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1.
利用微分电位溶出分析法研究了海水中痕量铋（III）的最适测定条件。结果表明，实验条件选择电解电位（E）为-1．10V，溶出上限电位（E上）为-0.70V，溶出下限电位（E下）为-0．00V，工作电极旋转速度2500rpm.洗电极时间和富集时间分别为30s和600s。适宜的盐度和酸度为5．8－29．0×10-2mol／L和1．00-2.00×10-mol／LHNO3。对在海水中加入5μg／L铋（III）的样品8次测定的相对标准偏差为53％。校正曲线方程为Y=4.77＋55X,相关系数（γ）为0．9993。对青岛沿岸海水测定的加入回收率为96．5％。1994年利用该方法测定青岛沿岸海水中铋（III）的浓度为0．017－0．103μg／L。 相似文献
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黄河水中镉（Ⅱ）与悬浮粒子液—固界面交换反应的研究 总被引：4，自引：1，他引：4
本文研究了黄河悬浮粒子与镉（Ⅱ）相互作用的离子交换率（％）—pH曲线，以及河水中赖氨酸存在下对该曲线的影响。主要结果有；（1）镉以Cd（OH）+形式在悬浮粒子上进行阳离子交换，在天然pH下（8．0×8．5），镉离子交换率接近最大值；（2）镉离子浓度由8．9×10－6mol·L－1增加到2×8．9×10－6mol．L－1时，离子交换率降低；（3）浓度为6．8×10－6mol·L－1的赖氨酸对提高离子交换率起促进作用；（4）交换剂为转化沙的镉离子交换率比未转化沙小；（5）海水、金沙江水中悬浮粒子对镉的吸附弱于黄河水。 相似文献
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长江干流营养盐通量的初步研究 总被引：34，自引：4，他引：34
分别于1988年2月（冬季）和1986年6月（夏季）利用比色法对长江干流上游至河口水中营养盐进行测定，根据所测定的营养盐含量和长江径流量计算营养盐通量。结果表明，冬季重庆至河口长江水中NO3－N，NH4-N，TIN，PO4-P和SiO3-Si的平均浓度分别为52.2±66μmol／L，51.8±16.9μmol／L，105.3±11.4μmol／L，0.55±0．06μmol／L和75.2±23.6μmol／L.夏季NO3-N,NH4-N,TIN和SiO3-Si的平均浓度分别为69.0±17.0μmol／L,4.0±1.7μmol／L，73.3±15.6μmol／L和55.8±16.4μmol／L。冬季营养盐通量（除NO2－N外）自上游至下游逐渐增加，它们主要来自中、下游流域。夏季NO3－N，TIN和SiO3－Si通量从上游至下游也有明显的增加趋势，NO3－N和TIN，上游和中、下游几乎各占一半，SiO3-Si主要来自中、下游。夏季NO3－N，TIN，PO4－P和SIO3－Si通量明显高于冬季。 相似文献
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钝顶螺旋藻的硝酸还原酶与氢酶之间的电子竞争 总被引：2，自引：0，他引：2
于1994年6－11月，运用生物化学方法以钝项螺旋藻为材料制备整体细胞和无细胞提取物。测定表明，整体细胞硝酸还原酶与氢酶活性的相互关系和无细胞提取物氢酶与硝酸还原酶的（对还原甲基紫精）Km值，分别为2．299×10－7mol／L和1．098×10－7mol／L；证实在硝酸还原酶与氢酶之间存在着电子竞争。 相似文献
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盐度对隐杆藻类胡萝卜素及脂肪酸含量的影响 总被引：2，自引：0，他引：2
于1992年6月，采集分离江苏台南盐场盐生隐杆藻，通过不同浓度的NaCl研究盐度对类胡萝卜素、脂肪酸含量的影响；类胡萝卜素，依Jones等（1974）方法提取，脂肪酸依Schwarzenbach等（1978）方法提取。结果表明，在0．5—1．5mol／LNaCl培养基中，类胡萝卜素的百分含量从2．76％下降到0．67％；然而当培养基NaCl浓度增加到3.5mol／L时，类胡萝卜素的百分含量又开始上升，到2.31％。在低盐度（NaCl，0．5－1．0mol／L）和高盐度NaCl，3．0－3．5mol／U）下培养的盐生隐杆藻中，总脂肪酸的含量高于中盐度（NaCl，10－25mol／L）的；软脂肪酸含量变化同总脂肪酸相似；此外，在不同盐度下各种脂肪酸的相对百分含量也是变化的。 相似文献
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血浆中同型胱氨酸的含量与高脂血症的关系 总被引：1，自引：0，他引：1
用氨基酸自动分析仪测定大鼠和人体血浆中的同型胱氨酸。实验指出：同型胱氨酸存在于高脂血症的动物和人体的血浆中,其含量随胆固醇增高而增高。高脂大鼠和高脂血症人血浆中的含量分别为１．６１３±０．１０４和０．２５３～０．６７１ｍｍｏｌ／Ｌ,而正常大鼠及健康人血浆中同条件下几乎检测不出同型胱氨酸。此外,作者用海洋药物＂９１６＂进行了降血脂动物实验,结果表明：给药后,在高脂大鼠的血浆中同型胱氨酸的含量随胆固醇含量下降而降低,与高脂大鼠对照有显著差异。 相似文献
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对东风盐场9个站位卤水中由藻类植物产生的可溶性糖浓度的变化规律及其与海盐产量和质量之间的关系进行了研究。结果表明，各站位可溶性糖含量的变化范围为0．7－124．3mg／L，以6月份最高，2月份最低；卤水中可溶性糖在111mg／L－215mg／L范围内，结晶盐的产量随卤水中可溶性糖含量的增加而提高，但同时降低了NaCl的含量，并增加了可溶性杂质及水分的含量，从而降低了盐质。初始可溶性糖浓度为111mg／L、137mg／L、160mg／L、193mg／L和215mg／L的25．4°Be’的卤水，在日照下实验12天，其对应结晶盐的NaCl含量分别为91．66％、90．63％、90．48％、90．23％和88．46％，可溶性杂质的含量分别为3．05％、3．32％、3．33％和4．54％。 相似文献
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Cu^2＋,Zn^2＋对罗非鱼鳃盖运动的影响 总被引：4，自引：1，他引：4
本文研究结果表明：（1）水体中含Cu2+和Zn2+的浓度越高，鱼中毒越深，鳃盖运动振幅的增大和频率的减小就越显著。（2）Cu2+／Zn2+混合液对鳃盖运动的影响具明显的协同作用，它的致毒效应分别为单一因子的3～5倍。（3）毒性次序：5×10－6Cu2+／50×10－6Zn2+＞2．5×10－6Cu2+／25×10－6Zn2+＞5×10－6Cu2+＞50×10－6Zn2+（V／V）。（4）频繁的咳嗽反应是Zn2+中毒的主要症状，驱逐反射是Cu2+中毒的主要症状，两者均可作为单一和混合重金属离子污染的敏感生物学监测指标。 相似文献
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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
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Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
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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
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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
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Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
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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
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The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
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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