Interactive Effects of Ultraviolet Radiation and Dissolved Organic Carbon on Phytoplankton Growth and Photosynthesis in Sanya Bay,Northern South China Sea

Ocean Science Journal - The effects of a simulated climate change scenario, i.e., increased ultraviolet radiation (UVR) and dissolved organic carbon (DOC), on the growth and photosynthesis of...     

Discrimination of spurious self-correlation in nondimensionalized analyses of fluid dynamical data

Nondimensionalization of variables enables us to treat experiment data much more simply and efficiently by decreasing the number of variables. In some cases, trivial conclusions (which Kenney, 1982, called spurious self-correlation) result from a formal application of dimensional analyses. In contrast, in some cases fully significant conclusions can be derived. We first discuss how to construct nondimensional variables retaining the physical meanings of variables. We then propose simple and efficient methods, especially the use of “spurious triangle (SpT)”, to discriminate between significant conclusions and spurious self-correlations in the analysis of nondimensionalized variables.     

Status of Macrobenthic Community and Its Relationships to Trace Metals and Natural Sediment Characteristics

Laizhou Bay, located in the northwest of Shandong Peninsula, has complex transitional environments between terrestrial and marine ecosystems. In the present study, a total of 122, 131, and 139 species were collected in spring, summer, and autumn 2011, respectively. Species constitutions of macrobenthos were grouped into four phyla, of which annelida were the most abundant phylum, the average biomass proportion of echinodermata was the lowest, and the proportion of important species for mollusca was the highest. The structure of the macrobenthic community showed significant differences between sites, and greater divergence was observed between the third site (S03) and other stations. The ABC plots showed that the biomass curve lay below the abundance curve, and the W‐statistic value was negative. The result of the BOPA index showed that two stations had moderate ecological status in spring and that there were two heavily polluted sites and one moderately polluted site in summer. The BIO‐ENV analyses indicated that the grain‐size fractions together with trace metals (Hg, Pb, Zn, Cu, and Cr) could be considered as the major environmental variables influencing the macrobenthic patterns. The results together demonstrated that the macrobenthic communities in Laizhou Bay were negatively affected, perhaps by the tremendous impact of heavy metals in the sediments.     

中国北部黄海近岸水体周丛硅藻的群落群集动态特征的研究

The colonization features of periphytic diatoms were studied in coastal waters of the Yellow Sea, northern China from May to June 2010, using glass slides as an artificial substratum. Samples were collected at a time interval of 1, 3, 7, 10, 14, 21 and 28 d from two depths of 1 and 3 m. The dynamics of diatom colonization process had a similar pattern in community structure and fitted the logistic model in growth curve at both depths. The maximum abundance and the time for reaching 50% maximum abundance （10 d） showed no significant differences （P〉0.05） between two depths 1 and 3 m. Although the diatom communities repre- sented similar taxonomic composition, they differed in the temporal pattern of structural parameters and in succession dynamics of dominant species between the two layers. The species richness showed significantly higher values during the colonization period more than 14 d, while the species diversity and evenness rep- resented a higher variability with significantly different values （P〈0.05） at a depth of 1 m than at a deeper layer. The results suggest that the diatom colonization follows the logistic model growth curve and differs in colonization features between different depths in the coastal waters, and that the sampling strategy at i m is more effective to detect the ecological features for bioassessment in marine ecosystems.     

中国近海海平面变化与ENSO的关系

利用中国沿海台站潮位和中国近海及赤道太平洋的卫星测高、海表温度、风及气压资料,分析了中国近海海平面变化与ENSO的关系。分析结果表明:中国沿海海平面季节变化受ENSO影响明显,在厄尔尼诺事件期间,中国沿海海平面Sa分潮的振幅明显减小,其中年振幅的历史极小值均出现厄尔尼诺年,不同区域历史极小值出现的年份不同;另外,中国沿海Sa分潮的振幅对厄尔尼诺事件的响应与其强弱有关,在强事件中,响应区域和幅度较大,弱事件中,响应区域和幅度偏小。在厄尔尼诺年,中国沿海海平面多低于相邻年份,并且其年际变化存在明显的2~3a、4~7a、准9a、11a和准19a的周期,其中4~7a的周期在冬春季节震荡最显著,其震荡幅度接近2cm。中国近海海平面与赤道东太平洋区域的海表温度年际变化之间存在反相关关系,其相关系数为-0.42;同时与Nio4和Nio3.4指数序列也呈现反相关关系。针对典型的1997/1998年尼诺事件发生前后的风场和气压场分析发现,尼诺发生前的冬半年,冬季风偏强,气压梯度加强,中国沿海海平面偏低;到了厄尔尼诺的盛期,出现较强的南风异常,气压梯度反向,季风转向,过渡到了厄尔尼诺事件的衰减期,为拉尼娜事件做准备,此时海平面偏高。     

