首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
研究了延迟投饵对裸项栉鰕虎鱼仔鱼存活、摄食及生长等方面的影响。实验设1个饥饿对照组(设10个平行)和5个延迟投饵组(各设4个平行),分别在孵化后第1、2、3、4和5d开始投喂褶皱臂尾轮虫。实验结果表明裸项栉鰕虎鱼仔鱼初次摄食时间为孵化后第1天,第3~4天时进入PNR期;初次摄食率以孵化后第2天最高,为54.55%,之后随日龄的增大而显著下降;仔鱼的存活率随延迟投饵天数的增加而显著降低;体长增长率的变化趋势与此相似。本研究表明:对裸项栉鰕虎鱼仔鱼进行投饵的最适时间为孵化后第1天。  相似文献   

2.
光色对豹纹鳃棘鲈幼鱼摄食、生长和存活的影响   总被引:1,自引:0,他引:1  
为探究光色对鱼类摄食、生长和存活的影响,作者在模块化小型循环水养殖系统中,以豹纹鳃棘鲈(Plectropomus leopardus)幼鱼(体长21.2 cm±1.22 cm,体质量112.46 g±2.632 g)为对象,设置5种光色环境(红、黄、绿、白和黑暗),进行了4个月的循环水养殖实验。结果表明:绿光下豹纹鳃棘鲈幼鱼摄食率高、饵料转化率高、饵料系数低,但不同光色下豹纹鳃棘鲈幼鱼的摄食不存在显著性差异(P0.05);幼鱼的体长增长,绿光组和红光组大,且与其余3组间差异显著(P0.05);幼鱼的体质量增长,绿光组最大,红光组和黑暗组次之,白光组和黄光组最小,且三者间差异显著(P0.05);各组幼鱼的肥满度并没有显著性差异(P0.05);除白光组幼鱼存活率(只有50%)最低外,其余各组幼鱼存活率均在80%以上,其中绿光组最高,为88.33%。可见,在循环水养殖生产中,绿光环境有利于豹纹鳃棘鲈幼鱼的摄食、生长和存活。  相似文献   

3.
The effects of Prudhoe Bay, Alaska, crude oil on the indigenous phytoplankton and zooplankton of tundra thaw ponds were studied under controlled conditions in situ during the summer of 1976. These effects were compared with uncontrolled oil spills on Pond Omega (a year previously) and Pond E (six years previously). In the uncontrolled spills, the phytoplankton species composition of both ponds remained appreciably different compared with control Pond C, although phytoplankton biomass did not differ greatly. Primary production remained low in Pond Omega but had recovered to control levels in Pond E. In controlled subpond experiments, oil caused a decrease of about 90–100% in primary production in five days but recovered to 40–50% of the control level within fifteen days. During that time, phytoplankton biomass decreased initially but recovered within fifteen days. Oil caused a shift in phytoplankton species composition from a predominance of cryptophytes to chrysophytes. Subponds containing two Daphnia middendorffiana and one Brachinecta paludosa per litre of pondwater were also affected by oil, causing zooplankton death within three or four days. After that time, changes in the phytoplankton species composition were similar to control subponds without zooplankton. Oil toxicity to zooplankton or experimental removal resulted in a loss of grazing pressure which caused the elimination of the cryptophyte Rhodomonas sp. This species was still absent from Pond Omega, but was seen in Pond E for the first time, when zooplankton also reappeared after six years. Oil perturbation of tundra thaw ponds causes a loss of zooplankton and a reduction in primary production. Phytoplankton primary production recovers somewhat but algal species composition remains changed because of the loss of zooplankton grazing pressure and the selective effects of oil.  相似文献   

4.
本文分析了Corexit 9527分散剂和中国胜利原油对海洋实验生态系中浮游动物群落的影响,得出的主要结论是:1.单独的Corexit 9527对草食性桡足类的生长发育稍有抑制作用,但种群可得恢复和发展,对肉食性桡足类及其他各类浮游动物没有影响;2.Corexit 9527和原油的混合物对所有类别浮游动物均有极大的抑制作用,它导致种群的迅速缩小且无法得以恢复。  相似文献   

