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1.
以小球藻(Chlorela sp.)和三角褐指藻(Phaeodactylum tricornutum)为研究对象,比较了其合成有机物中长链烷烃和脂肪酸的组成和丰度.结果表明,小球藻中的脂肪酸以14:0、16:1、16:0、20:5为主,其中16:0饱和脂肪酸的质量分数为43%,具绝对优势.三角褐指藻中的脂肪酸组成显示16:1、16:0、20:5占优势.其中16:1和16:0两种脂肪酸含量相当.长链烷烃在两种藻中均以低碳链分布,优势组分集中在C16～C21碳链之间.小球藻中C17具有明显丰度,而三角褐指藻中长链烷烃含量差别不大.两种微藻中的长链烷烃组成都没有奇偶优势碳链分布的特征,这与陆源植物中长链烷烃明显的奇偶优势分布特征相比,具有显著的差异.这些结果对判断不同微藻在食物链中的营养级别,以及对以长链烷烃和脂肪酸为生物标志物研究我国近岸海沉积物中有机物的来源均具有实际意义. 相似文献
2.
中国龙虾叶状幼体营养初步试验 总被引：6，自引：0，他引：6
通过多次对比重复试验,对用对虾液汁培育金藻Ｄｉｃｒａｔｅｉａｓｐ、扁藻Ｐｌａｌｙｍｏｍａｓｓｐ,用金藻、扁藻培育丰年虫Ａｒｌｅｍｉａ ｓａｌｉｎａ幼体和毛蚶Ｓｃａｐｈａｒｃａ ｓｕｂｃｒｅｎａｔａ,以及用金藻扁藻、丰年虫投喂中国龙虾Ｐａｎｕ欤椋颍酰? ｓｔｉｍｐｓｏｎｉ早期叶状幼体进行了探讨。结果表明,叶状幼体进入第Ⅲ 期后交替掺喂毛蚶卵巢刀额新对虾Ｍｅｔａｐｅｎａｅｕｓｅｎｓｉｓ肉,取得较好的培育 相似文献
3.
刀额新对虾幼体的培育及特点 总被引：3，自引：0，他引：3
在水温26～28℃,pH8.1～8.3,海水盐度27.6～29.7的条件下,刀额新对虾幼体从无节幼体第一期(N_1)培育至仔虾幼体第一期(P_1),历时10d,成活率81.9%;至仔虾幼体第8～10天(P_(8～10)),成活率为80%。刀额新对虾幼体发育具有许多不同于其他对虾类幼体的发育特点,其糠虾期身体仅稍倾斜而不呈倒悬状态,极少摄食丰年虫无节幼体,直至P_(3～4)摄食丰年虫幼体现象才较多见。 相似文献
4.
刀额新对虾染色体核型及细胞核DNA含量 总被引：9，自引：0，他引：9
以刀额新对虾胚胎、无节幼体、卵巢、精巢等为材料 ,空气干燥法制备染色体 ,并初步进行核型分析。结果表明 ,刀额新对虾的染色体数目为 2n=78,n =39,核型为 2n=78=40M 1 0SM 1 4ST 1 4T。以刀额新对虾血淋巴、卵巢、肌肉、鳃为材料 ,以鸡血细胞为DNA标准 (2 50pg/ 2c) ,使用PartecCCAⅡ型流式细胞仪测定了刀额新对虾细胞的基因组DNA含量 ,其值为鸡血细胞的 1 75倍 ,绝对含量为 4 375pg/ 2c。 相似文献
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通过模拟中肋骨条藻(Skeletonema costatum)和沉积物共存体系,探究了富营养化条件下,藻类与沉积物对无机磷的吸收/吸附作用的相互影响。采用自制的金汞伏安微电极测定了藻与沉积物共存体系中溶解氧(DO)的含量变化,分析了体系中溶解氧含量变化与磷消耗速率以及沉积物中磷形态分布变化之间的关系。结果表明,在本课题研究范围内,共存的藻类与沉积物互相影响彼此对磷的消耗过程,1.0×10^4、5.0×10^4和1.0×10^5 cells/mL三种初始藻密度的中肋骨条藻(Skeletonema costatum)48 h后对磷的吸收百分比分别达54.7%、73.4%、93.8%,添加沉积物后分别降至21.3%、34.1%和51.9%;沉积物对培养基介质中的无机磷的吸附百分比为42.5%,加入三种不同藻密度的藻体后分别降至9.1%、2.8%及0.3%。高密度藻与沉积物共存体系的耗磷速率与体系DO含量呈显著负相关(p<0.05)。体系中DO浓度降低会促进沉积物中Fe-P向水体中释放,从而导致沉积物中铁结合态磷(Fe-P)含量的降低。可交换态磷(Ex-P)、有机磷(OP)和Fe-P是藻类存在时沉积物向水体中较易释放的形态。 相似文献
6.
