Protoraphis Simonsen,a newly recorded marine epizoic diatom genus for China     

李朗  陈长平  孙琳  张家卫  梁君荣  高亚辉 《海洋学报(英文版)》2020,39(4):120-126

Epizoic diatoms on marine copepods are common in nature and may have a special ecological relationship with their hosts.However,this special ecological group is not well known,and it has only rarely been studied in the China seas.To address this knowledge gap,the species diversity and classification of epizoic diatoms on planktonic copepods were studied with samples collected from the East China Sea.In the present study,a marine araphid diatom genus Protoraphis and its type species,Pr.hustedtiana,were observed and identified by light and electron microscopy,thus representing the first record of this genus and its type species in China.This genus is characterized by a median sternum strongly bent to opposite sides and terminate in two transapical grooves at the valve ends.Protoraphis hustedtiana was found to be epizoic on the posterior body appendages and segments of the marine calanoid copepod Candacia bradyi.An internal view shows a complex,ear-shaped process that is close to the apical slit field.The ecological habitats and geographical distributions of Protoraphis were also discussed,and,together with complementary morphological studies,our results have increased the number of records for marine epizoic diatoms to three genera with three species in China,including Pseudohimantidium and Pseudofalcula.  相似文献   

Lateglacial to Holocene relative sea‐level changes in the Stykkishólmur area,northern Snæfellsnes,Iceland          下载免费PDF全文

MARTIN D. BRADER  JEREMY M. LLOYD  MICHAEL J. BENTLEY  ANTHONY J. NEWTON 《第四纪科学杂志》2015,30(5):497-507

Comparatively little research has been undertaken on relative sea‐level (RSL) change in western Iceland. This paper presents the results of diatom, tephrochronological and radiocarbon analyses on six isolation basins and two coastal lowland sediment cores from the Stykkishólmur area, northern Snæfellsnes, western Iceland. The analyses provide a reconstruction of Lateglacial to mid‐Holocene RSL changes in the region. The marine limit is measured to 65–69 m above sea level (asl), with formation being estimated at 13.5 cal ka BP. RSL fall initially occurred rapidly following marine limit formation, until ca. 12.6 cal ka BP, when the rate of RSL fall decreased. RSL fell below present in the Stykkishólmur area during the early Holocene (by ca. 10 cal ka BP). The rates of RSL change noted in the Stykkishólmur area demonstrate lesser ice thicknesses in Snæfellsnes than Vestfirðir during the Younger Dryas, when viewed in the regional context. Consequently, the data provide an insight into patterns of glacio‐isostatic adjustment surrounding Breiðafjörður, a hypothesized major ice stream at the Last Glacial Maximum.  相似文献   

云龙天池湖泊水深与硅藻生物多样性的关系     

邹亚菲  严瑶  张佼杨  张利周  旺罗 《第四纪研究》2015,35(4)

以云龙天池湖泊为研究对象,通过分析不同深度表层硅藻样品的生物多样性以及100年来硅藻生物多样性的变化特征,探讨硅藻生物多样性与水深变化之间的关系.虽然硅藻组合随水深发生了明显的变化,浅水区底栖硅藻占优势,深水区浮游硅藻占优势,但是不同深度表层样品中硅藻的属种数(简单分异度)基本相同,硅藻种群的生物多样性也没有发生显著的趋势性变化.这主要是由于硅藻各属种在不同深度的权重互补,导致云龙天池硅藻的多样性在湖泊的不同深度变化不大.近百年来的湖泊沉积速率显示,自1960年前后,湖泊水位在波动中逐步升高,但是硅藻种群的生物多样性并没有发生相应的变化.以上研究结果说明,云龙天池硅藻种群的生物多样性,不管是在时间上,还是空间上,与水深变化均无明显相关性.  相似文献   

池塘瓦片参礁养殖刺参的呼吸环境研究     

杨秀兰  杨建敏  刘相全  宋向军  张宇  王爱敏  臧金健 《海洋湖沼通报》2011,(2):20-26

研究了用瓦片参礁池塘养殖刺参(Apostichopus japonicus)的底层溶氧条件和呼吸环境;测定获得11.5～15.3℃时,新、老池塘瓦片参礁的平均增氧量分别为1.96mgO2/Ld与3.15mgO2/Ld(或1.17 gO2/m2d与2.30 gO2/m2d),相应底栖硅藻生物量为14.61 g/m2与48...  相似文献   

The early Matuyama Diatom Maximum off SW Africa: a conceptual model   总被引：1，自引：0，他引：1  

