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 796 毫秒
1.
近几年,河蟹人工育苗已成为我省沿海种苗培育单位的重要产业 ,随着育苗规模的不断扩大及所带来的可观经济效益,各地又因地制宜发展起地下海水、浓缩海水的育苗生产,为搞清这几种育苗水体的水质特点 ,作者对这几种水体进行了分析检测,以服务于生产 ,为河蟹育苗的健康发展提供科学依据。1工作内容和方法1.1采样点自然海水采于营口市老边区三道沟和盘锦市二界沟;浓缩海水采于营口市青石岭育苗室及营口盐  种型苗水p CD营盐含量Tab .1 pH ,CODandnutritionsaltofeverykindofbreedingwa…  相似文献   

2.
据文献报道,海水中若干微量金属离子的浓度,远低于饱和含量。并认为,对于Zn、Pb、Cu、Cd等许多元素来说,吸附可能是个控制浓度的因素。硫化物沉淀也可能出现,但可能不是浓度的控制因素。 本文用可靠的极谱法,对海水中Zn++、Pb++,Cu++、Cd++的饱和含量进行了研究,并与作者的单池示差反向极谱法现场海水测定数据作比较;进行了Zn++、Cu++的吸附试验;探讨了海水中微量金属离子与环境间可能存在的平衡过程。从而,探明了海水中微量金属元素的离子浓度(包括不稳定络合物)及其控制因素。  相似文献   

3.
A method for determination of malathion in natural water by cathodic stripping voltammetry using mercury film electrode is suggested in this paper. The method is based on the quantitativeformation of group generated by malathion as a result of elimination reaction inthe ethanol solution of sodium hydroxide. The group is similar to sulphide in electrochemical properties, and can be determined by cathodic stripping voltammetry. Interference from inorganic sulphide is prevented by the addition of Hg (NO3)2. This method has been applied to the determination of residual malathion in natural water (e. g. the sea, rivers, lakes, etc.). The waveheight is directly proportional to the malathion concentration within the range 5×10-9 - 1×10-7 mol/L. The method is simple and rapid, and the results of water sample determination is quite in accord with those of Gas Chromatograph.  相似文献   

4.
提出用B样条函数方法求解咸、淡水分界面的原理、方法和步骤,指出该方法原理简明、易于实现、计算可靠。作为实例,将此方法应用于莱州市滨海地区。  相似文献   

5.
In this paper SIT and Pitzer models are used for the first time to describe the interactions of natural and synthetic polyelectrolytes in natural waters. Measurements were made potentiometrically at 25 °C in single electrolyte media, such as Et4NI and NaCl (for fulvic acid 0.1 < I /mol L− 1 < 0.75), and in a multi-component medium simulating the composition of natural waters at a wide range of salinities (for fulvic and alginic acids: 5 < S < 45) with particular reference to sea water [Synthetic Sea Water for Equilibrium studies, SSWE]. In order to simplify calculations, SSWE was considered to be a “single salt” BA, with cation B and anion A representing all the major cations (Na+, K+, Mg2+, Ca2+) and anions (Cl, SO42−) in natural sea water, respectively. The ion pair formation model was also applied to fulvate and alginate in artificial sea water by examining the interaction of polyanions with the single sea water cation. Results were compared with those obtained from previous speciation studies of synthetic polyelectrolytes (polyacrylic and polymethacrylic acids of different molecular weights). Results indicate that the SIT, Pitzer and Ion Pairing formation models used in studies of low molecular weight electrolytes may also be applied to polyelctrolytes with a few simple adjustments.  相似文献   

6.
本文研究了用Aliguat-336萃取,无焰原子吸收分光光度法测定海水中不同价态铬的方法。该方法有较好的精密度,变动系数为6.0%。回收率在80%左右,其特征量为6.3×10~(14)g,较好地应用于海水中不同价态铬的测定。  相似文献   

7.
对虾养殖池水域环境细菌的动态变化   总被引:49,自引:0,他引:49  
郭平  许美美 《海洋与湖沼》1994,25(6):625-630
于1990年6月下旬-10月初期间,每隔7-10d在大连市金州区董家沟镇养虾场突池定点采样一次,3h内带回实验室进行细菌培养计数,研究对虾养殖池水域环境中细菌的动态变化。结果表明,对虾养殖池水中异养菌和弧菌的数量变化与水温的变化趋势相同;6—7月末,细菌增长比较缓慢;8月初开始,细菌数量增长较快,8月中旬达到全年的最高值,异养菌为3.4×105cell/ml,弧菌为1.9×105cell/ml;而后随着水温的下降,水中细菌逐渐减少。底记泥浆中,细菌数量一直呈上升趋势,不受水温的影响;异养菌最高达6×107cell/ml,弧菌达1.5×106cell/ml。  相似文献   