5.
This paper reviews the author's research on metabolic activities of marine zooplankton for which the Okada Prize of the Oceanographical Society of Japan was awarded in 1978. The term metabolic activities used here refers to various physiological rate processes of zooplankton, such as respiration, excretion, feeding and growth.On the basis of experimental data obtained by the author and other workers, it is emphasized that all these rates are power functions of the body weight of zooplankton. In other words, the weight specific rates (rates per unit body weight) increase with a decrease in body weight. The habitat temperature of zooplankton can also affect the level of these rates.The relationship between these rates and body weight established experimentally can be applied to the estimation of the total rates of a zooplankton community in the field, by knowing the size distribution of individual zooplankters. The feasibility of this method was tested with the zooplankton community in the Kuroshio region.Finally, the potential importance of microzooplankton in total zooplankton respiration was suggested, based on respiration rate data recently obtained in the author's laboratory.  相似文献   

6.
Subarctic marine sediments were exposed to fresh and ‘weathered’ crude oil from Cook Inlet, Alaska. The crude oil was thoroughly mixed with the sediment at various concentrations and some of the oil-sediment mixtures were placed on top of unamended sediments. Both sediments with added oil and those overlain by oiled sediments were investigated. These sediments were placed either in trays or aquaria. The trays were incubated in situ near the site from which the sediments were originally collected. The aquaria were maintained at simulated in situ conditions by maintaining a continuous flow of fresh seawater through them. The sediments were exposed to crude oil for periods up to 1.5 years. Sediments exposed to 50‰ fresh crude oil showed significant decreases in nitrogen fixation and denitrification rates and redox potentials. Also observed were increases in CO2 production rates and methane concentrations. These same changes were observed in sediments exposed to 1‰. When ‘weathered’ crude oil was added to the sediments, the same changes were observed except there was no reduction in nitrogen fixation activity. In most cases, the observed effects were less marked when the sediments were amended with ‘weathered’ crude oil than with the same concentration of fresh crude oil. Untreated sediments that were overlain with treated sediments showed the same changes as those sediments that were thoroughly mixed with crude oil. The presence of fresh crude oil at 50‰ essentially eliminated burrowing activity of the benthic infauna. Under these conditions, there was an accumulation of detritus particles on the oiled sediments that was not present in the untreated controls.  相似文献   

7.
海上原油泄漏在其风化迁移过程中会形成不同浓度的乳化物,严重威胁海洋生态环境。合成孔径雷达(SAR)因其不受雨、云影响,可昼夜监测的优势,在海上溢油监测过程中发挥着主力军的作用,但是它在原油乳化识别方面还存在着不足。本文利用C波段全极化散射计观测原油的自然乳化过程,并利用人工制备的不同含水率的乳化油品模拟原油乳化进程观测油膜后向散射系数(N_(RCS))的变化。实验结果表明乳化原油M_(RCS)高于未乳化原油,且油膜乳化程度越高相应的N_(RCS)越大。通过油水散射差值(Δσ~0)与阻尼比(D_R)发现能够识别乳化与未乳化原油,反映油膜乳化程度的变化,且在VV极化下效果最佳。  相似文献   

8.
The fate of Prudhoe Bay crude oil. labelled with n(1−14C)-hexadecane and dispersed with Corexit 9527, was studied for 24 days in a polyethylene bag enclosure of sea water by time-series observations of the alkane composition of the crude oil, oil fluorescence, 14C-labelled hexadecane in the particulate phase, bacterial biomass, amounts of sedimented material and parameters of temperature, salinity, particulate organic carbon and nitrogen, and nutrients. By the seventh day, convective and diffusive mixing, important mechanisms for the dispersion of oil, resulted in a fairly homogeneous distribution of oil throughout the enclosed water column. Rapid bacterial biodegradation removed the n-alkane fraction initially, while oil-Corexit dispersion suppressed phytoplankton growth. After 7 days, with the recovery of phytoplankton growth, much of the aged oil sedimented with sinking of diatoms.  相似文献   

