DA白矮星视向速度测量     

赵颖玥  罗阿理 《天文研究与技术》2019,(1):1-7

DA白矮星光谱在光学波段主要由巴尔默线主导,谱线比较宽,且谱线轮廓不对称,传统的线心方法确定视向速度非常困难。介绍了一种基于利用白矮星的有效温度(Teff)和表面重力加速度(log g)选择理论模板,通过交叉相关方法确定DA白矮星的APP速度,减去白矮星的引力红移得到白矮星的视向速度。测试发现对于有效温度高于10 000 K且信噪比大于20的DA白矮星的低分辨率光谱(R～2000),精度在10 km/s以内。基于这种方法测量了SDSS DR7的DA白矮星观测样本的视向速度,统计发现在1 000 pc内,视向速度的平均值接近于0。  相似文献   

东南亚近岸海区浮游植物光合色素和群落组成—印度尼西亚贯穿流和吉兰丹河口区的比较研究     

王磊  黄浩  安丽娜  THOHA Hikmah  BONG Chuiwei  肖武鹏  顾海峰 《海洋学报(英文版)》2018,37(12):18-27

Water samples were collected in order to study the spatial variation of photosynthetic pigments and phytoplankton community composition in the Lembeh Strait(Indonesia) and the Kelantan River Estuary(Malaysia)during July and August 2016, respectively. Phytoplankton photosynthetic pigments were detected using high performance liquid chromatography combining with the CHEMTAX software to confirm the Chl a biomass and community composition. The Chl a concentration was low at surface in the Lembeh Strait, which it was 0.580–0.682 μg/L, with the average(0.620±0.039) μg/L. Nevertheless, the Chl a concentration fluctuated violently at surface in the Kelantan River Estuary, in which the biomass was 0.299–3.988 μg/L, with the average(0.922±0.992) μg/L. The biomass at bottom water was higher than at surface in the Kelantan River Estuary, in which the Chl a concentration was 0.704–2.352 μg/L, with the average(1.493±0.571) μg/L. Chl b, zeaxanthin and fucoxanthin were three most abundant pigments in the Lembeh Strait. As a consequence, phytoplankton community composition was different in the two study areas. In the Lembeh Strait, prasinophytes(26.48%±0.83%) and Synechococcus(25.73%±4.13%) occupied ～50% of the Chl a biomass, followed by diatoms(20.49%±2.34%) and haptophytes T8(15.13%±2.42%). At surface water in the Kelantan River Estuary, diatoms(58.53%±18.44%)dominated more than half of the phytoplankton biomass, followed by Synechococcus(27.27%±14.84%) and prasinophytes(7.00%±4.39%). It showed the similar status at the bottom water in the Kelantan River Estuary,where diatoms, Synechococcus and prasinophytes contributed 64.89%±15.29%, 16.23%±9.98% and 8.91%±2.62%,respectively. The different phytoplankton community composition between the two regions implied that the bottom up control affected the phytoplankton biomass in the Lembeh Strait where the oligotrophic water derived from the West Pacific Ocean. The terrigenous nutrients supplied the diatoms growing, and pico-phytoplankton was grazed through top down control in the Kelantan River Estuary.  相似文献   

江蓠属藻胆体的研究 Ⅱ.藻胆体的荧光光谱特性     

张学成  程晓杰  隋正红  魏东  刘晨临  徐年军 《中国海洋大学学报(自然科学版)》1999,(3)

