Number and phylogenetic affiliation of bacteria assimilating dimethylsulfoniopropionate and leucine in the ice-covered coastal Arctic Ocean

The ability of bacteria to assimilate sulfur from dimethylsulfoniopropionate (DMSP) was examined in the western Arctic Ocean by combining microautoradiography and fluorescence in situ hybridization (FISH). Assimilation of leucine was also measured for comparative purposes since leucine is considered a universal substrate for bacteria, which use it for protein synthesis. Samples were collected at 3 m depth, through a hole in the ice, in the CASES (Canadian Arctic Shelf Ecosystem Study) overwintering station in Franklin Bay (eastern Beaufort Sea) in March and May 2004 to compare two contrasting situations: winter and early spring. FISH counts indicated that the bacterial assemblage consisted of α- (up to 60% of the EUB positive cells), β- (up to 10%) and γ-proteobacteria (around 20%), and Bacteroidetes (up to 60%). The β-proteobacteria were not active with any of the two substrates tested. The remaining groups were much less efficient at assimilating DMSP-sulfur (5% of the cells) than leucine (20–35%) both in winter and in spring. Only the Roseobacter group of α-proteobacteria showed a similar assimilation of both substrates.     

Intrusions of eastern North Atlantic central waters and phytoplankton in the north and northwestern Iberian shelf during spring

The influence of intrusions of eastern North Atlantic central water (ENACW) in the north and northwestern Iberian shelf on phytoplankton composition and abundance and on particle-size distributions of seston was analyzed using data collected on three extensive cruises during spring 1991 and 1992. Water with temperature and salinity values between 12.20 and 13.86 °C and between 35.66 and 35.98 psu, respectively, characteristics of the subtropical type of ENACW (ENACW_t), was detected in the upper 100 m of the water-column in all cruises, but particularly in the western coast in 1992. The highest salinity values of this water were found near the surface (0–100-m depth) and in early spring 1992, while minimum salinity values, and also minimum geographical extension, were found in late spring in both years. Phytoplankton blooms concentrated in frontal areas between different water types, with maximum intensity and extension in early spring.Using temperature and salinity characteristics, samples were classified in four groups corresponding to the major water types found in the region: Bay of Biscay central water (BBCW), two segments of ENACW of different salinity and surface water influenced by continental runoff. This classification was significantly confirmed by three independent discriminant analyses using hydrographic and chemical (dissolved nutrients and chlorophyll) variables, phytoplankton species abundance variables and particle-size concentration of seston variables. Phytoplankton blooms related to the presence of saline waters were characterized by the dominance of either chain-forming diatoms or a mixture of diatoms and phytoflagellates and high concentrations of seston. The diatom species dominating in saline waters were typical of upwelling-induced blooms occurring generally during summer. Blooms occurring in waters influenced by runoff also contained diatoms but in lower numbers than those of saline waters. Nutrients were not exhausted in the region, suggesting that phytoplankton populations were still in active growth. These results are interpreted taking into account the known variability in water-mass formation and in the poleward current driving ENACW_t along the shelf, and indicate that saline intrusions are a major feature affecting the distribution and composition of plankton in the spring in the southern Bay of Biscay, thus enlarging to a wider spatial scale their reported influence on the pelagic ecosystem.     

GPS定位技术在杭州湾大桥项目中的应用

GPS定位技术应用在大型和特大型工程项目施工测量中,有其特有的优势。本文通过对GPS定位技术在杭州湾大桥施工测量应用的总结,对在施工领域定位技术的应用作了有益的探索和推广。     

广西北部湾港口保税物流腹地经济圈构建研究

广西北部湾港口保税物流群的设立是我国为发展西部地带经济,推动中国-东盟自由贸易区而采取的重要举措。文章结合我国保税物流兴起的背景,介绍了广西北部湾港口保税物流业务分工内容及其对腹地经济区域的辐射作用,分析了广西北部湾港口保税物流腹地经济圈发展存在的问题,提出相应的发展思路和对策。     

杭州湾大桥非通航孔桥施工监理特点分析

根据杭州湾大桥非通航孔桥的工程特点,分析施工监理的重点和难点,并提出相关对策和措施。在确保工程安全和工程质量的前提下,确保工期。沉桩顺序和锚位合理安排、停锤标准的控制、桩的偏位纠正、质量事故的处理,是监控的重点和难点之一。     

Developing management guidelines for oil and gas activities: The louisiana experience

Abstract

Preliminary management guidelines have been derived for oil and gas activities in coastal Louisiana. Derivation of these guidelines was done in terms of the natural function of the coastal ecosystem; this means that all economic activities should be designed to complement natural function as much as possible. The guidelines range in scope from very specific, almost performance standards, to very general admonitions. For example, we have suggested that spoil banks, produced as a result of dredging, should not be higher than the height of the daily tide or roughly 15 cm in coastal Louisiana, and at the other extreme, we have suggested that all dredging should be done with great care during wildlife migrations, spawning, and nesting times.     

环厦门湾水域游艇活动安全现状及航路规划探讨

分析环厦门湾游艇活动现状,结合环厦门湾水域游艇泊位建设规划,提出环厦门湾游艇活动水域和游艇航路规划建议,供相关部门制订游艇航路规划和管理政策参考。     

铁山湾海域风浪数值模拟研究

随着北部湾的快速发展,铁山湾海域将规划建设数百个泊位．基于SWAN建立了该海域风浪数学模型,选取铁山湾海域影响较大的5个风向,研究不同风要素组合作用下的波浪特征,计算得到了建港方案实施前、后的波浪场分布．研究结果表明：S-SSW风向对该海域的风浪影响最大,SE-SSE和SW-WSW风向次之,E-ESE和W-WNW风向的影响相对较小．建港方案实施后,工程区的波浪强度整体小于工程前的;人工岛起到了很好的掩护作用．     

普兰店海湾大桥50m梁预拱度设置与施工控制

详细介绍了普兰店海湾大桥50m梁预拱度设置与施工控制,可为同类工程提供参考。     

混凝土结构外加电流阴极防护技术及其在工程中的应用

介绍混凝土结构外加电流阴极防护技术的原理,重点阐述杭州湾跨海大桥南、北航道桥外加电流阴极防护系统的组成、设计要点、关键技术和安装调试。