共查询到20条相似文献，搜索用时 546 毫秒
1.
2009年的枯水期（5月）和丰水期（7月）,在桃山水库对浮游植物结构群落和水质状况进行了调查研究,结合生物监测和理化监测手段,基于浮游植物优势度、丰度、优势度以及综合指数评价方法,对研究水库进行了生态评价。结果显示：（1）桃山水库浮游植物共有7门46属73种及变种,其中以绿藻为主,分别占44 %;（2）生物量在2.29-10.96 mg﹒L-1之间,丰度变幅在(38.76-124.44)×105 ind.﹒L-1之间;（3）枯水期优势种以硅藻为主,丰水期优势种以以蓝藻、绿藻为主;（4）综合营养指数为42.0-60.1。综合评价结果表明：桃山水库枯水期和丰水期水质营养状态为轻富营养化,化学需氧量是影响桃山水库浮游植物群落结构的主要环境因子。 相似文献
2.
2011-2012年对三角湖浮游植物进行季节性调查,以了解浮游植物群落结构特征及其对水质的指示作用,为污染防治和生态修复提供依据。结果表明,在三角湖共采集浮游植物94种(变种),隶属于8门、25科、51属;其中,绿藻种类最多,约占总种数的59.6%,其次是硅藻、蓝藻和裸藻,分别占12.8%、11.7%和8.5%,其他门类种类较少。浮游植物细胞密度平均值为(102.32±59.89)×106个/L;其中,蓝藻密度最大,占浮游植物总丰度的86.69%,其次是绿藻和硅藻,分别占7.77%和4.91%,其他门类密度较低。浮游植物密度具有明显的季节变化规律,夏季的密度最大,秋季次之,冬季和春季较低。夏季和秋季蓝藻细胞密度占绝对优势,绿藻和硅藻次之,而冬季蓝藻密度下降,硅藻和绿藻占优势,春季蓝藻又重新占据优势。三角湖浮游植物Margalef丰富度指数、Shannon-Weaver多样性指数和Pielou均匀度指数平均值分别为2.75、1.78和0.46。Shannon-Weaver多样性指数和Pielou均匀度指数以冬季和春季较高,秋季最低,表明冬季和春季浮游植物群落结构相对复杂,而秋季的群落结构相对简单。综合水质生物学和水体理化指标评价结果,三角湖水体为中-富营养型。 相似文献
3.
亚热带水库浮游植物群落结构季节演替及其春季水华成因分析——以浙江汤浦水库为例 总被引：1，自引：0，他引：1
为了研究汤浦水库浮游植物群落结构季节演替及水质状况,于2010年5、8、11月及2011年2月连续4个季节分别对其浮游植物、水文特征和理化因子进行调查分析.结果表明,浮游植物有7门、58属、105种,主要由绿藻、硅藻和蓝藻组成,其物种数季节变化为:夏＞秋＞冬＞春.各样点物种数呈现出由河流区向湖泊区递减的变化趋势.浮游植物丰度变幅较大,在3.27×106～128.90×106个/L,其中冬季丰度最低,春季最高.春季浮游植物主要由硅藻和蓝藻组成,夏季主要由蓝藻和绿藻组成,秋季为隐藻和硅藻,冬季主要由硅藻组成.浮游植物丰度及其多样性指数均表明春季水质最差,且暴发藻类水华,其中微型硅藻链状弯壳藻(Achnanthidium catenatum)为春季水华的绝对优势种.水华暴发可能受降水、水库调度、营养盐等因素的综合影响所致. 相似文献
4.
红水河流域梯级水库夏季浮游植物群落结构特征 总被引：1，自引：0，他引：1
为了解红水河流域水生态系统的健康状态,2009年夏季(6-7月)对其干流龙滩、岩滩、大化、百龙滩、乐滩、桥巩6座梯级水库及主要支流水体中浮游植物的种类组成和分布进行了调查。共鉴定出浮游植物6门、75属、84种,以硅藻种类最多,其次是绿藻和蓝藻;其中硅藻51种,占60.71%;绿藻17种,占20.24%;蓝藻门10种,占11.90%;甲藻门、金藻门、红藻门各2种,分别占2.38%。优势度分析表明,龙滩水库和百龙滩水库浮游植物优势种为硅藻和绿藻,岩滩水库、大化水库、乐滩水库浮游植物优势种为硅藻、绿藻和蓝藻,桥巩水库浮游植物优势种为硅藻、绿藻和金藻;6座水库浮游植物密度变化范围2.12×105~6.03×105个/L,百龙滩水库的密度最高,龙滩水库的密度最低;浮游植物生物量变化范围0.60~2.45 mg/L,龙滩水库的浮游植物生物量最高,大化水库的生物量最低。Shannon-Wiener多样性指数为2.14~3.22,均匀度指数为0.56~0.85。各梯级水库浮游植物组成相似性系数为0.35~0.70,龙滩水库和桥巩水库之间浮游植物组成相似性最大(0.70),岩滩水库和百龙滩水库的相似性最小(0.35)。综合多种指标对水质进行评估,龙滩水库为贫-中营养型,岩滩、大化、百龙滩、乐滩、桥巩水库为贫营养型。 相似文献
5.
