东风港滨岸缓冲带对水生生物群落结构的影响

选择苏州河的支流东风港为研究对象,选取其中一段人工建造滨岸缓冲带作为研究区,调查其水生生物群落并与对照区相比较,以具体说明滨岸缓冲带对水生生物群落结构的影响。通过对研究区与对照区内的浮游植物、浮游动物、底栖动物和大型水生植物的调查研究,结果显示,研究区浮游植物的种类数多于对照区,且以清水种占优势;浮游动物群落结构研究区明显比对照区复杂;底栖动物的种类数、密度和生物量研究区都多于对照区;另外研究区还有较为多样化的大型水生植物群落。这些都表明研究区的水生生物群落结构较对照区更为完善。说明滨岸缓冲带对提高水体生物多样性,完善水生生物群落结构具有较为明显的作用。     

滆湖入湖河流春季大型底栖动物群落结构及水质生物学评价

分别于2018年4月和2019年4月对滆湖入湖河流底栖动物开展调查,并利用生物指数对水质进行生物学评价。结果表明:共鉴定滆湖入湖河流底栖动物28种,以重度耐污种霍甫水丝蚓(优势度为0.46)和中等耐污种铜锈环棱螺(优势度为0.11)占据绝对优势。生物多样性方面以鹤溪河最高,湟里河、扁担河次之,夏溪河及入湖河口最低,水生植物分布是影响各区域底栖动物多样性的重要因素。卡尔森营养状态指数(TSI)与水质污染等级生物评价结果基本一致,以新孟河延伸拓浚工程沿线为界,鹤溪河、夏溪河、湟里河中上游河段处于中度富营养化水平,水体为轻-中污染状态,而下游河段、扁担河及入湖河口处于重度富营养化水平,水体为中-重污染状态。     

巢湖鲤鱼的繁殖及人工鱼巢的效果观察报告

巢湖是我省最大的湖泊,面积为113万亩。湖水一般2—3米深,最深处可达4.9米。底质多系沙质壤土和粘土,淤泥层较薄。湖内浮游生物、底栖动物种类较多,惟水生维管束植物贫乏。巢湖周围有柘皋河、南淝河、派河、丰乐河、杭埠河及鸡兆河等主要入湖河流,裕溪河由巢湖流往长江。     

香溪河水质空间分布特性研究

运用聚类分析和主成分分析对香溪河19个样点水质的理化特性进行研究,聚类分析表明,根据各采样点之间水质组分的相似性可将香溪河大致分为3个河段,分别属于不同的亚流域,各亚流域问的特征差异显著,对各河段水质的主成分分析表明,上述3河段的主要水质信息差异很大,第1河段(在河流上游)水质的信息主要体现为总碱度和硬度,第2河段(河流中游)主要体现为可溶性磷酸盐、总磷和氯离子,第3河段(河流下游)则为pH、亚硝酸盐氮、总氮和COD,文中结合香溪河流域地理环境背景,探讨了香溪河水质空间分布格局的成因,为分析流域水质状况及成因提供了一条简单有效的途径。     

雅鲁藏布江湘河流域浮游生物群落结构的探究与多样性分析

为了探究雅鲁藏布江湘河流域生物群落结构及物种多样性现状,为西藏地区湘河流域浮游生物资源的保护及开发利用提供科学依据。本研究于2017年3～4月对湘河流域浮游生物进行了生物采样与调查,共设置采样点8个。本次调查共检出浮游植物6门61种,其中硅藻门为优势种,共41种,占总种类数的67.21%;绿藻门、蓝藻门次之,分别占总种类数的11.48%;甲藻门、隐藻门与金藻门种类较少。浮游植物密度范围为0.43×10~5～7.2×10~5cells/L,生物量范围为0.036～2.03 mg/L。共检出浮游动物3门44种,其中原生动物门为优势种,共30种,占总种类数的68.18%;轮虫13种;枝角类1种。浮游动物密度范围为1.5×10~5～1.66×10~6cells/L,生物量范围为0.9×10~(-3)～5.7×10~(-2)mg/L。各调查点浮游植物/浮游动物Shannon-Wiener多样性指数(H)和均匀度指数(E)平均分别为4.38/3.13和0.93/0.93。多项指数综合评价表明,湘河流域水质处于轻度污染或清洁状态,浮游生物群落结构单一,密度及生物量较低,生态环境较脆弱。     

