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   

长江口邻近海域浮游细菌分布与环境因子的关系   总被引：5，自引：0，他引：5  

李云  李道季 《海洋通报》2007,26(6):9-18

利用2003年9-10月"东海陆架水交换"调查航次期间获得的浮游异养细菌、寡营养细菌和光合细菌的分布资料和实测水环境数据,探讨了这三类细菌的分布特征及其与相关环境因子的关系。结果表明:在长江口邻近海域,以30等盐线为界,三类细菌的空间分布具有显著差异;调节制约这三类细菌类群生长和分布的环境因子不同;表层硝酸盐浓度1μmol/L可作为一个特征浓度,高于1μmol/L的海域,陆源输入的硝酸盐对于这三类细菌的生长和分布具有重要影响,低于1μmol/L的海域,硝酸盐的影响较小或无影响。同时,采用法国梅里埃API STAPH系统,结合电镜观察,对两株已获得纯培养的有色菌株进行了属种的鉴定,分别是变异微球菌(Micrococcus varians)和玫瑰微球菌(Micrococcus roseus),目前尚未发现这两种细菌在长江口及其邻近海域分布的报道。  相似文献   

南海北部微微型光合浮游生物的丰度及环境调控   总被引：20，自引：5，他引：20       下载免费PDF全文

宁修仁  蔡昱明  李国为  史君贤 《海洋学报》2003,25(3):83-97

1999年夏季首次在南海北部海域进行了微微型光合浮游生物(photosynthetic picoplankton)的观测研究,发现了聚球藻(Synechococcus,Syn)、原绿球藻(Prochlorococcus,Pro)和真核球藻(Eukaryotes,Euk)3类微微型光合浮游生物存在,并对其丰度与分布及其环境调控机制进行了研究.结果表明,研究海区Syn,Pro和Euk丰度的总平均值分别为(5.0±7.6)×104,(4.6±4.2)×104和(1.8±1.1)×103个/cm3,Syn种群丰度的高值大多出现在营养盐丰富的雷州半岛及海南岛东部海域的河口、沿岸带与陆架,北部湾次之,是陆坡和开阔海的数十分之一;其水层分布主要在跃层以上,跃层以下其值迅速降低,发现Pro存在两个不同种群:表层种群和深层种群,前者分布型式与Syn相似,后者的分布型式迥然不同,其丰度向营养盐贫瘠的外海、陆坡和开阔海显著增高;同时发现Pro水层分布的高值主要出现在真光层的底部,并往往出现在硝酸盐跃层之上,Euk在不同海域的分布差异不如Syn和Pro来得大,但仍以沿岸带与陆架为高,陆坡与开阔海较低,水层分布的高值大多出现在真光层的底部,而且它是对次表层叶绿素a极大值的主要贡献者,这些分布型式的差异,取决于环境的调控和3类生物生态生理适应的差异.研究海区Syn,Pro和Euk 3类微微型光合浮游生物对微微型光合浮游生物生态生理适应的差异.研究海区Syn,Pro和Euk3类微微型光合浮游生物对微微型光合浮游生物群落总丰度的贡献分别为50.996,47.3%和1.8%.  相似文献   

地表“矿物膜”中锐钛矿-β-胡萝卜素协同增强日光响应特性研究     

葛潇  刘佳  黎晏彰  王长秋  鲁安怀  李艳  丁竑瑞 《矿物岩石地球化学通报》2021,40(2):491-498

为探究"矿物膜"中半导体矿物与光合色素间的日光响应协同作用,对采自安徽潜山市郊的"矿物膜"样品进行了矿物组成和色素组成分析。同步辐射X射线粉末衍射测定表明,样品富含锐钛矿、赤铁矿等半导体矿物;拉曼光谱证实其中存在地表广泛分布的光合色素:β-胡萝卜素。在此基础上开展锐钛矿-β-胡萝卜素协同增强日光响应模拟实验。合成锐钛矿电极并对其进行系统的矿物学表征,紫外-可见漫反射吸收谱计算其禁带宽度约为3.07 eV;莫特-肖特基计算得到的平带电位约为-0.16 V,载流子浓度约为3.25×1026 cm-3;光电化学测试结果显示其具有一定可见光光电转化能力。经β-胡萝卜素敏化处理后,锐钛矿电极平均光电流密度提升了400%,在425~550 nm间光吸收值提高,该波段位于日光辐射能量集中的波长范围内,且与β-胡萝卜素吸收范围吻合,表明二者间存在日光吸收及光电响应协同增强作用。  相似文献   

