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1.
A comparative study of ecosystems and biogeochemistry at time-series stations in the subarctic gyre (K2) and subtropical region (S1) of the western North Pacific Ocean (K2S1 project) was conducted between 2010 and 2013 to collect essential data about the ecosystem and biological pump in each area and to provide a baseline of information for predicting changes in biologically mediated material cycles in the future. From seasonal chemical and biological observations, general oceanographic settings were verified and annual carbon budgets at both stations were determined. Annual mean of phytoplankton biomass and primary productivity at the oligotrophic station S1 were comparable to that at the eutrophic station K2. Based on chemical/physical observations and numerical simulations, the likely “missing nutrient source” was suggested to include regeneration, meso-scale eddy driven upwelling, meteorological events, and eolian inputs in addition to winter vertical mixing. Time-series observation of carbonate chemistry revealed that ocean acidification (OA) was ongoing at both stations, and that the rate of OA was faster at S1 than at K2 although OA at K2 is more critical for calcifying organisms.  相似文献   

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The mummichog (Fundulus heteroclitus) has been shown to be responsive to peroxisome proliferating agents (PPAs). Peroxisomes function as important sites for fatty acid beta-oxidation. Peroxisome proliferation by PPAs or starvation can lead to changes in the size and number of peroxisomes and the expression of omega-hydroxylases (CYP2K1/2M1 in rainbow trout). Mummichogs were subjected to 96 h fasting or 96 h recovery from fasting. Expression of PMP70- and CYP2K1/2M1-like proteins in vehicle-treated or non-treated controls was compared in both males and females. Fasting and vehicle produced decreases in PMP70- and CYP2K1/2M1-like proteins in both males and females. In reproductive females, decreases due to fasting and vehicle treatment were greater than in female fish that were not gravid. Recovery from fasting resulted in levels of CYP2K1/2M1 near control levels in males while in recovered females, about 2-fold higher levels compared to controls were noted. These results indicate that gender, reproductive status and diet can produce changes in the expressed levels of peroxisomal PMP70 and microsomal CYP2K1/2M1-like proteins in the mummichog.  相似文献   

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利用113个沿岸和岛屿长期验潮站的调和常数,计算了研究海区S2对M2,N2对M2,K2对S2,O1对K1,P1对K1和Q1对O1分潮的相对导纳分布.结果表明,各相对导纳的模数在琉球群岛附近接近于1,且随着潮波向内海传播逐渐减小,亦即较小的分潮衰减较显著;相对导纳的幅角逐渐增加(若分潮对的角速度差为正)或逐渐减小(若分潮...  相似文献   

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Seasonal variations of baroclinic tides for K1 and M2 constituents were separately studied using two-dimensional numerical simulations along the 21°N section of the northern South China Sea (SCS). Results show that the continental slope of the northern SCS and the west ridge of the Luzon Strait are supercritical to K1 internal tides, which may be trapped in the deep basin of the SCS and form standing or partial standing waves. Meanwhile, these areas are sub-critical to M2 internal tides, which can transmit onto the shelf and are seldom reflected back into the basin. The trapped K1 internal tides are dominated by mode-2 and mode-3 in summer and by mode-1 and mode-3 in winter. Moreover, high mode K1 internal tides account for nearly 20–40 % of the total energy density in winter and 15–20 % in summer. The pattern of K1 internal tides in the basin is mainly determined by the percentage of reflected energy from the continental slope. The phase difference between the incoming mode-1 and mode-2 K1 internal tides near the continental slope are nearly out of phase in winter, which means that the percentage of reflection of the K1 internal tide is larger than that in summer. Both the convergence and high mode K1 internal tides can enhance the vertical shear. The above results indicate that, in the deep basin of the SCS, water mixing potentially induced by internal tides in winter is stronger than in summer.  相似文献   

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Progress in the introduction of coulometry for the analysis of total carbon dioxide (TCO2) in marine waters is described. An extractor—stripper removes CO2 that is measured coulometrically by the quantity of electricity (coulombs) used to electrogenerate OH? ions for the titration of the acid formed by the reaction of CO2 and ethanolamine. The equivalence point is detected photometrically with thymolphthalein as the indicator, and Faraday's Law relates coulombs to equivalents of titrant generated and CO2 determined so that there are no standard curves needed or titrants to standardize or store. Accuracy was determined by adding gelatin capsules containing 100–1500 μg C of pure CaCO3 into the stripper, and accuracies of better than ± 1 μg C were achieved. The best precision for natural seawater (± 1 standard error) of ± 0.5 μmol l?1 was found for 17 samples of Bermuda coastal waters having a mean TCO2 of 2007.2 μmol l?1 (0.05% CV). Sources of error and precautions are discussed. This method, which has been used successfully at sea, can be used to study a variety of marine phenomena involving TCO2.  相似文献   

