共查询到20条相似文献，搜索用时 379 毫秒
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光激发的臭氧是使用波长低于１８０ｎｍ的光量子激发氧分子（Ｏ２）而产生的，与常规的地臭氧的区别是：光臭氧为呈碱性负离子状态的气流，它的氧化电势为２．６０Ｖ，不呈现氮氧化物，在水中的半衰期超过２ｈ，是极强的氧化剂，其杀菌消毒效果远高于常用消毒剂。它可以一次同时完成杀菌消毒、净化水质和增氧三大任务，而且不产生二次污染，是当前水产养殖中水质消毒净化的理想物质具有极其广泛的推广应用前景。 相似文献
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国外对藤壶幼体附着的研究进展 总被引：5，自引：1，他引：5
藤壶的幼虫时期经历了一系列的变态 :浮游 ,无节幼体 ,腺介幼体。腺介幼体是一种特殊的幼体形式 ,它无须摄食 ,此阶段仅仅是为了选择附着、变态的适宜地方。游泳着的腺介幼虫被流动的水流牵引附着到底质上 ,它们开始用其小触角运动。这种附着是可逆的。如果幼体不变态 ,它们能重新恢复游泳阶段 ,因为它们还保留着游泳的能力。一旦幼体附着 ,腺介幼虫便开始探查它所附着底质的各方面的理化性质。腺介幼虫以有规律的“步伐”在底质表面上运动 ,运动的距离一般较短 ,且每一步都很少改变方向或停止。当幼虫找到适宜的附着物后 ,从其第一触角第三… 相似文献
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采用流水装置测定去眼柄对凡纳滨对虾稚虾 (Litopenaeusvannamei)耗氧率昼夜节律的影响。实验水温为 2 5℃± 0 .5℃ ,实验虾规格为 (2 .2 6 6± 0 .0 13) g。实验结果表明 :1、去眼柄对凡纳滨对虾稚虾耗氧率的高峰和低峰发生的时间产生影响。正常组对虾耗氧率的高峰多发生在夜间 ,低峰多发生在日间 ;去眼柄后 ,对虾耗氧率的高峰和低峰则大都发生在日间 ;2、去眼柄对虾的日间和夜间的平均耗氧率差异不显著 (P >0 .0 5 ) ,而正常对虾夜间平均耗氧率显著高于日间 34.79% (P <0 .0 5 ) ;3、去眼柄对对虾的平均耗氧率未产生显著的影响(P >0 .0 5 )。 相似文献
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臭氧处理水技术原理及其在水产养殖中的应用综述 总被引：3，自引：2，他引：3
自从1785年发现臭氧以来，臭氧作为氧化剂、消毒剂、催化剂在世界范围内获得广泛的应用，如利用臭氧消毒技术进行饮用水的处理；用于水产养殖用水上，既起杀菌作用，又达到增氧效果，为水产高密度养殖创造有利条件；用于环境消毒、食品保鲜（特别海产品）、储藏、去色、去味、防霉，海水淡化等方面（1、2、3、4、5），由于臭氧处理水法，克服因使用氯和其他化学药品而产生的致癌物质，并造成二次污染，人们也逐渐认识到臭氧处理技术的重要性。水是水生动物的生存环境，水质的好坏直接关系到水产养殖生物成活与否，特别水产动物的苗种生产对… 相似文献
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船舶压载水携带的微生物对目的海域的污染问题亟待解决。采用电解法,以渤海湾的海水为处理对象,以炭纤维材料为阴极,分别以碳棒、碳板和炭纤维为阳极,首先考察了施电2.00 V下3种阳极炭材料对应的杀菌效果,进而重点考查了碳板为阳极材料时施加不同槽压下的杀菌性能,并对其杀菌机理进行初步分析。结果表明,3种阳极材料对应的杀菌效果先后顺序为碳棒碳板炭纤维,各自的杀菌效果均较为明显,施电18 min时碳板对应的灭活率可达100%;以碳板为阳极时,施加槽压越高杀菌效果越显著,本研究范围内以1.81 V为佳,施电18 min时灭活率在99%以上;不同槽压下体系中氯离子浓度和p H都随时间整体呈减小趋势,一定程度上可用于解释杀菌作用过程。研究结果可为电解法处理船舶压载水提供参考和借鉴。 相似文献
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采用室内实验生态学方法对华贵栉孔扇贝的耗氧率和排氨率进行了研究。旨在为华贵栉孔扇贝养殖容量的调查及生态生理的研究提供参考,并可为海洋生态系统动力学和贝类能量学研究提供科学依据。实验结果表明,在实验温度(13—33℃)范围内,华贵栉孔扇贝的耗氧率(OR)和排氨率(NR)与体重(W)都呈负相关,可以用Y=aW-b表示。华贵栉孔扇贝的耗氧率和温度的关系可以表示为OR=-c+b1T-b2T2。在13—28℃温度范围内,华贵栉孔扇贝的耗氧率随温度的升高而增加,28℃时,耗氧率达到最大值,温度升高到33℃时,耗氧率反而下降。而排氨率与温度的关系可以表示为1NR=c1edT,在实验温度范围内,排氨率随温度的升高则呈持续升高趋势。华贵栉孔扇贝呼吸和排泄Q10值范围分别为0.466—2.471和1.129—2.437。在23—28℃温度范围内,不同规格华贵栉孔扇贝的耗氧率和排氨率的比值(原子数O:N)较高。方差分析表明,体重、温度及二者的交互作用对华贵栉孔扇贝的耗氧率和排氨率均有极显著的影响(P0.01)。华贵栉孔扇贝的日常代谢明显高于标准代谢,耗氧率和排氨率平均值分别提高29.9%和69.4%。 相似文献
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氢和氧稳定同位素示踪湖泊蒸发的对比研究 总被引：1，自引：0，他引：1
氢氧稳定同位素被广泛用于水文循环过程的研究。本文观测了2015年太湖湖水H~2HO和H_2~(18)O组分,分析了它们的时空变化规律及其控制因子,探讨亚热带大型浅水湖泊的同位素富集机制;基于稳定同位素质量守恒法计算太湖蒸发量;评价了动力分馏学系数的传统湖泊算法与海洋算法的适用性;重点分析了H~2HO和H_2~(18)O示踪湖泊蒸发的效果,对比二者之间的差异。研究结果表明,在空间上,太湖湖水和河水的氢氧同位素在南部特别是东南部较为富集但在北部区域较为贫化,这主要是受水流方向的控制,东南部湖水经历的蒸发时间较长,因此湖水中同位素累积较多;在季节上,冬季湖水同位素较贫化、春夏季较富集。对于2015年太湖的年蒸发量,用氢同位素示踪的结果与观测值较一致,为880mm;氧同位素的示踪结果略低,为690mm。使用传统湖泊研究中对动力学分馏系数的取值,会导致蒸发被显著低估,而氧稳定同位素的示踪结果对动力学分馏系数的取值更为敏感,同时氢稳定同位素在同位素分馏过程中主要是平衡分馏效应占主导,因此H~2HO在动力学分馏系数的参数化方案中影响较小,在实际应用中更为稳定。本文的研究结果表明了稳定同位素水文学研究中使用合适的动力学分馏系数的重要性。 相似文献