9.
饵料、温度和个体规格对脉红螺摄食的影响   总被引:1,自引:0,他引:1  
利用实验生态学方法,通过分析摄食喜好系数、单位体质量摄食量等参数,研究脉红螺(Rapana venosa)的摄食选择性,以及饵料种类、温度和个体规格对脉红螺摄食量的影响。结果表明,脉红螺(壳长100~120mm)具有明显的摄食选择性,喜食缢蛏(Sinonovacula constrzcta)、竹节蛏(Solen gouldi)和中国蛤蜊(Mactra chinensis),但不同饵料对其摄食量的影响不显著。随着温度的升高,不同规格脉红螺的摄食量变化趋势相似,即温度低于7℃时基本不摄食,温度高于16℃时开始大量摄食,22℃左右时达到摄食高峰。不同规格的脉红螺,随壳长的增加,单位体质量摄食量逐渐减小。不同壳长的脉红螺(38~108 mm),随壳长的增加,最低摄食温度先降低(壳长50~70 mm脉红螺最低摄食温度最低)后升高。本研究为脉红螺的人工养殖提供了理论依据,同时为脉红螺的生态影响评估提供参考。  相似文献   

10.
We report the laboratory survival, respiration, feeding and swimming behavior of zooplankton exposed to suspended tailing from a molybdenum mine that discharged into the Observatory Inlet fjord system in northern British Columbia. Test species were the copepods Calanus marshallae and Metridia pacifica and the euphausiid Euphausia pacifica. In the inlet, the discharge produced a turbid plume at intermediate depth and a near-bottom density flow down-slope into the deepest part of the fjord. The concentration of particles in the intermediate plume was always less than 15 mg liter−1 at 0·5 km from the outfall and declined with increasing distance.In toxicity experiments the lowest whole tailing solids concentration that produced a clear decrease in median survival time was 560 mg liter−1 for Euphausia pacifica at 112 h and Calanus marhallae at 464 h. All three test species ingested tailing particles. In several cases the presence of low tailing concentrations increased survival over that in filtered seawater. Oxygen consumption was affected at relatively low tailing concentration. The pattern of respiratory responses varied with species and nutritional condition. The swimming behavior of Calanus marshallae could be partitioned into five stereotypic patterns, of which one, “circles”, was associated with continuous feeding. ‘Circles’ was induced in Calanus when starved animals were fed a culture of the diatom Thalassiosira fluviatilis. ‘Circles’ was neither induced nor extinguished by the presence of tailing.  相似文献   

11.
Considering the sedimentation behaviour of suspensions, four states of different sediment-water mixtures are usually distinguished, these being (in increasing concentration) dilute suspensions, concentrated suspensions, fluid muds and mud deposits. As the concentration values delimiting these states vary considerably from one cohesive sediment to another, a procedure for their quantitative determination is proposed here. This paper deals mainly with the effects of hindered settling in interacting concentrated suspensions and of sedimentation in fluid muds. In contrast to the settling velocity of individual particles in a dilute suspension, which must be studied statistically as a stochastic variable denoted W, hindered settling and sedimentation velocities can be described by a scalar denoted V, as solids at any particular level of concentrated suspensions and fluid muds settle at the same velocity. On the basis of settlement tests carried out in this study and published data on organic-rich cohesive sediments, a concentration-dependent empirical law for a permeability coefficient (k) has been generated for cohesive sediments, using data from ten estuarine and nine marine environments, based on the one-dimensional Kynch theory of sedimentation. Based on the median diameters of the dispersed mineral fraction, the main provenances of the sediments are: fine to very fine clay from tropical marine/estuarine environments, medium clay to very fine silt from estuaries in western France, and fine to coarse silt from marine (harbour) environments in the Normandy region of France. A general trend for the influence of the grain size of the mineral fraction on the permeability coefficient has been established. It is demonstrated that the concentrations delimiting the different states of sediment-water mixtures can also be related to the grain size of the mineral fraction. Thus, hindered settling and sedimentation processes of muds, similar to the marine and estuarine cohesive sediments considered in this paper, can be studied as generic problems parameterized through a defined median diameter of the dispersed mineral fraction. Results for Loire estuary sediments are presented separately, based on specific tests to analyse the influence of experimental conditions on settlement. Moreover, the concentration values delimiting the different sediment-water mixture states have been largely established for this estuary.  相似文献   

