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1.
Cu^2+Zn^2+和Cd^2+对5种单细胞藻类生长的影响   总被引:9,自引:0,他引:9  
报道承Cu^2+Zn^2+和Cd^2+的毒性作用下,三角褐指藻、湛江叉鞭藻、路氏巴夫藻、青岛大扁藻和小球藻等单细胞藻类的生长速度,密度都发生了不同程度的变化,叉鞭、扁藻及巴夫藻易中毒且恢复慢,当金属离子浓度较低时生长仍然缓慢。而小球藻和三角褐指藻耐毒能力较强,在200×10^-6,甚至600×10^-6离子浓度下仍可生长 。  相似文献   

2.
本文用10倍稀释法确定了河流弧菌Ⅱ在Cu,ZnSe,Cd离子中的半致死浓度是3.56×10^-2,4.46×10^-3,3.69,2.78×10^-5μg/ml细菌吸收了这几种离子后其超微结构发生了明显变化,这些离子能诱导细菌内的核糖体增多,DNA纤丝凝聚成棍棒或块状,以Cu,Zn离子诱导DNA纤丝聚集较为明显,类核区扩大或出现透明区,而Se,Cd离子处理的菌核区不明显,而且4种离子对细胞壁不同程  相似文献   

3.
3种重金属离子和2种杀虫剂对梭鲈胚胎发育的影响   总被引:2,自引:0,他引:2       下载免费PDF全文
在常温静水条件下,研究了铜(Cu)、锌(Zn)、镉(Cd)3种重金属离子和甲醛、晶体敌百虫2种杀虫剂对梭鲈(Stizostedionlucioperca)胚胎发育的影响。结果表明,3种重金属离子对梭鲈胚胎的毒性大小依次为:Cd2+ >Cu2+ >Zn2+;当甲醛浓度为1000mg/L时,对梭鲈胚胎的毒性影响较强,而高浓度的晶体敌百虫对梭鲈胚胎有明显的毒性作用。在梭鲈繁殖用水中使用杀虫剂时,甲醛和晶体敌百虫的安全浓度分别为200mg/L和0.4mg/L。  相似文献   

4.
麦饭石对海水及水溶液中铜、锌、镉的吸附规律   总被引:7,自引:0,他引:7  
用天然麦饭石吸附海水及水溶液中重金属Cu(Ⅱ)、Zn(Ⅱ)、Cd(Ⅱ)。结果表明,吸附率随pH变化曲线呈“S”型,在天然水(pH7.5 ̄8.5)中,麦饭石对海水及水溶液中Cu(Ⅱ)、Zn(Ⅱ)、Cd(Ⅱ)均有较高饱和吸附量。;对3种重金属的吸附能力顺序为Cu(Ⅱ)〉Zn(Ⅱ)〉Cd(Ⅱ)。  相似文献   

5.
黑鲷幼鱼对Zn、Cu的营养需要   总被引:3,自引:0,他引:3       下载免费PDF全文
通过正交设计,进行了黑鲷幼鱼对Zn、Cu营养需求的试验,比较了饵料中不同含量的Zn、Cu对黑鲷幼鱼增重效果的影响及Zn、Cu影响作用的大小,分析了饵料中不同含量的Zn、Cu对黑鲷幼鱼体内Zn、Cu存积的影响。结果表明饵料中添加少量Zn(6.8~20.5mg/kg)有助于黑鲷幼鱼生长,Cu对其增重的作用不大,Cu的添加量以少于1.2mg/kg为宜;Zn的营养作用大于Cu;Zn、Cu存积随饵料中的含量增加而增加,Cu的累积毒性大于Zn。  相似文献   

6.
Cu^2+Zn^2+Cd^2+对五种单细胞灌类光和色素含量的影响   总被引:4,自引:0,他引:4  
报道了在Cu^2 Zn^2 和Cd^2 的毒害作用下,三角褐指藻、湛江等鞭藻、绿色巴夫藻、青岛大扁藻和小球藻等单细胞灌类中光和色素1、色素2和总色素的含量。三种离子以Cd的毒性最大,Cu次之,Zn最弱。色素1对重金属毒性较敏感。在5种藻类中,扁藻和巴夫藻的色素含量受毒性影响相对较小。  相似文献   

7.
Cu~(2+)Zn~(2+)Cd~(2+)对五种单细胞藻类光和色素含量的影响   总被引:5,自引:0,他引:5  
报道了在Cu2 +Zn2 +和Cd2 +的毒害作用下 ,三角褐指藻、湛江等鞭藻、绿色巴夫藻、青岛大扁藻和小球藻等单细胞藻类中光和色素 1、色素 2和总色素的含量。三种离子以Cd的毒性最大 ,Cu次之 ,Zn最弱。色素 1对重金属毒性较敏感。在 5种藻类中 ,扁藻和巴夫藻的色素含量受毒性影响相对较小  相似文献   

