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71.
72.
中国东海和韩国马山湾海域2株原甲藻的形态结构和分子序列比较 总被引:2,自引:0,他引:2
对采自我国东海温岭海域和韩国南部马山湾海域的2株原甲藻进行了藻种分离、纯化培养及rDNA ITS分子序列的PCR扩增与测序,并运用显微镜、扫描电镜、Jukes-Cantor距离矩阵及构建的系统发育树,比较研究了2株原甲藻的形态结构和分子序列.结果表明:温岭藻株(LAMB090508)和马山湾藻株(PDKS0206)具有... 相似文献
73.
老168平台丛式井组是2009年中石化及胜利油田的重点产能建设项目之一,平台上共部署58口海油陆采定向井。该丛式井组的施工主要有以下难点:井网密集,防碰工作量大;造斜点浅、井斜大、造斜困难;位移大、裸眼稳斜段长,稳斜难度大;钻井液技术必须考虑环境保护问题,可借鉴经验非常少。因此钻井施工难度极大,通过实施优化井场布局及井眼轨道技术、大井眼松软浅地层定向技术、高精度轨迹控制技术、大位移井安全钻进技术,优质无污染海水钻井液技术,最终实现了老168钻完井一体化作业,节约了成本,提高了效率,为今后胜利油田丛式井组施工提供了宝贵经验。 相似文献
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The trophic ecology of the small yellow croaker (Larimichthys polyactis) was studied using stable isotope analyses. Samples were collected from July to September 2009 and 34 individuals from eight sites were examined for stable carbon and nitrogen isotopes. Stable carbon isotope ratios (δ13C) ranged from -20.67 to -15.43, while stable nitrogen isotope ratios (δ15N) ranged 9.18-12.23. The relationship between δ13C and δ15N suggested high resource partitioning in the sampling area. Significant differences in stable isotope values among the eight sampling sites may be linked to environmental diversities involving various physical processes (such as ocean current, wind and tide) and different carbon sources. Furthermore, the stable isotope ratios may also explain the ontogenetic variability in diet and feeding, because δ13C and δ15N varied significantly with increasing body size. The findings are consistent with other studies on diet analyses in small yellow croaker. It was also demonstrated that stable isotope analysis could be used to estimate the trophic characters of small yellow croaker in feeding patterns and migrating habits. 相似文献
76.
Dissolved fluorescent organic matter was measured using fluorescence excitation-emission matrix spectroscopy at three temporal points during a Synechococcus bloom after diatom bloom dispersion in spring, 2007. Carbohydrate and dissolved organic carbon were also analyzed. The relationship between organic matter and red tide succession was examined. The results show that after the diatom bloom, tyrosine-like fluorescence B intensity was very high within the water column and exhibited a negative correlation wi... 相似文献
77.
渔业资源是一种可再生资源,其资源的可持续利用不仅与其种群大小有关,而且还与作业规模、单位作业的经济成本和贴现率等有关。传统生物经济模型通常忽视了贴现率对渔业资源配置的影响。本文根据1999年-2009年中、日、韩三国在东黄海捕捞的鲐鱼渔获量以及生产成本数据,结合贴现率和渔获价格等数据,构建基于贴现率的东黄海鲐鱼动态生物经济模型。结果表明,贴现率为10%,30%时,短期利益占长期利益的10%~20%.渔获价格在(2327—4654)元/t时,可保证鲐鱼渔获量低于最大可持续产量,从而有效地控制捕捞强度,确保鲐鱼资源的可持续利用。 相似文献
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东昆仑迪木那里克铁矿地质特征与找矿标志 总被引:1,自引:0,他引:1
迪木那里克铁矿位于阿尔金大断裂南侧,矿体主要赋存于中-上奥陶统祁曼塔格群浅变质的碎屑岩-火山碎屑岩中.矿体多呈似层状、条带状产出,部分矿体塑性变形较强,矿体与地层产状基本一致,层控作用比较明显;矿石主要为条带状石英-磁铁矿和块状磁铁矿矿石;矿石品位较低(TFe=20%~40%);围岩蚀变特征明显.该铁矿属沉积变质型铁矿... 相似文献
80.
The impact of the northward jump and westward movement of the East Asian westerly jet core from the western Pacific Ocean to the Qinghai-Tibet Plateau on precipitation distribution of eastern China is studied. It is concluded that on the one hand, the northward jump of the jet causes the precipitation belt to move northward from the middle and lower reaches of the Yangtze River valley and withdraw during the Mei-yu season; on the other hand, the westward movement of the jet core has no correspondence with withdrawal of the Mei-yu season. However, the earlier or later occurrence of the westward movement of the jet has an influence on the process of the rain belt moving northward than the northward jump of the jet: the rain belt moves northward from the middle-lower Yangtze River valley to the Huaihe River and then to an area between the Yellow River and Huaihe River during years when the time of the westward movement of the jet core is later than that of the northward jump of the jet and from the middle-lower Yangtze River valley to an area between the Yellow River and Huaihe River in other years. Further analysis shows that: (1) The northward jump of the jet and the westward movement of the East Asian westerly jet core causes significant variation of the general atmospheric circulation in middle latitudes and water vapor transport from the western Pacific, but not from the Bay of Bengal. (2) Impact of the northward jump and the westward movement of the East Asian westerly jet core on circulation are different, therefore, water vapor transport from the western Pacific and its impact on the rain belt are different. The earlier or later occurrence of the westward movement of the jet core than the northward jump of the jet causes the process of circulation and water vapor transport to be different which produces a different process of the rain belt moving northward. 相似文献