Seasonality of picophytoplankton chlorophyll a and biomass in the central Cantabrian Sea, southern Bay of Biscay

Seasonal changes in the abundance and biomass of cyanobacteria (Synechococcus and Prochlorococcus) and picoeukaryotes were studied by flow cytometry in the upper layers of the central Cantabrian Sea continental shelf, from April 2002 to April 2006. The study area displayed the typical hydrographic conditions of temperate coastal zones. A marked seasonality of the relative contribution of prokaryotes and eukaryotes was found. While cyanobacteria were generally more abundant for most of the year (up to 2.4 10⁵ cells mL^− 1), picoeukaryotes dominated the community (up to 10⁴ cells mL^− 1) from February to May. The disappearance of Prochlorococcus from spring through summer is likely related to shifts in the prevailing current regime. The maximum total abundance of picophytoplankton was consistently found in late summer–early autumn. Mean photic-layer picoplanktonic chlorophyll a ranged from 0.06 to 0.53 µg L^− 1 with a relatively high mean contribution to total values (33 ± 2% SE), showing maxima around autumn and minima in spring. Biomass (range 0.58–40.16 mg C m^− 3) was generally dominated by picoeukaryotes (mean ± SE, 4.28 ± 0.27 mg C m^− 3) with an average contribution of cyanobacteria of 30 ± 2%. Different seasonality of pigment and biomass values resulted in a clear temporal pattern of picophytoplanktonic carbon to chlorophyll a ratio, which ranged from 10 (winter) to 140 (summer). This study highlights the important contribution of picoplanktonic chlorophyll a and carbon biomass in this coastal ecosystem.     

温州海域研究与开发进展

在大量文献基础上,对温州海域水动力泥沙研究进展情况和主要的开发情况及相应的研究情况进行了综述,包括岸滩稳定、沉积过程、潮汐、潮流、泥沙、台风风暴潮、卫星遥感等的研究及温州浅滩围垦工程、瓯江南口工程、航道整治工程、30万t级航道工程、大、小门岛围垦工程、乐清湾港区工程等开发工程。     

湛江东海岛近岸潮流场数值模拟

将Smagorinsky亚网格模型引入ADCIRC潮流模型求解涡粘性系数,使模型在模拟近岸潮流方面更加合理。为进一步揭示中海油气开发利用公司广东沥青项目码头工程海域的潮流变化,利用改进的ADCIRC模型对湛江东海岛海域潮流场进行了合理地模拟和分析。结果表明该工程港池和进港支航道的开挖对湛江主航道影响很小。工程建设只改变了工程区海域的局部流态,并且新开挖航道的水动力条件有助于船舶顺流进港。     

杭州湾跨海大桥70m箱梁双栈桥式出海码头设计与施工

杭州湾跨海大桥自重2200t的70m跨箱梁,存在制造、运输、架设等重大技术难题,其预制场双栈桥式出海码头是箱梁陆海转运关键点。作为大桥建设的大型临时设施,设计采用预应力混凝土PHC管桩基础、钢筋混凝土承台、钢箱梁滑道结构,成功解决超大、超重型预制箱梁陆地移运与海上运输衔接难题,为杭州湾跨海大桥70m预制箱梁顺利出海架设奠定可靠基础。     

边际油田-WZ11—1N开发的工程策略

讨论了北部湾边际油田-WZ11-1N油田开发的工程策略，通过技术和经济上的综合分析，WZ11-1N油田采用了“三一”模式依托开发的成果，在应用涠洲地区成熟的、较先进的工程技术和开发经验的基础上，对依托平台／管线的处理工艺和寿命进行了详细的优化和校核，同时采用了电力组网新技术，达到了降低工程投资，提高油田收益的目的。另外在总体布置上为未来油田的依托开发预留了空间。     

温州乐清湾港区试挖槽监测分析

乐清湾避风条件好,潮流动力强,含沙量小,具有较好的建港条件。介绍了乐清湾试挖槽情况,对试挖槽进行了监测分析,指出数据分析表明试挖槽基本处于冲淤阶段,乐清湾港池开挖实行浅水深用的开发方案是可行的。     

Distribution of suspended sediment in the coastal sea off the Ganges–Brahmaputra River mouth: observation from TM data

Remote sensing technique was applied to estimate suspended sediment concentration (SSC) and to understand transportation, distribution and deposition of suspended sediment in the estuary and throughout the coastal sea, off the Ganges–Brahmaputra River mouth. During low river discharge period, zone of turbidity maximum is inferred in the estuary near the shore. SSC map shows that maximum SSC reaches 1050 mg/l in this period. Magnitude of SSC is mainly owing to resuspension of the bottom surface sediments induced by tidal currents flowing over shallow water depths. The influence of depth on resuspension is farther revealed from the distribution and magnitude of SSC along the head of Swatch of No Ground (SNG) submarine canyon. During high river discharge period, huge river outflow pushed the salt wedge and flashes away the suspended sediments in the coastal sea off the river mouth. Zone of turbidity maximum is inferred in the coastal water approximately within 5–10 m depth of water, where the maximum SSC reaches 1700 mg/l. In this period, huge fluvial input of the suspended sediments including the resuspended bottom sediments and the particles remaining in suspension for longer period of time since their initial entry control mainly the magnitude of SSC. In the estuary near the shore, seasonal variation in the magnitude of SSC is not evident. In the coastal sea (>5 m water depth), seasonal influence in the magnitude of SSC could be concluded from the discrepancy between SSC values of two different seasons. Transportation and deposition of suspended sediments also experiences seasonal variations. At present, suspended sediments are being accumulated on the shallow shelf (between 5 and 10 m water depth) in low discharge period and on the mid-shelf (between 10 and 75 m water depth) during high discharge period. An empirical (exponential) relationship was found between gradual settle down of suspended sediments in the coastal sea and its lateral distance from the turbidity maximum.     

Collaborative Management of Natural Resources in San Diego Bay

This article presents the results of a three-year effort at applying information technology to the problem of collaborative natural resource management in San Diego Bay. As such, it represents an approach to integrated coastal zone management (ICZM). This effort resulted from a collaboration between the San Diego Supercomputer Center at the University of California, San Diego and the San Diego Bay Interagency Water Quality Panel for the purpose of (1) developing an environmental data repository to facilitate the acquisition and sharing of data and (2) the development of a visual model of the bay in support of the development of a comprehensive, coordinated management plan for San Diego Bay. It was determined from this study that information technology is an important and key component to ICZM but that sociopolitical factors may override the benefits of decision-support systems and should be considered at the outset of any project of this kind.     

钢管桩三层熔结环氧粉末涂敷技术

杭州湾跨海大桥位于强潮河口浅海湾内,其基础工程处在潮差大、水流急、含砂量高和海水腐蚀性强等恶劣环境中,钢管桩防腐蚀采用三层熔结环氧粉末涂敷。钢管桩涂装生产线,日最大涂敷能力达6 800 m2,涂敷工艺处于国内领先水平,涂敷质量优于其他工艺。     

通州湾港区一港池回淤对策

通州湾港区一港池建在辐射沙洲南缘腰沙高滩上,港池航道开挖后的回淤问题是工程设计关注的焦点.设计时通过研究工程海域潮流、波浪、泥沙、底质等自然特征,分析影响回淤的主要因素,从挡沙堤平面布置、备淤深度确定、维护疏浚、船舶吃水控制等方面提出一系列针对性措施.研究认为:通州湾港区一港池建在粉砂质浅滩上,港池航道开挖必会出现回淤...