在春季,以中肋骨条藻和海洋原甲藻培养中华哲水蚤,以饥饿培养作为对照,测定了饵料的脂肪酸和挥发性不饱和醛类的组成和含量、雌体的产卵率和卵的孵化率,试图探讨藻类生化组成对桡足类繁殖的影响。结果表明,中肋骨条藻单不饱和脂肪酸、?16脂肪酸的含量相对较高,而海洋原甲藻则具有更高含量的总脂肪酸、多不饱和脂肪酸、?ω3、?ω6、?18脂肪酸。中肋骨条藻和海洋原甲藻分别测得了6种和3种不饱和醛类,二者醛类总含量分别为1438.95μg/g和114.58μg/g。在饥饿的情况下,中华哲水蚤的产卵会停止。中华哲水蚤在中肋骨条藻和海洋原甲藻培养下并没有表现出产卵率和孵化率的差异,一方面说明并非所有的硅藻都会对桡足类的繁殖产生抑制作用,另一方面说明藻类进入桡足类体内以后并未因其生化组成的差异对卵的孵化产生影响。中肋骨条藻培养下中华哲水蚤具有更高的死亡率,表明硅藻在浓度较高时会对桡足类的存活产生影响。 相似文献
7.
化感作用对中肋骨条藻与东海原甲藻竞争演替的影响 总被引：2，自引：2，他引：0
为了检验化感作用对赤潮藻类生长和竞争的影响,对中肋骨条藻滤液进行了培养实验,结果显示中肋骨条藻滤液对其自身的生长呈现出化感抑制现象,而且抑制作用在磷限制条件下尤为显著。自化感作用的程度与藻的生长阶段有关,指数期滤液对中肋骨条藻的抑制作用比衰亡期滤液略强。不同滤液添加比例实验进一步验证了中肋骨条藻自化感作用的存在。降解实验表明在某些机制的作用下,化感物质会随时间而发生降解。在所有的滤液培养实验中,中肋骨条藻对东海原甲藻的生长没有明显影响,这可能是由于东海原甲藻对滤液中的化学物质有较强的耐受能力。中肋骨条藻滤液的共培养实验结果显示,中肋骨条藻与东海原甲藻表现出演替现象,东海原甲藻最终获得竞争优势。实验结果表明化感作用可能会影响中肋骨条藻和东海原甲藻的竞争演替。 相似文献
8.
两种甲藻和两种硅藻脂肪酸组成的比较研究 总被引：3，自引：0，他引：3
研究了4种海洋微藻的脂肪酸组成。研究结果显示,锥状斯氏藻(Scrippsiella trochoidea)和海洋原甲藻(Prorocentrum micans)的主要脂肪酸有16:0、18:4ω3、18:5ω3、20:3ω6、22:6ω3,中肋骨条藻(Skeletonema costatum)和角毛藻(Chaetoceros sp.)的主要脂肪酸为14:0、16:0、16:1ω7、20:5ω3。两种甲藻和两种硅藻分别都表现出典型的甲藻门和硅藻门的脂肪酸特征。从总脂肪酸、PUFA、ω3和ω6脂肪酸的含量来看,单位干质量的两种甲藻能够比两种硅藻提供更多的脂肪酸类营养物质。但是某些动物生长发育所必需的脂肪酸(如20:5ω3)在硅藻中的含量却高于甲藻。因此实际应用中单种饵料往往不能提供足够的营养物质,通常需要将不同饵料混合以获得营养价值更高的饵料。对4种微藻的脂肪酸组成进行聚类分析和主成分分析,结果不仅反映了4种微藻在分类上亲缘关系的远近,也反映了几种微藻各自的脂肪酸组成特征。 相似文献
9.
