桂西乐业地区二叠系荷叶藻风暴岩的沉积特征   总被引：1，自引：0，他引：1  

陆刚  李文强 《南方国土资源》1992,(4)

二叠系荷叶藻风暴岩在广西属首次发现。它广泛发育在乐业背斜构造的二叠系中。本文通过对两条典型剖面研究,论述了风暴岩的层序、沉积特征、组合类型及其分布,并探讨其沉积模式。认为:该风暴岩主要产于下二叠统栖霞组中部和茅口组底部两个层位的生物屑灰岩中,由荷叶藻及其它生物屑构成各种风暴沉积特征(如粒序层、平行层、丘状层、底面构造……),风暴沉积形成于孤立碳酸盐台地环境,并具有从台缘→台地中心、由近积风暴岩→远积风暴岩→次风暴岩分布规律。指出风暴岩的发现不仅具有沉积学意义,而且对二叠系的地层对比和藻灰岩的成因提供了依据和信息。  相似文献   

倒刺鲃属鱼类物种分化的研究   总被引：1，自引：0，他引：1  

杨君兴  陈银瑞 《广东海洋大学学报》1995,(1)

依据倒刺属内部骨骼和外部形态特征，结合其地理分布．首次探讨了该属鱼的物种分化与区域地理演变历史的关系。研究结果表明，倒刺属鱼类共有３个共同离征。其一级姐妹群的分布范围在中国东南沿海地区有较大的重叠。二级姐妹群的分化与云贵高原的抬升和相应的水系分流有密切的关系。三级和四级姐妹群的分化主要是由于生活环境的差异所致。  相似文献   

Study on Optical Properties of Unpigmented Suspended Particles,Yellow Substance and Phytoplankton Algae in Taihu Lake   总被引：1，自引：0，他引：1  

俞宏蔡启铭  吴敬禄 《中国海洋湖沼学报》2004,22(1):24-33

The optical properties of a waterbody are subjects of research on limnological hydrooptics. The optical properties of, and parameterization methods for, three impurities in Taihu Lake, namely unpigmented suspensions, yellow substance and phytoplankton algae, are analyzed in detail in this paper dealing with the optical types of Taihu Lake waters both in winter and in summer. The results showed that : 1 ) The optical parameters of suspended particles can be calculated by the application of Mie Theory; 2) The absorption of yellow substance decreases exponentially with increasing wavelength, with the mean value of decreasing rate being about 0.014 nm^-1 ; 3) Taihu Lake waters appeared to be of type PY in winter, with suspended particles and yellow substance being the dominant light absorbers, and type CPY in summer, with suspended particles, yellow substance and phytoplankton algae being the dominant light absorbers; 4) In winter or summer, unpigmented suspension has the main effect on the scattering property of Taihu Lake waters.  相似文献   

COMBINED EFFECTS OF TEMPERATURE, IRRADIANCE AND SALINITY ON GROWTH OF DIATOM SKELETONEMA COSTATUM   总被引：2，自引：0，他引：2  

Yan Tian  Zhou Mingjiang  Qian Peiyuan 《中国海洋湖沼学报》2002,20(3):237-243

3-factor experiment was used to study the combined effects of temperature, irradiance and salinity on the growth of an HAB species diatomSkeletonema costatum (Grev.) Cleve. The results showed that temperature (12, 19, 25, 32 °C), irradiance (0.02, 0.08, 0.3, 1.6)×10¹⁶ quanta/(s·cm²)) and salinity (10, 18, 25, 30, 35) significantly influenced the growth of this species. There were interactive effects between any two of and among all three physical factors on the growth. In the experiment, the most optimal growth condition forS. costatum was temperature of 25°C, salinity of 18–35 and irradiance of 1.6×10¹⁶ quanta/(s·cm²). The results indicatedS. costatum could divide at higher rate and were more likely to bloom under high temperature and high illumination from spring to fall. It was able to distribute widely in ocean and estuary due to its adaptation to a wide range of salinities. This study was supported by the PREPP and National Key Basic Research Project (2001CB4097) NNSFC No. 39950001, 20177023, 49576301, 49906007 and KZCX2-206.  相似文献   

卡帕藻的营养成分分析及综合比较     

周歧存  刘东超  叶富良  揭振英  黎祖福 《广东海洋大学学报》2001,21(1):43-46

于1999年元月在海南陵水黎安港采集卡帕藻，应用HPLC、原子吸收等分析手段，系统测定其营养成分（主要包括蛋白质、氨基酸、脂肪、粗纤维、粗灰分、矿物质及微量元素等），并与其它几种大型藻类比较，综合评价卡帕藻的营养价值。结果表明卡帕藻蛋白质含量为6.20%，而粗脂肪和粗灰分较高，分别为2.88%和39.04%；卡帕藻中富含K、Na、Ca、Mg、P、Fe、Zn、Mn、Se等矿物元素，尤其是Se的含量远高于其它几种大型藻类。  相似文献   

初始密度对3种沉水植物生物量、节数和茎长的影响     

王永阳  罗芳丽  李红丽  于飞海 《湿地科学》2014,(6)

