共查询到20条相似文献，搜索用时 46 毫秒
1.
2.
通过羟自由基清除作用、超氧自由基清除作用、还原能力和金属螯合能力等抗氧化活性实验，测定了白色霞水母蛋白的抗氧化活性。实验结果表明：白色霞水母蛋白具有较高的清除羟自由基的能力，蛋白质量浓度为41μg／mL时，清除率可达到85％；白色霞水母蛋白对超氧阴离子的清除作用较弱，蛋白质量浓度为77．7μg／mL时，清除率〈50％；白色霞水母蛋白有较强的还原能力，但没有螯合能力；白色霞水母蛋白的抗氧化活性受温度影响不大，且巯基含量不是影响抗氧化活性的主要因素。 相似文献
3.
有机锡对海洋微藻的生理效应 Ⅰ.三苯基锡和三丁基锡对光合色素含量的影响 总被引：5，自引：0，他引：5
于1991年4月－1992年五月，以金藻和扁藻为材料，用室内一次培养法研究三苯基锡（TPTC）和三丁基锡（TBTC）化合物对光合色素含量的影响。结果表明，两种有机锡对两种藻均有影响，在0．2—0．4μg／L的浓度时有轻微毒性；浓度大于0．5μg／L时，能使光合色素明显减少。对于两种藻叶绿素a72hEC50影响结果：TBTC和TPTC对金藻的均为0．59μg／L；对扁藻的，TBTC是0．87μg／L，而TPTC本出现半效应浓度。对于两种藻的类胡萝卜素72hEC50影响结果：金藻，TPTC是0．57μg／L，TBTC是0．49μg／L；扁藻，TBTC是0．89μg／L，TPTC也未出现半效应浓度。认为，两种有机锡对光合色素有明显的破坏作用。 相似文献
4.
不同大小玉筋鱼摄食、生长和生态转换效率的比较 总被引：4，自引：0，他引：4
本研究将Eggers模型移入实验室大型玻璃钢水槽中，以细脚长蜮为饵料，在流水条件下，比较了黄渤海主要中上层小型鱼类玉筋鱼大小两种体重组的摄食、生长和生态转换效率等生态能量学特征。结果表明：小个体的摄食率、生长率和生态转换效率分别为12．36gW．W．／100g／d或12．44kJ／100g／d，2．22gW．W．／100g／d或9．09kJ／100g／d，0．18％W．W．或0．73％kJ；大个体的摄食率、生长率和生态转换效率分别为9．16gW．W．／100g／d或9．22kJ／100g／d，0．83gW，W．／100g／d或3．41kJ／100g／d，0．09％W．W．或0．37％kJ。不管是以湿重还是以能量计算，小个体的都比大个体的要高。 相似文献
5.
针对化学药剂和粘土絮凝法治理赤潮存在的问题，2002年8月在胶州湾近岸进行了海上围隔杀灭赤潮生物的试验。采用强电离放电的物理方法，将空气中O2和海水中H2O电离离解成OH等自由基，溶解到一部分海水中形成高浓度的羟基溶液，喷洒在围隔内水面上，其比值浓度为4．2mg／L。当海水中羟基浓度达到0．68mg／L时，赤潮生物叶绿素α含量低于检测的最低值。24h后检测杀死灰甲多甲藻、光甲多甲藻、多纹膝沟藻等33种赤潮生物，其致死率达99．8％，其中藻类孢子的致死率达100％，海水水质亦有明显的改善。试验结果表明，羟基溶液是目前治理赤潮可行的、有效的新方法。 相似文献
6.
为了解潮间带沉积物中底栖微藻的现存状况，于2003年10月至2004年4月，分4次测定分析了青岛湾潮间带沉积物中的叶绿素a和脱镁叶绿酸含量。结果表明，0-2cm层沉积物中叶绿素a的含量在1．73-5．71μg/g，脱镁叶绿酸含量在0．02-1．89μg／g，2-5cm层沉积物中叶绿素a的含量在0．51-4．32μg/g，脱镁叶绿酸含量在0．12-1．58μg/g。随深度增加，叶绿素含量减少；叶绿素a是主要存在形式，脱镁叶绿酸含量占叶绿素a含量的10％-75％；同时分析了水质和沉积物粒度对叶绿素含量的影响，结果表明叶绿素的含量和组成比例与水质有关；粒度越细的沉积物，叶绿素含量较高而且稳定。 相似文献
7.
