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1.
2009年秋季,对我国西南云贵高原8个处于不同营养水平的湖泊和水库的浮游细菌进行了调查,分析了浮游细菌的分布特征及其与温度、总氮(TN)、总磷(TP)、正磷酸盐(PO4-P)、氨氮(NH4-N)、硝氮(NO3-N)、化学需氧量(CODMn)和叶绿素a(Chl.a)的相关性。结果表明,8个湖库的浮游细菌数量存在明显差异,异龙湖最高,平均值为5.66×109个/L,阳宗海最低,平均值为2.25×109个/L,从大到小依次为:异龙湖>草甸海>松花坝水库>白沙河水库>月湖>松茂水库>石龙坝>阳宗海。对阳宗海4个点位的研究发现,同一湖泊内浮游细菌的数量存在空间异质性,沿岸带明显大于湖心区。浮游细菌数量与水温、总氮、总磷、叶绿素a均呈极显著性相关(P<0.01),表明上述因子可能是浮游细菌分布的主要限制因子。  相似文献   

2.
应用平板稀释涂布培养计数法和荧光显微镜计数法,对秋、冬季(2008年9月~2009年2月)刺参养殖池塘水体中的浮游细菌数量变化规律进行了分析。结果表明,吖啶橙染色直接计数法(AODC)测得细菌总数的变化范围是1.0×106~2.1×107个/ml,活菌直接计数法(DVC)测得活菌总数的变化范围是4.0×105~5.7×106个/ml。异养细菌平板计数法(HPC)测得异养细菌数量为0.6×102~1.7×105CFU/ml。TCBS平板培养的弧菌数量在6.6×103CFU/ml以下。从时间分布看,刺参养殖池塘水体中浮游细菌数量最高值出现在10月份,最低值出现在1月份,秋季细菌数量显著高于冬季(P0.01)。从空间分布看,水体底层细菌数量显著高于表层(P0.05)。利用SPSS13.0软件对所得到的数据进行统计分析表明,同一样品不同计数方法获得的细菌总数数值之间存在显著的相关性(P0.01)。  相似文献   

3.
金海水库浮游植物调查及群落结构研究   总被引:2,自引:0,他引:2       下载免费PDF全文
为了了解和掌握金海水库水质状况,于2012年6月至2013年5月对金海水库水体理化指标及浮游植物的群落结构进行了逐月监测。采样期间共鉴定出浮游植物7门33属45种,其中绿藻门最多,15属24种;硅藻门次之,8属11种;蓝藻门、裸藻门、甲藻门、隐藻门和金藻门分别鉴定出4属4种、2属2种、2属2种、1属1种、1属1种。金海水库浮游植物数量变化范围20.1×104~335×104个/L,夏季最多,春季最少。浮游植物数量与环境因子相关性分析表明,水体中浮游植物数量主要受水温以及总磷浓度影响。优势度分析表明,金海水库浮游植物优势种有小球藻、肥壮蹄形藻、中型脆杆藻、微小色球藻等31种。金海水库浮游植物多样性指数和均匀度指数分别变化在1.29~3.52和0.38~0.82。金海水库水体浮游植物群落结构较为稳定,整体上以绿藻-硅藻型为主。金海水库水质总体为轻度污染。  相似文献   

4.
2009年秋季,对我国西南云贵高原8个处于不同营养水平的湖泊和水库的浮游细菌进行了调查,分析了浮游细菌的分布特征及其与温度、总氮(TN)、总磷(TP)、正磷酸盐(PO4-P)、氨氮(NH4-N)、硝氮(NO3-N)、化学需氧量(CODMn)和叶绿素a(Chl.a)的相关性。结果表明,8个湖库的浮游细菌数量存在明显差异,异龙湖最高,平均值为5.66×109个/L,阳宗海最低,平均值为2.25×109个/L,从大到小依次为:异龙湖〉草甸海〉松花坝水库〉白沙河水库〉月湖〉松茂水库〉石龙坝〉阳宗海。对阳宗海4个点  相似文献   

