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对山东半岛南海岸3个地点虾池内的蟹类组成、分布和携带病毒的情况进行了调查,并用敌百虫和次氯酸钠对天津厚蟹(Helicana fridens)进行了杀灭试验。发现虾池内的蟹类组成相对简单,蟹洞分布 85％集中在水位线以上 100 cm至水位线下 30 cm区域内;敌百虫对天津厚蟹的 96 h半致死浓度 LTD_(50)(96 h)=1.25×10~(-6),96 h全部将天津厚蟹杀死的浓度为 2.75×10~(-6);次氯酸钠(以有效氯计)对天津厚蟹的 72 h半致死浓度为 LTD_(50)(72 h)=63.8×10~(-6),72 h内将天津厚蟹全部杀死的浓度为 111.1×10~(-6)。 相似文献
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敌百虫是使用最为广泛的有机磷农药之一,在水产养殖中主要用于防治甲壳类寄生虫。本文研究了72 h的急性暴露以及25 d的亚慢性暴露下,敌百虫对两种赤潮微藻海洋卡盾藻和锥状斯氏藻生长的影响,以了解敌百虫对海洋微藻的毒性及海洋初级生产力的影响。在急性暴露下,高质量浓度敌百虫能明显抑制两种藻细胞的生长,而低质量浓度则对藻细胞的生长影响不明显,敌百虫对海洋卡盾藻和锥状斯氏藻生长的72 h EC50分别为32.1 mg/L和22.1 mg/L。在亚慢性暴露下,两种藻细胞对敌百虫的敏感性相近,高质量浓度组(25 mg/L)的藻细胞在暴露的第7~9天就全部死亡;1 mg/L的低质量浓度组,藻细胞的生长状况与对照组相近;5 mg/L和10 mg/L质量浓度组在暴露初期对藻细胞生长具有抑制作用,但在暴露后期则明显刺激了藻细胞的生长。本研究说明水环境背景质量浓度下的敌百虫不会抑制浮游植物的生长,但施药一段时间后,可刺激藻细胞的生长,从而增加了引发赤潮的风险。 相似文献
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本研究以变态存活率、产卵量、成体头胸部长和体长为指标,研究了球等鞭金藻(Isochrysis galbana)和海洋原甲藻(Prorocentrum micans)不同浓度和配比对太平洋纺锤水蚤(Acartia pacifica)生长发育和产卵量的影响,以期探索培养太平洋纺锤水蚤最适合的饵料配方.实验结果表明:在饵料浓度(碳含量,下同)为1.70μg/cm3,配比为2∶1时,其变态存活率最高,可达到92.62%;在饵料浓度为4.25μg/cm3,配比为1∶2时,产卵量最高,雌体平均日产卵量可达47.1±2.7个;在饵料浓度为1.70μg/cm3,配比为2∶1时,成体头胸部长和体长均最长,分别为932.9、1 252.3μm.太平洋纺锤水蚤生长和发育的最优饵料组合为球等鞭金藻与海洋原甲藻浓度为1.70μg/cm3,配比为2∶1. 相似文献
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本工作使用一次培养法初步研究了Cr(VI)对菱形硅藻和隐藻的毒性,实验结果表明,当Cr(VI)浓度大于16ppb时,则对其生长率产生抑制作用,其72小时EC_(50)值分别为260ppb和230ppb.根据活性点位模式计算了Cr(VI)与藻体的结合常数,约为2×10~5藻体中Cr含量与培养液中Cr浓度有关,两者近似指数关系,根据藻体中Cr含量和溶液中Cr的浓度,估计每个硅藻细胞与Cr最大结合容量约为5×10~(-17)mol/cell. 相似文献
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两种海洋细菌对赤潮藻的细胞生物量的影响研究 总被引：17，自引：1，他引：17
在实验室培养条件下 ,研究了两种海洋杆菌属细菌S7 (Bacillusmegaterium)和S10(B.halmapulus)对赤潮藻 (Alexandriumtamarense(Lebour)Balech)的细胞生物量 (细胞密度及叶绿素含量 )的影响。结果显示 ,细菌滤液对藻细胞增殖的影响与细菌浓度、细菌的种属特性以及藻细胞自身的生长阶段有关。其中 ,细菌浓度较高的C1 处理 (2×1010个/ml)对藻细胞生物量具有明显的抑制作用 ,而浓度较低的C2 和C3 处理 (2×109,2×108 个/ml)则显示了一定程度的促进作用 ;对于同一种赤潮藻 ,S10 在抑制或促进的程度和倾向上均比S7 的更为明显。不管是抑制或促进作用 ,在藻细胞的生长前期 (10d)时比后期 (18d)的更为明显。 相似文献
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采用水生毒理学方法以及通过分析蒽对 2种海洋微藻的几种生理生化指标的影响 ,初步研究了蒽胁迫对 2种海洋微藻的毒性效应。结果表明 :随着蒽浓度的不断增大 ,1 2种海洋微藻的相对增长率逐渐降低 ,叶绿素 a和类胡萝卜素含量稍有下降 ,蒽对小新月菱形藻生长的 72 h· EC50为 2 51μg· L-1 ,蒽对亚心形扁藻生长的 72 h· EC50 为 387μg· L-1 ;2还原型谷胱甘肽 (GSH)含量逐渐降低 ;3加入外源性抗氧化剂 (GSH和甘露醇 )可缓解蒽胁迫所造成的 2种海洋微藻的细胞密度的降低 ,即可缓解蒽胁迫对微藻的毒害作用 相似文献