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We describe physical oceanographic conditions around the S1 biogeochemical mooring site (30°N, 145°E) between February 2010 and July 2013. At the S1 mooring site, there is a clear seasonal variability of the mixed layer depth, wind forcing as well as horizontal kinetic energy in a near-inertial band. Interannual variability of the winter mixed layer was observed. The winter mixed layer depth was shallower in early 2010 and became deeper afterwards. Several mesoscale eddies and typhoons passed by the S1 mooring sites every year. Based on observed events, we suggest that those physical processes possibly affected biogeochemical properties around the S1 mooring site.  相似文献   

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浅谈深海抗风浪网箱养鱼业   总被引:1,自引:1,他引:1  
1发展深海抗风浪网箱养鱼业的意义随着生活水平的不断提高,人们对水产品的需求量不断增加。由于海洋自然鱼类资源日趋衰退,所以水产养殖业在全国沿海得到了迅猛发展,致使中国的近海内湾海域已处于高度的饱和状态,不少内湾海域已破坏了生态平衡,导致病害频发,产量下滑,效益降低,严重制约了中国海水养殖业的健康可持续发展。但是湾外广阔的深海水域资源受环境和技术条件的限制,长期处于荒废闲置状态。  相似文献   

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缴健  高祥宇  丁磊  张新周 《海洋工程》2019,37(3):143-150
以概化分汊河口为研究对象,针对两汊中长期地貌演变对整治工程响应的问题,采用平面二维数学模型对整治工程前后分别进行20年地貌演变模拟。分析结果表明:整治工程对落潮含沙量影响较大,工程汊道落潮分沙比有显著下降;整治工程主要导致工程汊道坝田区淤积和航道冲刷,同时也增加了非工程汊道的冲刷及淤积厚度;工程后工程汊道淤积量增加,冲刷量减小,冲淤总量减小,非工程汊道淤积量不变,冲刷量增加,冲淤总量增加。  相似文献   

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234Th is an extremely useful radiotracer of particle dynamics in aquatic systems. Its utility, however, has yet to be realized by many within the aquatic science community. The reasons for this may in part be due to a lack of knowledge of how this nuclide has been used in the past as well as how and where 234Th might be profitably applied in future research. The purpose of this paper, then, is to examine the variety of 234Th applications that have been used to understand natural aquatic processes in four major areas: vertical transport, particle cycling, horizontal transport, and sediment dynamics. We provide a general overview of the possible applications of 234Th in the hopes of provoking an increased interest in the inherent potential and future application of 234Th in these systems. We end this paper with a discussion of future research avenues in the context of three specific regimes: (i) the upper 1000 m of the open ocean, (ii) coastal sediment/water processes and (iii) large freshwater lakes.  相似文献   

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建立了多指标灰色关联度工程项目评标决策模型。实际算例计算结果表明,该模型物理意义明确,与评标思维过程一致,比灰色关联投影法具有更高的分辩程度,有利于实际评标的操作。  相似文献   

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为评价舟山钓梁围垦一期工程对附近海域生态系统的影响,对工程海域水质、浮游植物、浮游动物、底栖动物和潮 间带动物在不同时间的调查数据进行了综合分析。结果表明,工程海域海水处于高度富营养化水平,无机氮和活性磷酸盐严 重超标。围海区内浮游植物细胞丰度在2007 年降到最低,2011 年8 月较2007 年8 月显著增加,均匀度指数呈现相反的变化 趋势。围海工程结束后浮游动物生物量显著降低,浮游幼体在种类数中所占比例增加;大型底栖动物栖息密度、生物量、多 样性指数均显著降低,多毛类种数所占比例增加;潮间带动物栖息密度、多样性指数和均匀度减少。围海造成的海水水质的 变化与浮游植物、浮游动物、底栖动物群落结构参数改变密切相关,海水悬浮物含量是影响浮游生物群落结构的重要因素, 围海工程结束后底栖动物群落结构发生了明显改变。  相似文献   

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为理解次季节—季节(subseasonal to seasonal,S2S)模式的预报技巧,利用台站降水观测资料对中国气象局(China Meteorological Administration,CMA)、欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)和美国国家环境预报中心(National Centers for Environmental Prediction,NCEP)模式公共回报期1999—2010 年108°E 以东的中国大陆东部夏季日降水及极端降水预报展开评估。结果表明,ECMWF 预报整体表现最佳、NCEP 次之、CMA 相对较弱,各模式随预报时间的增长均呈现当观测偏湿(干)时预报倾向偏干(湿)的特点,在 S2S 时间尺度基本丧失预报技巧,具有很大的改进空间。极端降水临界阈值的界定方法会直接影响单个台站的评估结果,但对区域整体预报技巧影响不大。S2S 模式预报的均方根误差在观测降水量越多时往往越大;预报值与观测值的相关系数在所有(极端)降水事件中呈连续(振荡)衰减,甚至出现负相关;均方技巧评分在所研究降水事件较多的情况下表现更好。各模式在所有降水事件中的空报率要远高于漏报率,但在极端降水事件中恰好相反。降水预报检验指标在绝对极端降水分级检验中的表现逐级变差,各模式预报中基本不出现特大暴雨,CMA 对极端降水事件发生的预报准确率较低。  相似文献   

