EFFECT OF LIGHT INTENSITY ON THE TOTAL LIPID AND FATTY ACID COMPOSITION OF SIX STRAINS OF MARINE DIATOMS     

梁英麦康森  孙世春于道展 《中国海洋湖沼学报》2001,19(3):249-254

The effect of light intensity ( 1500 Ix and 5000 Ix) on the total lipid and fatty acid composition of six strains of marine diatoms Cylindrotheca fusiformis (B211 ), Phaeodactylum tricornutum (Bl14, Bl18 and B221) Nitzschia closterium (B222) and Chaetoceros gracilis (B13) was investigated.The total lipids of B13, Bl14, and B211 grown at 5000 Ix were lower than those grown at 1500 Ix. No evident changes were observed in Bl18, B221 and B222. Fatty acid composition changed considerably at different light intensity although no consistent correlation between the relative proportion of a single FA and light intensity. The major fatty acids of the 6 strains were 14:0, 16:0, 16:l(n- 7) and 20:5(n-3) . Cylindrothecafusiformis had high percentage of 20:4n - 6 (9.2 - 10.9% ) . The total polyunsaturated fatty acid /rl all 6 strains decreased with increasing light intensity. The percentage of the highly unsaturated fatty acid eicosapentaenoic acid (EPA) decreased with increasing light intensity in all strains except Chaetoceros gracilis.  相似文献   

一种基于Ohta-Okamoto签名的门限群签名方案     

彭银桥  甘元驹  陈月峰  彭凌西  邓锐 《广东海洋大学学报》2005,25(4):76-78

在修改的Ohta_Okamoto数字签名方案基础上,设计出了一个新的(t,n)门限签名方案。该方案具有可验证性和防止内部成员合谋攻击;而且验证者在验证群签名的有效性计算的复杂性与一般个人签名方案一样。该方案的安全性是基于大整数的因式分解,因此在计算上是安全的。  相似文献   

Energy flow in Branchiura sowerbyi (Oligochaeta: tubificidae) in a shallow macrophyte-dominated lake, Biandantang Lake     

Yan Yunjun  Liang Yanling 《中国海洋湖沼学报》2004,22(4):403-407

The energy flow ofBranchiura sowerbyi was studied for the first time in China in a shallow macrophytic lake, Biandantang Lake, Hubei Province. The energy flow was calculated from the measurement of flesh production (12.5241kJ/m²a), egestion (517.7302kJ/m²a), metabolism (38.3273 kJ/m²a), and excretion (4.3798kJ/m²a). The net growth efficiency of the species is about 22.7%, which accords well with the generally reported value for oligochaetes. In addition, the relationship between starvation respiration (R, mgO₂/ind·d), wet weight (Ww, mg) and temperature (T, °C) were also measured, with the regression function beingR=0.008Ww^0.736 e^0.050T. Project supported by NSFC (30270278, 3960019), the foundation of the government of Hubei Province (No. 2000J109), and the foundation of Ecological Station, CAS in the Institute of Hydrobiology.  相似文献   

ENERGY FLOW OF BELIAMYA AERUGINOSA IN A SHALLOW ALGAL LAKE, HOUHU LAKE （WUHAN, CHINA）     

Yan Yun-jun  Liang Yan-ling  Wang Hong-zhu 《中国海洋湖沼学报》2001,19(3):243-248

The energy budget ofBellamya earuginosa in a shallow algal lake, Houhu Lake (Wuhan, China) was investigated by the measurement of flesh production (32.8 kJ/(m²·a)), egestion (337.7 kJ/(m²·a)), metabolism (246.7 kJ/(m²·a)), and estimation of excretion (21.4kJ/(m²·a)). The net growth efficiency of the species is about 10.9%, which accords with the generally reported value for gastropods. In addition, the relationships between starvation respiration (R, mgO₂/(Ind·d)), body weight (Wd, mg in dry wt) and temperature (T, °C) were also determined. The regression equationR=0.044Wd ^0.537 e ^0.061T was obtained by the least square method, The measured SDA of the species is 26.51% of its gross metabolism. Project No. 3960019 and 39430101 supported by NSFC and also a granted for the East Lake Ecological Experimental Station, CAS, Wuhan.  相似文献   

