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991.
Phylogenomic analysis of transcriptomic sequences of mitochondria and chloroplasts for marine red algae (Rhodophyta) in China 总被引:1,自引:1,他引:0
JIA Shangang WANG Xumin QIAN Hao LI Tianyong SUN Jing WANG Liang YU Jun LI Xingang YIN Jinlong LIU Tao WU Shuangxiu 《海洋学报(英文版)》2014,33(2):86-93
The chloroplast and mitochondrion of red algae (Phylum Rhodophyta) may have originated from different endosymbiosis. In this study, we carried out phylogenomic analysis to distinguish their evolutionary lin-eages by using red algal RNA-seq datasets of the 1 000 Plants (1KP) Project and publicly available complete genomes of mitochondria and chloroplasts of Rhodophyta. We have found that red algae were divided into three clades of orders, Florideophyceae, Bangiophyceae and Cyanidiophyceae. Taxonomy resolution for Class Florideophyceae showed that Order Gigartinales was close to Order Halymeniales, while Order Graci-lariales was in a clade of Order Ceramials. We confirmed Prionitis divaricata (Family Halymeniaceae) was closely related to the clade of Order Gracilariales, rather than to genus Grateloupia of Order Halymeniales as reported before. Furthermore, we found both mitochondrial and chloroplastic genes in Rhodophyta under negative selection (Ka/Ks〈1), suggesting that red algae, as one primitive group of eukaryotic algae, might share joint evolutionary history with these two organelles for a long time, although we identified some dif-ferences in their phylogenetic trees. Our analysis provided the basic phylogenetic relationships of red algae, and demonstrated their potential ability to study endosymbiotic events. 相似文献
992.
A direct-drive wave energy conversion system based on a three-phase permanent magnet tubular linear generator (PMTLG) and a heaving buoy is proposed to convert wave energy into electrical energy. Sufficient experimental methods are adopted to compare the computer simulations, the validity of which is verified by the experiment results from a wave tank laboratory. In the experiment, the motion curves of heaving buoy are with small fluctuations, mainly caused by the PMTLG's detent force. For the reduction of these small fluctuations and a maximum operational efficiency of the direct-drive wave energy conversion system, the PMTLG's detent force minimization technique and the heaving buoy optimization will be discussed. It is discovered that the operational efficiency of the direct-drive wave energy conversion system increases dramatically after optimization. The experiment and optimization results will provide useful reference for the future research on ocean wave energy conversion system. 相似文献
993.
SUN Weiping YU Jianjun XU Xiaoqun ZHANG Weiyan LIU Ruijuan PAN Jianming 《海洋学报(英文版)》2014,33(4):101-107
Heavy metals in the surface sediments and sediment core from the Xiangshan Bay, a mariculture base on the coast of the East China Sea, were determined by inductively coupled plasma mass spectrometry(ICP–MS) in order to evaluate their levels and sources. The results showed that the levels of Cu, Pb, Zn, and Cr in the sediments of the bay have been generally influenced by anthropogenic inputs since the founding of the People's Republic of China. In particular, Cu and Zn were polluted to some extent, as evidenced by high enrichment factors. Organic matter, grain size, wastewater discharge, and low energy hydrodynamic environment played dominant roles in the heavy metal enrichment in the sediments. The ratio of terrigenous source to marine biogenic deposit of trace metals in the sediments was calculated, revealing that terrigenous inputs were the main source of Cu, Pb, and Zn, while biological pellets contributed much more to the enrichment of Cr and Cd. Considering the influence of biological sources on the enrichment of Cd and Cr, and the fact that the sediment has been polluted by Cu and Zn, the development of mariculture and discharge of wastewater into the Bay should be restricted. 相似文献
994.
995.
996.
