Growth of Plankton (Scenedesmus acutus (Chlorophyceae) and Moina macracopa (Cladocera)) on Domestic Wastewater     

S. Nandini  Ricardo Alonso‐Soto  S. S. S. Sarma 《洁净——土壤、空气、水》2013,41(1):11-15

The population growth of the freshwater chlorophyte, Scenedesmus acutus and the cladoceran Moina macrocopa cultured in the laboratory and in microcosms of a wastewater treatment plant was studied. S. acutus was cultured in a defined algal medium and mixed with wastewater. On diets of S. acutus cultured using Bold medium or a mixture with wastewater, the peak densities of M. macrocopa were 6–7 ind. mL^?1, while on a diet of algae cultured on wastewater alone the cladoceran density fluctuated around 2 ind. mL^?1. Population growth rates of M. macrocopa, which ranged from 0.3 to 0.4 d^?1, were significantly lower on alga cultured in wastewater alone. The body size structure of M. macrocopa was larger on algae cultured in Bold medium than in wastewater. Peak densities of M. macrocopa were around 700 ind. L^?1 when the organic matter in the containers was supplemented with algae but it reached lower densities (400 ind. L^?1) when cultured on the organic matter in wastewater alone. Our study indicates that the nutrients in the final stages of wastewater treatment can support the growth of both phytoplankton and zooplankton.  相似文献   

湖南大龙洞流域不同岩性不同土地利用类型条件下碳酸盐岩试片的溶蚀速率   总被引：4，自引：2，他引：2  

王文娟  蓝芙宁  蒋忠诚  覃小群  劳文科 《中国岩溶》2013,32(1):29-33

选择湖南大龙洞流域寒武系中统熬溪组上段(∈2a3)白云岩、寒武系上统比条组下段(∈3b1)和奥陶系中统牯牛潭组(O2g)灰岩进行野外溶蚀试验,并测试林地和草地类型土壤剖面20cm、50cm深度土壤CO2浓度和有机质含量,以探讨林地、草地土地利用类型条件下试片溶蚀速率的差异特征。结果表明:(1)O2g、∈3b1和∈2a33种试片溶蚀速率在林地和草地土下20cm、50cm深度差异明显,∈3b1g灰岩林地土下20cm试片的溶蚀速率最大,达357.93mg/(m2?d);(2)试片溶蚀速率受岩性影响明显,CaO含量高,溶蚀速率大,O2g、∈3b1灰岩中CaO含量分别为35.38%、47.45%,较∈2a3白云岩的含量32.64%高,因而其溶蚀速率也较∈2a3的大;(3)埋放于林地土壤的试片其溶蚀速率大于草地,表明土地类型对溶蚀速率有较大的影响,植被从草地向林地的正向演替有利于岩溶作用的进行。   相似文献   

洋山港海域大型污损生物生态特点   总被引：4，自引：2，他引：2  

王宝强  薛俊增  庄骅  吴惠仙 《海洋学报》2012,34(3):155-162

洋山港是上海国际航运中心的枢纽港。为了解该海域污损生物的群落结构及演变趋势,2009年3月至2010年3月在洋山港海域进行了周年污损生物挂板调查研究。洋山港海域污损生物种类较少,共记录污损生物19种,隶属于5个类群,优势种为僧帽牡蛎(Ostrea cucullata)、网纹纹藤壶(Balanus reliculatus) 、大室膜孔苔虫(Membranipora grandicella)、厦门华藻苔虫(Sinoflustra amoyensis)、双钩楯琥珀苔虫(Aspidelectra bihamata)、中胚花筒螅(Tubularia mesembryanthemum)、曲膝薮枝螅(Obelia geniculata)和亚洲帚毛虫(Sabellaria ishikawai),种类组成以广布种为主,同时部分具有河口低盐种的特征;污损生物的附着高峰期是6—10月份,除冬季月份外,其余月份均有生物附着;受盐度、水流及泥沙含量的影响,洋山港污损生物的生物量变化较大,月板、季板及年板的平均附着生物量分别为9.20,127.20和774.04 g/m2。另外,通过对洋山港海域污损生物周年的物种组成和群落结构变化分析,发现该海域污损生物群落受季节变化和盐度的升高影响较大,群落结构不稳定,物种演替明显。  相似文献   

