiferal species are mainly controlled by the changes of surface primary productivity and hydrological conditions related to the East Asian monsoon. The lower carbonate and organic carbon fluxes in the lower trap are related to the dissolution.     

秋季黄海中南部鱼类群落对饵料生物的摄食量

研究鱼类与饵料生物之间食物定量关系进而为多鱼种资源评估提供依据,2000~2002年秋季(10~11月)在黄海中南部海域进行了定点底拖网调查,应用Eggers模型,计算了带鱼(Trichiurus lepturus)、小黄鱼(Pseudosciaena polyactis)、黄(Lophius litulon)、细纹狮子鱼(Liparis tanakae)等23种鱼类在秋季对饵料生物的摄食量。结果表明:黄海中南部23种鱼类在秋季对饵料生物的总摄食量约为309万t,其中,鱼(Engraulis japonicus)的摄食量最高(在250万t以上),占总摄食量的80.9%。中上层和底层鱼类对饵料生物的摄食量分别为262万t和47万t左右,占总摄食量的84.7%和15.3%,鱼和细纹狮子鱼分别是中上层和底层鱼类中最主要的捕食者。磷虾类是中上层鱼类最主要的食物来源,其次是桡足类、端足类和毛颚类;虾类和鱼类是底层鱼类最主要的食物来源,其次是磷虾类。太平洋磷虾(Euphausia pacifica)、中华哲水蚤(Calanus sinicus)、细长脚虫戎(Themisto gracilipes)、脊腹褐虾(Crangon affinis)和鱼同时是黄海中南部被摄食量最高的5种饵料生物,它们被摄食的生物量之和约为233万t,占总摄食量的75.5%。     

Effects of tributyltin at environmental levels on monooxygenase system of digestive gland in hard clam Meretrix meretrix

The effects on ethoxyresorufin O-deethylase （EROD）, NADPH-cytochrome c reductase and NADH cytochrorne b5 reductase activities of digestive gland in Meretrix meretrix exposed to tributyltin （TBT） at environmental levels （0.1,1.0,10.0 ng/dm as stannum concentration）,in experimental condition, were evaluated. The EROD, NADH cytochrorne b5 reductase activities were significantly inhibited after exposure to 10.0 ng/dm^3 TBT for 8 and 20 d, the NADPH cytochrorne c reductase activities were significantly inhibited after exposure to 0.1,1.0 and 10.0 ng/dm TBT for 8 d and to 1.0 and 10.0 ng/dm for 20 d, as compared with the matched control, while NADH cytochrorne b5 reductases and NADPH cytochrome c reductase activities were induced after exposure to 10.0 ng/dm^3 TBT for 2 d. The EROD activity in the 10 ng/dm^3 group,and the NADH cytochrome b5 reductases activities in 1.0 and 10.0 ng/dm groups, were significantly induced when transferred to clean recovery tanks for 7 d. The three enzymic activities in the clams exposed to TBT were recovered to the level corresponding to that of the control group after transfer to clean recovery tanks for 20 d. NADPH cytochrome c reductase activity in Meretrix meretrix seems to be more sensitive to exposure of TBT than that of the EROD and NADH cytochrome b5 reductases. The results suggest that induction and inhibition by TBT to the monooxygenase system enzymic activity in Meretrix meretrix would simultaneously exist. The enzymic activities were inhibited by exposure for a long time. The results suggest that inhibition of the monooxygenase system should be an indication of the exposure to environmentally relevant concentrations of TBT for a long time.     

Numerical simulation of solitary wave scattering by a circular cylinder array

The interaction of a solitary wave with an array of surface-piercing vertical circular cylinders is investigated numerically. The wave motion is modeled by a set of generalized Boussinesq equations. The governing equations are discretized using a finite element method. The numerical model is validated against the experimental data of solitary wave reflection from a vertical wall and solitary wave scattering by a vertical circular cylinder respectively. The predicted wave surface elevation and the wave forces on the cylinder agree well with the experimental data. The numerical model is then employed to study solitary wave scattering by arrays of two circular cylinders and four circular cylinders respectively. The effect of wave direction on the wave forces and the wave runup on the cylinders is quantified.     

