Vertical Migration of Sound Scatterers in the Southern Yellow Sea in Summer

Acoustic volume backscattering strength data were collected and Conductivity Temperature Depth (CTD) measur e m e n t s were conducted in the southern Yellow Sea in summer 2005 and 2006. The high temporal and vertical resolution acoustic data measured with a 307 kHz Acoustic Doppler Current Profiler (ADCP) and a 250 kHz acoustic Doppler profile (ADP) had dominant diel variation, which resulted from vertical migration of sound scatterers. Some scatterers congregating in the bottom layer in the daytime migrated upward at dusk, and migrated downward into the bottom layer at dawn. The migration speeds were estimated. More than 33 days data show that the diel migration varies with time. The feature of migration measured with ADCP and ADP is consistent to some extent with what is described in the study on vertical migration of zooplankton in the southern Yellow Sea with conventional net samples.     

胶州湾不同季节浮游动物昼夜垂直移动规律初步研究

在胶州湾内设置连续站(36°5'54″N,120°15'20″E),分别于2006-2007年分春季、夏季、秋季、冬季四季进行垂直分段拖网,研究了胶州湾浮游动物垂直移动的规律。结果显示,浮游动物在不同季节显示不同的垂直迁移行为。同时,对该海域出现的优势种类的垂直移动规律进行了研究并分类,发现不同物种同一季节迁移方式不同,对于同一种类,在不同季节也表现出不同的迁移规律。因此,浮游动物垂直迁移规律不是一成不变的,由外界环境因子和内在因素共同作用决定。不同季节影响浮游动物垂直迁移的关键因子不同,其中春季、夏季、秋季三季主要影响因子是光照,冬季除了光照,还有温度、盐度和浮游植物密度。总体与温度和浮游植物密度正相关,与盐度负相关。对于不同种类,影响其垂直迁移的主要因子也不尽相同。     

An Ecological-Physical Coupled Model with Ontogenetic Vertical Migration of Zooplankton in the Northwestern Pacific

A vertical one-dimensional ecosystem model with vertical migration of zooplankton was constructed and applied to Station A-7 off Sanriku district of Japan in the northwest Pacific Ocean. The model consists of an eight-compartment ecosystem model coupled with a physical model of the oceanic mixed layer. The transition of phytoplankton species responsible for the spring bloom is well reproduced by this model with vertical migration of zooplankton but is not simulated by the model without vertical migration. This new model also simulates an observed inter-annual variability of the spring bloom, with the timing and intensity of the simulated bloom in a given year depending upon the strength of mixing during the preceding winter. This revised version was published online in August 2006 with corrections to the Cover Date.     

Economic tradeoffs in the Gulf of Maine ecosystem: Herring and whale-watching

This research attempts to quantify some of the effects of localized depletion of herring by examining the search times of commercial whale-watching vessels. Whale-watching vessels are indirect users of herring; whales feed on herring and may disperse when prey availability is low. A dataset of daily whale-watching outcomes is combined with fishing effort and oceanographic data to test the hypothesis that intensive fishing effort increases the search time of whale-watching companies. Our results suggest that fishing may have a detrimental impact on search time; however, the magnitude of this effect is fairly small. We find policy that the recently enacted policy which prohibits fishing for herring in whale-watching areas would decrease search times by a small amount. We find some evidence of a localized aggregation effect; search times are the lowest when herring are spawning in the inshore areas. These results should be of interest to policymakers in determining future fishing regulations in an ecosystem-based fisheries management context.     

三维辐射应力引起的海底回流垂向分布

海底回流对近岸地形演变起到重要作用。文章给出了应用不同三维辐射应力得到的海底回流的解析解。在推导海底回流解析解时,涡黏系数分别选用了抛物线型、线性和垂向常数涡黏系数,讨论了他们对海底回流垂向变化的影响,给出了考虑不同三维辐射应力的海底回流解析解结果与试验结果的对比。最后将不同学者建立的三维辐射应力加入到本文数学模型中,对海底回流试验结果进行了数值模拟。     

Ontogenetic Shifts in Resource Use and Shoaling Tendency Related to Body Size in Red Sea Goatfish (Parupeneus forsskali, Mullidae)

Abstract. Red Sea goatfish show marked behavioral differences related to body size in food searching, substrate use, and shoaling tendency. While smaller fish mainly use their barbels to search for food hidden in the upper sediment layers or in crevices of corals, the largest fish frequently burrow with their mouths in deeper layers of the sediment. The conspecific shoaling tendency decreases with increasing size. Only smaller-sized fish are found in mixed-species shoals. The data are discussed with regard to the relations between ontogenetic changes in body size, resource utilization, and socialization patterns.     