Rickettsia-like organism infection associated with mass mortalities of blood clam, Tegillarca granosa, in the Yueqing Bay in China     

ZHU Zewen  XU Ting  HE Zhongyang  WU Xinzhong  WU Liuji  MENG Qingguo  HUANG Jiaqing 《海洋学报(英文版)》2012,31(1):106-115

A series of mass mortalities of the cultured blood clam, Tegillarca granosa, occurred in the Yueqing Bay of China from 2005 to 2009. An obligate intracellular prokaryote, designated as rickettsia-like organism (RLO), was frequently found in the moribund or dead blood clam sample during ultrastructural examination. These organisms were usually round, ellipsoid or occasionally dumbbell-shaped, ranged from approximately 0.28 to 0.71 μm in size and had a trilaminar cell wall. Two reproductive modes of organisms, transverse binary fission and budding, were observed. The organisms were able to form eosinophilic inclusions. Most inclusions were found within epithelial and connective tissues of the mantle, gills and digestive tube. The biological and morphological characteristics indicate that these organisms may belong to the family Rickettsiaceae. RLOs exhibited significant pathogenicity. Cytopathological examinations revealed extensive necrosis and destruction in the infected cell. The degree of tissue destruction was positively related to the number of RLO inclusions in the tissues, and the cytopathological effects were positively related to the number of intracellular RLO. RLOs and their inclusions were discovered throughout different disease areas and in different time periods. The infection intensity of the RLOs was positively correlated with the mortality rate of clams. Therefore, RLO infection might be associated with mass mortalities of cultured blood clams in the Yueqing Bay.  相似文献   

经典地缘政治理论研究视角及其对发展中国新地缘政治理论的启示   总被引：2，自引：0，他引：2  

胡志丁  骆华松  葛岳静 《热带地理》2014,34(2):184-190

纵观历史,任何一个国家的崛起都会给全球稳定和地缘格局带来影响。到目前为止,地缘政治学发展了4个经典的地缘政治理论,即国家有机体论、海权论、陆权论和边缘地带论。每一个理论的提出都是研究者根据自身所处国家现实、地缘格局和地理冲突而提出的。面对中国崛起、海外贸易激增、周边矛盾冲突不断,为了实现国家和平崛起,中国需要相应的地缘理论指导。通过对4个经典地缘政治理论文本的解读,文章首先归纳了经典地缘政治理论的2个视角,即空间视角和权力视角。其次结合英国、美国不同时间段地理冲突和国家实力的变化,从空间冲突和实力变迁2个方面对以上2个视角作历史佐证,并据此进一步以英国、美国和日本为例分析了经典地缘政治理论的缺陷,即理论上的合理性和实践上的不可行性。此外,经典地缘政治理论还存在现实和理论2个方面困境,现实困境是指任何理论都是特定历史背景产物,不能满足现实发展需求;理论困境是指经典地缘政治理论过于强调物质因素,忽视非物质因素。最后指出对发展中国新地缘政治理论的3点启示,并结合西方政治地理学新发展讨论中国政治地理学发展方向问题。  相似文献   

Re-interpretation of the classical geopolitical theories in a critical geopolitical perspective   总被引：2，自引：0，他引：2  

Zhiding Hu  Dadao Lu 《地理学报(英文版)》2016,26(12):1769-1784

Struggling for supremacy between great powers and the rise or fall and regime change of great powers are all subject to the Geopolitical Law. Geographers should keep in step with the times, accurately grasp the national interests, and seize the opportunity to contribute to the great rejuvenation of our nation. However, due to lack of criticism on the history and philosophy of geopolitics, we can neither accurately understand the geopolitical theory, nor effectively put the geopolitical theory into practice. This paper introduces the development of critical geopolitics, summarizes the three characteristics of critical geopolitics, and interprets the four classical geopolitical theories accordingly. In order to simplify the interpretation process, this paper firstly presents an analytical framework for interpretation of four classical geopolitical theories; secondly, focuses on interpretation of “The Geographical Pivot of History” put forward by Mackinder according to the analytical framework; finally, critically summarizes the four classical geopolitical theories. Through the critical interpretation, this paper draws a conclusion that there are the scientific, hypothetical and conceptual classical geopolitical theories. The construction of classical geopolitical theories is based on the international geopolitical structure, spatial distribution of national interests and inter-state spatial conflict, in order to show the identity of theoretical constructor, so as to reflect the historicality, sociality, situationality and geographical knowledge–power structure of geopolitical theories.  相似文献   

