双齿围沙蚕Perinereis aibuhitensis繁殖的生态

本文研究了栖息于厦门杏林海区的双齿围沙蚕的繁殖习性等。结果表明,其繁殖期出现在每年2～5月,3月末至4月初为繁殖高峰期;雌雄性比为1∶1.7;卵径为186～214μm;胚胎发育经担轮幼虫、膜内疣足幼虫、疣足幼虫和刚节幼虫而达稚虫。幼虫和幼体的体节(X_1)与体长(Y_1)的回归方程为Y_1=139.77X_1-24.62;幼虫的生长特性为Y_2=323.40X_2~(0.35);幼虫和幼体的实验表明,亚心形扁藻是较好的饵料;疣足幼虫对海水的适宜比重为1.010～1.025;幼虫的生长速度随着投饵密度的增加而加快;在幼虫培养期间应铺以泥沙底质为佳。     

双齿围沙蚕的人工育苗技术研究

报道了2003年5月1日~6月25日在玉环县东方海洋生物有限公司育苗厂80 m2的水泥池中育出平均体长2.34 cm的双齿围沙蚕(Perinereis aibuhitensisGrube)幼体13.16kg,并对双齿围沙蚕疣足幼虫进行了不同生态条件的单因子试验。结果表明,适宜的温度为24~26℃;盐度的适合范围为15.0~34.8,最适21.6;饵料以球等鞭金藻和混合藻(角毛藻 扁藻 微绿球藻)为佳,球等鞭金藻的密度以20×104个/mL组效果最佳;4刚疣足幼体起投细砂效果明显优于其它组。     

双齿围沙蚕的胚胎发育与纤毛虫病害

双齿围沙蚕(Perinereis aibuhitensis)亲体为2010 年半人工育苗的苗种, 人工培育至异沙蚕体后进行集中催产、人工授精, 受精卵经过消毒后, 孵化至囊胚期, 收集入水泥池进行中间培育, 经3 d 孵化至3 刚节幼体再次收集, 放入土池进行幼虫培育。卵子受精后, 定期(早期每隔1 h, 囊胚期后每隔3 h)取受精卵, 置于OLYMPUS－CX31 显微镜进行活体观察并进行拍照。结果表明, 在双齿围沙蚕的胚胎发育过程中, 出现了与已有结论不符的特殊现象, 例如油球与胚胎发育的关系, 胚胎的高温孵化。而且,在孵化期, 一种寄生纤毛虫导致沙蚕胚胎及出膜3 刚节疣足幼体的大量死亡, 其病害机理有待进一步研究。     

双齿围沙蚕(Perinereis aibuhitensis)主要器官的组织学观察及其生理功能研究

采用组织学方法,较系统地观察研究了双齿围沙蚕(Perinereis aibuhitensis)主要器官的组织学特点。首次以组织学的形式表现出多毛类刚毛的细微结构——中空的短管状结构,以及腹腔内主要器官组织学特性、位置关系及其可能的生理功能。结果表明:双齿围沙蚕疣足拥有丰富的毛细血管网并着生刚毛;循环系统发达,由背腹大血管、环体节血管网和毛细血管网共同构成一个发达的循环系统,这与其体节断裂存活、再生的进化机制相适应;肌肉组织分为三种不同类型——环肌、纵肌和斜肌,在三者协调配合下,疣足、各体节及整个虫体的运动功能得以完善;消化道由前向后的组织学变化,主要体现为肌肉类型的变化以及肠道褶皱的逐渐丰富,显示了形态与功能的高度适应性。本研究结果为更加系统掌握双齿围沙蚕的生物学特征奠定了基础,并为其人工繁育、指示环境污染物情况提供了一定的科学依据。     

对虾养殖池生态环境生物监控的初步研究

１９９０～１９９１年在山东半岛南部五垒岛湾地区，对浮游植物和纤毛虫原生动物等与对虾生长关系密切的生物进行监测与控制，使虾池形成和保持适宜的生物构成；对日本刺沙蚕［Ｎｅａｎｔｎｅｓ　ｊａｐｏｎｉｃａ（Ｉｚｕｋａ）］幼虫密度进行监测，适时抽水采集沙蚕幼虫入池，使虾池沙蚕幼体密度达到５０００～１００００个／ｍ２。从而为对虾生长创造了一个优良的生态环境。１条件与方法１．１试验池及条件试验地选在山东半岛南部五垒岛湾的烟台警备区养虾场，位于高潮区以上，通过河道进排水，每半月大潮汛期间，只能抽水６～７ｄ，半月…     

重金属对几种海洋双壳类和甲壳类生物的毒性

研究了重金属和污染疏浚物对缢蛏Ｓｉｎｏｎｕａｃｕｌａ ｃｏｎｓｔｒｉｃｔａ稚贝和幼贝，褶牡蛎Ｏｓｔｒｅａ ｐｌｉｃａｔｕｌａ幼虫，甲壳类的卤虫Ａｒｔｅｍｉａｓｐ．幼体和长毛对虾Ｐｅｎａｅｕｓｐｅｎｃｉｌｌａｔｕｓ幼体的毒性，结果表明受试生物的生长，摄食，存活均受到不同程度的影响。各重金属元素对褶牡蛎幼虫，卤虫无节细，长毛对虾糖虾期的毒性顺序为Ｈｇ＾２＾＋＞Ｃｕ＾２＾＋＞Ｚｎ＾２＾＋＞Ｃｄ＾２＾＋＞     

