共查询到20条相似文献，搜索用时 37 毫秒
1.
为了解乌溪江水库主要水质指标的时空分布特征,探究其营养化程度的变化趋势,2019-2020年,对丽水市乌溪江水库的7个采样点（S1-S7）的水温、pH、总氮、总磷、叶绿素a等理化因子进行了监测。分析对比了综合营养指数和理化因子等关键指标在不同时期的分布特征。结果表明,乌溪江水库的营养盐浓度呈现出春夏高秋冬低、从上游（S1）至下游（S7）逐渐下降的趋势,平均综合营养指数也从47.1（S1）下降到32.5（S7）,整体上属于中营养化水库。总磷浓度在0.002-0.040mg/L间,平均值为0.012mg/L;总氮浓度在0.412-2.826mg/L间,氮的主要赋存形式为硝酸盐。叶绿素a含量均值为3.77 ug/L,河流区的叶绿素a含量显著高于下游的过渡区和湖泊区。分析表明：汛期地表径流带来的富营养化压力最大,同时也是氮磷等外源性营养盐输入水体的主要途径;WD、pH、TP和叶绿素a含量中等程度相关,水库生态系统具备很强的净化能力。但近年来富营养化程度加剧。 相似文献
2.
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
3.
4.
为探求衢州市渔业水域水库水体富营养化水平和主要驱动因子,本研究基于2018年水质监测数据,综合评价黄坛口水库(S1)、铜山源水库(S2)、狮子口水库(S3)、花园垄水库(S4)和金仓垅水库(S5)5座不同水库水体富营养化水平,并采用相关性分析、主成分分析探讨水质环境因子对水体富营养化水平间的影响和相关关系。结果显示,叶绿素a(Chl-a)与综合营养状态指数法评价结果趋于一致,表明S1、S2和S3水库均为中营养,S4为轻度富营养,S5为重度富营养,水产养殖水域富营养化水平显著高于增殖放流水域(P<0.05)。5个水库中,S5为氮限制,其余水库均为磷限制。多元线性逐步回归分析表明,Chl-a与溶解氧(DO)、透明度(SD)、铜(Cu)、总磷(TP)、总氮(TN)、高锰酸盐指数(CODMn)的相关性较好,综合营养状态指数(TLI)与水温(T)、SD、Cu、TP、TN的相关性较好,得到模型:Chl-a=19.793 CODMn-32.065 TP-33.004,TLI=1.062 CODMn+18.468 TP-0.06 SD+0.450 T+1.765 TN+33.886。综合相关性分析、主成分分析结果,CODMn、TP、SD、T和TN是影响衢州市水库水体富营养化的主要因子,其中,氮、磷营养盐和有机物是造成水库水体富营养化的主要影响因子,水温是造成各水库富营养化季节性变化的主要原因,而pH、溶解氧是水体富营养化后的结果,可以作为水库富营养化水平的指示因子。 相似文献
5.
汤浦水库及入库支流水质时空变化特征与影响因素分析 总被引：2，自引：0，他引：2
运用聚类分析和主成分分析对汤浦水库及入库支流的水质时空特性进行了分析,聚类分析结果表明,汤浦水库水质可分为支流、支流入库库湾、水库库中3个典型空间区域和持续强降雨、雨季、非雨季3个季节时段。汤浦水库3个空间区域的主成分分析显示,第1、2主成分较好地反映了不同区域影响水质状态的主要因素。以水库库中为代表的水域水质明显不同于以北溪和南溪两条主要入库支流下游为代表和支流入库库湾两类区域,规律也不同,它主要受到随季节波动的库区初级生产力状况和无机盐的影响。汤浦水库3个典型季节的主成分分析显示,第1主成分较好地反映了不同季节影响水质状态的主要因素。以1至4月和9至12月非雨季为代表的水库水质变化与持续强降雨季节（6月）和降雨季节（5月、7月和8月）完全不同,主要受到气象因子和水位的双重影响,表现为营养水平波动、细菌等微生物的反硝化作用和水位涨落带的轻微有机及重金属污染。 相似文献
6.
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
7.
8.