遵义黄家湾镍钼多金属矿成矿特征与成因   总被引：4，自引：0，他引：4       下载免费PDF全文

周洁  胡凯  毛建仁 《地质找矿论丛》2009,24(2):111-116

贵州遵义地区黄家湾镍钼多金属矿是寒武系底部的黑色页岩型矿床。黑色岩系中微量元素特征显示镍钼多金属矿层的Ni,Mo,Cd,V,Cu,Zn明显富集,而高场强元素Nb,Th,Hf,Zr,Ti亏损。稀土元素显示多金属矿层的艿（Eu）呈正异常,中稀土富集,重稀土亏损。结合镜下观察发现的有机质、红藻囊果与金属硫化物之间密切的共生关系和前人研究结果,分析了黑色岩系镍钼多金属矿的成因,认为镍、钼、铜、锌等金属元素的来源与热液有关,通过生物作用聚集并在缺氧的还原沉积环境下大量堆积,富集形成Ni—Mo金属硫化物矿床。  相似文献   

青藏高原东北部全新世泥炭正构烷烃的生物记录   总被引：2，自引：0，他引：2  

郑艳红  周卫健  谢树成 《沉积学报》2009,27(1):142-146

通过对正构烷烃分布特点的系统分析,恢复了青藏高原东北部全新世以来泥炭的生物记录。正构烷烃nC25和nC31相对含量在泥炭序列中呈现的规律性变化揭示出,在全新世期间因气候的变化幅度不同而引起了生物形态种或化学种的取代,即当气候变化幅度大时,沼泽地可能出现了水生植物和陆生植物群落之间的相互演替;当气候波动小时,则出现了分子（化学）种之间的相互取代。将这一研究结果与同一地区的孢粉资料对比、验证,分析了它们之间的差异性,提出了类脂分子化石可作为恢复植被的有效工具,与孢粉相结合,可获取更为全面的植被演化历史。这一研究为青藏高原地区全新世以来的有关生物学信息提供了新的证据。  相似文献   

柴达木盆地东北缘石炭系生物礁发育特征及其地质意义     

王志金  陈世悦  马帅  汪峰 《沉积学报》2017,35(6):1177-1185

对柴达木盆地东北缘石炭系地层中生物礁的发育特征及区域展布进行了系统阐述。基于野外实地考察与室内镜下分析,采用地球化学与岩石学方法相结合,总结归纳柴达木盆地东北缘石炭系生物礁的岩石学特征、生物特征以及地层特征,分析生物礁主要产出层位及规模大小,探讨其古环境与油气地质意义。研究结果表明:柴达木盆地东北缘石炭系造礁生物主要为四射珊瑚,其次为横板珊瑚,发育锥状、盘状的单体珊瑚和管状、丛状、蜂窝状的群体珊瑚,附礁生物为腕足、等;珊瑚礁在岩层中以点状产出,呈不连续带状分布,依据其在地层中的发育规律与展布特征,分为簇状竖直丛生管状珊瑚、簇状水平延伸管状珊瑚以及簇状顶端向下倾斜管状珊瑚;根据岩石中的生物颗粒含量,生物礁灰岩储层岩石类型分为珊瑚骨架灰岩、珊瑚颗粒石灰岩、生物颗粒质石灰岩、含生物颗粒石灰岩以及泥晶灰岩。柴达木盆地东北缘早石炭世以碳酸盐台地环境为主,晚石炭世以海陆交互的潮坪环境为主。研究区石炭系生物礁主要位于下石炭统怀头他拉组三、四段,在石灰沟、旺尕秀等剖面可见厚层油砂,指示柴达木盆地东北缘石炭系具有良好的生烃潜力。  相似文献   

华北地区上古生界煤系有机质热演化与二次生烃探讨   总被引：8，自引：0，他引：8  

郑礼全  李贤庆等 《中国煤田地质》2001,13(4):16-19

根据实测和收集整理华北地区各区块约2000余个镜质组反射率Ro的分析数据,结合前人研究成果,较为系统地阐述了华北地区上古生界煤系有机质的热演化特征与成烃演化阶段性,探讨了其二次生烃条件,初步确定了华北地区二次生烃的分布范围。  相似文献