中国近海浮游桡足类中华哲水蚤（Calanussinicus Brodsky）的分子系统地理学和种群遗传结构研究

Planktonic copepod Calanus sinicus is the dominant meso-zooplankton in the Northwest Pacific Ocean. To better understand its population dynamics and phylogeographic patterns, 243 C. sinicus individuals were collected from seven locations across the shelf waters of China and its population genetics was studied by mitochondrial DNA cytochrome oxidase I(mtCOI) sequences analyses. Thirty-nine different sequences, or haplotypes, were detected with moderate haplotype diversity(h=0.749) and low nucleotide diversity(π=0.003) for all populations. The evolutionary divergence between geographic populations varied from 0.24% to 0.37%, indicative of very limited genetic differentiation. Visualized minimum spanning network(MSN) and phylogenetic analysis of all the detected haplotypes did not reveal any clear phylogeographic pattern. Furthermore, AMOVA data showed no significant spatial population differentiation existed among the individuals collected across China shelf waters. Pairwise FST values showed that population collected from northwest of the East China Sea(ECS) displayed a low difference to other populations. Mismatch distribution analyses and neutrality tests indicated that C. sinicus might undergo a demographic/population expansion. No significant population genetic structuring was detected, indicating an extensive gene flow among the C. sinicus populations. Our results provide molecular evidence for the hypothesis that C. sinicus in the northwestern South China Sea in winter is transported from the East China Sea and the Yellow Sea by the China Coastal Current during the northeast monsoon period.     

覆盖中国沿海地区的精细化台风风暴潮模型的研究及适用

精细化风暴潮预报是目前风暴潮预报重点发展方向之一,本文首次建立起了一个覆盖整个中国沿海地区的精细化台风风暴潮数值模型,克服了以往分区域数值模型的不足,该模型在中国沿海地区的分辨率达到300m左右。模型采用了并行计算,并对2012年和2013年灾害性台风风暴潮过程进行了数值检验,计算精度和计算所用时间都能够满足业务化运行的要求。本文同时还根据中国气象局、美国国家气象局等5家主要台风预报机构给出的24h台风预报,对2013年度灾害性台风风暴潮过程进行了24h数值预报检验,检验结果表明:根据中国气象局台风登陆前24h预报可以得到更准确的风暴潮预报结果,其预报结果优于其他各家预报结果。该结论可以为今后的台风风暴潮预报中台风路径的选取提供重要的参考。     

Heave compensation system of lifting pipeline for deep-sea mining based on combined action of vibration absorber and accumulator

ABSTRACT

A heave compensation system combined with a vibration absorber and accumulator is proposed, with regard to the requirement for poly-metallic nodule mining systems at an ocean depth of 6,000?m in China. The principle of the compensation system was analyzed, its main parameters were designed, and its mathematical model was established. The system performance was simulated and analyzed in MATLAB, and the frequency domain characteristics and compensation rate of the system with different volume accumulators, and with or without vibration absorbers, were compared. A simulation test of the compensation system was conducted. The proposed compensation system had a better compensation effect for a random wave interference under level-6 sea conditions, and the compensation rate being more than 72% with optimal system parameters.     

Turning depths of internal tides in the South China Sea inferred from profile data

Theoretically, propagating internal tides in the ocean may reflect at turning depths, where buoyancy frequencies equal tidal frequencies, before colliding with the air-sea interface or rugged bottom topography. Globally, the internal tide lower turning depths（ITLTDs） in the open ocean have been mapped; however, knowledge of the presence of ITLTDs in the South China Sea（SCS） is lacking. In this study, 2 125 high-quality temperature-salinity profiles（including 58 deep-sea hydrographic measurements...     

Hydrodynamic Response and Power Performance of A Heave and Pitch Buoy Wave Energy Converter Under Bimodal Ochi-Hubble Wave Spectrum

In coastal sea areas with the bimodal Ochi-Hubble wave spectrum, such as parts of the China Sea and Indian Ocean,wave energy is the superposition of wind wave and swell. Traditional heaving buoy wave energy converters developed with narrowband wave spectrums suffer from big energy loss in these areas, leading to lower power absorption efficiency and higher generating costs. In contrast, multi-freedom buoy has different resonant frequencies and maximal power capture wave frequencies in different ...