虾池浮游微藻的种类组成、数量和多样性变动   总被引：6，自引：1，他引：5  

李卓佳  张汉华  郭志勋  贾晓平 《广东海洋大学学报》2005,25(3):29-34

报道了在集约化养虾中应用有益微生物制剂对虾池浮游微藻的影响,分析了整个养虾周期浮游微藻的种类组成、生物量、优势种及多样性指数的周期变化情况。结果表明,早期虾池浮游微藻细胞数量维持在1×103~3×103mL-1的水平,养殖中期开始呈指数增长状态,后期达到顶峰,并维持在70×103~160×103mL-1的水平,生物量比自然海区高。优势种类明显,前期为中肋骨条藻和伏氏海毛藻等硅藻类,后期则为绿球藻和栅列藻等绿藻类,水色及藻相呈良好状态,而不施加芽孢杆菌制剂的对照池则在后期出现较大比例的有害的蓝藻。虾池藻类多样性指数、均匀度指数和种类丰度均呈现前期高后期低的趋势,而优势度指数则相反,呈现前期低后期高的趋势。浮游植物的多样性指数为0.60~3.80,平均为1.88,均匀度指数为0.14~0.83,平均为0.45;种类丰度为0.80~2.46,平均为1.38;优势度指数在0.17~0.85,平均为0.41。多样性指数和均匀度均比粤东海域低,但优势度则甚高。  相似文献   

一株H_5亚型禽流感病毒血凝素基因的克隆与序列分析     

高志杰  梁秋婵  刘铀  陈绍红 《广东海洋大学学报》2007,27(3):107-111

根据GenBank中发表的H5亚型禽流感病毒HA基因序列设计2对引物,用RT-PCR方法从禽流感病毒广东分离病毒株(A/Chicken/Guangdong/1997)中扩增HA基因cDNA片段,并将其克隆至pMD-18T载体进行核苷酸序列测定。结果表明:用2对引物所扩增的片段大小分别约为1300 bp和800 bp,经序列拼接获得的HA基因cDNA长度约为1601 bp,编码533个氨基酸,与国内己发表的11个代表株的核苷酸和氨基酸序列同源性为分别为96.9%~99.9%和86.5%~93.0%;HA基因编码的氨基酸序列的系统进化树也表明A/Chicken/Guang-dong/1997、A/Goose/Huadong/01/2000、A/Ck/Hk/37.4/2002、A/Chicken/Zhoukou/2/02、A/Duck/Guangxi/53/2002、A/Duck/Fujian/01/2002等毒株处于同一进化枝,亲缘关系较近;而与A/Silly/Chicken/Hongkong/SF189/01株处于不同进化枝,亲缘关系较远。  相似文献   

GENETIC DIVERSITY OF THE WILD AND REARED PSEUDOSCIAENA CROCEA     

王军  苏永全  全成干  丁少雄  张纹 《中国海洋湖沼学报》2001,(2)

ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅｌａｒｇｅｙｅｌｌｏｗｃｒｏａｋｅｒＰｓｅｕｄｏｓｃｉａｅｎａｃｒｏｃｅａｏｎｃｅｗａｓｏｎｅｏｆｔｈｅｆｏｕｒｉｍｐｏｒｔａｎｔｍａｒｉｎｅｆｉｓｈ ｅｒｙｏｂｊｅｃｔｓｉｎＣｈｉｎａ (Ｈｏｎｇｅｔａｌ.,1 983;ＨｕａｎｇａｎｄＣａｒｌ,1 983;ＣｈｅｎａｎｄＧｏｎｇ ,1 983) .ＴｈｅｐｒｏｄｕｃｔｉｏｎｏｆｔｈｅｗｉｌｄＰ .ｃｒｏｃｅａｉｎ 1 974ｒｅａｃｈｅｄ 1 971 78ｍｅｔｒｉｃｔｏｎｓ (ＭＴ)ｉｎＣｈｉｎａ (Ｌｉ,1 998) .Ｂｅｃａｕｓｅｏｆｏｖｅｒｆｉｓｈｉｎｇ ,ｔｈ…  相似文献   

Relationship of minimum winter temperature and temperature seasonality to the northern range limit and species richness of trees in North America     

Hong QIAN  ZHANG Yangjian  Robert E.RICKLEFS  Xianli WANG 《地理学报(英文版)》2022,32(2):280-290

