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1.
Zinc exchange isotherms in mixtures of hydrous metal oxides and clay minerals have been reported. The relationship between the isotherms of the mixtures and the isotherms of their components is studied. The isotherms of the mixtures are stepwise. And the formation constants for the zinc exchange in the mixtures are calculated. The results show that the stepwise equilibrium formation constants and the saturation exchange capacities for the zinc exchange in kaolinite/ mon-tmorrillonite, amorphous iron oxide/montmorrillonite and γ-AlOOH/montmorrillonite mixtures are equal in weight to those of their components. The interactions between fresh iron oxyhydroxide and δ-MnOz reduce the metal binding sites of the mixtures, while the stepwise equilibrium constants are not affected by the interactions. 相似文献
2.
In this study the zinc exchange process and the reason for the non-additive exchange of δ-MnO2/montmorrillonite have been investigated. The results suggest that with pH increasing from 2 to 8, the stepwise exchange of zinc occurs on δ-MnO. and montmorrillonite in their mixture.At low pH zinc ions are bound on δ-MnO2, while at high pH, the exchange on montmorrillonite dominates the surface interaction in the mixture. The study demonstrates that the stepwise exchange and the heterogeneity of the binding sites on δ-MnO2 surface are the reason for the non-additive exchange. It is also shown that when δ-MnO2 amounts to 5 %, zinc exchange on sea sediments is controlled by 8-MnO2. 相似文献
3.
ZhouWcihua WuYunhua ChenShaoyong YinKedong 《海洋通报(英文版)》2003,5(2):14-21
Concentrations of organic matter, iron and manganese in the deep sea surface sediments in the Nansha Islands sea area, South China Sea are measured, Horizontal and vertical distributions of iron and manganese are discussed. The vertical distribution of iron and manganese in the sediments results from reduction, diffusion, and redeposition of manganese (or iron) oxide and hydroxide in the sediment. There are the maxima of iron and manganese in solid phase in the top of the sediment, which is caused by the penetration of O2 and the upward flux of Mn^2 ( or Fe^2 ). Manganese bacteria play a very important role in the cycle of solid-phase iron and manganese in the ocean environment. Manganese bacteria oxidize Mn^2 ( or Fe^2 ) in dissolved state to Mn^4 ( or Fe^3 ) in oxidized state under the aerobic condition, whereas they reduce iron and manganese in anaerobic conditions. 相似文献
4.
In order to establish a new method to eliminate toxicities of heavy metal ions to larval penaeid shrimp, the effects of copper, zinc, lead and cadmium ions on larval metamorphosis of Penaeus chinensis at each stage were determined in detail, and two methods eliminating toxicities were compared. The results indicate that sensitivity of larvae to heavy metal ions decreases in the order of nauplii, protozoea, mysis and postlarvae. The phytoplankton food can reduce, by chetating, the toxicities of heavy metal ions. Both EDTA chelation and PHMA absorption can be used to eliminate the toxicities effectively and there is no significant difference between the two methods. EDTA is harmful to larval P. chinensis at high concentration but affects neither survival nor metamorphosis at below 10 mg/dm3. It is preliminarily observed that copper and zinc ions at low concentration are beneficial to the development of larvae after protozoea stage. It is suggested that it is unnecessary to e-liminate the effects of heavy 相似文献
5.
In this paper,the aquatic chemical characteristics in the Hangzhou Bay,Xiangshan Bay and Leqing Bay along the coastal region of Zhejiang Province are discussed . Results show that the seasonal variations of chemical elements are obvious. The distribution of silicate in Hangzhou Bay and contents of dissolved oxygen and nutrient in the Xiangshan Bay are found to be unusual in winter. Correlations among the elements are complex. The content of nutrient in the Hangzhou Bay is higher than that in Xiangshan Bay and the content of nutrient in the Xiangshan Bay is higher than that in the Leqing Bay . The variation of the ratio of N/P is obvious. This reflects the aquatic chemical characteristics in the bay. Finally, this paper also discusses the reason why the aquatic chemical characteristics in the bays are unusual. 相似文献
6.
Gas chromatographic determination of lignin in sediment 总被引：1，自引：0，他引：1
After the oxidation of river and marine sediments with CuO under alkaline conditions, the phenolic compounds in the oxidation products are determined gas chromatographically and compared to that of lignin oxidation products. The method of CuO oxidation is compared to that of nitrobenzen. The quantitative determination of produced phenolic compounds by capillary gas chromatography is examined and the blank and repetibility of the method are tested. 相似文献
7.