Vertical distributions of nitrogen,phosphorus and iron in Beppu Bay

Beppu Bay is a shallow basin located at the western end of the Seto Inland Sea with a sill depth ofca. 40 m. The bottom water (belowca. 65 m in summer andca. 70 m in winter) was anoxic and contained high concentrations of hydrogen sulfide, phosphate and ammonium. Maximum concentrations of nitrate and nitrite appeared near the top of the thermocline, suggesting the occurrence of bacterial nitrification in this layer and of bacterial denitrification in the anoxic bottom water. Concentrations of particulate phosphorus and particulate iron were highest near the bottom of the thermocline. The distribution of phosphorus in this bay is probably controlled by a dissolution-diffusion-precipitation cycle of iron or its hydrous oxides.     

The Importance of Computational Grids in Hydraulic Numerical Models

The importance of computational grids in hydraulic numerical models is studied by numericalsimulation of jet flow in a rectangular duct which is linked with a fixed width inlet and a different widthoutlet using a standard k-ε turbulence model.The computational results show the numerical solutionsmay not be reasonable because of the incorrect computational grid and each numerical model has a grid-in-dependent solution.The computational grid has a definitive effect on the accuracy and stability of thecomputational solution,which must be divided well according to the simulated geometry and physicalcharacters of hydraulic problems.The main guidelines about the formation of computational grid in suchaspects as node distribution,smoothness and skewness of grid,have been given.     

浅谈区域划分与环境调查对沉船考古工作的重要性

沉船考古是一项极为复杂的系统性工作,水下环境复杂、文物打捞操作困难、海洋人文资料缺失等因素制约我国水下文化遗产保护工作。沉船考古工作不仅要对沉船本身及所载器物进行考古发掘,还要结合陆域考古学、海洋学划分重点沉船区域进行系统性发掘研究,对沉船本身及所载器物所处的海底环境和受腐蚀状况进行详细调查和研究,为文物修复和保护工作提供支撑。     

光谱和体重对刺参耗氧率和排氨率的影响

实验采用室内受控的方法,研究了不同光色下,大(73.32±1.73) g、中(46.71±0.15) g和小(25.67±0.25) g 3种规格刺参(Apostichopus japonicus)的耗氧率和排氨率的变化.实验采用红、橙、黄、绿、蓝色和对照组(白色)6种光照处理.研究结果表明:光谱对刺参的耗氧率和排氨率均有显著性影响(P<0.05),3种规格刺参的耗氧率趋势相同:白色＞红色、黄色、绿色、蓝色＞橙色;3种规格刺参的排氨率有相似的变化趋势:白色＞红色＞橙色、绿色、黄色、蓝色.刺参的体重与单位体重耗氧率及排氨率之间的回归关系均可以表示为R=aW~b,耗氧率a值在0.005 9～0.012 1之间,b值范围是1.119 7～1.214 6,排氨率a值的变动范围为0.004 2～0.02,b值的变动范围为0.455 3～0.867 8.这说明光谱对刺参的耗氧率和排氨率有显著性的影响,丰富了刺参的基础研究,对于刺参养殖生产有一定的指导意义.     

Vertical Transport of Momentum by Internal Waves in a Shear Current

Izvestiya, Atmospheric and Oceanic Physics - Free internal waves are considered in the Boussinesq approximation with account for the rotation of the Earth and a plane–parallel current normal...     

Vertical and horizontal distribution of meiofauna in mangrove sediments in Transkei, southern Africa

The depth-distribution profiles of meiofauna in four transects in the Mngazana River, Transkei were studied during summer 1980. Highest densities [±1000(100 cm³)⁻¹] were encountered within the top 10 cm of the sediment. Nematodes dominated (80%) and the remainder was made up of ciliates, oligochaetes, gastrotrichs, and low numbers of polychaetes, copepods, kinorhynchs and various crustacean larvae. Among chemical parameters Eh correlated most consistantly with distribution, particularly at the lower tidal levels. Temperature and pH appeared to be of lesser importance. The maximum estimated depth of penetration was on average 72 cm at the HW levels; 32 at MW and 23 at LW. The mean dry biomass was estimated at 1073 mg m⁻²; 941 mg m⁻² and 196 mg m⁻² at these tidal levels respectively. The importance of preliminary studies designed to estimate the depth distribution of meiofauna is discussed.     