报道以青岛野生型龙须菜（ｗｔ）、黄色突变体（ｙｅ１００）、４株绿色突变体（ｇｒ１８０、ｇｒ１８４、ｇｒ１８６、ｇｒ１８８）、委内瑞拉野生型龙须菜（ｌｖ）、南非野生型龙须菜（ｓａ）及真江蓠（ｇａ）为材料,用蔗糖密度梯度离心法得到完整的藻胆体。用５４０ｎｍ激发,野生型的荧光发射峰位于５７８ｎｍ和６７０ｎｍ,相对荧光强度ＦＡＰＢ／ＦＰＥ的比值为１．５０。几种材料的ＰＥ和ＡＰＢ荧光发射峰没有明显区别（不超过２ｎｍ）,但两峰荧光强度比值显著差异。结果显示ｌｖ的ＦＡＰＢ／ＦＰＥ比值最低,只有１．２０,ｇｒ１８６的比值最高,为５．６７,野生型中ｓａ也比较高,为４．７９。用６７０ｎｍ激发,野生型龙须菜的荧光社发光谱有５个峰,分别为４９９ｎｍ、５４０ｎｍ、５６８ｎｍ、６１４ｎｍ、６５０ｎｍ,与其吸收光谱一一对应。野生型和突变体、不同产地龙须菜及真江蓠的荧光发射峰的波长都与其吸收光谱相对应。  相似文献   

Evaluating the Potential of an Airborne Laser-scanning System for Measuring Volume Changes of Glaciers     

Etienne Favey  Alain Geiger  G. Hilmar Gudmundsson  & Aloysius Wehr 《Geografiska Annaler: Series A, Physical Geography》1999,81(4):555-561

Airborne laser scanning (ALS) is well suited for the production of digital elevation models (DEM), and can, in contrast to photographic methods, be used to acquire a DEM independently of surface texture and external light sources. ALS thus serves as a tool to generate DEMs of firn areas where photogram- metric methods often fail.
The potential of an integrated ALS system – comprising a laser scanner, precise differential global positioning system, and a gyro platform – for DEM generation of firn areas is currently being assessed. The Unteraargletscher, Bernese Alps, Switzerland, has been chosen as a test site. As part of a pilot project aimed at determining the mass balance distribution of that glacier without the use of in situ information, ALS measurements were conducted in autumn 1997. The DEM derived from laser measurements is extremely sensitive to the position and attitude of the aircraft. Currently the main work focuses on assessing and improving the system's accuracy by error modelling and by the development of error-correction algorithms.
Preliminary results from Unteraargletscher are presented, and the potential of this method for the generation of DEMs of firn areas is discussed.  相似文献   

近200a来泸沽湖沉积物色素记录与区域气候变化的关系   总被引：2，自引：2，他引：0  

陈传红  汪敬忠  朱迟  赵良元  蒋金辉  杨娇艳  杨劭 《湖泊科学》2012,24(5):780-788

近百年来云贵高原区域气候变暖明显.为探讨湖泊生态系统变化与气候变化的关系,本文采集泸沽湖沉积物柱,分析测定了近200 a来沉积物柱芯中叶绿素及其衍生物(CD)、总胡萝卜素(TC)、颤藻黄素(Osc)和蓝藻叶黄素(Myx)4类色素及烧失量(LOI550℃)、生物硅、C/N值等指标,并与1951-2010年丽江地区气温和降雨量资料进行相关性分析.结果表明,以上4种色素含量及其比值(CD/TC,Osc/Myx)对区域气温变化较为敏感;近60 a来CD、TC、Osc、Myx、LOI550℃和生物硅含量与年均气温呈显著正相关;而CD、TC、Osc、Myx和C/N仅与5 a滑动年均降雨量呈正相关,表明气温可能是驱动泸沽湖初级生产力升高的主要因素之一,降雨量为次要因素.1990年后4种色素和有机质含量明显增加,C/N值呈下降趋势,湖泊初级生产力增强,内源有机质在沉积物总有机质中的比重增高.此外,Osc和Myx含量及其比值升高,反映蓝藻类生产力增长,颤藻类比重呈增大趋势,表明近20 a来在气温为主导因素的影响下不仅泸沽湖初级生产力增加,初级生产者群落组成也发生了变化.  相似文献   

Effects of heavy metals (Pb2+ and Cd2+) on the ultrastructure, growth and pigment contents of the unicellular cyanobacterium Synechocystis sp. PCC 6803     