8.
UV-B辐射对两种海洋微藻生长的影响   总被引:13,自引:2,他引:11  
研究了两种微藻--小新月菱形与青岛大扁藻在一范围内(小新月菱形藻0~3.00j/m^2,青岛大扁藻0~11.25J/m^2)UV-B辐射对其相对增长率(K),蛋白质含量、类胡萝卜素含量以及超氧化物歧化酶(Superoxide dismutasc,SOD)活性的影响。结果表明,(1)随着辐射剂量的升高,两种微藻的相对增长率(K)逐渐下降,其各自的半数有效抑制浓度48h,EC50分别为,小新月菱形藻1  相似文献   

9.
几种重金属离子毒性对黑鲷孵子和稚鱼的影响   总被引:4,自引:0,他引:4  
在黑鲷人工繁殖中,发现海水中重金属离子对黑鲷的稚鱼及孵子的发育有影响,因而作了Hg^2+,Cr^6+,Fe^2+,Cu^2+几种重金属离子对黑鲷雅鱼影响的探讨。找出安全浓度,并提出亚铁的毒性不可忽略,其特点为死亡界限明显,过渡段;时发现几种毒物随着水温的升高。其毒性由强到弱的排列顺序为:Hg^2+>Fe^2+>Cu^2+>Cr^6+,用直线内插法求出了TLm24、TLm18、TLm96浓度。  相似文献   

10.
南海北部海域经济鱼类的重金属含量与分布研究   总被引:8,自引:0,他引:8  
研究了南海北部海域经济鱼类的重金属Cu、Pb、Zn、Cd、Cr和Ni等的含量与分布。结果表明,重金属在鱼体不同器官组织中的分布是不均衡的,肌肉中的重金属含量最低;底层鱼类的重金属含量相对较高;肉食性鱼类的Cd含量较高,但其余5种金属含量与鱼类食性的关系不明显;近海鱼类的重金属含量与河口咸淡水鱼类的重金属含量之间无显著差异;经济鱼类受重金属污染的影响不明显,其食用价值尚未受影响。  相似文献   

11.
Mulloway (Argyrosomus japonicus) occur in estuarine and coastal waters surrounding Australia, Africa, India, Pakistan, China, Korea and Japan, where they are important in fisheries. This study identified that mulloway in south-eastern Australia had similar growth rates, but matured at smaller lengths and younger ages, to those in South Africa and Western Australia. Growth of both sexes was similar to about 5 years, after which females grew faster and attained a greater maximum length than males. Female mulloway matured at 4–5 years of age with a L50 of 68 cm, whereas males matured at 2–3 years of age with a L50 of 51 cm. The commercial fishery in New South Wales was characterised by declining catches and a reduction in the proportion of mulloway of mature lengths in landings. During 2002–2005 commercial landings were dominated (83%) by fish within 15 cm of the current minimum legal total length of 45 cm and aged 2 and 3 years (>80%), even though mulloway can attain lengths of 200 cm and live >30 years. Estimates of the rates of instantaneous total mortality ranged between 0.34 and 0.45, whilst the rate of instantaneous natural mortality (M) was estimated to be approximately 0.12. Yield-per-recruit analyses indicated that mulloway in New South Wales are being growth overfished and substantial increases in yield could be achieved by increasing the length at first harvest. Values of the spawning potential ratio were below 0.2 under a range of mortality estimates, suggesting that mulloway are at risk of recruitment overfishing. These results suggest that the spawning stock of mulloway in south-eastern Australia has been depleted and that remedial management action is required to protect this iconic species.  相似文献   

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13.
The purpose of this study was to evaluate the acute toxicity of lead for different life stages of shrimp, Litopenaeus vannamei, and to determine the effect of its sublethal concentrations on osmoregulatory capacity (OC) as well as the possible histological alteration in the gills of juvenile shrimp. The 24‐, 48‐, and 96‐h LC50 values for lead to L. vannamei increased progressively with increasing life stage, from nauplii < zoeae < mysis < postlarvae < juvenile. After 15‐d exposure to 3.25, 6.50, and 9.75 mg Pb/L, the OC values of exposed shrimp were reduced by 39, 73, and 157%, respectively compared to control animals. Compared to controls, the lead concentrations in gill tissues increased significantly by 127,500, 137,500, and 141,000% in shrimps exposed to 3.25, 6.50, and 9.75 mg Pb/L, respectively. After lead exposure, hemocytic congestion in efferent vessels and multiple hyperplasia were observed in gill filaments, resulting in narrowed hemolymphatic lacuna. The histopathological effects increased with increasing Pb concentration.  相似文献   