利用卫星测高技术监测厄尔尼诺和拉尼娜现象

利用美国宇航局和法国空间局联合公布的T／P数据（1993-2000年）和Jason-1数据（2002—2006年），由共线法计算了热带太平洋地区海平面高度的变化。根据T／P和Jason-1数据计算的海面月变化异常图，分别研究了和分析了1997-1998年的厄尔尼诺和拉尼娜现象、2002-2003年厄尔尼诺现象的变化发展过程。     

人工饲料饲养的对虾肠道菌群和水体细菌区系的研究

对人工饲料饲养的凡纳滨对虾Litopenaeus vannamei成虾肠道菌群组成及其水体细菌区系组成进行了研究.分离纯化后的革兰氏阴性菌鉴定到种的水平.对虾肠道菌群主要由弧菌Vibrio spp.、希瓦氏菌属Shewnella spp.、嗜氢菌属Hydrogenophaga spp.、伯克霍尔德氏菌Burkholderia spp.、气单胞菌Aeromonas spp.、食酸菌Acidovorax spp.和芽孢杆菌Bacillus spp.组成.水体细菌区系主要包括弧菌Vibrio spp.、希瓦氏菌属Shewnella spp.、艾肯菌Empedobacter spp.、无色杆菌Achromobacter spp.和芽孢杆菌Bacillus spp..肠道菌群和水体细菌区系的优势菌是副溶血弧菌Vibrio parahaemolyticus和芽孢杆菌Bacillus spp..利用Shannon-Wiener指数进行多样性分析,发现虾肠道多样性指数（H）和均匀度（J）高于水体细菌区系,而丰度（D）较低.     

赤点石斑鱼(Epinephelus akaara)精子超微结构及环境因子对精子活力的影响

为揭示赤点石斑鱼精子的超微结构及环境因子对其精子活力的影响,利用扫描电镜和透射电镜观察赤点石斑鱼精子的超微结构,设置不同梯度的温度、盐度、pH值及不同浓度的NaCl、KCl、CaCl₂、MgCl₂、EDTANa₂溶液,探究这些因子对赤点石斑鱼精子活力的影响。结果表明:赤点石斑鱼成熟精子的结构特点是细胞核圆形或卵圆形,核内染色质致密,没有核泡(核空隙)。精子尾部细长,横切面为典型的"9+2"微管结构。温度、盐度、pH值等环境因子对精子活力的影响表明,精子活力的适宜温度范围为23~31℃,27.5℃时精子寿命最长为37min;适宜的盐度范围为15~35,盐度15时精子寿命最长为50min;适宜的pH范围为7~9,pH为9时精子的运动时间最长为33min。赤点石斑鱼精子在EDTANa₂溶液中呈抑制状态,在400~700 mmol/L的NaCl溶液、400~600mmol/L的KCl溶液和500 mmol/L的CaCl₂溶液中精子均具有较好的活动能力。在MgCl₂溶液中赤点石斑鱼精子的活动能力不佳。赤点石斑鱼精子的最适温度范围与繁殖季节的最适水温范围符合,适宜盐度范围较广,对pH值的变化适应性较强。赤点石斑鱼精子在NaCl、KCl、CaCl₂溶液中活力较佳,在MgCl₂溶液和EDTANa₂溶液中呈抑制状态。     

Artificial upwelling induced by ocean currents —Theory and experiment

A submerged apparatus, which consists of a buoy, several horizontal contraction and expansion tubes (Venturi-type tubes) and a long pipe, is expected to be used to pump the subsurface sea-water (200–300 meter depth) containing abundant nutrients to surface layer (50–100 m) by the dynamic of ocean currents. i.e. an artificial upwelling without energy cost. A preliminary experiment and analysis are undertaken and shows that the capacity of pumping the nutrient-rich sea-water is worth to build a pilot prototype model.     

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。     

A NUMERICAL MODEL FOR THE TIDES AND TIDAL CURRENTS IN THE TAIWAN STRAIT

Semidiurnal and diurnal tidal waves in the Taiwan Strait are computed simultaneously by using finite difference method with two-dimensional nonlinear hydrodynamic equations. The agreement between the computed and observed results is considered satisfactory.