栉孔扇贝体内麻痹性贝毒的累积与排出过程研究

通过室内摄食实验,研究了栉孔扇贝(Chlamys farreri)对麻痹性贝毒(PSP)产毒藻的敏感性及其累积和排出毒素的特征.有毒微小亚历山大藻(Alexandrium minutum)在短时间内可对栉孔扇贝的摄食有一定的抑制作用,且投喂毒藻的浓度越大,对摄食作用的抑制越明显.栉孔扇贝对PSP贝毒的累积能力很强,实验中,48 h后内脏累积毒素就高达5000μg STXeq100g-1,但其毒素排出速率较慢,在24d解毒阶段后内脏中的毒素还没有下降至国际贝毒食用安全标准水平的80μg STXeq 100g-1.各毒素组成比在整个累积与排除过程中有较大变化,GTX1,GTX4在累积阶段比例下降,同时GTX2,GTX3比例上升;内脏中GTX2:GTX3的比值逐渐增加.毒藻中PSP贝毒毒素组成和贝体中PSP贝毒毒素组成之间的主要差别是GTX4含量的减少和GTX1含量的升高;而扇贝粪便中的毒素组成却与对数生长期的毒藻极为接近.     

链状裸甲藻所产麻痹性贝类毒素在翡翠贻贝体内的累积、转化和排出

为研究链状裸甲藻所产麻痹性贝类毒素(paralytic shellfish toxins, PST)在翡翠贻贝体内的累积、转化和排出规律,设置试验组和对照组,采用链状裸甲藻和中肋骨条藻投喂翡翠贻贝,开展短期累积(12 h)、长期累积(10 d)和排出(28 d)试验。结果表明:翡翠贻贝具有较强的毒素累积能力,内脏团是PST累积的主要部位, PST含量与产毒藻密度呈显著正相关关系。当链状裸甲藻密度为1.0×106cells/L时,贻贝内脏团PST含量累积2 h已接近食用贝类毒素安全标准,累积8 h超标。当产毒藻密度为5.0×105 cells/L时,贻贝内脏团PST含量累积2 d超标,累积8 d达到峰值(3 590.4±545.7)μg/kg。贻贝对PST具有累积快排出慢的特点,内脏团PST含量在排出16 d达标,排出速率先快后慢。内脏团对PST的累积和排出速率显著高于闭壳肌和其他组织,闭壳肌和其他组织则无显著差异。PST进入贻贝体内后发生了代谢转化,贻贝可能将产毒藻中膝沟藻毒素GTX3转化为GTX2, N-磺酰氨甲酰基膝沟藻毒素C2转化为C1,部分C1转化为脱氨甲酰基膝沟藻毒素2(dc...     

微小亚历山大藻投喂量与菲律宾蛤仔对麻痹性贝毒累积、转化和排出的动态关系

选用高毒性微小亚历山大藻台湾株和菲律宾蛤仔为研究对象,研究了不同毒藻投喂量对贝类累积和排出麻痹性贝毒(PSP)的影响。实验分为累积和排出2个部分,累积实验设计了4个投喂梯度(A组:2.0×107cell/d、B组:7.0×107cell/d、C组:1.1×108cell/d和D组:2.0×108cell/d),在排出毒素阶段,每实验组又分成投喂无毒饵料藻组和饥饿组并进行比较。结果显示不同投喂梯度组间PSP毒素累积存在明显差异。随着毒藻投喂量的增加,PSP毒性增加,但毒素累积率下降,这说明在一定范围内毒藻投喂量的大小对蛤仔的毒素累积有影响。A组、B组、C组的最高累积量依次为6.5,82.9,113.9μgSTXeq/100g,D组达到本实验的最高累积量154.1μgSTXeq/(100g),但累积率却随着投喂量的增加而递减,分别为1.79%,0.92%,0.42%和0.39%。停止投喂毒藻后蛤仔体内的PSP毒性迅速下降,在排出阶段,对投喂饵料组和饥饿组的比较结果用单因素方差分析(ANOVA)得出P0.05,结果差异显著,饥饿组的毒性均高于投喂饵料藻组,说明投喂无毒饵料有助于菲律宾蛤仔体内的毒素排出。其中D饵料组和饥饿组间排出速率差异最明显,饵料组的排出速率为13.2μgSTXeq/(100g.d),饥饿组的仅为8.3μgSTXeq/(100g.d),因此将菲律宾蛤仔归属于快速排毒者。     

