The equatorial undercurrent, meridional overturning circulation, and their roles in mass and heat exchanges during El Niño events in the tropical Pacific ocean   总被引：1，自引：0，他引：1  

Takeshi Izumo 《Ocean Dynamics》2005,55(2):110-123

The equatorial undercurrent (EUC), the shallow meridional overturning cells feeding it, and their role in El Niño and decadal variability in the equatorial Pacific are studied using both in situ data and an ocean general circulation model. Using temperature and current data from the TAO/TRITON moorings at the equator, their data gaps are filled and it was shown that continuous time series of mass transport, temperature, depth, and kinetic energy of the EUC could be constructed for the period 1980–2002 with an excellent accuracy. This dataset was analysed and used to validate the output from an oceanic general circulation model (OGCM). The OGCM was then used to find that variations in the strength of the EUC, shallow meridional overturning (pycnocline convergence and surface divergence), and equatorial upwelling had the same variations in mass transport on interannual and longer time scales within the period 1951–1999. These variations are all caused by variations of the zonal wind stress zonally integrated, in agreement with simple linear and steady dynamics theories. Impact of these mass transport variations and of temperature variations on heat budgets in the entire equatorial band of the Pacific and in its eastern part are quantified.  相似文献   

The Sequence-of-Bifurcations Approach towards Understanding Turbulent Fluid Flow     

F. H. Busse 《Surveys in Geophysics》2003,24(3):269-288

The sequence-of-bifurcations approach for the analysis of transitionsfrom simple to complex forms of fluid flow is described.Formulated for fluid systemswith external conditions that are homogeneous in two spatial dimensionsand in time,this approach determines bifurcations through theirsymmetry breaking properties.Solutions that are periodic in the homogeneous dimensionsand in time are generatedin this way. While the secondary solution induced by theinstability of the basichomogeneous state generically assumes the form of rolls orstripes, higher bifurcationsintroduce solutions exhibiting structures specific for thephysical system underconsideration. These structures often persist in the formof coherent structures inthe turbulent state of the system. Examples from the caseof thermal convection in alayer heated from below are used to illustrate thesequence-of-bifurcations approach.  相似文献   

磁流体在医药中的应用进展   总被引：6，自引：2，他引：6  

罗新  方裕勋  陈建新 《华东地质学院学报》2003,26(4):397-400

介绍了用于医药中的磁流体的生物兼容性和生物可降解性，指出药用磁流体的三个组成部分即纳米磁粒子、载液和表面活性剂都必须具有生物兼容性和可降解性，并从以下八个方面综述了磁流体在医药中的应用，即癌症病人的红血球细胞和白血球细胞的磁流体分离、肿瘤的磁栓塞封死治疗、磁流体在人体内受交变磁场的作用产生热量而实现的局部热疗和全身热疗、X-射线造影剂和核磁共振造影剂、磁性靶向药物载体、用于视网膜修复手术的硅氧烷磁流体、磁示踪剂以及血流的磁测量等。  相似文献   

牙鲆鳃淋巴样组织内免疫相关细胞的超微结构   总被引：2，自引：0，他引：2  

刘云  姜国良  姜明  张士璀 《中国海洋大学学报(自然科学版)》2001,31(6):872-876

利用电镜技术观察海水鱼类牙鲆鳃小片的基本结构及其免疫相关细胞的分布和形态。牙鲆的鳃小片主要由扁平上皮细胞和柱细胞构成 ,血窦腔极为发达。鳃小片在功能上可分为两个区 :气体交换区和免疫区。气体交换区位于上半部分 ,血窦内主要分布着红细胞 ;免疫区位于鳃小片基部 ,血窦腔中分布着各种免疫相关细胞 :淋巴细胞、单核细胞、中性粒细胞和酸性粒细胞。此外 ,还观察到了泌氯细胞和粘液细胞。研究结果证明 ,牙鲆的鳃在局部粘膜免疫中具有重要的作用 ,是鱼类免疫体系中的有机组成成分之一  相似文献   

Sea-to-air flux of contaminants via bubbles bursting. An experimental approach for tributyltin     