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The idea of modified water masses is introduced and a cluster analysis is used for determining the boundary of modified water masses and its variety in the shallow water area of the Huanghai Sea (Yellow Sea) and the East China Sea. According to the specified standards to make the cluster, we have determined the number and boundary of the water masses and the mixed zones.The results obtained by the cluster method show that there are eight modified water masses in this area. According to the relative index of temperature and salinity,the modified water masses are divided into nine different characteristic parts. The water, masses may also be divided into three salinity types. On the TS-Diagram, the points concerning temperature and safinity of different modified mater masses are distributed around a curve, from which the characteristics of gradual modification may be embodied. The variation ranges of different modified water masses are all large, explaining the intensive modification of water masses in th 相似文献
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长江口及济州岛附近海域变性水团的初步分析 总被引：1，自引：0，他引：1
基于变性水团的概念,本文把聚类分析用于确定长江口及济州岛附近海域变性水团的边界。由聚类分析得到的结果表明,在该海区有十个水团。对它们的特征、分布与变化进行了初步分析。作者得出的结论是:1、在十个水团中,有四个大洋性水团,六个变性水团。2、该海域水团变性的特点为暧季增温、降盐、降氧,而冷季则相反。3、水团变性是由海区内、外因素综合作用而发生的,而后者在浅水区域起主要作用。4、水团边界的舌状分布与流向之间有明显关系。因之,海流的方向及强度,大致可依水团舌状分布而判断。5、底层中心渔场基本上位于各变性水团之间的混合区或其附近。 相似文献
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《Marine Geology》1999,153(1-4):41-55
The oxygen and carbon stable isotope compositions of the present-day Mediterranean waters have been measured in order to evaluate their variability, which is related to the specific climatic and hydrological conditions within the basin. The experimental equation between the δ18O value and the salinity of water, based on 300 measurements on surface, intermediate, and deep waters sampled during the VICOMED 2 and 3 cruises in the western, central and eastern Mediterranean, has a slope of 0.27, a value which is significantly lower than the slope of 0.45, as defined in the northeast Atlantic Ocean. This difference in the δ18O–salinity relationship, which occurs immediately in the Alboran basin, is basically a characteristic of the climatic regime of the Mediterranean, i.e., of an excess evaporation over fresh water input. The largest variations of these two parameters, δ18O of water and δ13C of ∑CO2, are observed in the surface waters, mostly in the western Mediterranean. This evolution mirrors the progressive eastward restriction, which separates the less-evaporated and more-productive western basins from the more-evaporated and less-productive eastern basins. The intermediate waters constitute a homogeneous layer. However, their δ18O values decrease eastward by 0.35‰ at maximum, due to progressive dilution by mixing with overlying and underlying water masses; their δ13C values decrease also eastward by 0.35‰ at maximum, due to an increasing input of nutrients issued from the regeneration of sinking organic particles. The deep waters have similar δ18O values but slightly higher δ13C values (often by less than 0.1‰) than the overlying intermediate waters, indicating generally well ventilated conditions due to active winter convection. 相似文献