光合作用微生物席主导的寒武系苗岭统崮山组均一石:以山东省泗水县圣水峪剖面为例^*          下载免费PDF全文

梅冥相 《古地理学报》2021,23(2):335-358

作为一种缺乏沉积构造的隐晶质块状泥晶所表征的非纹层状微生物碳酸盐岩类型,均一石自从命名之后就很少被描述或自古老的地层记录之中被识别出来,再加上缺乏现代实例,造成了对这种微生物碳酸盐岩类型研究的困难。来自于山东省泗水县圣水峪剖面寒武系苗岭统崮山组中的均一石,以厚层块状、缺乏沉积构造的泥晶灰岩为主,表现为生物层状的微生物礁,与相对较深水的中厚层中至深缓坡相的条带状泥晶灰岩和泥灰岩一起,构成较为典型的潮下型碳酸盐岩米级旋回,集中发育在淹没不整合型三级沉积层序顶部的强迫型海退体系域之中,代表着相对海平面下降阶段的沉积记录。在这些主导着生物层状微生物礁灰岩的均一石中,不均匀地高密度保存着致密缠绕以及较薄的泥晶壁所成型的丝状葛万菌物质体是其最为基本的特征,表明均一石形成于光合作用微生物席复杂的钙化作用。另外,在均一石的致密泥晶组构中,局部发育毫米级至厘米级大小而且形态极端不规则的亮晶显微管状组构。基于其特别的组构特征,将这样的组构解释为具有公共鞘的丝状蓝细菌即念珠菌菌落的钙化作用残余物,其致密泥晶组构可能代表着蓝细菌公共鞘的钙化作用残余物,其中的亮晶显微管则可能为蓝细菌丝状体的钙化作用残余物,而且在这样的组构之中还发育和共生着丝状葛万菌菌落,从而延伸了对蓝细菌菌落钙化作用残余物的认识和解释,并对具这种组构的海绵木乃伊解释提供了另外一种重要的研究镜像。因此,山东省泗水县圣水峪剖面寒武系苗岭统崮山组上部生物层状微生物礁体中的均一石,不仅提供了一个较为典型的寒武纪苗岭世不借助于二氧化碳浓缩作用机制(CCM机制)的蓝细菌钙化作用的实例,而且提供了一个在丝状蓝细菌主导的微生物席之中发育着念珠菌菌落的多重状微生物席的典型实例,从而拓宽了对显生宙最高的大气圈CO₂含量以及较高的大气圈O₂含量条件下的较为典型的方解石海中与寒武纪后生动物大爆发相平行的蓝细菌繁荣和钙化作用的了解。  相似文献   

Middle Cretaceous pCO2 Variation in Yumen,Gansu Province and its Response to the Climate Events     

LEI Xiangtong  DU Zhen  DU Baoxi  ZHANG Mingzhen  SUN Bainian 《《地质学报》英文版》2018,92(2):801-813