微小亚历山大藻投喂量与菲律宾蛤仔对麻痹性贝毒累积"转化和排出的动态

选用高毒性微小亚历山大藻台湾株和菲律宾蛤仔为研究对象,研究了不同毒藻投喂量对贝类累积和排出麻痹性贝毒(PSP)的影响.实验分为累积和排出2个部分,累积实验设计了4个投喂梯度(A组:2.0×107cell/d、B组:7.0×107cell/d、C组:1.1×108cell/d和D组:2.0×108cell/d),在排出毒素阶段,每实验组又分成投喂无毒饵料藻组和饥饿组并进行比较.结果显示不同投喂梯度组间PSP毒素累积存在明显差异.随着毒藻投喂量的增加,PSP毒性增加,但毒素累积率下降,这说明在一定范围内毒藻投喂量的大小对蛤仔的毒素累积有影响.A组、B组、C组的最高累积量依次为6.5,82.9,113.9μgSTXeq/100g,D组达到本实验的最高累积量154.1μgSTXeq/(100g),但累积率却随着投喂量的增加而递减,分别为1.79%,0.92%,0.42%和0.39%.停止投喂毒藻后蛤仔体内的PSP毒性迅速下降,在排出阶段,对投喂饵料组和饥饿组的比较结果用单因素方差分析(ANOVA)得出P＜0.05,结果差异显著,饥饿组的毒性均高于投喂饵料藻组,说明投喂无毒饵料有助于菲律宾蛤仔体内的毒素排出.其中D饵料组和饥饿组间排出速率差异最明显,饵料组的排出速率为13.2 μgSTXeq/(100g·d),饥饿组的仅为8.3μgSTXeq/(100g·d),因此将菲律宾蛤仔归属于快速排毒者.     

麻痹性贝毒在文蛤体内的累积及净化技术研究

试验研究分毒素累积和解毒两个阶段,丈蛤（Meretrix meretrix）对麻痹性贝毒（Paralytic Shellfish Poisoning,PSP）的累积能力试验中每天投喂一定量塔玛亚历山大藻（Alexandrium tamarense）,定期测定丈蛤体内的毒素含量;解毒试验通过投喂饵料和水体消毒的“内排外解...     

紫贻贝对124sb累积、排出和结合的实验研究

锑在生物体内是一种有害元素。它能抑制某些酶的作用,与血清中的巯基结合,干扰蛋白质、醣的代谢和肝内产生糖元。关于锑对海洋生物的影响,研究得很少。Friedrich Walz用酒石酸锑钾研究了紫贻贝对锑的吸收与排出。本实验从~(124)Sb(NO_3)_3作为示踪剂,研究锑在紫贻贝体内的累积、排出及结合的情     

麻痹性贝毒毒素在中华哲水蚤体内的累积及排出

本文研究了中华哲水蚤对可产生麻痹性贝毒毒素的塔玛亚历山大藻的摄食情况,以及麻痹性贝毒毒素在中华哲水蚤体内的累积和排出过程。实验发现,中华哲水蚤可以摄食有毒塔玛亚历山大藻,并在体内累积麻痹性贝毒毒素;麻痹性贝毒毒素各成分在中华哲水蚤体内发生相互转化的现象,同时中华哲水蚤又可通过自身代谢作用降解掉大部分毒素;中华哲水蚤可通过其排泄物在空间上转移麻痹性贝毒毒素。     