14.
Argopecten irradians is one of the most important commercial species of Pectinidae family in China. The internal defense system of mollusks consists of circulating haemocytes. In order to characterize the haemocytes of the scallop A. irradians, light and electron microscopical studies were carried out. Four types of haemocytes were recognized: type I small hyalinocytes (2.38 ± 0.08 μm, 30-35%), type II large hyalinocytes (4.41 ± 0.33 μm, 15-20%), type III small granulocytes (4.15 ± 0.26 μm, 20-25%), and type IV large granulocytes (8.26 ± 0.52 μm, 25-30%). Granulocyte types showed smaller N/C ratios than hyalinocytes. The mean haemocyte concentration was about (3.75 ± 0.65) × 107 cells ml− 1 of haemolymph. Among haemocytes, 44.7% are granular and 55.3% are agranular. These gave a relatively systematic classification scheme for haemocytes of A. irradians. Three types of granules were identified: type I, with high electron-density; type II, with low electron-density; and type III, with a middle level of electron-density, based on TEM studies. Different haemocyte types were not separated with DDGC of Percoll in this study. Both granulocytes and hyalinocytes showed a phagocytic response to the two strains of bacteria, Escherichia coli and RLOs. The phagocytic ability of granulocyte was significantly higher (41-48%) than that of hyalinocyte (9.2-11.2%).  相似文献   

15.
Adult common bullies, Gobiomorphus cotidianus McDowall, are small (total length =  30–120 mm), benthic fish commonly found in the littoral zones of New Zealand lakes where they are a major prey species for trout and eels. Differences in their relative abundance (CPUE) were determined between 21 shallow North Island lakes. Mean CPUE ranged from 2 to >  1000 fish net− 1 night− 1 and was inversely related to water transparency. The abundance of bullies was not reduced in lakes containing rainbow trout, Oncorhynchus mykiss (Walbaum), but was reduced in all lakes containing self-recruiting populations of eels, Anguilla spp. Mean densities of planktonic larval bullies in the limnetic zone were also inversely related to water transparency. Since low water transparency is related to increased trophic status for these lakes, the abundance of bullies is likely to be related to lake productivity, rather than turbidity.  相似文献   

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The spiny lobster Panulirus argus is of ecological and commercial importance in the South Florida coast of the continental USA and throughout the Intra‐Americas Sea. Essential spiny lobster habitat in South Florida is primarily located in the Florida Keys coastal zone (including the Dry Tortugas), where the dynamic regional circulation coupled with the long planktonic larval duration (6–12 months) of P. argus raises questions of larval retention and recruitment. Locally spawned phyllosomata entrained in the Florida Current are likely to be expatriated out of the Straits of Florida, which implies that the local spiny lobster population is sustained by the transport of larval recruits from upstream locations. We examined the physical processes that may influence recruitment. Transport processes in the Keys coastal zone are spatially variable. Observed and modelled data suggest that the upper Keys is a point of onshore larval transport via the inshore meandering of the Florida Current, and the lower Keys to Dry Tortugas region apoint of retention through wind‐driven onshore/countercurrents and eddy recirculation. Eddies that propagate between the Dry Tortugas and the lower Keys facilitate the exchange of larvae between the Florida Current and the coastal zone. Northerly wind events associated with cold fronts can enhance recirculation of larvae in the upper Keys. The association of older larvae with the Florida Current front supports the hypothesis that spiny lobster larval recruits come from upstream sources in the Caribbean.  相似文献   

19.
The dietary requirements of Penaeus monodon for eicosapentaenoic (20:5n‐3; EPA) and docosahexaenoic (22:6n‐3; DHA) acids were examined. These requirements were examined when dietary levels of linoleic (18:2n‐6; LOA) and linolenic acids (18:3n‐3; LNA) were also provided at previously established optimal levels of 14 and 21% respectively of the total lipid fatty acids. A 5 × 5 factorial design was used with incremental amounts (0, 4, 8, 12 and 16% of total fatty acids) of EPA and/or DHA. An additional diet containing cod‐liver oil was provided as a reference diet. The total lipid content of all of the 25 treatments and reference diets was maintained at the same level of 75 g kg?1. Growth of prawns fed with the reference diet after 50 days was 244 ± 21%. The greatest response to singular additions of EPA or DHA was with a 12% inclusion of either fatty acid, resulting in 287 ± 21 and 293 ± 18% weight gain, respectively. Growth was generally better when combinations of EPA and DHA were used, the optimal combination being EPA 4% and DHA 4%, resulting in 335 ± 25% weight gain. Addition of high levels of either of the highly unsaturated fatty acids (HUFA) in the diet had a negative effect on growth. Digestibilities of the total neutral lipid and specific fatty acids were examined during the growth trials. The digestibility of total neutral lipid was usually higher when either or both HUFA were present, however there were few significant differences between treatments that contained either or both HUFA. Following the growth trials, digestive glands (DG) of prawns fed with the various diets were analysed to determine the total lipid content and fatty acid composition. Total lipid in the digestive gland increased with the inclusion of DHA, but was not significantly affected by the addition of EPA. The fatty acid composition of the digestive gland lipid generally reflected that of the diet. However, the maximum retention of EPA (11.1% of total DG fatty acids) and DHA (10.7% of total DG fatty acids), was not directly proportional to the amount of either fatty acid present in the diet. These results demonstrate that both EPA and DHA have considerable growth promoting capacity. This growth promoting capacity is enhanced when an optimal balance of both fatty acids are incorporated into the diet.  相似文献   

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