6.
江苏横山水库浮游植物群落结构的动态变化 总被引：2，自引：0，他引：2
研究横山水库浮游植物群落的动态变化特征和综合分析水质,为库区的水资源保护和开发利用提供参考依据。2014年7月至2015年6月,设置5个采样点,每月上旬上午9时左右、天气状况良好时采水样1次。共采集鉴定浮游植物7门63属147种(包含变种及变型),绿藻门28属63种、硅藻门16属46种、蓝藻门10属23种、甲藻门3属6种、裸藻门3属3种、隐藻门2属3种、金藻门1属3种,浮游植物的种类组成为绿藻-硅藻-蓝藻型。浮游植物密度2.3×106~8.0×106个/L、平均4.2×106个/L,硅藻门、绿藻门和蓝藻门密度占比分别为57.3%、29.8%和8.4%。浮游植物的多样性指数H'变化范围为1.52~3.67,平均2.48;均匀度指数J 0.53~0.86、平均0.71;丰富度指数d 0.83~3.32、平均2.05。浮游植物主要优势种为绿藻门的美丽鼓藻(Cosmariumformosulum),硅藻门的变异直链藻(Melosiravarians)、颗粒直链藻(Melosira granulate)、尖针杆藻(Synedraacus)和肘状针杆藻(Synedra ulna)等。相关性分析表明,游植物密度与总磷、水温、透明度呈正相关关系,与溶解氧呈负相关关系,与总氮没有相关关系。硝酸盐和溶解氧对浮游植物密度有显著影响,亚硝酸盐氮、氨氮、CODMn、浊度、p H、UV254的水平变化和浮游植物密度没有相关性。根据浮游植物多样性分析以及富营养化指数值TLI(∑)评价,横山水库水质属于轻度富营养状态。 相似文献
7.
汤浦水库位于浙江省曹娥江支流的小舜江流域,是绍虞平原区域性供水专用水源地。为了研究其浮游植物群落结构季节演替及其水质状况,于2010年5、8、11月及次年2月连续四个季节分别对其浮游植物、水文特征和理化因子进行调查分析。共鉴定到浮游植物7门58属105种,主要由绿藻、硅藻和蓝藻组成。浮游植物物种数季节变化为：夏>秋>冬>春。各样点物种数呈现出由库尾至取水口递减的变化趋势。浮游植物丰度变幅较大,在3.27×106~128.90×106 Cells /L之间,其中冬季丰度最低,春季最高。春季浮游植物主要由硅藻和蓝藻组成,夏季主要由蓝藻和绿藻组成,秋季为隐藻和硅藻,冬季主要由硅藻组成。浮游植物丰度及其多样性指数均表明春季水质最差,且暴发藻类水华,其中微型硅藻链状弯壳藻(Achnanthidium catenatum)为春季水华的绝对优势种。此次水华暴发可能受降水、水库调度、营养盐等因素的综合影响所致。 相似文献
8.
牧野湖浮游植物时空分布及水质分析 总被引：1，自引：0，他引：1
2012年9月至2013年8月,按月对牧野湖的水质及浮游植物群落结构开展了初步调查。共发现浮游植物87属147种;其中,黄藻门和隐藻门各6种,金藻门和甲藻门各4种,绿藻门57种,裸藻门23种,硅藻门29种,蓝藻门18种。2012年秋季到2013年春季浮游植物密度在7 400×104~9 100×104个/L,2013年夏季最高,为16 000×104个/L。秋、冬、春季密度较高的为绿藻和硅藻,所占比例:秋季绿藻32.2%、硅藻23.9%,冬季绿藻39.2%、硅藻24.5%,春季绿藻40%、硅藻51.7%;夏季密度较高的种群是蓝藻,占83%。湖区秋、冬、春、夏季Shannon多样性指数分别为1.3、1.27、1.06、0.48,Pielou均匀度指数也从0.35下降到0.175,表明从2012年秋季到2013年夏季牧野湖的水质是不断下降的。皮尔逊相关分析表明,湖区浮游植物的平均密度与Chl-a、CODCr、水温显著正相关(P0.05);与TN、TP、NH+4-N也有一定的正相关性,但未达到显著水平;与SD、NO-3-N之间有一定的负相关,但未达到显著水平。 相似文献
9.
