共查询到20条相似文献,搜索用时 515 毫秒
1.
厦门海域二氧化碳及其生物生产力的估算 总被引:3,自引:0,他引:3
根据1995年4月在厦门海域对CO2系统作定点连续观测的资料,讨论了海-气CO2交换以及生物活动对海水总CO2变化的影响。结果表明:海水CO垢变化主要受生物活动所控制,生物过程引起的CO2变化远大于海-气CO2交换的影响。得胜平衡法估算出厦门海域的生物生产力为62.4mmol/)m^2.d)。 相似文献
2.
在体外O·-2损伤CAT的过程中,对CAT辅基Fe(Ⅲ)的ESR波谱进行了分析研究。发现:辅基Fe(Ⅲ)的ESR谱线特征有显著改变,如:g因子、ΔHpp及线型等均有显著变化。说明:辅基Fe(Ⅲ)的微观环境发生了变化,提示:这些变化可能是O·-2造成CAT活性改变的主要分子机制。 相似文献
3.
台湾海峡西部海域水体中的二氧化碳体系 总被引:7,自引:0,他引:7
据1984年5月至1985年2月的调查资料,计算了该水体中二氧化碳体系各要素的统计值,着重研究了它们的季节变化及其与水文,化学和生物因子的关系。结果表明该水体中PCO2,CO2(T),CO^2^-3,HCO3,∑CO2,CO^2^-3/∑CO2,HCO3/∑CO2,HCO2,CO2(T),CO^2^-3,∑CO2/Cl,Ωc,Ωa和C:N:P平均值依次分别为251dPa,8.43μmol/dm×3 相似文献
4.
海水中磷酸盐在固体粒子上阴离子交换作用──海水中磷酸盐-固体粒子相互作用的V形交换率-pH曲线 总被引:4,自引:0,他引:4
于1990年2月在青岛鲁迅公园采得海水样品;189年5月在南京采得伊利石样品,在苏州有得高岭石样品;1990年3月实验室合成针铁矿和δ-MnO3样品。用振荡平衡实验、离心分离方法和光度分析方法测定3种电溶液(NaCl溶液、NaCl-CaCl2溶液和海水)中酸盐在上述4种固体粒子上的交换率-PH曲线。测定结果表明,海水中磷酸盐在固体粒子上的交换率-PH曲线为V形,并建立阴离了液-固界面作用的交换率- 相似文献
5.
实验研究水溶液中二甲基硫(DMS)和H2O2进行氧化反应的动力学。结果表明DMS被H2O2氧化的速率会受到介质、pH以及重金属离子的影响。其二级反应速率常数为2.21×10-2~4.90×10-2L·mol-1·S-1.Hg2+的存在会加快反应速率,特别在人工海水条件下十分明显。DMS易被H2O2氧化的事实说明,在海水中化学氧化过程会对DMS的浓度和分布产生重要影响 相似文献
6.
均相沉淀法制备Ni(OH)_2和NiO纳米晶 总被引:6,自引:0,他引:6
以NiSO4·6H2O 为主要原料、以CO(NH2)2 为沉淀剂,采用均相沉淀法合成了纳米级Ni(OH)2 和NiO粉末,用X射线衍射分析(XRD) 、差热分析(DTA) 等实验手段对样品的热稳定性、相转变温度、相结构和粒子形状等进行了表征。结果表明所合成的NiO粉末的粒径约为6nm ,且基本成球形。 相似文献
7.
不同磷源对藻类生长及其生化组成的影响 总被引:13,自引:0,他引:13
在实验室培养条件下,对KH2PO4及多种溶解有机磷化合物对藻灶进行了一次性培养,考察要对DOP的利用和不同磷源对藻类生物及其生化组成的影响。结果表明;甘油磷酸钠,6-磷酸葡萄糖,蛋黄卵磷脂和酵母核糖核酸均可被藻类吸收利用,并且培养藻类都生长良好;碱性磷酸酶在大分子DOP利用过程中起重要作用。 相似文献
8.
9.
寿命较短的O·-2不能用ESR直接检测到,可以DMPO先将其捕获形成自旋加合物后进行ESR分析。这种自旋加合物的ESR谱线较为复杂,且有变化。本文对DMPO—OOH谱线的变化进行了分析。且对谱线变化中出现的DMPO—OH谱线的来源进行了深入探讨,对与文献报道相左的现象,据实验结果本文提出了新的观点。 相似文献
10.
据1984年5月至1985年2月调查资料,计算了该水体中二氧化碳体系各分量的含量,研究了它们与pH,HCO^-3/CO^2-3,Alk,DIN,PO^3-4-9,Chl-aDO,S,t等环境因子的相关性。结果表明PCO3,CO2(T),HCO^-3,CO^2-3与pH,HCO^-3/CO^2-3呈极显著的线性相关;HCO^-3,CO^2-3ΣCO2与Alk也呈非常显著的线性相关。 相似文献
11.
Chandralata Raghukumar G. Sheelu P. A. Loka Bharathi Shanta Nair C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance. 相似文献
12.
海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明:土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。 相似文献
13.
Geoacoustic Inversion via Genetic Algorithm and Its Application to Manganese Sediment Identification
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm. 相似文献
14.
15.
16.
Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans 总被引:1,自引:0,他引:1
A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria ( 〉 99% ), but also between polar marine bacteria and bacteria from other aquatic environments ( ≥ 98.8% ), including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level. 相似文献
17.
Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations. 相似文献
18.
Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges. 相似文献
19.
A vertically integrated model has been used to study the tidal circulation and currents in the Gulf of Kachchh along the west coast of India. The model is fully nonlinear and uses a semiexplicit finite difference scheme to solve the basic hydrodynamic equations on a staggered grid. The model is forced by prescribing the tides along the open boundary of the model domain. The flow is simulated both with and without the presence of the proposed tidal barrage across the Hansthal Creek in the Gulf of Kachchh. The results show a considerable change in the behavior of the tidal flow in the presence of the barrage. 相似文献
20.