Biologists have considered both winter coldness and temperature seasonality as major determinants of the northern limits of plants and animals in the Northern Hemisphere,which in turn drive the well-known latitudinal diversity gradient.However,few studies have tested which of the two climate variables is the primary determinant.In this study,we assess whether winter coldness or temperature seasonality is more strongly associated with the northern latitudinal limits of tree species and with tree species richness in North Amedca.Tree species were recorded in each of 1198 quadrats of 110 km × 110 km in North America.We used correlation and regression analyses to assess the relationship of the latitude of the northern boundary of each species,and of species richness per quadrat,with winter coldness and temperature seasonality.Species richness was analyzed within 38 longitudinal,i.e.,north-south,bands (each being ＞1100 km long and 110 km wide).The latitudes of the north-ern range limits of tree species were three times better correlated with minimum temperatures at those latitudes than with temperature seasonality.On average,minimum temperature and temperature seasonality together explained 81.5％ of the variation in the northern range limits of the tree species examined,and minimum temperature uniquely explained six-fold (33.7％versus 5.8％) more of this variation than did temperature seasonality.Correlations of tree species richness with minimum temperatures were stronger than correlations with tempera-ture seasonality for most of the longitudinal bands analyzed.Compared to temperature sea-sonality,winter coldness is more strongly associated with species distributions at high lati-tudes,and is likely a more important driver of the latitudinal diversity gradient.  相似文献   

Geomorphic connectivity and its application for understanding landscape complexities: a focus on the hydro-geomorphic systems of India     

Manudeo Singh  R. Sinha  S.K. Tandon 《地球表面变化过程与地形》2021,46(1):110-130

Geomorphic processes operate at multiple spatio-temporal scales and different levels of hierarchy. It is therefore necessary to understand the linkages of landscapes across various scales and levels to gain insights into their interactions and feedbacks. Connectivity is an emergent property of the hydro-geomorphic systems, and it is gradually evolving into a unifying concept in geomorphology. The connectivity approach has the potential to be applied extensively to diverse hydro-geomorphic systems of India to understand their complexity as well as for designing effective management practices for river systems and wetlands, optimizing water resources for agriculture, and monitoring and restoration of habitats. Studies on connectivity, particularly in geomorphic context, have been growing steadily in India, albeit at a much slower pace compared to the global trends. This article undertakes a brief overview of the global developments particularly in terms of providing some clarity among the different types of geomorphic connectivity and their inter-relationships and feedbacks. We then take stock of the connectivity research in India in recent years as applied in different hydrogeomorphic systems across the country. We utilize a number of Indian case studies to illustrate the important developments and applications of connectivity concepts, and also present future perspective of this important field with special relevance to India. © 2020 John Wiley & Sons, Ltd.  相似文献   

Influence of cage farming and environmental parameters on spatio-temporal variability of fish assemblage structure in a tropical reservoir of Peninsular India     

《Limnologica》2021

Fish assemblage structure in Palair reservoir, a medium tropical reservoir along the river Paleru, a tributary of river Krishna in Southern India, was studied along the spatial gradient of the impoundment. The abundance and assemblage structure of wild fish aggregated around the fish cage units installed in the reservoir were assessed and compared with other sites. Seasonal sampling was carried out and fish community structure in terms of species composition and abundance, trophic guild, niche, tolerance, resilience and conservation status were analyzed. A total of 38 fish species were recorded wherein the family Cyprinidae dominated in the number of species (15) followed by Cichlidae and Channidae (3 each). Margalef richness index (d), Pielou’s evenness index (J’), Simpson’s index (1-λ) and Shannon index (H’) revealed significant variation across different zones. Species richness was maximum in the Site1 (d = 4.44–5.12), whereas the abundance of individuals was maximum at Site4 (H’ = 2.65–2.86) i.e. near cage in the lacustrine zone. The important species contributing to the dissimilarities among the zones were identified and percentage of their contribution was estimated using SIMPER analysis. Trophic guild of fishes indicated the dominance of omnivorous species followed by carnivores, indicating the heterotrophic phase of the reservoir. The spatial and seasonal variations in the fish assemblage structure were tested applying statistical analyses such as PERMANOVA and nMDS. The results indicated a positive impact of cage farming in supporting the wild fish fauna, influencing the large aggregations of fishes around the cages. The temporal variability in the cage-associated fish assemblage was related to recruitment periods of juveniles (e.g. E. maculates and E. suratensis in summer, and S. seenghala in monsoon seasons). The links between fish assemblages and environmental parameters were explored through DISTILM and the deterministic factors for fish abundance in the reservoir were phosphate, pH, dissolved Oxygen, total hardness and depth. The study also indicated the impacts of cage culture with record of accidental escapes of farmed fish to the reservoir system. The baseline information generated and recommendations formulated in the study are crucial for the conservation of fish diversity, fisheries enhancement and management planning of tropical peninsular reservoirs.  相似文献   