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在实验室条件下开展了中华哲水蚤(Calanus sinicus)对海洋赤潮藻环状异帽藻(Heterocapsa circularisquama)的生物滤食及其影响因子研究。结果表明藻浓度、温度、盐度和光周期等对中华哲水蚤的滤食率均有显著的影响(P0.01)。中华哲水蚤对环状异帽藻的滤食率随藻浓度的增加呈递增趋势;在10～20℃时,中华哲水蚤对环状异帽藻的滤食活动随温度的升高而增强,表现为滤食率G和清滤率F都同时上升,最佳滤食温度是20℃;18～24盐度是中华哲水蚤滤食环状异帽藻的适宜盐度,低于或高于该盐度范围,F和G都降低;中华哲水蚤对环状异帽藻的滤食率和清滤率对光周期的响应完全一致,均在全黑暗条件下为最佳,在全光照条件下达最低。 相似文献
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链霉素对海洋微藻的毒物刺激效应 总被引：1，自引：0，他引：1
实验选用链霉素对六种海洋微藻进行实验 ,发现六种海洋微藻普遍对链霉素具有抗性。其中只有角毛藻和三角褐指藻在实验范围内 (0～ 50 0 mg/ L)测到了 72 h的半抑制浓度 ,EC50 分别为346 mg/ L和 4 4 5mg/ L。其它四种均未测到。而且当链霉素浓度为 30 mg/ L时 ,对六种海洋微藻普遍具有生长刺激效应 ,即毒物刺激效应。 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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Derek V. Ellis 《Marine Georesources & Geotechnology》2001,19(1):51-63
This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested. 相似文献
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G. Parthiban 《Marine Georesources & Geotechnology》2000,18(3):223-235
Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement. 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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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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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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The advanced piston corer (APC) has been used by the Ocean Drilling Program since 1985 for recovering soft sediments from the ocean floor. The pullout force measured on extracting the core barrel from the sediment is shown to correlate with the average shear strength of the sediment core measured in the ship's laboratory. A simple rule of thumb is derived relating the shear strength of the sediment to the pullout force. Multiple APC holes at individual sites allow the consistency of the pullout measurements to be assessed. The effects of different operational procedures during APC coring are also explored. Although generally applicable, the correlation between pullout force and laboratory measurements of shear strength breaks down for some APC holes, possibly because of the disturbance of some sediment types during the APC coring process. A better understanding of the physical process of APC coring, and its effect on the properties of the sediment both inside and immediately outside the core barrel, would indicate what confidence can be put on the measurement of pullout force as a way of evaluating the in situ shear strength of deep sea sediments. 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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