三道河水库浮游植物群落结构特征及其渔产潜力分析 总被引：1，自引：0，他引：1
2007年8月-2008年4月调查并分析三道河水库浮游植物的群落结构及时空分布特征,并探讨水库的浮游植物多样性及渔产潜力.结果显示,该水库浮游植物有8门49属79种,主要由绿藻、硅藻和蓝藻组成;各采样点浮游植物种类数为43 ～56,但种类组成相似;不同季节浮游植物种类组成有很大差异,秋季种类数最多,冬季最少.浮游植物年平均细胞数量为20.33×104个/L,年平均生物量为0.21 mg/L.Shannon-Wiener多样性指数年均值为2.10,Pielou均匀度指数为0.85,且冬季最高,秋季最低.根据浮游植物水质评价标准,三道河水库为中营养型.据估算,三道河水库浮游植物渔产潜力9 072.45 kg,单产为22.68 kg/hm2. 相似文献
10.
浮游植物是判断水体富营养化程度的关键指标之一,藻类水华中有害蓝藻释放的蓝藻毒素会危害人类健康,对饮用水的安全构成威胁。2010年4月至2011年3月,按月对广东省深圳市茜坑水库的浮游植物群落进行了调查。结果表明,茜坑水库共采集到浮游植物7门、66属、127种,种类组成以绿藻(54%)和硅藻(25%)为主,水库属绿藻-硅藻型水体;浮游植物细胞密度年均值为1.10×107个/L,绿藻门、硅藻门、隐藻门和蓝藻门细胞密度所占比例较高;浮游植物多样性在茜坑水库各样点间不存在显著性差异(P>0.05),表明水体交换能力较强;结合3种水质评价方法,初步判断茜坑水库为轻污-中污型水体,并通过对潜在产毒蓝藻现存量的分析来评价水质安全存在的风险。7月的水质风险最大,应进行藻毒素测定。对理化因子的测定显示,水库总氮和总磷浓度均超过《GB3838-2002地表水环境质量标准》中Ⅱ类标准值。 相似文献
11.
12.
Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean 
下载免费PDF全文
下载免费PDF全文 The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna. 相似文献
13.
Liping Li Rui Wang Wanwen Liang Xi Gan Ting Huang Yan Huang Jian Li Yunliang Shi Honglin Luo Ming Chen 《广西水产科技》2014,(1)
Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China. 相似文献
14.
15.
Iciar Martinez Amaya Velasco Ricardo Pérez-Martín Eskil Forås Michiaki Yamashita Carmen G. Sotelo 《Journal Of Aquatic Food Product Technology》2013,22(4):289-297
The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus. 相似文献
16.
In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg. 相似文献
17.
Growth hormone (GH) and reproduction: a review 总被引：5，自引：0，他引：5
Florence Le Gac Odile Blaise Alex Fostier Pierre-Yves Le Bail Maurice Loir Brigitte Mourot Claudine Weil 《Fish physiology and biochemistry》1993,11(1-6):219-232
Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations. 相似文献
18.
Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL?1 (1.25 ng well?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation. 相似文献
19.
20.
Qin-Cheng Huang Di‐Gen Qin Bei‐Ping Tan Tao Du Yuan-Zhi Yang Qi-hui Yang Shu‐Yan Chi Xiao-hui Dong 《Aquaculture Research》2020,51(2):816-827
A 5 × 3 factorial growth trial was conducted to evaluate optimal dietary protein and lipid levels (dietary protein level, DP; dietary lipid level, DL) for juvenile Sillago sihama (S. sihama) (2.0 ± 0.02 g, initial weight). Fish were fed 15 diets containing 5 DPs (350, 400, 450, 500 and 550 g/kg) and 3 DLs (60, 90 and 120 g/kg) for 8 weeks. The interaction between proteins and lipids significantly influenced the feed conversion ratio, condition factor, body composition, antioxidant indices and lipase activity (p < .05). DP 450 g/kg showed the highest average final body weight. DPs 500 and 550 g/kg significantly decreased the protein efficiency ratio (p < .05). DL 120 g/kg showed the highest percentage weight gain. The low feed conversion ratio was found in diets P45L12, P55L9 and P55L12. Diet P45L12 showed high superoxide dismutase activities. DP 450 g/kg showed the lowest average malondialdehyde content. Lipase activity was increased by increasing DP (p < .05) with a fall at DP 550 g/kg. Under the present experimental conditions, the optimal DP for S. sihama was 450 g/kg under the DL 120 g/kg. 相似文献