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The waters in the shallow part of the Yellow Sea and East China Sea are affected greatly by climatic and geographical conditions and fail to possess homogeneity and conservativeness like oceanic waters. They have apparent difference in modified degrees, so we may regard a certain range of mixed water as a relatively independent one. In fact, the study of water masses in the shallow sea means a modified analysis of waters. The idea of modified water masses is introduced, i. e., a water body which holds the similar physical and chemical characters, occupies a certain space, and varies seasonally and regularly. On the T-S diagram, it displays as a certain amount of points aggregated together, the centre of which changes regularly and may have a process of combination and separation.According to the clustering method, there are eight modified water masses in this area. They may also be divided into three salinity types. On the T-S diagram, the points concerning temperature and salinity of different modified 相似文献
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南沙群岛海区有机碳沉积作用与古生产力估算 总被引：1，自引：0，他引：1
根据南沙群岛海区５个沉积柱样和大量表层样的分析资料讨论了有机碳的沉积作用。深海有机碳含量一般为０．２％－１．３％。水柱深度对其分布的控制作用不明显。分析结果发现冰期、间冰期，尤其是本次冰期有机碳含量变化明显，４个柱样晚第四纪的质量堆积速率在末次冰期时最大。有机碳保存的主要控制因素是溶解氧浓度、粘土矿物含量、水柱深度和底栖混合强度，其中溶解氧浓度是最重要因素。底栖有孔虫的相对丰度，如Ｕｖｉｇｅｒｉｎａ和Ｂｕｌｉｍｉ－ｎａ，可用来指示溶解氧和有机碳含量。有机碳含量与海洋生产力关系极为密切，它可用来重建海洋古生产力的长期变化。采用Ｍｌｌｅｒ和Ｓｕｅｓｓ方程以及Ｓａｒｎｔｈｅｉｎ方程的计算结果与目前生产力值结果比较表明，后一种方法因充分考虑了溶解氧浓度和水柱深度而更接近现代值。 相似文献
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Seawater and brine samples collected along vertical profiles above the Bannock and Tyro Basins (eastern Mediterranean), and gypsum samples collected by dredging and coring the anoxic section of the Bannock Basin, have been studied for their δ18O values. The following conclusions may be drawn from these data: (1) The water of the deep brines is isotopically slightly different from modern Mediterranean bottom water and might be a ‘fossil water’ possibly formed during a recent, climatically cooler stage or when the evaporation was slightly higher than nowadays. (2) The similarity between the δ18O values of the brine samples from the Bannock and Tyro Basins supports the possibility that the ages of the two basins are very close to each other. (3) Gypsum crystals on the bottom of the Bannock Basin are probably being formed by the dissolution and reprecipitation of sub-bottom (or outcropping) Messinian evaporites. This hypothesis is supported by the oxygen isotopic values exhibited by the gypsum crystallization water and by the oxygen and sulphur isotopic composition of gypsum. (4) The shells of pelagic organisms included in gypsum are probably very recent, but not contemporary, and may be referred to cooler environmental conditions. 相似文献