初始密度是影响沉水植物生长的重要因素之一。研究5种不同初始密度(分别为19株/m2、57株/m2、113株/m2、227株/m2和454株/m2)对穗花狐尾藻(Myriophyllum spicatum)、伊乐藻(Elodea nuttallii)和金鱼藻(Ceratophyllum demersum)在种群和单株水平生长的影响,实验结束后,将种群和单株的生物量、节数和茎长作为主要研究生长指标进行测定。研究结果表明,3种沉水植物种群总生物量、总节数和总茎长都随着初始密度的增大而显著增加,其中,金鱼藻和伊乐藻甚至产生了爆发生长的趋势。然而,初始密度对3种沉水植物的单位重量节数和单位重量茎长无显著影响。穗花狐尾藻和伊乐藻的单株生物量、节数和茎长都随着初始密度的增大而显著减小,而金鱼藻的单株3项指标则随着初始密度的增大无显著差异。在3种沉水植物恢复过程中,可以适当提高金鱼藻的初始密度,而对于穗花狐尾藻和伊乐藻,则可以根据实际情况进行合理的初始密度选择。  相似文献   

扁藻在对虾育苗中的应用   总被引：3，自引：0，他引：3  

孙德孟  孙盛川 《海洋科学》1994,18(4):8-9

对虾蚤状幼体期，幼体以食植物活性饵料为主，许多地方，以三角褐指藻（Ｐｈａｅｏｄａｃｔｙｌｕｍ　ｔｒｉｃｏｒｎｕｔｕｍ　Ｂｏｈｌｉｎ）和新月菱形藻（Ｎｉｔｚｓｃｈｉａ　ｃｌｏｓｔｅｉｕｍ）为主，这虽然适合幼体摄食，但因不适合于２０℃以上水温生长繁殖，投喂后适应环境能力差，易下沉死亡，败坏水质。扁藻（Ｐｌａｔｙｍｏｎａｓ　ｓｐｐ．）是一种绿藻，适盐、温范围广，与其他藻类相比，繁殖速度快，适应能力强，不易死亡，要求温度与育苗水温相近，是水产养殖幼体的理想饵料之一。牟平县林北盐场于１９９２年，１９９３年…  相似文献   

麻黄属的起源时间讨论          下载免费PDF全文

杨永 《地质论评》2011,57(1):9-15

利用分子钟对麻黄属起源时间的估测和基于带有生殖特征的大化石标定的最小起源时间有很大的差距,分子钟估测麻黄属起源于古近纪的渐新世,而大化石则标定麻黄属起源不晚于早白垩世巴列姆期.麻黄属化石和分子钟结果之间的冲突至少有三种不同的解释:即古近纪瓶颈、古老支系缓慢绝灭和频繁的基因交流减缓了分子进化速率.本文的分析表明古老支系缓...  相似文献   

Primary species recognitionand phylogeny of Chondrus （Gigartinales, Rhodophyta） using 18S rDNA sequence data     

胡自民  曾晓起  段德麟 《中国海洋湖沼学报》2007,25(2):174-183

The nuclear-encoded small subunit ribosomal RNA gene (18S rDNA) of 16 isolates of Chondrus from 8 countries were sequenced. A total of 1796 nucleotides were obtained and aligned with the phylogenetic analysis conducted. The results suggest that the entity from Dalian, China, regarded as C. sp1 is C. pinnulatus. The C. sp2 previously depicted as C. yendoi or Mazzaella japonica may belong to genus Chondrus. So, 4 Chondrus species, i.e. C. ocellatus, C. nipponicus, C. armatus, and C. pinnulatus are distributed in China. However, the entity from Connemara, Ireland, named C. crispus, is not a Chondrus species but that of Mastocarpus stellatus, although it is morphologically similar to C. crispus. Phylogenetic analysis based on complete 18S rDNA sequence data shows that genus Chondrus includes 3 main lineages: the Northern Pacific lineage, containing C. ocellatus, C. yendoi, and C. nipponicus; C. armatus, and C. pinnulatus form the sub-North Pacific lineage; and the Northern Atlantic Ocean lineage, comprising samples of C. crispus from Canada, Portugal, Ireland, Germany and France. The phylogenetic relationships indicate that genus Chondrus might have a North Pacific ancestral origin, radiated to North Atlantic area, and then formed the species C. crispus.  相似文献   

有害藻华的预测技术和防灾减灾对策研究进展   总被引：1，自引：0，他引：1  

王丹  刘桂梅  何恩业  李津 《地球科学进展》2013,28(2):233-242

有害藻华给海洋生物、海水养殖业、海洋环境和公共健康安全造成了极大的威胁,已经成为世界性的海洋环境灾害之一.近几十年,我国近海有害藻华的发生频率和发生规模不断扩大,给国家经济发展和公共医疗卫生造成了极大的经济损失和不利影响.主要介绍了国内外常用的有害藻华预测技术,并参考国内外有效的有害藻华防治措施,为我国有害藻华的防灾减灾工作提出建议.我国亟需逐步建立有害藻华综合预警报业务体系和完备的应急减灾体系,才能进一步提升有害藻华等海洋环境灾害的应对能力.  相似文献