8.
GEOCHEMICAL CHARACTERISTICS OF INTERSTITIAL WATER OF THE BOHAI GULF   总被引:1,自引:0,他引:1  
This paper discusses the geochemical characteristics of the interstitial water of the Bohai Gulf, where the main salt contents (K+, Na+, Ca++ Mg+ + , C1-, HCO3-, SO4-) in 55 sedimentary layers of 13 cores (3-4 m in length) and those of bottom seawater have been determined and the exchange capacity and exchange cations (K+, Na+, Ca++, Mg++) of the layers analysed (see Fig. 1)Fig. J. The stations of core samplings in the Bohai Gult.  相似文献   

9.
在1961-1962年中国科学院海洋研究所渤海底质调查中,作者对表层沉积物样品和部分柱状样品进行了现场测定,所得资料不仅为研究辽东湾现代沉积过程和成岩作用提供了依据,而且在石油开发前期工程的地基评价上也有重要的现实意义。本文根据这些资料,对辽东湾表层沉积物的天然湿容重和含水量的分布,及其与粒度之间的关系进行了初步探讨,调查站位见图1。  相似文献   

10.
象山港水交换数值研究 Ⅱ.模型应用和水交换研究   总被引:21,自引:4,他引:21  
使用水平二维对流-扩散型水交换模式模拟研究了象山港的水交换,对不同区域的水交换控制机理作了初步探讨,象山港水交换状况与其控制机制的区域性变化很大。牛鼻水道至佛渡水道是一个潮流较强的潮通道;90%水交换周期为5天左右。象山港狭湾内水交换周期较长,湾顶处90%水交换的周期约为80天左右。  相似文献   

11.
养殖水体水质的优劣直接影响养殖对象的成长,准确、快速、全面地掌控养殖水环境的水质参数变化情况具有重要意义。传统的水质指标监测方法都通过人工采样的方式,不仅耗费时间长,且只能体现局部水体情况。针对这些问题,提出了一种乌鸦搜索算法(CSA)结合偏最小二乘回归(PLSR)的高光谱特征波段筛选方法,快速构建回归模型,实现光谱数据的精准预测反演。以连片的养殖小区为研究对象,采集养殖水体样本并拍摄同时期的高光谱影像数据。首先对提取的采样点光谱数据利用多种数据变换方法分别预处理;其次利用这些数据,对水质指标总氮(TN)、氨氮(NH4+-N)、总磷(TP)和化学需氧量(COD)分别构建全波段的SVR和AdaBoost回归模型,同时与提出的CSA-PLS自动筛选波段方法和传统的连续投影算法(SPA)筛选波段后构建的模型进行比较分析;最后根据决定系数(R2)和均方根误差(REMS)选出适合各水质指标的最优模型。从实验结果可以看出,所提波段筛选方法的AdaBoost模型预测结果优于SVR和传统SPA方法提取特征波段后构建的模型,与全波段最优模...  相似文献   

12.
本文根据青岛地区已评价的42处矿泉水点资料,从有益元素的种类水化学性质及形成条件三个方面对矿泉水进行了不同性质的分类;从岩石、构造、地貌环境方面阐明了矿泉水的分布规律;探讨了矿泉水成因,指出了含有益元素的岩石是矿泉水形成的基础奶利的构造,地貌环境是矿泉水的形成条件,深成地下循环水的溶解作用是矿泉水的归宿的初步论断,提出了断裂破碎带及其次级构造裂隙发育区、大理岩、中基性火山岩分布区及第四系底部有良好  相似文献   

13.
云贵高原湖泊沉积物─水界面碱度扩散通量研究   总被引:4,自引:0,他引:4  
于1991-1995年间5次在云贵高原泸沽湖,洱海湖和贵州阿哈湖,百花湖的湖心采集沉积物柱芯,界面水和湖水样品,通过其pH值和HCO3浓度剖面及界面碱度扩散通量的研究,首次定量评估高原湖泊界面扩散作用上不体碱度的影响程度,研究结果表明,云贵高原某些湖水寄宿时间对较长,湖水深度相对小的湖泊,界面扩散作用是水体碱度的重要来源之一,湖水寄宿时间较短,深度较小的湖泊,界面扩散对上覆水体的影响可以忽略不地。  相似文献   

