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81.
综述了近10a国内外有关重金属、氨态氮、亚硝酸盐、有机污染物等几种环境因子对虾蟹类非特异性免疫影响的研究成果,以期为通过改善养殖环境条件提高虾蟹类自身免疫抗病力提供理论依据.同时,为进一步深入开展该领域的研究工作积累资料. 相似文献
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ZHENG Lianming LIN Yuanshao LI Shaojing CAO Wenqing XU Zhenzu HUANG Jiaqi 《海洋学报(英文版)》2009,28(1):109-115
Aequorea taiwanensis, a new hydrozoan species from the Taiwan Strait was described using morphological and molecular characteristics. Both morphological and mitochondrial cytochrome oxidase subunit I (mtCOI) data supported A. taiwanensis n. sp. as a valid species. Sequence divergence and genetic distance of A. taiwanensis n. sp., A. papillata and A. conica were analysed based on the mtCOI gene sequences. The mtCOI sequences from these three species of the genus Aequorea showed high variation frequency, with sequence divergences ranging from 9.10% to 11.9%, and pairwise genetic distances ranging from 0.097 to 0.130. MtCOI sequence analysis provided diagnostic molecular systematic characteristics for accurate identification and discrimination of the species of Aequorea or their populations, and will be used to resolve evolutionary relationships among them.It was suggested that 10%—20% pairwise mtCOI sequence differences indicated the specieslevel divergence among congeneric species in the Hydromedusae. 相似文献
84.
Hypoxia in the East China Sea: one of the largest coastal low-oxygen areas in the world 总被引:18,自引:0,他引:18
Anoxia and hypoxia have been widely observed in estuarine and coastal regions over the past few decades; however, few reports have focused on the East China Sea (ECS). In June and August 2003, two cruises sampled at stations covering almost the entire shelf of the ECS to examine hypoxic events and their potential causes. In August, DO concentrations <2-3 mg l(-1) covered an area estimated at greater than 12,000 km(2) (or 432 km(3) volume). In contrast, water column DO concentrations exceeded 4 mg l(-1) throughout most of the shelf region. A sharp density gradient was observed under the mixed layer in August, restricting vertical re-aeration across this strong pycnocline. Oxygen depletion events, such as that described here for the ECS shelf, are fueled by decomposition of newly produced marine and river-borne biogenic substances (as well as older residual organic matter) deposited to the bottom waters. 相似文献
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南北半球副热带高压对赤道东太平洋海温变化的响应 总被引:16,自引:0,他引:16
本文利用1974年1月到1996年12月重分析(NOAANCEP-NCARCDAS-1)全球500hPa位势高度场资料,及同期赤道太平洋各海区SST资料,研究了南北半球副热带高压的变化特征及其对赤道东太平洋SST变化的响应。结果表明,全球副热带高压的变化及对SST的响应,在南北两个半球有很好的一致性。全球副热带高压强度的变化与超前3个月SST的正相关最为显着。对SST响应最强烈的区域主要在南北纬30°之间的低纬,低纬地区局地SST对副热带高压也有强烈的影响。从10°到30°纬度,对SST的响应分别落后于赤道2~9个月。在中、高纬大气环流的响应表现为波列特征,对暖SST及冷SST的响应波列基本相反,但对暖SST的响应更为显着。海温和副热带高压的月际持续性有明显的季节变化,副热带高压9-10月的相关障碍可能与NinoC区SST8-9月的相关障碍低点有关。 相似文献
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88.
Xianrong Zhang Jianming Gong Zhilei Sun Jing Liao Bin Zhai Libo Wang Xilin Zhang Cuiling Xu Wei Geng 《海洋学报(英文版)》2021,40(9):23-32
Cold seeps are pervasive along the continental margin worldwide,and are recognized as hotspots for elemental cycling pathway on Earth.In this study,analyses of pore water geochemical compositions of one-400 cm piston core(S3) and the application of a mass balance model are conducted to assess methane-associated biogeochemical reactions and uncover the relationship of methane in shallow sediment with gas hydrate reservoir at the Makran accretionary wedge off Pakistan.The results revealed that approximately 77% of sulfate is consumed by the predominant biogeochemical process of anaerobic oxidation of methane.However,the estimated sulfate-methane interface depth is-400 cm below sea floor with the methane diffusive flux of 0.039 mol/(m~2·a),suggesting the activity of methane seepage.Based on the δ~(13)C_(DIC) mass balance model combined with the contribution proportion of different dissolved inorganic carbon sources,this study calculated the δ~(13)C of the exogenous methane to be-57.9‰,indicating that the exogenous methane may be a mixture source,including thermogenic and biogenic methane.The study of pore water geochemistry at Makran accretionary wedge off Pakistan may have considerable implications for understanding the specific details on the dynamics of methane in cold seeps and provide important evidence for the potential occurrence of subsurface gas hydrate in this area. 相似文献
89.
福建罗源湾浮游桡足类的分布 总被引:3,自引:2,他引:3
本文利用1986年11月至1987年10月在福建罗源湾采集的浮游生物样品,分析研究了该海区桡足类的种类组成和数量分布。结果表明,其优势种大网为中华哲水蚤、亚强真哲水蚤、真刺唇角水蚤和太平洋纺锤水蚤,中网为强额拟哲水蚤、小型拟哲水蚤、短角长腹剑水蚤。桡足类总量年高峰大、中网分别为2个和1个。中网桡足类与叶绿素a、温度和盐度等因素显著相关。 相似文献
90.
White dwarfs are the evolutionary endpoint of the low-and-medium mass stars. In the studies of white dwarfs, the mass of white dwarf is an important physical parameter. In this paper, we give an analysis about the velocity distribution of DA white dwarfs in the Sloan Digital Sky Survey (SDSS), and hope to find the relation between mass and velocity distribution of white dwarfs. We get the radial velocity and tangential velocity of every DA white dwarf according to their proper motion and spectral shift. Through analyzing the velocity distribution of DA white dwarfs, we find that the small-mass white dwarfs, which are produced from the single-star evolution channel, have a relatively large velocity dispersion. 相似文献