5.
为了解包头市南海湖水体水质状况及富营养化趋势,于2017年4月-2018年3月,在南海湖中选取20个采样点,对水体中叶绿素a含量及主要营养盐进行测定,并对叶绿素a和营养盐含量进行相关系分析。结果表明:南海湖水体总氮和总磷指标均超过了地表水Ⅴ类标准。南海湖氮磷营养盐存在着时空差异,总氮和氨氮随季节变化明显,其含量均呈现冬季>秋季>夏季>春季;总磷的含量主要表现为秋季最高,春季最低;硝态氮的含量在四个季节差异不大。空间上各营养盐均呈现东部、北部高,西部、南部低的趋势。水体中叶绿素a含量的变化区间为21.94~40.92μg·L-1,时间上呈现秋季>夏季>春季>冬季。空间上呈现东北高、西南低的趋势,与氮磷营养盐的分布趋势相同。叶绿素a在四个季节中与总氮,氨氮,总磷均呈现显著正相关(P<0.05)。  相似文献   

6.
用水声学评估水库鱼类资源增殖放流的效果   总被引:1,自引:0,他引:1  
合理开展水库鱼类增殖放流,可提高水库鱼产力、修复水库生态环境和防治水库富营养化等,对水库健康运行具有重要意义。而科学评估水库鱼类资源动态及增殖放流净化效果将为合理开展增殖放流提供基础和指导。本研究于2015年运用BioSonics DT-X科学回声探测仪(208kHz)在老虎潭水库增殖放流完成后(夏季)和渔获期(冬季)对其鱼类资源进行走航式水声学调查。结合渔获物调查,对老虎潭水库的鱼类大小组成、空间分布、密度和资源量等进行测定,评估增殖放流活动对水体的净化效果。结果显示,夏季鱼类的平均目标强度为(-51.76±3.37)dB,冬季为(-45.058±4.26)dB,夏季和冬季鱼类目标回声强度大小存在显著性差异(P0.001)。夏冬两季鱼类密度的垂直分布存在显著性差异(P0.001)。老虎潭水库库区夏季鱼类的总尾数为1.297×10~6尾,资源量约10 246kg。冬季鱼类的总尾数为4.8×10~5尾,资源量约43 085kg。增殖放流后鱼类资源量增长明显,达32 839kg,共转移出碳、氮、磷的净含量分别为3.379×10~3、1.031×10~3、1.81×10~2 kg,实现了对水体营养物质的转移。后续研究可关注每年渔获量的科学设置,合理利用鱼类资源并有效降低库区水体营养水平。  相似文献   

7.
本实验在2012年9月~2013年9月期间,每季节采样一次,测定泼河水库叶绿素a(chl.a)的浓度,分析泼河水库叶绿素a的分布特征及其与总氮(TN)及总磷(TP)等环境因子的相关性。结果发现,泼河水库叶绿素a浓度的季节分布由高至低为夏季春季秋季冬季;空间分布为春季和夏季河流入库口叶绿素a的浓度高于其他水域;因子相关性分析表明,春季和夏季泼河水库叶绿素a浓度与水体中总磷的浓度相关,其中夏季相关性极其显著。  相似文献   

8.
2020年春季(4月)、夏季(6月)、秋季(9月)在沧州段大运河7个代表性断面采集水样,研究该段大运河浮游植物群落结构特征及其水体营养状况,监测主要水环境因子,利用生物学指标与水环境指标综合评价了水质污染等级,运用Pearson相关性分析方法探究浮游植物群落特征与水环境因子间的相关性,为大运河水环境改善及生态修复提供理论依据。结果表明:2020年春季、夏季和秋季在沧州段大运河共监测出浮游植物8门85种,三季浮游植物的平均密度为2.49×108cells/L,优势种为4门6种。秋季各项多样性指标污染等级低于春夏两季,大运河沧州段的污染等级为中度污染,说明大运河(沧州段)水体存在一些污染,季节变化对污染等级有一定的影响。沧州段大运河夏季平均最高水温为26.52℃,春季最低平均水温为7.77℃;春季、夏季、秋季水体p H平均值分别为7.82、8.43、8.25,水体均为弱碱性。春、夏两季的营养状态指数TSIM平均值分别为68.16和64.85,表现均为富营养型水体;秋季的TSIM平均值为51.4,为中营养型水体。Pearson相关性分析表明,浮游植物多样性指数与Chla...  相似文献   

