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利用人工配制的生活污水先进行单胞藻（斜生栅藻 Ｓｃｅｎｅｄｅｓｍｕｓ ｏｂｌｉｑｕｕｓＴｕｒｐ）的 培养,再接种田螺（Ｃｉｐａｎｇｏｐａｌｕｄｉｎａ ｓｐ）和短钝溞（Ｄａｐｈｎｉａ ｏｂｔｕｓａ Ｋｕｒｚ）,对栅藻密度的经时变化, 短钝溞种群增长及水体中氮、磷、碳在培养过程中的变化作了测定与分析结果如下：（１）田螺组和 对照组中栅藻密度（Ｎ）经时变化的函数为：田螺组Ｎ＝ｅ（１．１１３６）ｔ（１．７２０４）;对照组Ｎ＝ｅ（１．４１７５）ｔ（１．８０９９）;（２）田 螺组短钝溞在静态条件下的种群增长模型为： Ｎ＝ ０． ７５ｅ（０．４７６）ｔ,（３）以短钝溞问收方式收获量的累加 值作为种群增长量（产出量）,其数学模型为：Ｎ＝ｅ（０．２８３７）ｔ（２．５５３７）;（４）经栅藻、田螺、短钝溞培养后,生 活污水的氮、磷、碳含量分别下降了 ８０、 ６０％, ７２． ４０％, ４５． ７０％． 本研究既为枝角类集约化培养提供了某些生态学理论参数,也为污水调控及资源化提出一个 值得参考的技术途径 相似文献
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桂林中、晚泥盆世微生物碳酸盐沉积、礁和丘及层序地层、古环境和古气候的意义 总被引：4，自引：0，他引：4
钙质碳酸盐的微生物沉淀作用从太古代开始一直在碳酸盐台地的发育中起到了至关重要的作用. 微生物碳酸盐在重大的环境变化中(包括台地环境的海侵事件和生物绝灭后的复苏阶段)是碳酸盐沉积体的重要贡献者; 在层序地层不同体系域中有不同的微生物形成的碳酸盐沉积.桂林晚泥盆世法门期碳酸盐台地中的生物礁和丘完全由微生物和胶结物形成, 代表了弗拉-法门期生物事件后骨骼后生生物完全缺失的礁生态系中微生物为主的、独特的生物礁类型; 它们与特定的古环境和古气候有关, 可以用作研究环境变化和生物事件的指标. 相似文献
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阳澄湖若干水质资料的分析与评价 总被引：12，自引：0，他引：12
根据１９９４年５月于阳澄湖湖区７个采样点水质分析结果,表明湖水中矿化度较高,硬度较大,主要离子以ＨＣＯ３＾－,Ｎａ＾＋为主,分别占阴阳离子摩尔总数的５７．６１％、６３．９％。湖水水型西湖、中湖为重碳酸盐钠组Ⅰ型,东湖为重碳酸盐钠组Ⅱ型水。湖水中Ｎ、Ｐ营养元素丰富,ＮＨ３－Ｎ、ＮＯ２－Ｎ指标与７０年代相比明显增高,表明水体已曹室不程度地轻污染。 相似文献
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从地质微生物学和碳酸盐沉积学两方面对海南岛三亚鹿回头水尾岭海滩岩中的微生物碳酸盐沉积进行研究, 研究结果显示三亚鹿回头海滩岩中含有微生物碳酸盐沉积, 与微生物活动有关的胶结物也很常见. 海滩岩中的微生物碳酸盐沉积主要发育在珊瑚(碎屑和碎块)骨骼孔穴中或珊瑚体的表面, 而很少发育在珊瑚和其他生物碎屑堆积而形成的空隙中. 微生物碳酸盐沉积一般呈叠层状、薄的结壳状、穹状、微生物石等多种形态生长, 黏结细小的生物碎屑, 大多具有微生物的管形丝状体和纹层状的生长纹. 珊瑚骨骼孔穴中的微生物碳酸盐沉积呈叠层的尖锥体, 生长方向不定, 随珊瑚骨骼孔穴的延伸方向生长, 具有清晰的生长纹层, 显示明显的阶段性, 是隐生微生物碳酸盐沉积的一种独特发育形式. 微生物成因的胶结物多以针纤状方解石、钙化的菌类丝状体和莓状钙球的形式出现, 并以针纤状方解石最为常见. 这表明微生物活动和微生物碳酸盐沉积在热带海洋受季风影响下的以碳酸盐为主要成分的海滩岩形成中起着重要的作用. 研究工作第一次发现和描述了我国南海北部海岸海滩岩中的微生物碳酸盐沉积和与微生物活动有关的胶结物, 研究结果支持海滩岩中的胶结物部分是源于微生物成因的, 肯定了微生物在碳酸盐沉积方面的重要作用, 从一个新的研究角度拓宽了海滩岩的认知领域. 相似文献
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为进一步探讨上地幔的高导层成因,了解碳酸盐在上地幔电性方面的作用并估算上地幔高导层的碳酸盐含量,本文对不同碳酸盐含量的橄榄岩及玄武岩样品在2~3 GPa、300~1300℃的条件下进行了电性实验研究.研究初步发现:碳酸盐熔体显著增强橄榄岩、玄武岩样品的导电能力;单纯用含硅酸盐熔体的橄榄岩或单纯用含水橄榄岩可能难以解释上地幔某些区域的异常高导现象;同样,单纯用碳酸盐化的橄榄岩可能也难以解释上地幔某些区域的高导现象;上地幔的高导区很可能是碳酸盐熔体、硅酸盐熔体及水的共存区域. 相似文献
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模拟水氡仪与数字化水氡仪对比观测实验 总被引：1，自引：0，他引：1
在相同观测条件下,选用平凉地震台北山2号泉水样作为实验目标,用 FD-125型模拟水氡仪与 SD-3B 型数字水氡仪进行对比观测实验;搜集全国用相同方法观测的5个地震台的观测资料进行对比分析,结果表明：FD-125型模拟水氡仪性能明显优于 SD-3B 型数字水氡仪。 相似文献
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在对贮液圆柱壳进行动水压力计算时常常仅仅采用整体弯曲和整体剪切两种计算模型。本文作者针对短壳的特点,又提出了局部弯曲和局部剪切两种计算模型,并根据实际情况对贮液短壳的整体剪切和局部弯曲两种力学模型的动水压力进行了一系列计算和比较。结果表明:局部弯曲模型更能反映贮液短壳的实际情况;径高比是影响动水压力的主要因素,但不能忽视壁厚与高度之比这个因素。 本文的研究成果已被国家标准(《构筑物抗震设计规范》所采用。 相似文献
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比较Biot和Yamamoto两种模型下饱和土的动态响应, 指出了这两种土模型的特点. 首先从土骨架和孔隙水所满足的运动方程出发分析了两种土模型所反映能量损耗, 然后计算了粗砂质和细砂质土层内弹性波随加载频率及土参数的衰减规律, 总结了黏性摩擦和Coulomb摩擦在两种模型中具体体现, 最后讨论了当加载为海浪时, 两种模型对应的波浪衰减特点以及土床内孔隙水压力和应力相位角随孔隙度、渗透系数、黏性系数及剪切模量等土参数的变化. 相似文献