14.
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   

15.
Submarine canyons represent natural conduits for preferential transport of particulate material, including anthropogenic contaminants, from coastal zones directly to the deep sea. To assess related dispersal of natural and anthropogenic lead (Pb), we analyzed Pb concentrations and stable isotope ratios in surface sediments and sediment trap particulate material from the Portuguese margin Nazaré and Setúbal/Lisbon canyons. Geochemical data are integrated with previously obtained data on near-bottom hydrodynamics and processes and pathways of sediment transport. The two canyon systems are located in close geographic proximity to each other, but represent contrasting settings in terms of sediment input and down-canyon sediment transport processes.Concentration–isotope diagrams and three-isotope plots (206Pb/207Pb vs. 208Pb/206Pb) suggest binary mixing between natural and anthropogenic end members. The inferred isotopic signature of pollutant Pb (206Pb/207Pb=1.143 [1.134–1.149, 95% confidence interval]) is most consistent with industrial Pb; ongoing influence from gasoline Pb additives is at most of minor importance. Two proposed natural end members most likely bracket the isotopic signature of natural Pb. Accordingly, binary mixing calculations indicate that on average 20–45% vs. 35–55% of total Pb is derived from anthropogenic sources in the Nazaré and Setúbal–Lisbon canyon systems, respectively. Enhanced anthropogenic influence in the latter area is consistent with its proximity to heavily populated and industrialized areas and with sediment input from the Tagus and Sado rivers, potential major carriers of pollutant particles. In both canyon systems, the anthropogenic component generally decreases with increasing water depth.Isotopic signatures of sediment trap particulate material are generally consistent with surface sediment data at similar water depth, but show large variability in the upper Nazaré canyon and major deviations from surface sediments in the lower canyon. In the lower canyon, Pb isotopic ratios of sediment trap particulate material mostly reflect low pelagic fluxes from the overlying water column, whereas surface sediment signatures are dominated by episodic down-canyon mass transport events. Such gravity flows appear to incorporate older (pre-industrial) material masking the isotopic signature of pollutant Pb. Large variability in the upper canyon reflects continuous sediment resuspension by bottom currents. Stronger average bottom currents are associated with higher 206Pb/207Pb ratios of sediment trap particulate material and hence decreased influence of pollutant Pb. This may reflect preferential resuspension of natural Pb at the canyon floor and/or additional remobilization of older, less-polluted sediment in adjacent areas such as the canyon walls.  相似文献   

16.
多种水面类型蒸发的研究   总被引:1,自引:0,他引:1  
毛锐  高俊峰 《海洋与湖沼》1996,27(4):445-450
分析有水草水面、污水面、受热水面、盐水(盐水)面等特定水面类型的蒸发量,并与清水、淡水对照,求出蒸发比,还计算了太湖地区有水草水面和受热水面的蒸发模型,为确定湖泊的蒸发量提供一新途径,最后建议用水生植物的蒸腾规律来控制水面蒸发,调节水面温度。  相似文献   

17.
Stoichiometric association constants, which have been measured for the ion pairs of Cl? and SO4?2 with Na+, K+, Mg2+, and Ca2+, were used to determine the speciation in an artificial sea water containing only these ions. The resulting distribution is quite different to that found in earlier models in which chloride ion association was ignored. The concentrations of chloride ion pairs with the cations are 4 to 5 times larger than the concentrations of the sulphate ion pairs with the same cations. The total activity coefficients of the neutral salts in sea water calculated from the model are in good agreement with the experimentally measured values. The concentration of MgSO40 calculated to be present agrees with the amount determined from ultrasonic absorption data. The calculated solubility of gypsum is also in good agreement with the measured values.  相似文献   

18.
低合金钢是海洋用钢的主要材料之一。它在海水中,由于表面局部物理化学条件的差异而构成局部腐蚀电池。局部腐蚀严重程度取决于局部腐蚀发生后蚀坑深入发展的速度。  相似文献   

19.
南海近海海水中人工放射性核素 90Sr的含量及分布   总被引:1,自引:0,他引:1  
刘怀 《海洋科学》1987,11(5):36-37
在调查研究的基础上,通过对丰、枯水期海水中~(90)Sr含量变化的讨论,说明南海近海水中~(90)Sr的浓度与沿岸河水的流入有一定关系。  相似文献   

20.
Monosaccharides were determined in waters and sediment pore waters from a wide variety of environments and locations. Desalting was performed by electrodialysis and concentrated extracts were analyzed by two forms of liquid chromatography. At least 12 sugars were identified. Glucose and fructose were the dominant monosaccharides in nearly all samples examined. Analyses of over 150 seawater and sediment pore water samples showed that fructose is highly significantly correlated (>0.99) with glucose concentrations. Laboratory kinetic experiments on the epimerization reaction, glucose ? fructose, in sterilized natural seawater in the dark, yielded a forward rate constant, k1, of 1.2 × 10?5 h?1 at 25°C and 1.6 × 10?7 h?1 at 2°C. The approximate time required to attain equilibrium at 25°C was 1.1 y and at 2°C, 15.4 y; the measured equilibrium constant was in the range 0.3–0.4. The actual ratio of fructose to glucose in natural water samples was usually in the range 1.0–1.4/l, independent of the total monosaccharide concentrations, which varied in the samples by a factor of ~100. Several possible explanations for the apparent discrepancy in the determined and found ratios are discussed: the presence of universal, as yet, undiscovered major biological sources for fructose in marine environments; preferential utilization of glucose; preferential incorporation of fructose into or onto inorganic colloids; and preferential formation of fructose-transition metal ion associations.  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