Lale BALAS 《中国海洋工程》2001,(4):565-578
The circulation pattern and the pollutant transport in the Marmaris Bay are simulated by the developed three-dimensional baroclinic model. The Marmaris Bay is located at the Mediterranean Sea coast of Turkey. Since the sp ring tidal range is typically 20- 30 cm, the dominant forcing for the circulation and water exchange is due to the wind action. In the Marmaris Bay, there is sea outfall discharging directly into the bay. and that threats the bay water quality significantly. The current patterns in the vicinity of the outfall have been observed by tracking drogues which are moved by currents at different water depths. In the simulations of pollutant transport, the coliforms-counts is used as the tracer. The model provides realistic predictions for the circulation and pollutant transport in the Marmaris Bay. The transport model component predictions well agree with the results of a laboratory model study. 相似文献
8.
Some of the results about vertical profile of heavy metals of seawater to the south of Japan in Oct. 1990 are presented and discussed in relation to the concentration of dissolved Cu, Cd and Ni to biogeochemical environments. It points out that the distribution of dissolved Cu is higher in surface water than that in/upper 500 m layer, and maxima value attains the 8. 2 n mol/dm3 in depth of 4 000 m. The concentrations of dissolved Ni ranges from 3. 4 n mol/dm3 in surface seawater to 8. 5 n mol/dm3 in the deep to the south of Japan. The highest values are observed in the colder waters. This paper shows also that the vertical profile of dissolved Cd is perfect nutrient-type distribution. And dissolved Cd and Phosphate are linearly correlated by the regression equation. The ·Cd : ·N : ·P atomic ratio is 3. 5 × 10-4 : 14 : 1. 相似文献
9.
Jianming Pan Chuanyu Hu Jianfang Chen Xiaoya Liu Huaiyang Zhou Weidong Ji 《海洋学报(英文版)》2003,22(3):385-394
According to two cruises investigation information in summer and winter during 1998 and1999, the phosphorous concentration distribution and changes of summer and winter were discussed pri-marily in the South China Sea. The results show that the phosphate concentration of surface seawater insummer is distinctly lower than that in winter, averaging 0.04 μmol/dm3 in summer and 0.35 μmol/dm3 in winter. The organic phosphorous concentration of surface seawater in summer is higher than thatin winter, averaging 0.12μmol/dm3 in summer and 0.04 μmol/dm3 in winter respectively. The season-al changes of total phosphorus are similar to phosphate, averaging 0.22 μmol/dm3 in summer and 0.61μmol/dm3 in winter respectively. In vertical direction, phosphate, TDP and TP content are the lowestin upper 50 m water column, and increase in linearity rapidly with water depth, increasing slowly under500 m, reach to maximum about 1 000 m, then decrease slightly with water depth increasing. The ver-tical distribution is typical in summer, and there is small dispersed for phosphorus concentration for thesame depth of different stations. However, in winter there is a large disperse for phosphate, TDP andTP, specifically for phosphate at 200 m at which the concentration is maximum. This result indicatesthat there are large differences in hydrology and biology conditions that affect largely the chemical envi-ronment of the South China Sea. The organic phosphorus is the predominant in surface seawater of theSouth China Sea, but the inorganic phosphorus is the predominant in layers below depth of 150 m. Theorganic phosphorus concentration in deep water usually decreases with water depth increasing. The or-ganic phosphorus in summer is remarkably more than that in winter because of the strong biology activi-ties in summer. 相似文献
10.
The Bedload Movement in the Changjiang Estuary 总被引：6，自引：0，他引：6
- Sandwaves in the Changjiang estuary were measured with a shallow sediment profiler and an echosounder from 1978 to 1988. The data, together with grain size and bedform of sediment indicates that the bedload movement by rolling and saltation is of great significance to sediment transport and is the principal factor responsible for sandwave and sandbody development in the estuary. The sandwaves were found well-developed, which is related to the tidal range and the velocity of ebb current. However, the further growth is restricted by strong flood current prevailing in the estuary. Because of the significant bedload, the sandbodies shift obviously and frequently, and sometimes the exchange of position occurs between the sandbodies and tidal channels. As a result, ships are regularly forced to change their navigation course. 相似文献
11.
