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1.
几种环境因子对厚壳贻贝浮游幼虫生长与存活的影响   总被引:1,自引:0,他引:1  
研究了在室内控制条件下,海水盐度、温度、pH对厚壳贻贝浮游幼虫生长和存活的影响。结果表明,厚壳贻贝浮游幼虫生长的适宜盐度在15~35,最适生长盐度在25~35之间,适宜温度为15~30℃,最适生长温度在20~25℃,适宜pH为6.00~9.00,最适pH为8.00左右。  相似文献   

2.
盐度对岐脊加夫蛤幼虫与稚贝的影响   总被引:1,自引:0,他引:1  
叙述盐度对岐脊加夫蛤Gafraiumdivaricatum(Gmelin)幼虫及不同大小稚贝(壳长0.8~1.4mm)生长和存活的影响.水温30±1℃时,加夫蛤幼虫阶段的适盐范围为19.93‰~33.22‰,最适盐度为22.59‰.其下限和上限分别为15.95‰和38.53‰,其存活率低于30%.水温25±1℃时,稚贝Ⅰ(壳长0.8~1mm)适盐度范围为19.93‰~33.22‰,最适盐度为22.59‰;较大稚贝Ⅱ(壳长1.3~1.4mm)适盐范围为15.95‰~38.53‰,最适盐度为25.24‰,其下限和上限分别为9.30‰和45.17‰.  相似文献   

3.
研究了不同盐度对可口革囊星虫(Phascolosoma esculenta)孵化、幼体存活和生长的影响。结果表明:1)可口革囊星虫孵化适宜盐度范围为15~30,最适盐度为20~26,呈现出偏低盐的倾向;2)在盐度为10、15、20、25~26、30、35时可口革囊星虫幼虫不投饵存活系数(survival activity index,SAI)分别为9.8、78.3、60.9、12.6、12.2、10.7,即,盐度为15、20时幼虫存活时间较长(达7 d),盐度为10、25~26、30、35时幼虫不投饵存活系数迅速下降;3)在盐度为15、20、25~26、30时,经过9 d的培育,幼虫体长从251.7μm生长至542.9~568.5μm,生长速度为60.3~63.2μm/d,其中生长速度最快的是在自然盐度(25~26)条件下,最慢的是在盐度30条件下。  相似文献   

4.
目的:在室内控制条件下,研究不同海水盐度对全长为(13.70±0.91)cm,体质量为(9.74±0.85)g的军曹鱼幼鱼存活和生长的影响.方法:将30 d 70%存活率的盐度作为适宜存活临界盐度,将增长率为最佳增长率70%时所对应的盐度作为适宜生长临界盐度,最适存活盐度、最适生长盐度范围则为多重比较无统计学差异且存活率、日生长率最高的几个实验组所对应的盐度范围.结果:在水温为26.5~28℃,溶解氧大于6 mg/L的条件下,军曹鱼幼鱼的适宜存活盐度范围为3.68~37.43,最适存活盐度范围为10~34;适宜生长盐度范围为5.91~37.15,最适生长盐度范围为22~31.结论:军曹鱼作为广盐性鱼类,对盐度有较强的适应性,当盐度变化超出最适范围时,养殖军曹鱼幼鱼对高盐更为敏感.  相似文献   

5.
盐度对龟足胚胎及幼虫发育的影响   总被引:1,自引:0,他引:1  
叙述了盐度对体外培育的龟足胚胎及幼虫发育的影响 .水温 2 5± 1℃时 ,胚胎发育的适宜盐度范围为 1 5 .33~ 4 1 .78;最适盐度为 2 1 .38~ 2 8.5 5 .幼虫发育耐盐上限为 4 1 .78,下限为 2 1 .38;最适盐度为 2 8.5 5~ 35 .1 6  相似文献   