南极长城站空气微生物的分子生态学分析   总被引：1，自引：0，他引：1       下载免费PDF全文

夏晓敏  汪建君  陈立奇  颜金培  张锐 《极地研究》2014,26(2):186-192

微生物是气溶胶的重要组成部分。本研究通过收集南极长城站附近气溶胶,构建气溶胶中空气微生物16S rRNA基因文库,发现南极空气微生物具有很高的多样性,93个克隆子包含了53个OTU(Operational Taxonomic Unit),Shannon指数为3.58,Simpson指数为0.04。南极长城站空气微生物的主要细菌类群为Actinobacteria、Cyanobacteria/Chloroplasts、Bacteroidetes、Firmicutes、Planctomycetes、Proteobacteria及Verrucomicrobia等7个门,Proteobacteria门的细菌是优势类群,占长城站空气微生物细菌克隆文库的65.7%。克隆文库中海源微生物序列及陆源微生物序列各占30.1%,说明长城站附近具有较强的海陆大气交换。我们发现有15个克隆子序列与人类活动相关,占总克隆子数的16.1%,说明人类活动已经影响到了长城站的空气微生物群落结构。  相似文献   

假单胞菌(Pseudomonas sp.cn 4902)甘露醇-1-磷酸脱氢酶基因克隆及表达   总被引：1，自引：1，他引：1  

刘广发  谭静  陈启伟 《海洋与湖沼》2004,35(2):183-188

参照几种生物的甘露醇—1—磷酸脱氢酶基因(mtl D)的序列设计引物，以极端耐盐的假单胞菌(Pseudomonas sp．cn 4902)的总DNA为模板，采用PCR扩增、构建重组高效表达载体以及生物信息学研究等方法，进行基因克隆、表达及功能定性等研究。结果表明，克隆获得一长为1149bp的基因。经蛋白质保守区域研究，初步判别该基因为mtl D结构基因。将该基因与pBV220质粒构建成高效表达原核重组载体pBH。SDS—PAGE电泳表明，含pBH的转化子产生特异的、分子量约为41kD的蛋白带，表达量约占菌体可溶性蛋白6．7％。转化子的耐盐水平比对照提高了约1／5。在含0．9mol／L NaCl的液体培养基中，转化子培养24h后其生物量约是对照的10．2倍，甘露醇含量约是对照的4．1倍。可见，假单胞菌的甘露醇—1—磷酸脱氢酶基因是一个重要的耐盐相关基因，该基因已在GenBank登记，代号为AY112696。  相似文献   

Endocrine effects of methoxylated brominated diphenyl ethers in three in vitro models     

Hu W  Liu H  Sun H  Shen O  Wang X  Lam MH  Giesy JP  Zhang X  Yu H 《Marine pollution bulletin》2011,62(11):2356-2361

Methoxylated brominated diphenyl ethers (MeO-BDEs) in aquatic environments have been found to be primarily of natural origin in the marine environment and not from biotransformation of synthetic PBDEs. Two of the eight MeO-PBDEs (2′-MeO-BDE-68 and 6-MeO-BDE-47) that were detected in anchovy from the Yangtze River Delta, were natural products from marine organisms. So 2′-MeO-BDE-68 and 6-MeO-BDE-47 were chosen to study the potential to modulate androgen, estrogen, or thyroid hormone receptor- (AR, ER, ThR) mediated responses by use of reporter gene assays. 2′-MeO-BDE-68 was antiandrogenic at 50 μM, estrogenic at 10 μM and antiestrogenic at 10 and 50 μM (IC₅₀ = 4.88 μM). 2′-MeO-BDE-68 enhanced luciferase expression by 5 nM T3 at 50 μM. 6-MeO-BDE-47 exhibited potent antiandrogenicity at 1 μM and greater (IC₅₀ = 41.8 μM) and possessed estrogenic activity at 10 μM and antiestrogenic activity at 10 and 50 μM (IC₅₀ = 6.02 μM).  相似文献   

Macrobenthic community response to copper in Shelter Island Yacht Basin, San Diego Bay, California     

Neira C  Mendoza G  Levin LA  Zirino A  Delgadillo-Hinojosa F  Porrachia M  Deheyn DD 《Marine pollution bulletin》2011,62(4):701-717

We examined Cu contamination effects on macrobenthic communities and Cu concentration in invertebrates within Shelter Island Yacht Basin, San Diego Bay, California. Results indicate that at some sites, Cu in sediment has exceeded a threshold for “self defense” mechanisms and highlight the potential negative impacts on benthic faunal communities where Cu accumulates and persists in sediments. At sites with elevated Cu levels in sediment, macrobenthic communities were not only less diverse but also their total biomass and body size (individual biomass) were reduced compared to sites with lower Cu. Cu concentration in tissue varied between species and within the same species, reflecting differing abilities to “regulate” their body load. The spatial complexity of Cu effects in a small marina such as SIYB emphasizes that sediment-quality criteria based solely on laboratory experiments should be used with caution, as they do not necessarily reflect the condition at the community and ecosystem levels.  相似文献