水电梯级开发对河流生境质量及纵向连通性影响评价——以五布河和藻渡河为例

河流物理生境是维持河流生物多样性及生态功能的关键因素。生境质量的好坏能反应河流健康的程度。以我国西南地区的五布河和藻渡河为例,采用河流生境调查方法(RHS)和树状水系连通性指数(DCI)定量评估水电梯级开发和水坝建设对河流物理生境质量和河流纵向连通性的影响。结果表明,水电梯级开发后,五布河干流未受水坝明显影响河段、库区河段、减水河段分别为20.48、43.34、18.09 km,占总长度的25.0%、52.9%、22.1%。藻渡河干流河口至双河口段未受水坝明显影响河段、库区河段、减水河段分别为58.61、8.28、18.99 km,占总长度的68.2%、9.6%、占22.1%。水电梯级开发后,五布河干流河流片段由26个增至29个,藻渡河干流河流片段由2个增至5个。两条河流纵向连通性分别降低了7.8%和38.0%。五布河坝下减水河段生境质量降低14.1%,库区河段生境质量变化不明显。藻渡河减水河段生境质量与近自然河段无显著差异;两座坝后式电站库区河段生境质量明显低于近自然河段。水电梯级开发对两条河流物理生境的影响与水坝位置选择、建坝前的自然阻隔数量与分布、河流地貌特征、水电资源开发方式等密切相关。     

巢湖及其支流浮游动物群落结构特征及水质评价

2013年9月至2014年6月对巢湖及柘皋河、杭埠河、南淝河3条支流的浮游动物进行了调查,共检出浮游动物297种,其中,原生动物124种,轮虫135种,枝角类29种,桡足类9种。南淝河浮游动物物种数最多,为203种,巢湖最少,为130种;巢湖及3条支流均以原生动物和轮虫物种数最多。浮游动物总密度为644 223 ind/L,柘皋河浮游动物密度最高,巢湖浮游动物密度最低,巢湖及3条支流原生动物密度占浮游动物总密度的比例均为最高;四个季节柘皋河浮游动物密度均为最高。浮游动物总生物量为253.14 mg/L,南淝河浮游动物生物量最高,杭埠河和巢湖浮游动物生物量较低;春季和冬季柘皋河浮游动物生物量最高,夏季和秋季南淝河浮游动物生物量最高。相较3条支流,巢湖浮游动物优势种数最少。依据理化指标,巢湖及3条支流为富营养或超富营养水平,营养水平为:南淝河巢湖柘皋河杭埠河。浮游动物群落结构和环境因子的冗余分析(RDA)表明,巢湖及3条支流浮游动物群落结构在四个季节均未能明显区分开,浮游动物群落和环境理化因子的相关性较小。     

河乌繁殖生态的研究

河乌为栖息于水域的鸟类中生活习性较特殊的种类,以水中的昆虫和河流附近的害虫为食,在新疆分布于天山南北。3月左右开始婚配,夏、秋两季一般可以繁殖1—2次。每窝产4—5枚卵,孵化期为16—18天,雏鸟需要25—28天育成。河乌通常成对活动,贴水面飞行,生活在湍流溪河的两岸。冬季聚成小群常以2—7只在河道的冰洞及不冻水域活动、觅食。     

封面说明

正封面图片由重庆大学建筑城规学院袁兴中教授于2018年11月18日拍摄于三峡库区重庆澎溪河湿地市级自然保护区(31°08′60″ N,108°33′50″ E)。其气候属亚热带湿润季风气候,年均气温18.5 ℃,年降水量1385 mm。该区属盆东平行岭谷中低山丘陵区,受地质构造和岩性控制,形成"四山三丘三分坝"的地貌特征。区内紫色土、冲积土广布。澎溪河干流为保护区内主要河流,普里河、白夹溪分别于右岸和左岸汇入澎溪河。由于三峡水库"蓄清排浑     

企业群落与企业群落学

根据自然生物群落学的原理,通过分析企业群落的形态和机能特征、群落演替和生命周期等规律,证明了企业群落也是自然生物群落。从而提出了“企业群落学是研究企业群落形态结构和功能、群落内部、群落之间、群落与宏观经济系统以及群落与其他环境之间相互作用的生态关系的学科”这一新的概念。企业群落学是自然科学——生物群落学向社会科学的拓展,是社会科学与自然科学原理相互融合的新探索。     