Richard Saint-Louis  Emilien Pelletier   《Marine Chemistry》2004,84(3-4):211-224

Although seawater concentration of tributyltin (TBT) should decrease when the direct inputs from ship hulls will cease after the incoming world ban of organotin-based antifouling paints in 2003 or later, the TBT environmental issue will still be present for decades as contaminated sediments in shallow waters will be acting as a long-lasting reservoir for TBT and its degradation products. The lost of TBT to the atmosphere by volatilization has already been proposed as a part of its molecular motion through the aquatic environment but most recent calculated values of water-to-air rate of exchange of TBT (from 20 to 510 nmol m⁻² year⁻¹) do not take into account the potential contribution of aerosols ejection to the atmosphere upon bubbles bursting, an important process for pollutants transport in the marine environment. In this work, an experimental approach to measure the seawater-to-air flux of TBT mediated by bubbles bursting is described, and the influence of phytoplankton cells and dissolved organic matter from exudates and culture weathering on flux rates was assessed. The results demonstrate that TBT can be transferred from water to air via the ejection of droplets from bubbles bursting and that cell density strongly affected the transfer. Under a bubbling regime, the water-to-air flux (pmol TBT cm⁻² min⁻¹ level) is estimated up to 1000-fold the flux measured for the molecular diffusion and volatilization under static quiescent conditions. The surface microlayer acted as a transient boundary between the water column and the atmosphere where the dynamic of TBT accumulation has the same trend as the dynamic of TBT ejection. This physical transfer mechanism might be of high significance in nearshore environments, harbors, and shallow channels where clouds of bubbles generated in the wake of large ships play an important role for the atmosphere/seawater chemical exchanges.  相似文献   

鱼类孵化酶的研究进展及其应用前景   总被引：15，自引：0，他引：15  

樊廷俊  史振平 《海洋湖沼通报》2002,(1):48-56

自上世纪以来，各国学者均开展了鱼类孵化酶领域的研究工作，包括鱼类孵化过程中孵化腺细胞的超微结构、孵化酶的生化特性、孵化酶基因的表达及其调控机制、孵化酶合成与分泌的影响因素等，取得了可喜的研究进展。本文谨以该领域的最新研究进展为基础，对鱼类孵化酶的研究现状及其应用前景进行综述。  相似文献   

马粪海胆的染色体制备和染色体数目     

董宝贤  林泰禧 《中国海洋大学学报(自然科学版)》1991,(3)

以马粪海胆胚胎为材料,提出染色体制备方法。并指出马粪海胆染色体数目为2n=46  相似文献   

''''93中国对虾流行性肝胰腺坏死综合症研究 Ⅰ.病毒和类支原体合并感染对虾肝胰腺     

杨季芳  郑胜江  马殿荣 《海洋学研究》1993,(3)

本文首次报道今年浙江省对虾大范围流行性肝胰腺坏死综合症及患病对虾肝胰腺组织中类支原体与病毒的合并感染。  相似文献   

外界因素对条斑紫菜体细胞分化发育的影响——Ⅰ. 温度、光强实验     

何培民  王素娟 《海洋科学》1991,(4)

本实验利用酶解技术得到单个体细胞,较详细地研究了不同温度、光照强度对体细胞分化发育的影响,从而确定出体细胞培养的最佳条件,为进一步利用条斑紫菜体细胞育苗这一新技术打下了基础。  相似文献   

急性淡水胁迫对斜带石斑鱼幼鱼鳃线粒体丰富细胞形态结构的影响          下载免费PDF全文

王雯  温久福  区又君  李加儿  王鹏飞  陈世喜  谢木娇 《应用海洋学学报》2016,35(4):544-549

为探讨淡水(盐度为0)对斜带石斑鱼(Epinephelus coioides)幼鱼鳃线粒体丰富细胞(MRCs)形态结构的影响,进一步探究其对鳃MRCs渗透调节机制的影响,以盐度30为对照,在斜带石斑鱼幼鱼急性淡水胁迫过程中,对鳃MRCs的结构变化进行光学显微镜(2、6、12、48 h)和扫描电镜观察(48 h).结果显示:淡水组鳃MRCs长径和短径均显著小于对照组(p0.05),H.E染色较浅;鳃小片直径显著变宽(p0.05),且鳃小片上增生出鳃MRCs;鳃MRCs表面存在一个特殊的顶膜结构,淡水组顶膜较为平坦,开口较大,且其表面存在大量微绒毛,对照组顶膜向内凹陷成一个开口较小的顶隐窝.推测在急性淡水胁迫下,斜带石斑鱼鳃MRCs的结构发生变化,导致其渗透调节功能部分丧失,幼鱼死亡,所以斜带石斑鱼幼鱼直接转入淡水时,不能长期存活.  相似文献