12.
低盐度对方斑东风螺摄食与生长的影响   总被引:1,自引:1,他引:1  
方斑东风螺的适宜盐度在21以上,适应盐度下限应为15.在21~33的盐度范围内,小水体的实验条件下,平均体重0.27g、平均壳长11.2mm的方斑东风螺.投喂小管枪乌贼,日平均掇食率10.2%~11.6%,体重日均生长11.3~12.0mg,壳长日均生长123.1~141.91μm,盐度逐渐降至15时,方斑东风螺的摄食率和生长速度都明显下降.把近岸自然海水的盐度29作为盐度瞬间下降或上升的起点和终点.当盐度从29瞬间下降时,不影响其摄食和生长的最低终点盐度应高于21.当盐度瞬间上升至29时,不影响其摄食和生长的最低起点盐度应高于18.  相似文献   

13.
Mussels (Mytilus edulis L.) were exposed to North Sea crude oil, microencapsulated oil and dispersants, singly and in combination, and growth rates measured at 24–48 h intervals.Exposure to microencapsulated pure oil (2·0–2·1 mg litre−1) and to microencapsulated mixtures of oil (2·2−2·5 mg litre-1+5 % of the different dispersants (FINASOL OSR 5, COREXIT 9527, DISPOLENE 36 S) gave approximately the same reduction in growth rate (80–90%) within 170h.Oil chemically dispersed with DISPOLENE 36 S and a pure oil mechanically dispersed in water were significantly less toxic. In high concentrations (2 mg litre−1) all disperants are toxic, DISPOLENE 36 S ssignificantly more than the others.Mussels exposed for 170 h to microencapsulated oil and to microencapsulated oil dispersant mixtures recovered to control growth within 300 h in clean seawater, while in those given pure oil-in-water suspension, the recovery was slower.It is concluded that the toxicity of oil is mainly related to size and concentration of oil particles, while the effect of 5% dispersants added is negligible.  相似文献   

14.
温度对凡纳滨对虾幼体生长、变态和存活率的影响   总被引:1,自引:0,他引:1  
通过不同水温的比较实验,研究了凡纳滨对虾人工育苗的适宜水温,旨在了解33℃及其以上水温对凡纳滨对虾幼体生长、变态和存活率可能造成的不良影响.实验结果表明,在29、31、33、35℃这4种温度实验组中,33℃组幼体的生长最快.Z1—P15期幼体的存活率以31℃组的最高(为29.8%),其次是33℃组(为20.9%),35℃组的最低(为4.7%).实验过程中31℃组幼体的活力状态最佳、最稳定.因此,31℃左右是凡纳滨对虾幼体生长、发育的适宜水温.考虑到33℃组幼体的总存活率虽然低于31℃组,但其具有生长较快的优势,因此可认为目前凡纳滨对虾人工育苗普遍采用的31~32℃水温是合适的.  相似文献   

15.
The study investigated the effects of salinity on growth,antimicrobial activities and secondary metabolites of 47 marine filamentous fungi isolated from the East China Sea near the western shore of the Taiwan Straits.The results indicate that NaCl promoted the growth up to 91.5% of test strains.However,only 14.9% of them showed a significant increase of antimicrobial activity against Candida albicans.When incubated in different concentrations of NaCl,the colony growth, antimicrobial activities and composition of secondary metabolites of the strain Ty01b-8 of Penicillium sp.varied.Treatment with KCl also showed a similar effect.An alkaloid isolated from the fermentation broth of Ty01b-8 was identified as chrysogine,inhibition activity of which against Hela cells was 15.05% at 20 μ g/ml,and yield was 4.4 and 4.9 times higher in 3 percent and 6 percent NaCl treatments,respectively, compared with the non-salt culture condition. These findings prove that salinity is an important factor influencing growth and secondary metabolites of some marine fungi,which can be used to screen for new metabolites from marine fungi,and to enhance their metabolites production in industrial fermentation.  相似文献   