《海洋学报(英文版)》2017,(7)
As a case study, refined iron(Fe) speciation and quantitative characterization of the reductive reactivity of Fe(Ⅲ)oxides are combined to investigate Fe diagenetic processes in a core sediment from the eutrophic Jiaozhou Bay.The results show that a combination of the two methods can trace Fe transformation in more detail and offer nuanced information on Fe diagenesis from multiple perspectives. This methodology may be used to enhance our understanding of the complex biogeochemical cycling of Fe and sulfur in other studies. Microbial iron reduction(MIR) plays an important role in Fe(Ⅲ) reduction over the upper sediments, while a chemical reduction by reaction with dissolved sulfide is the main process at a deeper( 12 cm) layer. The most bioavailable amorphous Fe(Ⅲ) oxides [Fe(Ⅲ)am] are the main source of the MIR, followed by poorly crystalline Fe(Ⅲ) oxides [Fe(Ⅲ)pc)]and magnetite. Well crystalline Fe(Ⅲ) oxides [Fe(Ⅲ)wc] have barely participated in Fe diagenesis. The importance of the MIR over the upper layer may be a combined result of the high availability of highly reactive Fe oxides and low availability of labile organic matter, and the latter is also the ultimate factor limiting sulfate reduction and sulfide accumulation in the sediments. Microbially reducible Fe(Ⅲ) [MR-Fe(Ⅲ)], which is quantified by kinetics of Fe(II)-oxide reduction, mainly consists of the most reactive Fe(Ⅲ)am and less reactive Fe(Ⅲ)pc. The bulk reactivity of the MR-Fe(Ⅲ) pool is equivalent to aged ferrihydrite, and shows down-core decrease due to preferential reduction of highly reactive phases of Fe oxides. 相似文献
12.
Based on the time dependent mild slope equation including the effect of wave energy dissipation, an expression for the energy dissipation factor is derived in conjunction with the wave energy balance equation, and then a practical method for the simulation of wave height and wave set-up in nearshore regions is presented. The variation of the complex wave amplitude is numerically simulated by use of the parabolic mild slope equation including the effect of wave energy dissipation due to wave breaking. The components of wave radiation stress are calculated subsequently by new expressions for them according to the obtained complex wave amplitude, and then the depth-averaged equation is applied to the calculation of wave set-up due to wave breaking. Numerical results are in good agreement with experimental data, showing that the expression for the energy dissipation factor is reasonable and that the new method is effective for the simulation of wave set-up due to wave breaking in nearshore regions. 相似文献
13.
Based on the high order nonlinear and dispersive wave equation with a dissipalive term, a numerical model for nonlinear waves is developed. It is suitable to calculate wave propagation in water areas with an arbitrarily varying bottom slope and a relative depth h/ L0≤ 1. By the application of the completely implicit slagger grid and central difference algorithm, discrete governing equations are obtained. Although the central difference algorithm of second-order accuracy both in time and space domains is used to yield the difference equations, the order of truncation error in the difference equation is the same as that of the third-order derivatives of the Boussinesq equation. In this paper, the correction to the first-order derivative is made, and the accuracy of the difference equation is improved. The verifications of accuracy show that the results of the numerical model are in good agreement with those of analytical solutions and physical models. 相似文献
14.
Elemental compositions are measured in manganese nodules collected from the Northern Mid-Pacific floor by inductively-coupled plasma atomic emission spectrometry (1CP-AES) and their growth rates are determined by radiometric methods. The result shows that depth distributions of elements in nodules vary with depth as follows; (i) increase, (ii) decrease and (iii) fluctuation. These internodule variations in elemental compositions are considered to be caused by diffusion and migration of elements in nodules and heterogeneities in textures of nodules. In the present paper, a diffusive model is used to elucidate the inward-increase profile of some elements in nodules. The effective diffusive coefficients are estimated to be of the order of 10-9 cm2/a for Ni, V and Zn in the nodules, which is less than the value reported for radionuclides. 相似文献
15.
In this paper the seasonal variation and structural characteristics of the sea/ land breeze in the northern coastal area of" Shandong Peninsula are studied in two ways: one is the analysis of the observed wind data, and the other is numerical simulation and experiments. Firstly, the hour to hour wind data through the year 1984 at Longkou Meteorological Station and Yantai Oceanographic Station are analysed through energy spectra and hodograph. It is revealed from the analysed results that the effects of the sea/ land breeze in the area are notable in spring, summer and fall, especially in May. However, in winter the effects of sea / land breeze are not obvious. because the cold noitherly is prevailing. Secondly, a two-dimensional non- linear model of primitive equations is used to study the sea / land breeze circulation in May in the area. The results of numerical simulation consist basically with the analysed results of the observed sea / land breeze. A reasonable theoretical structure of the sea / land 相似文献
16.