K. K. I. U. Arunakumara  ZHANG Xuecheng 《中国海洋湖沼学报》2009,27(2)

The unicellular cyanobacterium Synechocystis sp. PCC 6803, a model organism known for its unique combination of highly desirable molecular genetic, physiological and morphological characteristics, was employed in the present study. The species was cultured in BG11 liquid medium contained various initial concentrations of Pb2+ and Cd2+ (0, 0.5, 1, 2, 4, 6 and 8 mg/L). The experiment was conducted for six days and the metal induced alterations in the ultrastructure, growth and pigment contents were assessed. Alterations in the ultrastructure of the Synechocystis sp. PCC 6803 ceils became evident with the increased (>4 mg/L Pb2+) metal concentration. The photosynthetic apparatus (thylakoid membranes) were found to be the worst affected. Deteriorated or completely destroyed thylakoid membranes have made large empty spaces in the cell interior. In addition, at the highest concentration (8 mg/L pb2+), the polyphosphate granules became more prominent both in size and number. Despite the initial slight stimulations (0.2, 3.8 and 6.5% respectively at 0.5, 1 and 2 mg/L Pb2+), both metals inhibited the growth in a dose-dependent manner as incubation progressed. Pigment contents (chlorophyll a, βcarotene and phycocyanin) were also decreased with increasing metal concentration. Cells exposed to 6 mg/L Pb2+, resulted in 36.56, 37.39 and 29.34% reductions of chlorophyll a, β carotene and phycocyanin respectively over the control. Corresponding reductions for the same Cd2+concentrations were 57.83, 48.94 and 56.90%. Lethal concentration (96 h LC50) values (3.47 mg/L Cd2+ and 12.11 mg/L Pb2+) indicated that Synechocystis sp. PCC 6803 is more vulnerable to Cd2+ than Pb2+.  相似文献   

2014年冬季热带西太平洋雅浦Y3海山光合色素分布及其对浮游植物群落的指示作用     

赵永芳  郑珊  孙晓霞 《海洋与湖沼》2019,50(4):830-837

应用高效液相色谱结合二极管阵列检测器分析技术,研究了西太平洋雅浦Y3海山区域2014年冬季浮游植物的光合色素组成。结果表明：100m以浅,玉米黄素（Zeax）是水柱中浓度最高的光合色素,浓度为22.64—84.31ng/L,叶绿素a（chl a）浓度在水柱中均值为（37±34） ng/L,在贫营养海区的数值范围内,水柱积分高值分布区与海山走向一致,二乙烯基叶绿素a（Dvchl a）和19''-丁酰氧岩藻黄素（19''BF）也是调查海区较高浓度的色素,在水柱中均值分别为（27±22）和（31±30） ng/L。其他色素新黄素（Neox）、叶黄素（Lute）、叶绿素b（chl b）、青绿素（Pras）平均水柱含量极低（<1.00ng/L）。通过CHEMTAX程序因子分析估算了浮游植物群落结构,调查区浮游植物群落以原绿球藻为优势藻,贡献率与环境因子不具有相关性,其次主要为蓝细菌和金藻,蓝细菌贡献率高值区分布在海山东南和东北侧0和30m水层,金藻贡献率高值区分布在75和100m水层,两者贡献率均与环境因子显著相关。  相似文献   

广东省粤西地区凡纳滨对虾3种主要病毒的PCR与LAMP检测及流行病学特点分析     

江晓  任春华  胡超群  赵哲 《热带海洋学报》2011,(6)