9.
为探究北京密云水库大型底栖动物群落结构及其与环境因子和水质的关系,根据水库形状和水位季节变化规律,在潮河库区(1~3号)、库中区(4~5号)以及白河库区(6~8号)共设置8个采样点,于2015年4月(春季)、8月(夏季)、10月(秋季)下旬进行采样,冬季由于水库结冰采样困难而未采集底栖动物样本。结果显示,密云水库共检出大型底栖动物15种,隶属2门2纲2科10属,其中环节动物门颤蚓科4种,节肢动物门摇蚊科幼虫11种,优势种为正颤蚓(Tubifex tubifex)和红裸须摇蚊(Propsilocerus akamusi)。不同采样点的种类数为2~11种,年均密度和年均生物量分别为1864个/m2和3.10g/m2,显示密云水库为中营养型水库。底栖动物年均密度:白河库区潮河库区库中区,年均生物量:白河库区潮河库区及库中区。在库西、白河电站等深水区,颤蚓类密度和生物量占比较高;而浅水区摇蚊幼虫密度和生物量占比较高。底栖动物总密度:夏季春季秋季;总生物量:春季夏季≈秋季。水库中颤蚓类的密度和生物量与水深、沉积物中总有机碳及总氮含量呈显著线性或幂函数正相关,与沉积物中总磷含量相关不显著;摇蚊幼虫的密度和生物量与上述4个环境变量均无显著相关性。底栖动物Shannon-Wiener多样性指数、Margalef丰富度指数、Goodnight修正指数和Pielou均匀度指数在浅水区高于深水区。Pielou均匀度指数和Wright指数评价表明,密云水库水质为轻污染,与水化评价结果比较一致,可作为水质生物学评价的重要参考。  相似文献   

10.
为研究养殖库区水域氮的时空分布特征,于2014年3月至2015年2月在福建省水口水库范围内主要养殖库区选取15个采样点进行每月的监测和动态研究,全面分析了不同养殖库区、不同时期水体各形态氮的时空变化特征。结果表明,养殖库区水体总氮、氨氮、亚硝态氮平均浓度分别为1.38~2.15、0.24~0.53,0.03~0.06 mg/L。不同养殖库区水体各形态氮含量因季节更替而变化较大,总体趋势是总氮浓度冬季较高;除太平养殖库区外,其他养殖库区水体的氨氮浓度春季较高,浓度范围为0.466~0.596 mg/L;亚硝态氮浓度变化幅度不大,范围为0.009~0.031 mg/L。不同养殖区域水体中各态氮含量具有一定的相关性,雄江和太平养殖库区中总氮和氨态氮、亚硝态氮之间相关性不显著,黄田库区和湾口库区养殖区水体中总氮和氨态氮、亚硝态氮呈现负相关;尤溪口养殖库区水体中氨态氮和亚硝态氮呈显著负相关。  相似文献   

11.
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   

12.
13.
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   

14.
Growth hormone (GH) and reproduction: a review   总被引:5,自引:0,他引:5  
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   

15.
Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg?1 protein) than essential amino acids (425.82 ± 9.15 g kg?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.  相似文献   

16.
17.
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   

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.
Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).  相似文献   

20.
The endemic, anadromous cyprinidChalcalburnus tarichi is the only fish species known to occur in alkaline Lake Van (Eastern Anatolia, Turkey). EightC. tarichi were maintained individually in Lake Van water (17 – 19°C; pH 9.8; 153 mEq·I–1 total alkalinity; 22 total salinity) and tank water samples analyzed for 24 h in 2 to 4 h intervals. At zero time, < 1µM ammonia was present and urea was undetectable in the tank water; at 24 h, total ammonia and urea made up 114±32 and 35±25µM, respectively. Over the experimental period, ammonia-N and urea-N excretion averaged 1041±494 and 607±169moles·kg–1 fish·h–1, respectively. The extent of urea excretion was highly variable between specimens. Uric acid excretion was not detectable.Urea was present at high concentrations in all tissues and plasma (25 – 35moles·g–1·ml–1) of freshly caughtC. tarichi; total ammonia content of the tissues was by a factor of 1.9 (liver) to 3.0 (brain) lower. High arginase activity (2.4±0.2 U·min–1·g–1) was detected in the liver ofC. tarichi but ornithine carbamoylphosphate transferase, a key enzyme of the ornithine-urea-cycle, was absent. Ureagenesis is likely through degradation of arginine and/or uricolysis. High glutamine synthetase activity (11±0.6 U·min–1·g–1) and low ammonia content in brain suggest that, like other teleosts,C. tarichi has an efficient ammonia detoxification in the brain, but in no other tissue.Nitrogenous waste excretion at alkaline pH is discussed. The ability ofC. tarichi to excrete high levels of ammonia at extremely alkaline pH is unique among teleosts studied so far. The mechanism of ammonia excretion under Lake Van conditions remains to be elucidated.  相似文献   

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