A 43 cm long E271 sediment core collected near the East Pacific Rise(EPR) at 13°N were studied to investigate the origin of smectite for understanding better the geochemical behavior of hydrothermal material after deposition.E271 sediments are typical metalliferous sediments. After removal of organic matter, carbonate, biogenic opal,and Fe-Mn oxide by a series of chemical procedures, clay minerals(2 μm) were investigated by X-ray diffraction,chemical analysis and Si isotope analysis. Due to the influence of seafloor hydrothermal activity and close to continent, the sources of clay minerals are complex. Illite, chlorite and kaolinite are suggested to be transported from either North or Central America by rivers or winds, but smectite is authigenic. It is enriched in iron, and its contents are highest in clay minerals. Data show that smectite is most likely formed by the reaction of hydrothermal Fe-oxyhydroxide with silica and seawater in metalliferous sediments. The Si that participates in this reaction may be derived from siliceous microfossils(diatoms or radiolarians), hydrothermal fluids, or detrital mineral phases. And their δ30 Si values are higher than those of authigenic smectites, which implies that a Si isotope fractionation occurs during the formation because of the selective absorption of light Si isotopes onto Feoxyhydroxides. Sm/Fe mass ratios(a proxy for overall REE/Fe ratio) in E271 clay minerals are lower than those in metalliferous sediments, as well as distal hydrothermal plume particles and terrigenous clay minerals. This result suggests that some REE are lost during the smectite formation, perhaps because their large ionic radii of REE scavenged by Fe-oxyhydroxides preclude substitution in either tetrahedral or octahedral lattice sites of this mineral structure, which decreases the value of metalliferous sediments as a potential resource for REE. 相似文献
17.
黄东海沉积物中的还原无机硫 总被引：2，自引：1，他引：1
Cold diffusion methods are used to separate and quantify the three reduced inorganic sulfur species into acid volatile sulfide(AVS), pyrite–S and element sulfur(ES) in the sediments of the Yellow and East China Seas. The results show that up to 25.02 μmol/g of AVS, 113.1 μmol/g of pyrite–S and 44.4 μmol/g of ES are observed in the sediments of the Yellow Sea and East China Sea. Pyrite–S is the predominant sulfide mineral in the sediments, while the concentration of AVS is quite low at most stations in the study area. The amounts and reactivity of organic matter are the primary limited factor for the sulfide formation, while an iron limitation and a sulfate limitation are not observed in the sediments of the Yellow Sea and East China Sea. The irregular profiles of the three reduced inorganic sulfur species also reflected the comprehensive influence of sediment composition and sedimentation rates. 相似文献
18.
Organic matter and iron and maganese oxides have been considered as the major affecting factors for metals in anoxic or oxidized sediment. In recent research, clay and sulfide are found as major factors in oxic or oxidized sediments that might affect bioavailability of metals. To test this hypothesis, the influence of sulfide, measured as acid-volatile sulfide （AVS）, and clay content on the bioavailability of zinc and cadmium in sediments was examined. Laboratory simulative experiment and field verification experiment were conducted, showing that the bioavailability of zinc and cadmium is strongly correlated to AVS and clay content in sediments. Taking into account both AVS and clay parameters in sediments together can better indicate the bioavailability of zinc and cadmium rather than considering one of them alone. 相似文献
19.
The North Yellow Sea Basin ( NYSB ), which was developed on the basement of North China (Huabei) continental block, is a typical continental Mesozoic Cenozoic sedimentary basin in the sea area. Its Mesozoic basin is a residual basin, below which there is probably a larger Paleozoic sedimentary basin. The North Yellow Sea Basin comprises four sags and three uplifts. Of them, the eastern sag is a Mesozoic Cenozoic sedimentary sag in NYSB and has the biggest sediment thickness; the current Korean drilling wells are concentrated in the eastern sag. This sag is comparatively rich in oil and gas resources and thus has a relatively good petroleum prospect in the sea. The central sag has also accommodated thick Mesozoic-Cenozoic sediments. The latest research results show that there are three series of hydrocarbon source rocks in the North Yellow Sea Basin, namely, black shales of the Paleogene, Jurassic and Cretaceous. The principal hydrocarbon source rocks in NYSB are the Mesozoic black shale. According to the drilling data of Korea, the black shales of the Paleogene, Jurassic and Cretaceous have all come up to the standards of good and mature source rocks. The NYSB owns an intact system of oil generation, reservoir and capping rocks that can help hydrocarbon to form in the basin and thus it has the great potential of oil and gas. The vertical distribution of the hydrocarbon resources is mainly considered to be in the Cretaceous and then in the Jurassic. 相似文献
20.
In this paper the impacts of the anomalous SST in the warm pool area of the Western Equatorial Pacific on the winter time circulation and the East Asian monsoon are studied by using the NCAR CCM. It is found that the abnormal heating in the warm pool area will change the strength and the position of the Walker Cell in the Equatorial Pacific and the anti-Walker Cell in the equatorial Indian Ocean. Both the Walker and anti-Walker Cells are strengthened. The local Hadley Cells over two hemispheres near the warm pool are also strengthened. The subtropical highs in two hemispheres become stronger and move poleward slightly. The westerly jets in the extratropical regions have similar changes as the subtropical highs. The winter monsoon in South-East Asia is weakened by the abnormal heating in the warm pool. The experiment also show that there are wave trains emanating from surrounding areas of the warm pool to the high latitudes, causing various changes in circulations and local weather. 相似文献