AREAL DIFFERENTIATION AND CONSTRUCTION OF OASIS AGRICULTURAL ECOSYSTEM IN THE SHIYANG RIVER BASIN     

张维祥  梁智睿 《中国地理科学(英文版)》1993,3(4):357-364

On the basis of the study on areal differentiation of the natural environment of oasis agriculture ecosystems in the Shiyang River Basin, this paper comparatively analyzes the natural productivities, water economic benefits, production efficiency, ecological stabilities and developmental conditions of the Wuwei Oasis agricultural ecosystem in the middle reaches of the river basin and the Minqin Oasis agricultural ecosystem in the lower reaches. Under a same management level and investment of . material and energy, primary productiveness and economic benefits of the former are higher than those of the latter. Construction directions of Wuwei and Minqin oases should be different in order to alleviate the water- use contradiction between the middle and lower reaches. The construction objective of Wuwei Oasis should be efficient irrigated farming production system and Minqin Oasis should become a mixed forestry-pastoral-farming ecosystem taking ecological protection as its major function.  相似文献   

东秦岭二郎坪群中火山成因块状硫化物矿床地质地球化学特征及其成因讨论   总被引：4，自引：1，他引：3  

燕长海  徐勇航  彭翼  赵太平 《矿床地质》2008,27(1):14-27

二郎坪群是东秦岭造山带重要的组成部分,其火山建造中广泛发育有火山成因块状硫化物(VMS)矿床.文章总结并分析了南阳盆地东、西两侧二郎坪群中3个典型矿床(刘山岩、水洞岭和上庄坪)的研究资料,把二郎坪群VMS矿床分为3类:Zn-Cu型矿床(刘山岩矿床);Zn-Cu型与Zn-Pb-Cu型矿床(水洞岭矿床);Zn-Pb-Cu型矿床(上庄坪矿床).从刘山岩矿床到水洞岭矿床,再到上庄坪矿床,铜的含量减少,铅的含量增多.二郎坪群VMS矿床矿石富集LREE、Ce负异常及Eu正异常,说明矿床为热液成因.石英和重晶石中流体包裹体的氢氧同位素特征表明,成矿流体主要来自建造水,南阳盆地以西,矿床成矿流体中伴有较多古大气降水.矿石的硫同位素特征说明,二郎坪群VMS矿床中的硫可能为地幔岩浆硫和海水硫的混合硫.围岩与矿石的铅同位素组成基本一致,说明矿石和围岩可能来源于相似的物源区,成矿元素主要来源于地幔或下地壳深源物质,而水洞岭矿床明显有上地壳浅源物质的混染.研究表明,南阳盆地以西的水洞岭和上庄坪矿床可能形成于大陆边缘海环境,盆地规模较小,受陆源物质影响较大;而南阳盆地以东的刘山岩矿床可能形成于远洋盆地,盆地到达成熟阶段.用地震泵模式可解释二郎坪群VMS矿床的成因机制.  相似文献   

湖北徐家山锑矿床流体包裹体特征及其意义     

沈能平  彭建堂  袁顺达  张东亮  胡瑞忠  王国强 《矿床地质》2008,27(5):570-578

文章利用激光拉曼光谱和显微测温学方法,对湖北徐家山锑矿床成矿期的石英、重晶石和方解石中的流体包裹体进行了研究。研究表明,这些矿物中的流体包裹体主要有纯液体包裹体和液体包裹体(气相 液相)2类,其液体包裹体的气相成分为H2O±CO2±N2;石英、重晶石和方解石的均一温度分别为134~258℃、154~259℃和145~230℃,主要集中于150~200℃;流体的盐度w(NaCleq)和密度分别集中于3%~6%和0.90~0.96g/cm3。流体包裹体资料揭示出该矿床为典型的中低温热液锑矿床,其成矿流体为中低温、低盐度、中等密度热液。结合H、O、Sr、Pb同位素等研究结果,进一步推断该成矿热液主要是经深部循环演化的大气降水。  相似文献   