Recent advances in the study of Kaposi's sarcoma-associated herpesvirus replication and pathogenesis

It has now been over twenty years since a novel herpesviral genome was identified in Kaposi's sarcoma biopsies. Since then, the cumulative research effort by molecular biologists, virologists, clinicians, and epidemiologists alike has led to the extensive characterization of this tumor virus, Kaposi's sarcoma-associated herpesvirus(KSHV; also known as human herpesvirus 8(HHV-8)), and its associated diseases. Here we review the current knowledge of KSHV biology and pathogenesis, with a particular emphasis on new and exciting advances in the field of epigenetics. We also discuss the development and practicality of various cell culture and animal model systems to study KSHV replication and pathogenesis.     

The structure, reproduction and taxonomy of Vidalia and Osmundaria (Rhodophyta, Rhodomelaceae)

Comprises species occurring mostly in subtidal habitats in tropical, subtropical and warm-temperate areas of the world. An analysis of the type species, V. spiralis (Sonder) Lamouroux ex J. Agardh, a species from Australia, establishes basic characters for distinguishing species in the genus. These characters are (1) branching patterns of thalli, (2) flat blades that may be spiralled on their axis, (3) width of the blade, (4) primary or secondary derivation of sterile and fertile branchlets and (5) position of sterile and fertile branchlets on the thalli. Application of the latter two characters provides an important basic method for separation of species into three major groups. Osmundaria , a genus known only in southern Australia, was studied in relation to Vidalia , and its separation from the Vidalia assemblage is not accepted. Species of Vidalia therefore are transferred to the older genus name, Osmundaria. Two new species, Osmundaria papenfussii and Osmundaria oliveae are described from Natal. Confusion in the usage of the epithet, Vidalia fimbriala Brown ex Turner has been clarified, and Vidalia gregaria Falkenberg, described as an epiphyte on Osmundaria pro/ifera Lamouroux, is revealed to be young branches of the host, Osmundaria prolifera.     

New or rare chromosome counts in Artemisia L. (Asteraceae, Anthemideae) and related genera from Kazakhstan

Fifteen chromosome counts of six Artemisia taxa and one species of each of the genera Brachanthemum, Hippolytia, Kaschgaria, Lepidolopsis and Turaniphytum are reported from Kazakhstan. Three of them are new reports, two are not consistent with previous counts and the remainder are confirmations of very scarce (one to four) earlier records. All the populations studied have the same basic chromosome number, x = 9, with ploidy levels ranging from 2x to 6x. Some correlations between ploidy level, morphological characters and distribution are noted.     

肝癌中HBV和HCV基因和抗原的分布及意义

采用原位分子杂交方法检测HCV RNA及HBV X基因;采用免疫组织化学方法研究HCV核心抗原,非结构区C33c抗原及HBxAg在肝细胞肝癌中的定位及分布.结果表明(1)HCV RNA、HBV X基因在肝细胞肝癌组织检出率分别为40%(55/136)和82%(112/136).HCV RNA定位于癌细胞的胞浆内,阳性细胞呈散在、灶状及弥漫分布三种形式;HBV X基因在肝癌细胞中的分布呈胞浆型、核型及核浆型,阳性细胞也呈上述三种分布形式;(2)HCV C33c抗原、核心抗原在肝细胞肝癌中的阳性率为81%(133/164)及86%(141/164).C33c抗原定位于癌细胞及肝细胞的胞浆内;核心抗原既定位于癌细胞核中,又可定位于胞浆中.C33c抗原阳性细胞以灶状分布为主;而核心抗原阳性细     

Selection with two alleles and complete dominance

For a plant selection model with frequency-independent viabilities, fertilities and selfing rates, it is shown that apart from global fixation, for certain parameter combinations a protected polymorphism and facultative fixation (either allele may become fixed according to initial frequencies) may both occur. Facultative fixation requires different selling rates for the dominant and recessive type. Protection of the polymorphism requires resource allocation for male and female function. In this connection the problem of purely genetically caused population extinction is discussed.
For general frequency dependence and regular segregation, the chances for establishment of a completely recessive gene are compared to those of a completely dominant gene. It is proven that the process of establishment of the recessive gene, despite a fitness advantage, may be considerably endangered by drift effects if random mating prevails. The recessive gene may reach the same effectivity in establishment as a dominant gene, only if the recessive homozygote mates exclusively with its own type during the period of establishment.