日本刺沙蚕大规模移植的生态学研究

1991年11月—1992年5月在文登市高岛盐场总面积1665亩的30个虾池进行了日本刺沙蚕的移植研究,沙蚕的总投放量为1849/kg,每亩平均11.11kg。3月中旬测得的幼虫平均密度为20130个/m~3,4月中旬测得的定着幼虫和幼体的平均密度为3352个/m~2。对两次6组随机抽样总计1215条成体沙蚕测得的雌雄比为1:2。成熟雌体的平均怀卵量为24×10~4(±3.6×10~4)个,平均粒径为209(±3.7)μm。在移植沙蚕的虾池中,沙蚕幼虫定着的数量和生长发育的情况同自然纳潮虾池中的情况无任何差异。提出了两个简易的公式,以便计算对虾生长盛期为保持一定数量的沙蚕密度每亩所需投放的沙蚕数量。     

人工养殖条件下多齿围沙蚕亲体培育和繁殖生物学的初步研究

通过生态学及组织学方法对人工养殖条件下多齿围沙蚕(Perinereis nuntia Savigny)亲体培育条件及繁殖生物学进行了研究.结果表明,多齿围沙蚕雌雄异体,非成熟季节外观上无法辨别雌雄,性成熟时,雌(异沙蚕体)灰绿色,雄(异沙蚕体)红白色.生殖细胞起源于体腔膜上皮,不久就释放到体腔中,在体腔内卵原细胞和精原细胞http://ebook/成都,今夜请将我遗忘/index.htm分裂增殖形成卵原细胞群和精原细胞群,体腔中充满了外形不规则或近圆形的滋养细胞,细胞内可见嗜伊红颗粒,滋养细胞之间可见发达的微血管.卵原细胞群不断增殖发育,至初级卵母细胞后游离至体腔中继续发育为次级卵母细胞和成熟卵子;精原细胞群形成精子合胞体(syncytium),各级精母细胞在合胞体内发育,直至形成成熟精子时才分散游离.水温18℃以上,多齿围沙蚕的生长体经培育才可能形成异沙蚕体.特别是在经历了一定的低温期后,再提高温度可以有效的促进异沙蚕体形成.胚胎发育的适宜温度为18～25℃;适宜盐度为25～32.胚胎发育过程经历卵裂期、囊胚期、原肠期、担轮幼虫期、后担轮幼虫期、膜内游毛幼虫期等阶段,在水温25℃、盐度30条件下,从受精至孵出3刚节幼虫约需65 h.3刚节游毛幼虫至10刚节幼体约需28 d.     

国外对藤壶幼体附着的研究进展

藤壶的幼虫时期经历了一系列的变态 :浮游 ,无节幼体 ,腺介幼体。腺介幼体是一种特殊的幼体形式 ,它无须摄食 ,此阶段仅仅是为了选择附着、变态的适宜地方。游泳着的腺介幼虫被流动的水流牵引附着到底质上 ,它们开始用其小触角运动。这种附着是可逆的。如果幼体不变态 ,它们能重新恢复游泳阶段 ,因为它们还保留着游泳的能力。一旦幼体附着 ,腺介幼虫便开始探查它所附着底质的各方面的理化性质。腺介幼虫以有规律的“步伐”在底质表面上运动 ,运动的距离一般较短 ,且每一步都很少改变方向或停止。当幼虫找到适宜的附着物后 ,从其第一触角第三…     

hairy和hedgehog在单环刺蜢幼虫体节形成过程中的表达特征分析

hairy作为成对控制基因参与果蝇等体节动物的体节形成;体节极性基因hedgehog是节肢动物和环节动物体节边界维持的关键基因。本研究分析了单环刺螠hairy的序列特征以及hairy和hedgehog在其幼虫体节发生过程中的时空表达特征,结果显示:单环刺螠Hairy序列中含有保守的HLH结构域、Hairy_orange结构域和四肽WRPW;其mRNA在早期体节幼虫中的表达量显著高于晚期担轮幼虫,并且定位于每个体节的边界处。单环刺螠hedgehog mRNA在体节幼虫中的表达水平显著高于早期体节幼虫,并且呈现保守的体节边界表达特征。研究结果表明,hairy和hedgehog在单环刺螠幼虫体节中的表达图式与小头虫等典型体节动物中的表达图式基本一致。     

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.     

A Review of Some Environmental Issues Affecting Marine Mining

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.     

Increased Particle Fluxes at the INDEX Site Attributable to Simulated Benthic Disturbance

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.     

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.     

Determination of In Situ Sediment Shear Strength from Advanced Piston Corer Pullout Forces

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.     

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.