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Desorbed gas analyses of cuttings from the Gravberg—1 well, the culmination of the Swedish deep gas project, were undertaken every 100 m from 219 to 5907 m. A sample at 6517 m, from sidetrack 2, was also included. The desorbed gas method performed by hot acid treatment in an evacuated system was superior to both ball mill crushing and thermodesorption methods. Two types of hydrocarbon gases were found in trace quantities. One type associated with the dolerite sills was an isotopically heavy, δ13C1: −11 to −15‰, dry gas, with a methane content up to 98%. The other type, occurring throughout the granitic rocks, was an isotopically lighter gas, δ13C1: −21 to −39 ‰, containing 30–45% of C2C4 olefins and paraffins were present in almost equal amounts in the second type of gas. The dry gas observed in the dolerites is assumed to be abiogenic gas existing in inclusions of basic minerals which react with acid during the analytical procedure. The other type of hydrocarbon gas is thought to be formed from H2 and CO2 by a catalytic reaction since it is mainly associated with the magnetic fraction of the rock. A Fischer-Tropsch reaction over a magnetite catalyst is the most likely reaction since it produces both paraffins and olefins. Studies on thin sections of cores and coarse cuttings suggest that the wet gas is not isolated in inclusions and the changes with time observed for a few thin sections indicate that it diffuses quite freely. The potential risks of contamination from drilling fluids and bit metamorphism were examined by comparing the hydrocarbon results with changes in the mud system, rate of penetration and bit life. Hydrocarbon analyses of a few mud additives were included as well. The result of these examinations plus the results of hydrocarbon analyses of cores from pilot core holes in the Siljan Crater suggest that the hydrocarbons observed in the cuttings are indigeneous.Comparing the results of the present study with other hydrocarbon occurrences outside of the Siljan Crater indicates that the hydrocarbons found in the Gravberg—1 well occur widespread in crustal rocks.  相似文献   

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The Convention for ballast water management is approaching the threshold of enforcement. Many countries around the world formulate national laws and regulations to mitigate the hazards of non-indigenous aquatic species (NIAS) brought about by the discharge of ballast water from ships. Taiwan’s critical location as an important transportation hub in the Western Pacific Ocean makes it a hot spot for the invasion of NIAS. Therefore, devising strategies for the management of ballast water is urgently needed. This study explores the global trend in ballast water management, and discusses the possible strategies which Taiwan may adopt in response to the Ballast Water Convention, from the perspective of Taiwan’s stakeholders in relation to the ballast water issue. Some of the proper actions that Taiwan should take in the future regarding the management of ballast water include: delineating the area for ballast water exchange, establishing the ballast water declaration system for incoming vessels, assisting shipping companies in installing ballast water treatment systems, determining risk priority for incoming vessels, and inspecting ballast water-related parameters by means of port state control (PSC). In this way, the invasion of NIAS may then be prevented in compliance with the global standards.  相似文献   

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渤、黄、东海M2和K1分潮潮流场的有限元模拟   总被引:1,自引:0,他引:1  
使用有限元模式(QUODDY)数值模拟了渤、黄、东海浅水区的M2和K1分潮潮流场。对于M2分潮潮流场,东分量和北分量的潮流调和常数与16个测站观测资料的平均绝对误差分别为8.23 cm/s,23.74°();7.36 cm/s,27.78(°)。对于K1分潮潮流场,则分别为8.39 cm/s,36.48(°);9.40 cm/s,38.04(°)。文中得到的M2分潮流在模拟海区共有9个圆流点(秦皇岛附近1个,莱州湾口1个,山东半岛北部海域2个,黄海北部2个,苏北辐射沙洲的外侧1个,舟山群岛东南海域2个)。K1分潮流在模拟海域也存在9个圆流点(秦皇岛附近1个,莱州湾口1个,北黄海2个,南黄海1个,苏北辐射沙洲的外侧1个,济州岛东南海域3个),其中黄海北部偏北的圆流点(39°25′N,123°05′E)和济州岛东南海域最东南的圆流点(32°50′N,127°50′E)以前未见过报道。  相似文献   

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