十四株海洋微藻脂肪酸组成的研究 总被引：5，自引：0，他引：5
对 4个门的 14株 (红藻门 8株 ,甲藻门 1株 ,隐藻门 2株 ,绿藻门 3株 )海洋微藻进行了脂肪酸含量测定 ,微藻在确定的条件下生长 ,指数生长末期收获。结果表明 ,各门的微藻都有其独特的脂肪酸特征 :红藻中含有大量的 2 0 :4 n- 6和 2 0 :5n- 3,其中紫球藻 R2 5含量最高 ,占总脂肪酸的4 9.8% (AA占总脂肪酸的 2 0 .5% ,EPA占总脂肪酸的 2 9.3% )。隐藻的主要脂肪酸是 16 :0、18:1n- 9、18:3n- 3、18:4 n- 3、2 0 :5n- 3、2 2 :5n- 3。与其它甲藻有别的虫黄藻 ,18:4 n- 3含量很少并且不含EPA,其主要合成的是 16 :0、18:1n- 9和 2 2 :6 n- 3。 C16和 C18的不饱和脂肪酸是本实验研究的 3株绿藻的主要脂肪酸 相似文献
10.
哈氏仿对虾 (Parapenaeopsishardwikii)的C、N和H含量的平均值分别为 40 .0 2 %± 1 .2 2 %、1 0 .0 4%± 0 .42 %和 5 .5 4%± 0 .2 0 % ;哈氏仿对虾的C含量有明显的季节变化 ,同样体长的雌虾春季的平均C含量较夏季的高。同一季节雌雄虾体平均C含量大致相同。而且它们的C含量变化与性产物的量有一定的关系。哈氏仿对虾产卵期的C∶N和C∶H的元素比率较产卵前和产卵后为高。哈氏仿对虾的C含量较长毛对虾 (Penaeuspenicillatus)和日本对虾 (P .japenicus)的低 ,而比刀额新对虾 (Metapenaeusensis)稍高 ;其N、H含量均比这 3种对虾略低。 相似文献
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Statistical characteristics of the irradiance of an electromagnetic wave propagating in a dissipative random medium are studied. For the propagation regime of strong irradiance fluctuations, asymptotic expressions are obtained for the second statistical moment of the irradiance. The behavior of the relative variance of irradiance fluctuations is analyzed for different propagation conditions. It is shown that, if the outer scale of turbulence exceeds the maximum correlation length of irradiance fluctuations because of random attenuation, no saturation of the relative variance of irradiance fluctuations to unity occurs. Depending on the ratio between the structure characteristics of the real and imaginary parts of the permittivity and on the degree of their correlation, the relative variance of irradiance fluctuations in this case may be either an increasing, or a decreasing, or a nonmonotonic function of the path length, deviating from the level corresponding to a transparent turbulent medium. It is found that the saturation of the relative variance of irradiance fluctuations to unity in a randomly absorbing medium occurs in the region of strong fluctuations if the correlation length of irradiance fluctuations is greater than the outer scale of turbulence. 相似文献
13.
Saturation of crab traps: reduced entry and escapement 总被引：1，自引：1，他引：1
14.
为了探讨甲烷通量或SMT对自生碳酸盐岩埋深和水合物饱和度的影响，综述了第六届国际水合物论文集中的相关论文得出如下结论：海底发生富含甲烷的孔隙水渗漏和甲烷气的排出，有利于海底自生碳酸盐岩的沉积；甲烷通量和海底侵蚀可能控制了自生碳酸盐岩和SMT的埋深，然而，甲烷通量或SMT埋深是否控制沉积物中水合物的饱和度目前尚无定论。 相似文献
15.
Gao Bingchun Gong Zhiping Huang Xiaoqin Head of the Medical Department The No. Hospital of PLA Shanghai
Vice Head of the Medical Department The No. Hospital of PLA Shanghai
Resident Physician The No. Hospital of PLA Shanghai 《中国海洋工程》1991,(3)
The study deals with the observation of the changes in the electrical activities of 8 healthy divers in the 80 msw saturation-100 msw excursion heliox dive by DCG. Results showed significant changes in the 24 h of average heart rate, the decrease of heart rate at saturation storage depth and decompression periods being 15.5% and 19.7% respectively. Fortuitous supraventricular premature beats appeared in 8 divers and ventricular premature beats in 5 divers during exposure. Transient ischemic ST-T changes in 6 divers occurred repeatedly during diving operations. The discussion puts up the view that the ST-T changes were due to the stress reaction of the body induced by the combined effect of such stress factors as hyperbaric pressure per se, high partial pressure of oxgen, noise and the closed restricted chamber environment. 相似文献
16.