6.
温度和盐度对斜带石斑鱼幼鱼生长与存活的影响   总被引:5,自引:0,他引:5  
研究了水温及盐度渐变和突变条件下斜带石斑鱼幼鱼的生长和存活情况.结果表明:1)斜带石斑鱼幼鱼在温度15~32 ℃的海水中均能存活和生长,最适温度范围为22~28 ℃.在突变条件下,斜带石斑鱼幼鱼在温度为14~32 ℃范围内48 h的存活率均在92.5 %以上,其中17~29 ℃的存活率为100 %;在渐变条件下,温度为12~32 ℃范围内幼鱼存活率可达80 %~95 %.2)斜带石斑鱼幼鱼的盐度适宜范围是9~39.在突变条件下,斜带石斑鱼幼鱼在盐度为4~39范围内48 h的存活率均在95 %以上,盐度为0时不能存活;在渐变条件下,盐度为4~39范围内幼鱼存活率可达91 %~100 %,其中盐度为14~39范围内幼鱼的存活率均在98 %以上.  相似文献   

7.
本文运用生物统计法确定西施舌幼虫和贝苗的适宜盐度范围,结果表明。D形幼虫、壳顶幼虫和贝苗对盐度的耐受力不同。D形幼虫生长的适盐范围为17.27~27.90‰,且生长和存活的最适盐度是17.27~19.93‰;壳顶幼虫生长的适盐范围向低盐度延伸,为13.29~27.90‰,生长和存活的最适盐度为19.93‰。平均壳长2.9mm的贝苗存活适盐范围向高盐度延伸,为13.29~35.87‰,其中27.90‰是贝苗生长和存活的最适盐度。  相似文献   

8.
温度对龟足胚胎和幼虫发育的影响   总被引:1,自引:0,他引:1  
在室内海水盐度为27~28的条件下,观察了18,21,24,27,30,33,36 ℃等7个温度对龟足(Pollicipes mitella)胚胎发育时间、孵化率和幼虫生长、存活率和变态率的影响.实验结果表明:在18~36 ℃之间,龟足的胚胎均能正常发育并且孵化,其发育时间随温度的升高而缩短,18 ℃的发育时间最长为12 d,而30~36 ℃所需的发育时间最短,仅需5.5 d.实验结束时(20 d)温度对累积孵化率的影响不明显,但在胚胎发育过程中(14 d之前)低温(18,21 ℃)对累积孵化率的影响明显,其他温度(24~36 ℃)对胚胎孵化率的影响不显著.结合胚胎发育时间和孵化率两个指标,龟足胚胎发育的最适温度为24~33 ℃.根据存活率和变态率,龟足幼虫生长发育的温度上限和下限分别是36 ℃和18 ℃,在21~33 ℃之间,龟足幼虫可以不同程度地生长和变态,幼虫发育的最适温度范围是24~30 ℃.  相似文献   

9.
为给单环刺Yi(U.unicinctus)的苗种生产提供有效的基础资料,本文研究了水温对单环刺Yi胚胎发育的影响。结果表明:单环刺Yi各胚胎发育期的发育速度(h)随水温(T)升高而加快,有明显的正相关性。求得胚胎发育的生物学零度为平均2℃。不同水温条件下,各期幼虫期的存活率以20℃为最高,培育水温高于或低于20℃时生存率逐渐降低。幼虫培育适宜温度为15-20℃。  相似文献   

10.
利用实验生态学方法,模拟浙江省南部自然海区生态环境条件,研究了温度、盐度、培育密度、投饵量、底质对刺参幼体(6.42±0.84 g)生长和存活的影响.结果表明:自然海水温度为(12.5±0.5)℃,盐度为27±0.3时,温度向上突变至30℃时,幼参在第2天和第6天的存活率分别为50%和20%;温度向下突变至0℃时,幼参在第4天和第6天的存活率分别为90%和50%;盐度向下突变至15时,幼参在第4 d和第6 d的存活率分别为80%和0%,向上突变至39时,幼参在第2天和第4天的存活率分别为70%和0%.实验周期30 d,温度10~15 ℃时,幼参第30 d的相对增重率显著高于其它各温度组(P<0.01),温度20℃时,幼参不夏眠;幼参分别在盐度24~30,培育密度20~40 ind/m2,日投饵量为刺参体质量6%~9%时,第30d的相对增重率显著高于其他各盐度组、培育密度组和日投饵量组;以水泥、轮胎、轮胎+瓦片、泥为底质,幼参第30 d的相对增重率和存活率均较好.在浙江省南部沿海海区环境条件下,幼参生长适宜温度为10~15℃,适宜盐度为24~30,最适培育密度为40 ind/m2,最适日投饵量为幼参体重的6%,室内水泥池养殖和潮间带网箱养殖是适宜的养殖方式.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

19.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

20.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

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