改性粘土对虾夷扇贝(Mizuhopecten yessoensis)体内麻痹性贝毒的影响

目前,改性粘土技术已成为国内外普遍认可的有害赤潮治理方法,但在利用该技术治理产毒藻赤潮过程中,对底栖滤食性贝类体内毒素累积和排出的影响尚不清楚。通过室内实验,考察了聚合氯化铝改性粘土(MC I)絮凝典型产毒藻——太平洋亚历山大藻(Alexandrium pacificum)后,虾夷扇贝食用组织和消化腺组织中麻痹性贝毒(paralytic shellfish poisoning,PSP)含量、组分的变化情况。研究结果表明,在前期毒素累积阶段,虾夷扇贝暴露于A. pacificum 3 h后,未添加改性粘土的对照组中虾夷扇贝食用组织毒素水平由空白组的未检出迅速升高至13.24µg STXeq/kg,消化腺组织毒素水平由0.68µg STXeq/kg升高至42.97µg STXeq/kg,第4 d时对照组食用组织、消化腺组织毒素水平达到最高,分别为258.67和3 208.40µg STXeq/kg。添加0.2 g/L MC I的实验组中,3 h后水体中97%的A.pacificum藻细胞被絮凝沉降,此时虾夷扇贝食用组织和消化腺组织毒素水平远低于对照组,分别为6.33和18.39µg STXeq/kg,第2 d时达到98.92和574.54µg STXeq/kg,均显著低于对照组(P<0.05),随后呈下降趋势。在随后的毒素排出阶段,实验组虾夷扇贝食用组织和消化腺组织毒素水平显著低于对照组(P<0.05)。另外,在累积阶段,对照组和实验组虾夷扇贝食用组织和消化腺组织中PSP各组分相对含量差异不大,说明改性粘土未对虾夷扇贝体内的PSP转化造成明显影响。由实验结果可见,改性粘土可有效絮凝去除水体中的A.pacificum藻细胞,减少虾夷扇贝对其的滤食,从而降低了PSP在贝类体内的积累,该研究结果将为改性粘土治理底栖贝类养殖水体有毒赤潮提供科学依据。     

渤海裸甲藻和链状亚历山大藻的麻痹性贝毒毒素分析

目的:分析渤海裸甲藻(Gymnodinium sp.)和链状亚历山大藻(Alexandrium catenella)的麻痹性贝毒毒素,为渤海天津海域的赤潮研究积累基础数据。方法:通过实验室培养裸甲藻和链状亚历山大藻,选取对数生长期、平台生长期的裸甲藻以及平台生长期的链状亚历山大藻,利用高效液相色谱法(HPLC)对这两种微藻进行麻痹性贝毒(PSP)毒素分析。结果:裸甲藻细胞内不含有麻痹性贝毒(PSP);链状亚历山大藻细胞内含有C毒素和GTX1-4毒素,该微藻每个细胞毒素含量约为10.81 fmol/cell。结论:裸甲藻细胞内虽不含有麻痹性贝毒(PSP),但不能排除其含有其它毒素的可能。链状亚历山大藻细胞内含有麻痹性贝毒(PSP),属于有毒微藻,需要对其进行密切监测。     

翡翠贻贝对塔玛亚历山大藻的摄食及毒素积累的初步研究

塔玛亚历山大藻是一种可产生PSP毒素的海洋微藻，通过室内摄食实验，初步研究了厦门港水产养殖动物翡翠贻贝对塔玛亚历山大藻的滤食率与光照度、温度、藻液浓度等因素的关系，并对比了翡翠贻贝对其它饵料微藻的摄食压力．同时对比了不同细胞密度的塔玛亚历山大藻浓度对翡翠贻贝毒素累积的影响．     

Microbial Biomass and Organic Nutrients in the Deep-Sea Sediments of the Central Indian Ocean Basin

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.     

海上大直径钢管桩打桩过程中桩周土强度弱化研究

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。     

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.     

Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans

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.     

Deep-Sea Sediment Compression Curves: Some Controlling Factors, Spurious Overconsolidation, Predictions, and Geophysical Reproduction

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.     

INFORMATION FOR AUTHORS

<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology,     

Evaluation of the Risk of Marine Slope Instability: A Pseudo-3D Approach for Application to Large Areas

This article presents a methodology developed to evaluate the instability of submarine slopes that extend over a large area. Special attention was paid to (1) the complex geometry (bathymetry) and the expanse of the slope, (2) the heterogeneity of the sediment, and (3) the distribution of the pore pressure. The safety factor was considered as a spatially varying quantity. The General Formulation (GLE, Fredlund and Krahn 1977), which fully satisfies equilibrium conditions, was used for evaluating the stability of the marine slope. The submarine slope failure, which occurred on 16 October 1979 during the construction of the new Nice airport, was studied in order to test the developed model. Geotechnical parameters were taken from experimental tests carried out by IFREMER on 19 cores extracted at different depths (from 27 m to 1300 m) (Cochonat, Bourillet, and Savoye, 1993; Mulder et al., 1994). Many scenarios were proposed in order to explain the cause of the Nice slope failure (Habib, 1994). In this article, two of those scenarios were tested. Simulation results are presented and discussed.