为探究桂江鱼类群落结构现状,保护桂江鱼类物种多样性,于2015年1月（冬）、4月（春）、7月（夏）和10月（秋）,对桂江平乐（S1）、昭平（S2）、五将（S3）、马江（S4）、木格（S5）、大郎（S6）、京南（S7）、倒水（S8）、梧州（S9）共计9个采样点,进行4次鱼类资源调查。分析了桂江鱼类物种组成、优势种和鱼类群落结构的时空变化;结果表明,本次调查共采集鱼类93种,隶属于6目、17科、 66属,其中以鲤形目为主（63种）,占总种数的67.74%。鱼类相对多度（Relative density）显示,全年优势种为?（Hemiculter leucisculus）,占总个体数的12.75%。不同季节的优势种有差异,冬季优势种为伍氏半?（Hemiculterella wui）、?和宽鳍鱲（Zacco platypus）;春季优势种不明显,个体数较多的有南方拟?（Pseudohemiculter dispar）和泥鳅（Misgurnus anguillicaudatus）;夏季优势种为?、大眼华鳊（Sinibrama macrops）和南方拟?;秋季优势种为?、莫桑比克罗非鱼（Tilapia mossambicus）和尼罗罗非鱼（T. niloticus）。无度量多维排序图（NMDS）和单因素相似性分析（ANOSIM）结果显示,除夏季与秋季之间外（P=0.178>0.05）,其余季节之间鱼类群落结构存在显著性差异（P<0.05）,这可能是珠江水系鱼类繁殖期（4-6月）及降水的季节性变化所致。采样点S1与S7、S8、S9,S6与S7、S8、S9,S2与S6、S9之间存在显著性差异。目前河流库区化、过度开采以及外来物种入侵是导致鱼类群落结构变化的主要原因。 相似文献
9.
重庆大洪湖氮、磷周年变动与浮游生物多样性 总被引：1，自引：0，他引：1
摘要：2008年3月到2009年1月,对大洪湖上、中、下游3个点的浮游生物和氮、磷进行了两月一次的监测。水质检测数据显示：大洪湖水体的富营养化程度较为严重;主要富营养化物质是氮;氮的富营养化评价指数冬季高于夏季;始终徘徊于Ⅳ类与Ⅴ类水之间;网箱养鱼产生的沉积物对大洪湖下游水体中的磷含量仍有较大的贡献,分别占下游水体总磷量的87.2%（夏季）和62.5%（冬季）;大洪湖的氮、磷等富营养化物质主要来源于上游水源;目前,大洪湖实施的生态渔业具有一定的生态环保功能。大洪湖的水体自净作用使水体中的总氮下降了27.9-59.2%,总磷下降了10.0-56.9%;浮游植物的生物多样性指数也有所提高。
关建词：大洪湖,生物多样性指数,富营养化评价指数。 相似文献
10.
为研究卫河新乡市区河段底泥-间隙水-上覆水中营养盐的时空分布特征,分别于2013年1、4、7、10月对卫河新乡段上游（S1）、人口密集区（S2）、人工拓宽河道形成的牧野湖入湖水口（S3）、湖岸静水区（S4）、湖心处（S5）和湖区下游（S6）共计6个样点进行采样分析。结果表明：（1）S1和S2底泥中总氮（TN）、氨氮（NH4+-N）含量呈现随深度增加而上升的趋势,除S3外,各样点底泥中总磷（TP）含量的垂向分布在15～20 cm处比表层含量低,但并无明显规律性;（2）S2、S3、S4样点在4月时底泥(干重)中的TN含量达到最大值,分别为5.8、2.2、1.7 g/kg,10月时TP含量达到最大值,分别为0.88、0.22、0.21 g/kg,除S3号样点外,其余各样点底泥NH4+-N的含量均在7月出现最大值,按样点号依次为25.42、37.19、14.23、12.28、34.11 mg/kg;（3）间隙水中TN和NH4+-N含量的垂向分布与底泥中的分布相似,间隙水和底泥中的TN、NH4+-N之间呈显著的正相关,TP之间无明显相关性;（4）间隙水和上覆水中的各营养盐之间均无明显相关性。 相似文献
11.
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
12.
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
13.
14.
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
15.
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
16.
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
17.
Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection 下载免费PDF全文
下载免费PDF全文 G Sharon M Pimenta‐Leibowitz M C L Vilchis N Isakov D Zilberg 《Journal of fish diseases》2015,38(1):67-74
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
18.
Sandra García‐Garrido Ismael Hachero‐Cruzado Carlos Rosas Pedro Domingues 《Aquaculture Research》2013,44(11):1741-1751
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
19.
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
20.
There has been growing concern about the overuse of antibiotics in the ornamental fish industry and its possible effect on the increasing drug resistance in both commensal and pathogenic organisms in these fish. The aim of this study was to carry out an assessment of the diversity of bacteria, including pathogens, in ornamental fish species imported into North America and to assess their antibiotic resistance. Kidney samples were collected from 32 freshwater ornamental fish of various species, which arrived to an importing facility in Portland, Oregon from Colombia, Singapore and Florida. Sixty‐four unique bacterial colonies were isolated and identified by PCR using bacterial 16S primers and DNA sequencing. Multiple isolates were identified as bacteria with potential to cause disease in both fish and humans. The antibiotic resistance profile of each isolate was performed for nine different antibiotics. Among them, cefotaxime (16% resistance among isolates) was the antibiotic associated with more activity, while the least active was tetracycline (77% resistant). Knowing information about the diversity of bacteria in imported ornamental fish, as well as the resistance profiles for the bacteria will be useful in more effectively treating clinical infected fish, and also potential zoonoses in the future. 相似文献