皮状丝孢酵母利用大米草水解液发酵生产微生物油脂 总被引：4，自引：0，他引：4
研究了产油酵母菌皮状丝孢酵母（Trichosporon cutaneum）利用经过简单脱毒处理的大米草水解液，直接发酵生产微生物油脂。首先分别用1％、2％、4％和6％稀硫酸，在122℃水解大米草，大米草／硫酸（固／液比）为10％。结果表明，在6％的酸浓度下水解40rain后总还原糖含量最高。而1％稀硫酸在140℃下水解大米草，2．8h后，水解液中葡萄糖产量达到最高14．2g／L。然后将该条件下大米草水解液冷冻干燥浓缩为不同的倍数，作为皮状丝孢酵母菌的发酵培养基，水解液浓缩倍数为4．0时，产油量最高达6．0g／L。为高效利用大米草，将大米草开发为一种能源植物，提供了新的途径。 相似文献
8.
南日岛海域溶解态Cu、Pb、Cd含量及其与营养盐的关系 总被引：3，自引：0，他引：3
本文首次报道了福建南日岛海域溶解态Cu、PB、Cd的含量，探讨了它们与营养盐的关系。1990年5月溶解态Cu、Pb、Cd的平均含量分别为0．84、0．230、0．023μg／dm3；1990年10月分别为0. 78、0．290、0. 033μg／dm3。其5月溶解态Cu与无机氮N（NO3-＋NO2-＋NH4 ）线性回归的相关式为Cu（μg／dm3）＝-0. 789＋0．328N（μmol／dm3），相关系数r＝0．853，原子比△Cu：△N＝5．17×10－3：1。 相似文献
9.
硒对钝顶螺旋藻生长的影响及其在细胞中的累积和分布 总被引：6，自引：0，他引：6
本文研究了硒对纯顶螺旋藻（Spirulinaplatensis）生长的影响及其在细胞生化组成中的分布。结果表明,当硒浓度低于50mg／dm3时,对钝顶螺旋藻生长的抑制作用不明显,在低浓度下（＜10mg／dm3）可促进其生长;当硒浓度超过50mg／dm3时则起抑制作用,高浓度对藻体起毒害作用。藻细胞中总硒含量与培养液中的硒浓度有关,在0～40mg／dm3范围内,硒含量随着培养液中硒浓度的增加而增加：从0mg／dm3的2．50×10-5（m／m,dw）到40mg／dm3的231．45×10-6（m／m,dw）,至50mg／dm3,又开始降低为174.26×10-6（m／m,dw）;硒在S．platensis生化组成中的分布,以蛋白质含量为最高,可达总硒的49．22％～71．49％,而脂类及碳水化合物-氨基酸中的含量则较低,分别为总硒含量的3．59％～6．18％和1．45％～2．56％,硒在各组成中的含量与培养液中的硒浓度有关,其变化趋势与总硒含量的一致。 相似文献
10.
11.
Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
12.
Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
13.
The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
14.
Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
15.
16.
《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
17.
Hoi-Soo Jung Kap-Sik Jeong Yong-Shik Chu Sung-Hyun Park Ki-Hyune Kim 《Marine Georesources & Geotechnology》2001,19(3):181-195
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors. 相似文献
18.
Shigehisa Nakamura 《Marine Geodesy》2001,24(1):27-33
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake. 相似文献
19.
This study tests the hypothesis that the in situ void ratio of surficial marine sediments may be predicted from shear wave velocity-depth data with a reliability equal to that of other methods currently available. Shear wave velocity is fundamentally controlled by the number of grain-to-grain contacts per unit volume of material and by the effective stress across those contacts. In this study, three previously established empirical formulae are used to predict void ratio from velocity-depth data. Field data were acquired along a transect off the northern Californian coast across which water depth increased from 35 to 70 m and seafloor sediment type varied from sand to silty-sand, respectively. A towed seafloor sled device was used to collect shear wave refraction data, and a marked, systematic decrease in velocity was observed along the line, ranging from 35-70 m/s for the coarse, near-shore material to 25-40 m/s for the finer, offshore deposits. Void ratios predicted from these velocities were compared with data measured directly from box-core samples. Of the formulae used for prediction, two agree remarkably well with the control data. Both predicted and control values increase from 0.6-0.8 for the sandy material to 1.1-1.5 for the silty-sand. Thus, this study does not disprove the hypothesis set and demonstrates the potential of field shear wave velocity-depth data as a means of delineating spatial variation in void ratio for surficial marine sediments in a remote, nondestructive manner. 相似文献
20.
Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ～ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream. 相似文献