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银鱼生产的发展是通过银鱼的引种来实现的,银鱼的引种主要是采取向水体投放受精卵的方式来完成,受精卵又是通过人工繁殖而获得银鱼的人工繁殖不同于常规养殖鱼类,因其一经捕起很快就会死亡而不能进行人工催产因此银鱼人工繁殖的亲本是在银鱼的繁殖季节从天然水体中捕捞而获得,而大量的性成熟好的、可以立即进行人工受精的亲本只能在产卵高峰期才能捕获得到．所以了解并掌握银鱼的性腺发育规律和产卵时期对银鱼的人工繁殖十分重要 １９９２年４月至１９９６年５月在湖北省徐家河水库对近太湖新银鱼的性腺发育规律和产卵时期进行了长期的研究,并从１９９５年５月至１９９６年４月（银鱼的一生）周年标本中逐月进行了组织切片通过对近太湖新银鱼（Neosalanx pseudotaihuensis）卵细胞的组织学研究表明该鱼为分批产卵类型根据卵巢外部形态和内部组织结构,建议将近太湖新银鱼的卵巢划分为六个阶段;从卵巢每月发育期趋势和卵细胞大小以及卵的成熟度得出近太湖新银鱼的产卵期为３－５月,其中４月中旬至５月中旬为产卵高峰期;根据体长频率分布来看,近太湖新银鱼产完最后一批卵就死亡,因此,它的寿命仅一年从其周年体长和成熟系数分布并结合秋季大捕捞大量样本的检查,得出近太湖新银鱼只有春季产卵群 相似文献
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湖北省水库与湖泊银鱼移植与增殖试验 总被引：2，自引：0，他引：2
在受试水库、湖泊中,移植与增殖二种银鱼,即近太湖新银鱼和太湖新银鱼。经三种人工采卵受精技术的比较试验,采用半干法人工受精最为理想。经多种受精卵运输方法的比较试验,采用塑料袋充氧运输最为理想。经散撒受精卵和网箱孵化的比较实验,采用网箱孵化最为理想。经不同放流鱼苗技术的比较实验,采用鱼苗平游后放流最为理想。经不同季节、不同开捕时间的比较实验,二种银鱼的合理捕捞时间为秋冬季,严禁在春季捕捞;最合理的开捕时间为国庆节前后。近太湖新银鱼和太湖新银鱼的人工采卵授精时间为3月上旬和4月上旬,严禁在非繁殖盛期采卵。银鱼的捕捞强度应控制在资源量的2/3或3/4范围内。 相似文献
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Fecundity and spawning mode of three introduced fish species in Lake Banyoles (Catalunya, Spain) in comparison with other localities 总被引：1，自引：0，他引：1
Anna Vila-Gispert Ramon Moreno-Amich 《Aquatic Sciences - Research Across Boundaries》2000,62(2):154-166
Analysis was conducted during 1991 into the fecundity and oocyte size distribution of pumpkinseed, roach and rudd in Lake Banyoles. We found that individual fecundities of these species in Lake Banyoles were lower in comparison with other localities. In roach, there was a moderately significant negative relationship between latitude and egg number. The temporal pattern of the pumpkinseed's oocyte size distribution suggests that it is a multispawner fish that spawns several batches of eggs from mid-May to mid-August. In contrast, roach and rudd seem to be monospawners fish that release only one batch of eggs before mid-May. The monospawning behaviour of rudd in Lake Banyoles is in contrast to the evidence from other waters. Variations in fecundity and spawning mode are discussed on the basis that they are due mainly to differences in local conditions. 相似文献
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2008年5月12日汶川MS8.0地震主震发生后至2012年5月12日,我国地震台网在龙门山断裂区域内（102°E-105°E,30°N-34°N）共记录93837个地震事件,其中80995次事件含有深度信息.本文以台网地震目录为主要研究对象,分析了汶川地震余震序列的时空分布与演化特征.与构造活动密切相关的余震频次-震级关系变化显示,与主震断裂活动直接相关的余震活动在主震后4个月内基本结束.余震释放能量的空间分布及演化分析显示,在主震后6~24 h即有可能捕获未来余震区的大致展布乃至余震发展趋势. 相似文献