16.
The present study established an experimental marine food chain of three levels (microalgae → zooplankton → fish) to investigate the effect of feeding selectivity on the transfer of methylmercury (MeHg) through the food chain. Total Hg concentrations in Chlorella sp., Nitzschia closterium and Isochrysis galbana exposed to 1 μg L−1 MeHg for three days were 27.91, 32.74 and 40.03 μg g−1 respectively and were significantly different (p < 0.05) between species. Moina mongolica and Artemia sp. primarily selected Chlorella sp. as the sole diet, though the Artemia sp. partly grazed on I. galbana as well. Harpacticus uniremis, however, preferred to graze N. closterium and I. galbana and avoided Chlorella sp. The varying concentration of Hg in the microalgae species as well as the selectivity of zooplankton to the algal diet resulted in varying Hg accumulation in three zooplankton species (M. mongolica < Artemia sp. < H. uniremis with total Hg concentrations of 0.14, 0.66 and 0.82 μg g−1, respectively). Scophthalmus maximus and Paralichthys olivaceus mainly preyed on H. uniremis and partly on M. mongolica, while Fugu rubripes primarily preyed on M. mongolica and secondarily on Artemia sp. Thus, similar reasoning as above could explain the significant difference in Hg accumulation in the fish (S. maximus > P. olivaceus > F. rubripes with total Hg concentrations of 0.0042, 0.0031 and 0.0020 μg g−1, respectively). These investigations suggested feeding selectivity plays a key role in the transfer of MeHg along marine food chains.  相似文献   

17.
Many studies have been conducted in northern Norwegian shelf regions to assess distributions and abundances of zooplankton in the last decade using towed Scanfish-conductivity, temperature and depth sensors (CTD)–optical plankton counter (OPC), and plankton nets. Significant progresses have been made in understanding dominant species, life histories and behavior, and in using size-structured data to identify dominant species in a certain size range. Using these Scanfish–CTD–OPC data, the analysis of zooplankton community size structures, compositions and their relationships with water types is made along the shelf region from Lofoten, North Cape to Varangerfjorden. From the relationships between the water types and zooplankton communities, the transports and exchanges of zooplankton communities between the Norwegian Coastal and Norwegian Atlantic Waters in regions near Malangsgrunnen and Nordvestbanken are examined. The biovolume (biomass) spectra are further analyzed for the productivity, trophic levels and seasonality of communities in these regions, indicating a steeper slope of the biovolume spectrum for a community dominated by herbivorous species in spring and a flatter slope for a community dominated by carnivorous–omnivorous species in winter. The comparison with the zooplankton biovolume spectra obtained in areas west of Antarctic Peninsula is made to examine and understand the differences in the zooplankton biovolume spectra, their trophic dynamics and potential human impacts between different regions.  相似文献   

18.
19.
活性氧对3种海洋微藻生长的影响   总被引:6,自引:0,他引:6  
谢荣  唐学玺  李永祺  王悠 《海洋学报》2001,23(1):94-101
以Fe2+/Vc为活性氧诱生系统,对活性氧作用下3种海洋微藻的生长情况进行了研究.结果表明,低浓度的活性氧可以促进3种海洋微藻的生长,使藻细胞的脂质过氧化程度升高,同时刺激细胞的SOD活性使其略有上升,加入抗氧化剂可以抑制其促进作用;高浓度的活性氧能抑制3种海洋微藻细胞的生长,使细胞的脂质过氧化程度过量增高,抑制细胞的SOD活性,抗氧化剂可以缓解其对藻细胞的毒性作用.不同种类的微藻对活性氧的敏感性存在差异.  相似文献   

20.
窦勇  王悠  唐学玺 《海洋科学》2011,35(8):89-94
环境污染导致的臭氧层衰减是当今最引人注目的全球变化现象之一。臭氧层的衰减使得到达地球表面的紫外线,尤其是对生物具有严重损伤作用的紫外线B波段(ultrovioletB,UV.B,280~315nm)的辐射增强,从而对全球产生明显的生态学和生物学效应。研究表明,北海海水表面uv.B辐射率的10%能够穿透到6m深的水层;而...  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号