湘中奥陶纪锰矿带成矿特征及资源前景     

彭三国  付群和  张殿春 《矿床地质》2008,27(5):622-630

湘中奥陶纪沉积锰矿带位于湖南省安化县、桃江县、宁乡县境内,呈近EW向展布,矿带内锰矿以质量好而著称。该成矿带的成锰沉积盆地受控于加里东期张性断裂系统,为一断陷盆地。盆地内发育一组NW向同沉积断裂,形成了一系列断陷槽,控制了沉积岩相的分布。锰矿主要产于盆地中心亚相的黑色页岩夹碳酸锰矿微相内。据矿带中锰矿的地质和地球化学特征以及微量元素和碳、氧、锶同位素组成,笔者认为,该锰矿属于热水沉积成因。综合对比表明,该成矿带具有良好的成矿条件和值得注意的资源潜力,有可能发展为大型锰成矿带。  相似文献   

冈底斯驱龙斑岩铜钼矿床的岩浆侵位中心和矿化中心:破裂裂隙和矿化强度证据   总被引：8，自引：1，他引：7  

肖波  李光明  秦克章  李金祥  赵俊兴  刘小兵  夏代祥  吴兴炳  彭震威 《矿床地质》2008,27(2):200-208

驱龙斑岩铜钼矿床是迄今为止在西藏冈底斯成矿带上发现的规模最大的铜矿床.文章根据对驱龙矿区各类岩石破裂裂隙的野外实测数据,结合矿区已有钻孔品位资料,分别绘制了矿区地表破裂裂隙等值线图、走向投影图及梅花图、钻孔5 000 m海拔标高水平切面Cu、Mo品位等值线图.研究结果表明,驱龙斑岩铜钼矿床的岩石中破裂裂隙相当发育,连成一片,没有明显的多个高值中心,空间上破裂裂隙呈放射状产出;5 000 m海拔标高水平切面显示Cu、Mo矿化较强、较均匀,矿化呈面状,为典型的由单一斑岩体侵位造成的中心式矿化特征.据破裂裂隙和Cu、Mo矿化空间分布,可确定驱龙矿区岩浆中心和矿化中心均位于钻孔405、1205、801、809所围成的矩形区域附近.  相似文献   

An experimental study of the grain-scale processes of peridotite melting: implications for major and trace element distribution during equilibrium and disequilibrium melting   总被引：1，自引：0，他引：1  

Mauro Lo Cascio  Yan Liang  Nobumichi Shimizu  Paul C. Hess 《Contributions to Mineralogy and Petrology》2008,156(1):87-102

The grain-scale processes of peridotite melting were examined at 1,340°C and 1.5 GPa using reaction couples formed by juxtaposing pre-synthesized clinopyroxenite against pre-synthesized orthopyroxenite or harzburgite in graphite and platinum-lined molybdenum capsules. Reaction between the clinopyroxene and orthopyroxene-rich aggregates produces a melt-enriched, orthopyroxene-free, olivine + clinopyroxene reactive boundary layer. Major and trace element abundance in clinopyroxene vary systematically across the reactive boundary layer with compositional trends similar to the published clinopyroxene core-to-rim compositional variations in the bulk lherzolite partial melting studies conducted at similar P–T conditions. The growth of the reactive boundary layer takes place at the expense of the orthopyroxenite or harzburgite and is consistent with grain-scale processes that involve dissolution, precipitation, reprecipitation, and diffusive exchange between the interstitial melt and surrounding crystals. An important consequence of dissolution–reprecipitation during crystal-melt interaction is the dramatic decrease in diffusive reequilibration time between coexisting minerals and melt. This effect is especially important for high charged, slow diffusing cations during peridotite melting and melt-rock reaction. Apparent clinopyroxene-melt partition coefficients for REE, Sr, Y, Ti, and Zr, measured from reprecipitated clinopyroxene and coexisting melt in the reactive boundary layer, approach their equilibrium values reported in the literature. Disequilibrium melting models based on volume diffusion in solid limited mechanism are likely to significantly underestimate the rates at which major and trace elements in residual minerals reequilibrate with their surrounding melt. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献