Vertical Structure of Currents in Northern Black Sea,October 2016

The paper presents the results of an analysis of hydrological data obtained on cruise 89 of the R/V Professor Vodyanitskii from September 30 through October 19, 2016, in the central area of the northern Black Sea. Currents were measured using a lowered acoustic Doppler current profiler (LADCP) to a depth of 350 m. Examples of the current velocity profiles and conditional density at individual stations are presented. The averaged characteristics of the vertical current structure in the seasonal and permanent pycnoclines are discussed. The isopycnally averaged kinetic energy (KE) demonstrates an almost linear dependence on the conditional density (σ_θ). In the seasonal pycnocline, EK = 0.2–0.013σ_θ; in the permanent pycnocline, EK = 0.12–0.007σ_θ. An interpretation is given for the variability of the kinetic energy with depth. It is shown that the maxima of the averaged vertical shear profile correspond to the occurrence depth of the seasonal and permanent pycnoclines. The mean Richardson number has a value of ~10 in the upper sea layer and decreases with depth, assuming a value of ~3 at the 300 m horizon. The estimate for the vertical turbulent diffusion coefficient from the simplified model shows its increase with depth.     

Light absorption by phytoplankton,non-algal particles and dissolved organic matter at the Patagonia shelf-break in spring and summer

Satellite image studies and recent in situ sampling have identified conspicuous phytoplankton blooms during spring and summer along the Patagonia shelf-break front. The magnitudes and spectral characteristics of light absorption by total particulate matter (phytoplankton and detritus) and colored dissolved organic matter (CDOM) have been determined by spectrophotometry in that region for spring 2006 and late summer 2007 seasons. In spring, phytoplankton absorption was the dominant optical component of light absorption (60–85%), and CDOM showed variable and important contributions in summer (10–90%). However, there was a lack of correlation between phytoplankton biomass (chlorophyll-a concentration or [chl a]) and the non-algal compartment in both periods. A statistically significant difference was found between the two periods with respect to the CDOM spectral shape parameter (S_cdom), with means of 0.015 (spring) and 0.012 nm^?1 (summer). Nonetheless, the mean S_cdm values, which describe the slope of detritus plus CDOM spectra, did not differ between the periods (average of 0.013 nm^?1). Phytoplankton absorption values in this work showed deviations from mean parameterizations in previous studies, with respect to [chl a], as well as between the two study periods. In spring, despite the microplankton dominance, high specific absorption values and large dispersion were found (a*_ph(440)=0.04±0.03 m² mg [chl a]^?1), which could be attributed to an important influence of photo-protector accessory pigments. In summer, deviations from general trends, with values of a*_ph(440) even higher (0.09±0.02 m² mg [chl a]^?1), were due to the dominance of small cell sizes and also to accessory pigments. These results highlight the difficulty in deriving robust relationships between chlorophyll concentration and phytoplankton absorption coefficients regardless of the season period. The validity of a size parameter (S_f) derived from the absorption spectra has been demonstrated and was shown to describe the size structure of phytoplankton populations, independently of pigment concentration, with mean values of 0.41 in spring and 0.72 in summer. Our results emphasize the need for specific parameterization for the study region and seasonal sampling approach in order to model the inherent optical properties from water reflectance signatures.     

黄海、渤海底层温、盐度与其垂直平均值的统计关系

文中根据黄渤海区１９５９～１９８２年间水温和盐度垂向剖面历史资料，建立了在给定水深下底层温、盐度与其对应的垂向平均值间的线性关系，进而对所获得的系数建立其与水深和时间（月份）间非线性关系，最终发展了底层温、盐度与其平均值、水深和时间的普适经验关系式ＴＨ（Ｓｕ）＝ｆ（ＴＡ（ＳＡ），Ｈ，ｔ），为建立避开来自海面的热量、质量和动量在会向上分配的复杂物理过程的简易底层温、盐度二维数值预报模式奠定基础。     

台湾海峡南部海区1997年8月温度、盐度的垂直结构

对台湾海峡南部海区1997年8月的CTD资料进行了温、盐垂直结构分析.结果表明:大部分调查海域存在温、盐跃层;台湾浅滩南部和东南部海域的温、盐垂直结构较为复杂,这与多种水系在此交汇有关,但下层海水的低温高盐特性仍表明这一海域是上升流区;泉州外海的下层存在低温高盐海水的爬升,但没有影响到表层.     

混合坐标大洋环流模式Hycom的坐标选取与参数化设置敏感性试验

在移植并拓展建立一个全球范围Hycom模式的基础上,针对混合坐标的选取和参数化设置设计了几组敏感性试验,初步揭示了选取不同的混合坐标和设置不同的参数值对模式模拟结果的影响.研究表明:混合坐标中的z坐标的设置差异对混合层的模拟影响较大;对混合坐标中的等密度坐标而言,前几层取值稍小些会提高模拟效果:动量耗散的辐散速度是影响模拟结果的重要参数.