琼东南盆地深水区构造热演化特征及其影响因素分析 总被引:5,自引:1,他引:4
To reveal the tectonic thermal evolution and influence factors on the present heat flow distribution, based on 154 heat flow data, the present heat flow distribution features of the main tectonic units are first analyzed in detail, then the tectonic thermal evolution histories of 20 profiles are reestablished crossing the main deep-water sags with a structural, thermal and sedimentary coupled numerical model. On the basis of the present geothermal features, the Qiongdongnan Basin could be divided into three regions: the northern shelf and upper slope region with a heat flow of 50–70 m W/m2, most of the central depression zone of 70–85 m W/m2, and a NE trending high heat flow zone of 85–105 m W/m2 lying in the eastern basin. Numerical modeling shows that during the syn-rift phase, the heat flow increases generally with time, and is higher in basement high area than in its adjacent sags. At the end of the syn-rift phase, the heat flow in the deepwater sags was in a range of 60–85 m W/m2, while in the basement high area, it was in a range of 75–100 m W/m2. During the post-rift phase, the heat flow decreased gradually, and tended to be more uniform in the basement highs and sags. However, an extensive magmatism, which equivalently happened at around 5 Ma, has greatly increased the heat flow values, and the relict heat still contributes about 10–25 m W/m2 to the present surface heat flow in the central depression zone and the southern uplift zone. Further analyses suggested that the present high heat flow in the deep-water Qiongdongnan Basin is a combined result of the thermal anomaly in the upper mantle, highly thinning of the lithosphere, and the recent extensive magmatism. Other secondary factors might have affected the heat flow distribution features in some local regions. These factors include basement and seafloor topography, sediment heat generation, thermal blanketing, local magmatic injecting and hydrothermal activities related to faulting and overpressure. 相似文献
997.
对两种原油进行混合配比实验,将混合后油样置于人工气候箱进行风化模拟实验,采用气相色谱质谱联用仪(GC-MS)检测风化样品中的生物标志化合物,短期风化作用对混合溢油的油指纹、生物标志化合物诊断指标等的影响。结果表明,混合溢油的正构烷烃总质量变化与单一原油油品的变化规律相近,即前期风化较快,质量减损较多,而后期风化趋缓,不同混合比例的溢油表现差异不明显。常用于短期风化的诊断比值对各混合油样的风化具有指示意义,但难以定性鉴别油品是否发生混合。重复性限法检验只能判定短期风化过程前后的油样为同一油源,而难以反映油样是否为混合油源的特征,各诊断比值的RSD%值较大可能是混合溢油的一个表现。 相似文献
998.
走航式海洋多参数剖面测量系统(MVP)是一种集成程度和自动化程度都较高的海洋调查设备,能对多要素进行同时观测,获得高水平空间分辨率的数据资料。MVP由于温度和电导率传感器响应时间的不匹配,下放速度过快(峰值速度4m/s)而造成非常严重的盐度尖峰现象。本研究通过结合F法、GM法和Grose法提出的盐度尖峰订正方案,提出了一种新的方法Match conductivity and temperature response times法,对压力、温度和电导率传感器三者进行响应时间的匹配来减弱盐度尖峰。与SBE-9型CTD资料进行对比发现订正后的资料误差比订正前减小80%,与CTD盐度曲线互相关程度为0.917。对比35N断面修正前后的盐度资料发现订正后温盐跃层处出现的低盐区域消失,与CTD断面资料对比结果显示MVP资料比CTD资料在细结构上更具有优势。 相似文献
999.
1000.
关于冰雹的融化层高度 总被引:20,自引:8,他引:12
冰雹尤其是强冰雹预报的重要参数之一是冰雹融化层到地面的高度。长期以来国外英文文献上一直都将湿球温度0℃层(Wet Blub Zero,WBZ)作为冰雹融化层的近似高度,但这一事实一直没有引起国内预报人员和部分研究人员(包括作者在内)的足够注意。以至于一直到现在,国内绝大多数预报人员仍然将干球温度0℃层(Dry Blub Zero,DBZ)作为冰雹融化层的近似高度,这是一个错误。在WBZ和DBZ之间和上下一定范围内存在明显干空气(即温度露点差较大)时,二者高度会有明显的差距。本文主要阐明冰雹融化层的高度应该采用湿球温度0℃层(WBZ)高度而不是干球温度0℃层(DBZ)高度,说明了当对流层尤其对流层中层存在明显干层时,由于蒸发冷却引起的水膜再冻结会有利于大冰雹落地,而此时的冰雹融化层也就是湿球温度0℃层(WBZ)的高度明显低于干球温度0℃层(DBZ)的高度。文中给出了如何根据探空资料的T-logp图确定湿球温度垂直廓线进而确定湿球温度0℃层(WBZ)高度的方法。最后给出两个对比鲜明的例子,进一步说明对流层中层明显干层存在与否对冰雹融化层高度的影响,以及冰雹融化层高度的高低是决定冰雹大小甚至降雹与否的主要因子之一。 相似文献