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Seasonal measurement of zinc levels in mussels (Mytilus edulis) from the Tyne estuary showed a small spring peak and an annual low in September. Zinc concentration was found to be significantly lower in gonadal tissue than in nongonadal tissue. Although gonadal dry weight was strongly negatively correlated with gonadal zinc concentration there was no significant relationship between gonadal dry weight and whole body zinc levels, indicating that gonadal state has little effect on zinc variability in these animals. However, a strong negative correlation was found between log gonadal zinc concentration and log nongonadal dry weight. Construction of a gonadal index (gonadal/nongonadal dry weight) shows that the seasonal peak zinc concentration in early May occurs before major spawning has taken place. It is concluded that the seasonal dynamics of zinc in this species can be explained in terms of growth of somatic rather than germinal tissue. 相似文献
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《Limnologica》2016
At the Lower Rhine, three congeneric, invasive Gobiidae constitute the major part of local fish assemblages. Reproduction strategies play an important role in biological invasion processes and help to predict future population development. Up to now, studies on the reproductive traits of the three species have led to contradictory findings in invaded areas, and studies on native populations are scarce, especially when regarding a co-occurrence of the three species. This study provides an overview over already existing knowledge of reproductive traits in native as well as invaded regions and describes the reproduction modes of all three species at the Lower Rhine. Based on intensive beach seine sampling in nursery habitats for three consecutive years, detailed information about the spawning habits of the bighead goby Ponticola kessleri, the round goby Neogobius melanostomus, and the monkey goby N. fluviatilis is provided. Spawning onset as well as length and intensity of the spawning season were determined by estimating growth rates and subsequent back-calculations of hatching and spawning events. Gonadosomatic index (GSI) analyses of adult gobies were used to cross-validate results and to assess validity of the used method. Growth rates for the first three months of all three species were highly variable and ranged between 0.3 mm and 0.95 mm total length per day. All three Gobiidae displayed different reproductive modes with bighead gobies spawning first in March/April, but probably only once a season. In contrast, round and monkey gobies started reproducing slightly later, but then continued spawning throughout the season until September, exhibiting temporal separation with varying intensities. High variation in spawning onset, length and reproductive output for all three species was observed over the years and no relationship between spawning onset and temperature could be detected. For the first time, highly resolvent information on spawning onset and spawning season length is obtained and the fine-tuned differences between the three species are highlighted. 相似文献