应用聚合酶链式反应(Polymerase Chain Reaction,PCR)和环介导等温扩增(Loop-Mediated Isothermal Ampli-cation,LAMP)两种检测技术分别对2009年广东省粤西地区养殖体系中凡纳滨对虾Litopenaeus vannamei白斑综合症病毒(White Spot Syndrome,WSSV)、桃拉病毒(Taura Syndrome Virus,TSV)和传染性皮下及造血组织坏死病毒(Infectious Hypodermal and Hematopoietic Necrosis Virus,IHHNV)的携带情况进行了调查。结果显示,WSSV和TSV的携带率较高,是该地区凡纳滨对虾的主要流行病毒种类;LAMP检测方法与PCR方法具有相当的灵敏度和特异性,但LAMP检测方法更加简单方便、快速且成本低。  相似文献   

Grazing impact of mesozooplankton in an upwelling region off northern California, 2000–2003     

Anne M. Slaughter  Stephen M. Bollens  Gretchen Rollwagen Bollens   《Deep Sea Research Part II: Topical Studies in Oceanography》2006,53(25-26):3099

Mesozooplankton (>200 μm) grazing impact (% phytoplankton standing crop consumed d⁻¹) was determined by the gut fluorescence method during three springs (2000, 2001 and 2002) and two winters (2002 and 2003) in a coastal upwelling region off northern California. Wind events, in terms of both magnitude and duration, varied inter-annually and seasonally and included both upwelling-favorable and relaxation events. Grazing impact of mesozooplankton also varied inter-annually and seasonally, and was highest during June 2000 (mean=129% of standing crop d⁻¹), a prolonged period of wind “relaxation” and phytoplankton bloom. In contrast, mean grazing impact was lower during periods of stronger, more persistent winds, more active upwelling, greater cross-shelf transport, and lower chlorophyll concentration (25% and 38% in May–June 2001 and 2002, respectively). Wintertime conditions (January 2002 and 2003) were characterized by weakly upwelling or downwelling-favorable winds, low chlorophyll concentration, and lower mean mesozooplankton grazing impact (13% and 12%, respectively). The larger (>500 μm) size class contributed proportionally more to total mesozooplankton (>200 μm) grazing impact than the smaller (200–500 μm) size class during all sampling periods except spring 2002. These results suggest that mesozooplankton grazing impact is higher in spring than in winter, and that during the spring upwelling season, grazing is higher during periods of wind relaxation (weak upwelling) than during periods of stronger upwelling. Further, these results suggest an important role of mesozooplankton grazers on phytoplankton dynamics in the upwelling region off northern California.  相似文献   

胶州湾产蓝色素海洋链霉菌的初步研究     

侯竹美  王淑军  赵方庆  王宏华  秦松  崔洪霞 《海洋科学》2007,31(5):39-44

在胶州湾沿海采取泥样和水样,从中分离了300余株海洋链霉菌(marine Streptomyces),并对其生理生化性质作了初步研究,建立了胶州湾海洋链霉菌菌种库。在该菌种库中,约有3%的菌株可产生天然蓝色素。其中一株海洋链霉菌(marine Streptomycessp.)M259能够高产天然蓝色素。M259对绿脓杆菌(Pseudomonas areuginosa)、隐球菌(Crytococcal meningitis)有较强的抑菌活性。对其生理生化性质进行了鉴定,结果表明它可以利用可溶性淀粉、甘油、蔗糖、甘露醇、葡萄糖、D-半乳糖、果糖、阿拉伯糖、肌醇、木糖、D-甘露糖、核糖等碳源;能利用大部分氮源,尤其对酵母粉的利用很显著;最适生长pH为7.0~7.4;最适培养温度为28~30℃。结果提示它属于蓝色类群,并与天蓝色链霉菌(Streptomyces cyanogenus)和产蓝链霉菌(Streptomyces ceolicolor)亲缘关系最为密切。此外还优化了M259的发酵培养基和培养条件,使得蓝色素在摇瓶条件下,OD590达到7.74。通过对M259所产蓝色素性质的研究,发现此色素水溶性较强,耐热性较好,在酸性条件下呈红色,在碱性条件下呈蓝色。此外,毒性实验的结果表明所提纯的蓝色素没有毒性,为进一步开发和利用该色素提供了可能。  相似文献