The palaeo-atmospheric CO_2 concentration(pCO_2) variation in the Yumen, Gansu Province during the middle Cretaceous has been reconstructed using the newly established plant photosynthetic gas exchange mechanistic model, and the results show that the p CO_2 values are in the range of about 550–808 ppmv. The present pCO_2 values are higher than the p CO2 results(531–641 ppmv) of the previous study according to the Recent standardization of the stomatal ratio method, and much lower than the pCO_2 results(882–1060 ppmv) according to the Carboniferous standardization of the stomatal ratio method. The present pCO_2 variation is not only within the error range of GEOCARBⅡ and GEOCARB Ⅲ but also is similar to the reconstructed results based on the biochemistry and carbon isotope models. Besides, the present Brachyphyllum specimens were collected from four consecutive horizons of the upper Zhonggou Formation of the Hanxia Section, and the reconstructed pCO_2 exhibits the reconstructed pCO_2 exhibits a decline trend during the late Aptian to early Albian. This decline variation is probably associated with the Oceanic Anoxic Events(OAE1 b) and the Cold snap event. With the combination of p CO_2 during the Albian to Cenomanian recovered by the plant photosynthetic gas exchange mechanistic model, the pCO_2 showed a prominent increase during the late Aptian to early Cenominian, which indicates a response to the greenhouse warming during the middle Cretaceous. Therefore, the mechanical model of the plant photosynthetic gas exchange shows a relatively strong accuracy in the reconstruction of the pCO_2 and can reflect a strong relation between the atmospheric CO_2 concentrations and climatic events.  相似文献   

Role of carotenoids in lake sediments for reconstructing trophic history during the late Quaternary     

Hans Züllig 《Journal of Paleolimnology》1989,2(1):23-40

Cultural eutrophication of lakes occurring over the last 100 years is well known. Less well known is the eutrophication of lakes in earlier, late Quaternary time due to human and other causes. The recent and earlier trophic changes are documented in the sedimentary record by several groups of parameters. Among the most revealing of these are the diverse carotenoid pigments that originate from phytoplankton, photosynthetic bacteria, and other biota. The interpretation of the carotenoids in ancient sediments is facilitated by the study of carotenoids in recent sediments from lakes with relevant limnological and historical information. I support these contentions with evidence from several Swiss lakes, with emphasis on the late Quaternary development of Pfaffikersee and Soppensee.This is the eighth of a series of papers to be published by this journal that was presented in the paleolimnology sessions organized by R. B. Davis and H. Löffler for the XIIth Congress of the International Union for Quaternary Research (INQUA), which took place in Ottawa, Canada in August 1987. Drs. Davis and Löffler are serving as guest editors of this series.  相似文献   

ASPECTS OF IRON NUTRITION IN MACROALGAE ULVA PERTUSA (CHLOROPHYTA) UNDER IRON STRESS     

刘静雯  董双林  刘晓云 《中国海洋湖沼学报》2002,20(2)

ＩＮＴＲＯＤＵＣＴＩＯＮＩｒｏｎｉｓａｎｉｍｐｏｒｔａｎｔｎｕｔｒｉｔｉｏｎａｌｅｌｅｍｅｎｔｉｎａｌｇａｅｊｕｓｔａｓｉｔｉｓｉｎｈｉｇｈｐｌａｎｔｍｅｔａｂｏｌｉｃｐａｔｈｗａｙｓ.Ｐｈｏｔｏｓｙｎｔｈｅｓｉｓｉｓｄｅｐｅｎｄｅｎｔｏｎｔｈｉｓｅｌｅｍｅｎｔｂｅｃａｕｓｅｃｈｌｏｒｏｐｈｙｌｌｓｙｎｔｈｅｓｉｓｒｅｑｕｉｒｅｓｉｒｏｎｎｕｔｒｉｔｉｏｎ .Ｉｒｏｎｉｓａｌｓｏｅｓｓｅｎｔｉａｌｆｏｒｃｙｔｏｃｈｒｏｍｅｓ,ｆｅｒｒｅｄｏｘｉｎ ,ａｎｄＦｅ ｓｐｒｏｔｅｉｎ .Ｉｔｓｂｉｏｃｈｅｍｉ…  相似文献   

Treating ballast water with hydroxyl radical on introduced organisms   总被引：4，自引：0，他引：4  

张芝涛  白敏菂肖宇 白敏冬杨波  白希尧 《中国海洋湖沼学报》2006,24(2):161-167

1 INTRODUCTION The introduction of invasive marine species into new environments by ship’s ballast water, by attaching to ships’ hulls or via other vectors has been recognized as one of the four major threats to the world’s oceans by Global Environment…  相似文献