W. H. Berger  C. B. Lange  M. E. Prez 《Marine Geology》2002,180(1-4):105-116

An important discovery during Ocean Drilling Program Leg 175, when investigating the record of upwelling off Namibia, was the finding of a distinct Late Pliocene diatom maximum spanning the lower half of the Matuyama reversed polarity chron (MDM, Matuyama Diatom Maximum) and centered around 2.6–2.0 Ma. This maximum was observed at all sites off southwestern Africa between 20°S and 30°S, and is most strongly represented in sediments of Site 1084, off Lüderitz, Namibia. The MDM is characterized by high biogenic opal content, high numbers of diatom valves, and a diatom flora rich in Southern Ocean representatives (with Thalassiothrix antarctica forming diatom mats) as well as coastal upwelling components. Before MDM time, diatoms are rare until ca. 3.6 Ma. After the MDM, in the Pleistocene, the composition of the diatom flora points to increased importance of coastal upwelling toward the present, but is accompanied by a general decrease in opal and diatom deposition. Here we present a simple conceptual model as a first step in formalizing a possible forcing mechanism responsible for the record of opal deposition in the upwelling system off Namibia. The model takes into account Southern Ocean oceanography, and a link with deepwater circulation and deepwater nutrient chemistry which, in turn, are coupled to the evolution of North Atlantic Deep Water (NADW). The model proposes that between the MDM and the Mid-Pleistocene climate revolution, opal deposition off Namibia is not directly tied to glacial–interglacial fluctuations (as seen in the global δ¹⁸O record), but that, instead, a strong deepwater link exists with increased NADW production (as seen in the deepwater δ¹³C record) accounting for higher supply of silicate to the thermocline waters that feed the upwelling process. The opal record of Site 1084 shows affinity to eccentricity on the 400-kyr scale but not for the 100-kyr scale. This points toward long-term geologic processes for delivery of silica to the ocean.  相似文献   

硅藻粘附性EPS提取方法的比较研究          下载免费PDF全文

于兆伟  谢雅清  张珮璇  鲍金  孙陈炼  靳翠丽  周晓见 《应用海洋学学报》2019,38(4):592-599

底栖硅藻是可见光能照射到的水下表面生物膜中的主要污损生物,胞外多聚物(Extracellular Polymeric Substances,EPS)是硅藻生物膜形成和发育过程中的关键物质,可溶性EPS和粘附性EPS的提取方法不同,对粘附性EPS的分离提取仍没有统一的方法。本研究选用了4种方法提取底栖硅藻(Amphora sp.)粘附性EPS:30℃水浴处理、70℃水浴处理、福尔马林-NaOH处理和阳离子交换树脂处理,研究了不同分离方法条件下,Amphora sp.粘附性EPS中各主要成分的提取量。结果表明,粘附性EPS中各主要成分普遍受提取方法的影响,其中DNA含量变化幅度最大,其次是蛋白质、总糖和糖醛酸含量,硫酸基含量受提取方法的影响最小。低温水浴处理提取效率低,高温水浴处理可能影响EPS的后续分析,阳离子交换树脂提取粘附性EPS的效果较好,但对细胞的破坏最严重,福尔马林-NaOH处理提取的EPS总量最高,提取总糖、糖醛酸的效果最好,而且没有造成严重的细胞破裂。因此福尔马林-Na OH处理是相对均衡和高效的提取硅藻粘附性EPS的方法。  相似文献   

Study of light signal receptor of Stephanopyxis palmeriana during sexual reproduction     

胡韧林均民  林秋奇韩博平 《中国海洋湖沼学报》2005,23(3):330-334

We collected centric diatom Stephanopyxis palmeriana samples in coastal waters of Xiamen for characteristic red light/far red light (R/FR) phytochrome reactions to identify its photoreceptor in the course of sexual reproduction. The result showed that pre-illumination of 2-3h red light before darkness could induce sexualization of S.palmeriana, while the follow-up illumination of far red light could reverse the effect of red light, which is a featured reaction of phytochrome. The Southern Dot Blot was carried out to identify the type of phytochrome that induces the sexualization. The result also showed high homogeneity of DNA fragment of S. palmeriana with phyB, but phyA. This means the photoreceptor in the process of sexual reproduction of S. palmeriana is phytochrome B (phyB).  相似文献   

福建漳浦前湖湾硅藻组合及其古环境意义   总被引：1，自引：0，他引：1  

吴彩容  刘剑秋  王绍鸿  俞鸣同 《海洋通报》2008,27(1):75-80

在福建漳浦前湖湾QHP剖面和QHZ钻孔1共取28个硅藻样品,依据硅藻种类的含量变化和硅藻组合特征,自下而上划分为4个硅藻带,其中B带划分出4个亚带,B4亚带进一步划分为2个小亚带.结合14C测年和沉积地层岩性资料,探讨了该地区晚更新世以来的古环境演化,得出其环境变迁过程由老到新依次为:河流环境-海湾环境-河流环境-海湾河口环境-河流环境-陆相淡水环境-湖泊-风沙环境-滨岸小海湾环境.  相似文献   

The use of multivariate statistics to resolve multiple contamination signals in the oxygen isotope analysis of biogenic silica          下载免费PDF全文

KATY E. WILSON  MELANIE J. LENG  ANSON W. MACKAY 《第四纪科学杂志》2014,29(7):641-649

  相似文献   

Fronts and surface zonal geostrophic current along 115°E in the southern Indian Ocean     

HE Zhigang  DONG Zhaoqian 《海洋学报(英文版)》2010,29(5):1-9

硅藻具有形态各异、结构复杂、精美绝伦的硅质细胞壁,是海洋中进行生物硅化最主要的生物体。硅质细胞壁的形成同样是一个错综复杂的过程,它涉及硅藻细胞将硅酸从胞外转运到胞内;硅酸在细胞内的转移;在硅沉积囊泡(SDV)中的浓缩沉积;最后合成具种类特异性的细胞壁。重点介绍硅酸转运基因(SITs)的分子特征与作用机制;与生物硅化相关的三种蛋白即硅体蛋白(frustulins)、亲硅蛋白(silaffins)和侧壁蛋白(pleuralins)的结构与功能;硅质结构如何在硅沉积囊泡内最终形成的模式。  相似文献