A common fault of atmospheric general circulation models (AGCMs) is an overestimation of orographic precipitation. One basic reason is that water vapour advection schemes do not use information about the local temperature. When water vapour is advected from a warm grid point to a colder one, supersaturation may occur on the way, and the water vapour advected may partly precipitate before reaching the latter. This process is particularly important when moisture is advected upward mountain slopes along terrain‐following coordinates. Not taking it in account, i.e., letting all the moisture reach the colder point, leads to artificial drying of the windward valleys and foothills, and to overestimation of rainfall over summits and plateaux. This spurious behaviour is amplified by the resulting biases in the circulation, due to misplacement of the moisture convergence. It is a general bias, although its magnitude may be reduced, for instance when σ-coordinates are replaced by hybrid coordinates, or increased by highly diffusive schemes such as the upstream finite differencing. A simple way of correcting this bias is to test the advected water vapour with respect to saturation values, and redistribute it accordingly over the grid points found along the advecting path. This method is tested on a finite difference model using σ-coordinates and an upstream advection scheme. The effect on the distribution of moisture and rainfall is dramatic: precipitation is displaced from summits and plateaux to slopes and foothills, leading to much more realistic patterns, in particular for the Indian and Amazonian monsoons. 相似文献
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Settling characteristics of soils carry great importance for geotechnical engineers since sediments properties are formed during the settling of soil particles in an aqueous environment. In this study, settling characteristics of kaolinite are investigated. Different ionic strengths of NaCl, CaCl2 and AlCl3 were considered as a function of pH in aqueous environment of varying solid concentrations. Factors affecting the settling characteristics and fabric of kaolinitic sediments have been identified. The results of the study reveal that kaolinite settles in either flocculated or dispersed forms depending on pH and ion concentration. Flocculated settling occurs in acidic pH due to formation of flocs in edge-to-face structure with increasing positive charges at the particle edges. Dispersed settling occurs in alkaline pHs when ionic strength is low. When ionic strength is increased in alkaline pHs, kaolinite particles settle in flocculated form. Furthermore, the results show that pH has a significant role on the final sediment thickness or void ratio of kaolinite. Densely packed structures in alkaline and loosely packed structures in acidic aqueous environments are formed depending on pH level. Results also show that as the solid concentration increases, the settling rate decreases due to buoyancy effect. Finally, the zeta potential of kaolinite is correlated with the final sediment thickness or void ratio of kaolinite as a function of pH. This correlation proves that there is a good agreement between zeta potential and the final sediment thickness or void ratio, especially when the soil is settled in a dispersed form. 相似文献
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《Marine Georesources & Geotechnology》2006,24(3):203-218
Settling characteristics of soils carry great importance for geotechnical engineers since sediments properties are formed during the settling of soil particles in an aqueous environment. In this study, settling characteristics of kaolinite are investigated. Different ionic strengths of NaCl, CaCl2 and AlCl3 were considered as a function of pH in aqueous environment of varying solid concentrations. Factors affecting the settling characteristics and fabric of kaolinitic sediments have been identified. The results of the study reveal that kaolinite settles in either flocculated or dispersed forms depending on pH and ion concentration. Flocculated settling occurs in acidic pH due to formation of flocs in edge-to-face structure with increasing positive charges at the particle edges. Dispersed settling occurs in alkaline pHs when ionic strength is low. When ionic strength is increased in alkaline pHs, kaolinite particles settle in flocculated form. Furthermore, the results show that pH has a significant role on the final sediment thickness or void ratio of kaolinite. Densely packed structures in alkaline and loosely packed structures in acidic aqueous environments are formed depending on pH level. Results also show that as the solid concentration increases, the settling rate decreases due to buoyancy effect. Finally, the zeta potential of kaolinite is correlated with the final sediment thickness or void ratio of kaolinite as a function of pH. This correlation proves that there is a good agreement between zeta potential and the final sediment thickness or void ratio, especially when the soil is settled in a dispersed form. 相似文献
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为促进海洋环境监测信息化发展,提高实验室资源管理和质量控制水平,文章以山东省海洋环境监测中心研发的实验室信息管理系统(LIMS)为例,概述其在海洋环境监测工作中的应用。研究结果表明:该系统涵盖海洋环境监测工作的全过程和实验室资源管理的主要内容,包括业务任务、样品管理和质控管理等模块,具有功能全面、样品交接快速和准确、质量控制管理到位、预警提醒及时、报表和报告自定义配置、可与大型监测设备对接、全程溯源以及数据管理自动化等特色,应注重其本地化以及后续维护和升级;该系统可提高海洋环境监测质量控制水平,有效管理实验室资源,保证监测数据和资料的真实和准确,具有广阔的应用前景和推广价值。 相似文献