南黄海表层沉积物天然湿容重和含水量的分布及其与粒度之间的关系

本文论述了南黄海表层沉积物天然湿容重和含水量的分布,并利用回归分析的方法讨论了容重和含水量与粒度之间的关系。结果表明,容重和含水量与粘土粒级相关性最好,容重与粘土粒级含量(相似文献   

斜带髭鲷幼鱼生长和生态转换效率的研究

在实验室内, 22. 5±0. 5℃条件下以去头去骨去鳞片去皮的金色小沙丁鱼的纯肉糜为饵料饲养斜带髭鲷幼鱼,测定体重范围在 4. 6~6. 5g的斜带髭鲷的体重、体长的生长曲线及其生态转换效率和特定生长率.实验结果表明,斜带髭鲷的体重、体长在实验期间直线增长,体重、体长的生长曲线分别为Wt(w.w.湿重,下同 ) =0. 391 7t 5. 766 2(R=0. 999 6)和Lt=0. 105t 6. 265(R=0. 989 9).用胃含物法测定斜带髭鲷的胃排空率、日摄食量、日生长量、生态转换效率和特定生长率.实验得到斜带髭鲷消化道的瞬时排空率Rt= 1. 23 4×10-3 (m/m) /h,日摄食量Cd= 1. 342 9g(w.w. ),生态转换效率Eg=29. 50% ±2. 77% [m/m(w.w. ) ],特定生长率SGR=4. 71%±0. 69% [m/m(w.w. ) ].     

闽南近海常见鲨鳐类肝油的四种理化常数和角鲨烯含量

本文分析测定了闽南近海常见鲨鳐类肝油的理化常数和角鲨烯含量。尖头斜齿鲨肝油的碘值特别高，说明其中脂肪酸的不饱和程度很高；非皂化物含量很低，约占肝油重的38×10－3（m／m）；角鲨烯含量极微，在肝油中仅占84×10－5（m／m）。闽南近海常见鲨鳐类肝油的角鲨烯含量均很低，变化在（31～116）×10－5（m／m）之间。在相同的气相色谱条件下，小孔沙条鲨和狭纹虎鲨肝油中没有检测到角鲨烯。     

Diet of albacore Thunnus alalunga from the waters of Mauritius (western Indian Ocean) inferred from stomach contents and fatty acid analysis

The diet of albacore Thunnus alalunga from their spawning ground in the waters of Mauritius was investigated. The stomach contents of 249 albacore individuals, caught by industrial longliners and artisanal fishers, was analysed, and the dominant prey taxa were selected for lipid and fatty acid (FA) analysis. The FA profiles of prey were compared with those of liver tissue of spawning-capable and post-spawning female albacore, using multivariate analysis. Whereas stomach content analysis identified cephalopods and crustaceans as the dominant prey items in number, FA-profile analysis identified crustaceans and fishes as the most-frequently consumed prey of post-spawning female albacore. In contrast, the FA profiles of spawning-capable albacore and those of prey showed very low similarity. Analysis of the prey suggests that although cephalopods, crustaceans and fishes could all provide albacore with the required lipids and FAs, cephalopod prey seem to be less desirable owing to their lower energy content (i.e. low in total lipid, triacylglycerol, 16:0, 18:0 and 18:1ω9). Instead, the most beneficial food appeared to be locally available fishes, which are more energy-rich and have a higher docosahexaenoic acid/ eicosapentaenoic acid ratio. These results provide new information on the trophic ecology of albacore, promote our understanding of the importance of prey type for successful reproduction of albacore, and highlight the advantages of FA profiling to study diet.     

光照强度对海洋微藻脂肪含量及脂肪酸组成影响的研究

近年来，海洋微藻脂肪酸组成的研究及其应用越来越受到国内外科学家的重视。高度不饱和脂肪酸(PUFA)，特别是长链的n-3 PUFA，如二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)对海洋动物和人类都具有营养学和医学上的价值。在海洋微藻的培养过程中，光照强度是海洋微藻生长的条件之一，光线的明与暗，光度的强与弱，不仅对微藻的生长速率、产量有影响，而且对其脂肪含量和脂肪酸的组成也有影响(Teshima et al.，1983；Thompson et al.，1990； Renaud et al., 1991)。 作者在以往研究的基础上，选择了3种有代表性的海洋微藻：(1)小球藻Chlorella sp-2(李荷芳等，1999)，此藻脂肪酸中EPA含量高、且不含DHA；(2)球等鞭金藻(Isochrysis galbana)，该藻DHA含量较高，但几乎不含EPA；(3)前沟藻(Amphidinium sp.)的EPA、DHA含量均高。将以上3种微藻作为原料，在不同的光照强度下进行培养，测定并分析藻体中的脂肪含量和脂肪酸组成的变化，从而了解光强对海洋微藻脂肪含量及其脂肪酸组成的影响。     

海鳗肌肉及鱼头营养成分的比较研究

对海鳗肌肉和头的营养成分进行分析研究的结果表明：海鳗肌肉和头的粗蛋白含量分别为19.6%和15.2%，第一限制氨基酸均为色氨酸（Trp）、氨基酸价分别为92和80；必需氨基酸分别各占氨基酸总量的45.5%和36.3%，谷氨酸(Glu)、天门冬氨酸（Asp）、丙氨酸（Ala）和甘氨酸（Gly）等呈味氨基酸在肌肉和头中的含量基本持平，两者均含有丰富的钙、磷等无机元素。从蛋白质和氨基酸的分析结果看，肌肉的营养价值比头高。     

Spatial and temporal variability of heat content above the thermocline in the tropical Pacific Ocean

Abstract-Heat content of the upper layer above the 20℃ isotherm in the tropical Pacific Ocean isestimated by using the sea temperature data set with a resolution 2°latitude×5°longitude (1980～1993)for the water depths (every 10 m) from 0 m to 400 m, and its temporal and spatial variabilities are an-alyzed. (1) The temporal variability indicates that the total heat in the upper layer of the equatorial Pa-cific Ocean is charcterized by the interannual variability. The time series of the equatorial heat anomaly5 months lead that of the El Nino index at the best positive lag correlation between the two, and theformer 13 months lag behind the latter at their best negative lag correlation. Therefore the equatorialheat content can be used as a better predictor than the El Nino index for a warm or cold event. In addi-tion, it is also found that less heat anomaly in the equator corresponds to the stronger warm events inthe period (1980～1993) and much more heat was accumulated in the 4 years including 1992/1