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鄱阳湖产银鱼的繁殖生物学 总被引：7，自引：1，他引：6
本文记述了鄱阳湖产太湖短吻银鱼(Neosalanx tangkahkeii taihuensis)、乔氏短吻银鱼(Neosalanx jordani)、雷氏银鱼(Reganisalanx brachyrostralis)等三种银鱼的成熟年龄、繁殖时期、生殖群体的体长、性比、生殖力、卵的特征等繁殖生物学资料,并记述了太湖短吻银鱼性腺成熟系数的周年变化、太湖短吻银鱼和乔氏短吻银鱼的产卵生态条件等。近二十年来鄱阳湖银鱼产量急剧下降的主要原因是产卵场遭到了严重破坏。银鱼生命周期仅一年,繁殖力强,认为加强繁殖保护、合理安排捕捞时间是恢复鄱阳湖银鱼资源的关键措施。 相似文献
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Jean d’Elbée Iker Castège Georges Hémery Yann Lalanne Claude Mouchès Françoise Pautrizel Frank D’Amico 《Continental Shelf Research》2009,29(8):1136-1144
From September 2000 to December 2006, surface plankton samples were collected on a monthly basis, from a station located in the southern Bay of Biscay (43°37N; 1°43W France), near the deep Capbreton canyon. In this paper, the results for the ichthyoplankton assemblage are presented. Among the 62 taxa recorded, only 35 were present in the larval stage whilst only 10 were represented by their eggs. Taxa represented by both stages (eggs+larvae; N=17) had the highest abundance. The presence in the surface plankton assemblage of species, at either or both stage, is interpreted within the context of the bathymetric distribution of species. The maxima in abundance and diversity occurred in February–March, for eggs, and May–June, for larvae. This 3-month time-lag between the stages is proposed to be related to the timing of egg spawning and larval recruitment to the pelagic environment. Mean egg abundances (82.4±29.8 eggs/10 m2) were 10-fold higher than the larval abundances (7.1±1.8 larvae/10 m2). Despite pronounced monthly variability, no statistically significant decrease in either egg or larvae abundance was observed during this 6-year study period. Compared with previous published studies, this study shows that the peak in ichthyoplankton diversity occurred two months earlier. In addition, the spawning period occurred over the whole year, even during autumn and winter. Using ordination techniques, the annual sequence appearance of taxa are described at the study site: Gadiforms, Ammodytidae and Pleuronectiforms were present during the winter whilst Sparidae, Blennidae, Labridae and Gobiidae, formed the summer group. Only three species, European anchovy Engraulis encrasicolus, European pilchard Sardina pilchardus and Atlantic horse mackerel Trachurus trachurus were recorded throughout the year. 相似文献