星斑川鲽胚胎发育的形态观察

为了掌握星斑川鲽早期发育的规律,2006年4月在实验室利用显微镜和显微数码摄像系统,通过电脑活体观察测量拍摄星斑川鲽受精卵胚胎发育和初孵仔鱼的形态特征,详细描述记录其发育过程和时间。星斑川鲽为游离的半浮性卵,无油球,卵径平均924μm。在水温11.0~12.6℃孵化,大约受精后1h30min胚盘形成,9h30min进入囊胚期,11h后进入原肠胚,35h左右进入胚体器官分化期,62h左右尾部游离,70h后心跳开始,胚体搐动,89h孵出。实验表明,星斑川鲽受精卵的孵化进度与水温相关。孵化时间(Ht)与水温T(℃)关系方程为Ht=1044.3T-0.9712(R2=0.9785)。     

犬齿牙鲆胚胎及仔、稚、幼鱼形态发育观察

犬齿牙鲆(Paralichthys dentatus)卵为端黄卵,受精卵浮性,卵径950~1100μm,油球径200~225μm.在水温20.5~22.0℃,盐度33条件下培育,受精后1 h 20 min 进入卵裂期,6 h 10 min 进入囊胚期,11 h 20 min 进入原肠胚期,19 h 10 min 发育到胚孔封闭期,胚体形成,26 h 50 min 尾芽出现,33 h 35 min心跳开始,48 h 10 min 开始孵化出仔鱼.初孵仔鱼平均全长2.59 mm±0.02 mm,在培育水温为17.0~21.0℃,盐度24~34条件下,胚后发育时序为:1日龄~9日龄为仔鱼前期,10日龄平均全长5.52 mm±0.05 mm,卵黄囊和油球完全吸收进入仔鱼后期;40日龄平均全长20.82 mm±0.67 mm,各鳍鳍条发育形成进入稚鱼期;65日龄平均全长41.13 mm±0.88 mm,全身鳞被完整进入幼鱼早期     

小黄鱼(Larimichthys polyactis)胚胎发育及仔、稚鱼形态特征观察

采用干法授精方法获得受精卵,在人工培育条件下对小黄鱼的胚胎及仔稚鱼形态发育进行观察,描述了各发育时期的发育时序和形态特征。结果表明,小黄鱼受精卵呈圆球形,无色透明,单油球,浮性,卵径(1413±73)μm,油球径(465±23)μm。在水温(18±0.5)?C,盐度28下,历时50h40min完成孵化。初孵仔鱼全长(3256±112)μm,卵黄囊长径(1260±50)μm,短径(894±65)μm,肌节32对。在水温(19±1)?C下,仔、稚鱼发育历时35天,4日龄仔鱼开口摄食,6日龄卵黄囊消失,10日龄油球消失,15日龄尾椎骨向上弯曲,25日龄全长(7467±550)μm,各鳍发育基本完成,进入稚鱼期,35日龄全长(22158±420)μm,全身被鳞,进入幼鱼期。     

条斑星鲽早期发育生物学研究——受精卵的形态、生态和卵胚发育特征

条斑星鲽(Verasper moseri)的受精卵为圆球形、分离透明、无油球的悬浮卵。卵膜具粗波纹状的纹络。卵黄均匀,浅黄色或米黄色。卵径平均为1.70 mm±0.02 mm。卵黄囊径1.57 mm±0.025 mm。卵黄间隙狭窄,约为0.11 mm。受精卵的可孵化水温为6.0~11.0℃,最适孵化水温8.0~10.0℃。可孵化盐度为27.00~36.00,最适孵化盐度为33.00~35.00。受精卵在不同盐度的海水中,呈现不同的生态分布特征。在水温8.0~10.0℃,盐度33.00,光照500~6000 lx,pH值7.5~8.4的孵化条件下,受精卵约历时216 h孵化出膜,出膜方式以头部首先破膜为主。优质卵的孵化率可达90%以上。在条斑星鲽胚胎发育过程中,原肠期及原肠期以前的时期对温度的敏感性明显强于原口关闭后各个发育时期。卵胚卵裂期的不同步分裂现象要比其他硬骨鱼类提前,出现在第三次卵裂时期。多细胞期的裂球均一程度较低。在孵化育苗生产中,出现大量带有"空泡"的不正常的卵胚和前期仔鱼。该研究结果为比较鲆鲽鱼类早期发育过程提供了基础参考资料,同时揭示作为冷温性鱼类条斑星鲽受精卵发育过程中出现的特殊规律,从而为该鱼种进一步大规模苗种生产提供了理论依据。     

四指马鲅胚胎发育观察

利用人工培育的2龄四指马鲅(Eleutheronema tetradactylum)亲鱼自然产卵受精而获得的受精卵在实验室中孵化和培育,对受精卵胚胎发育到仔鱼孵出的全过程进行详细的观察记录.结果表明:四指马鲅受精卵呈圆球形,卵膜光滑,单油球.平均卵径675.78μm,油球平均直径258.46μm.在水温为31~33℃,盐度为27.50~28.00,p H值为8.2条件下,胚胎发育用时13 h 52 min,可分为卵裂、囊胚、原肠胚、胚体形成、器官分化和孵化6个阶段,初孵仔鱼全长1.46±0.25 mm,3DAH仔鱼全长2.42±0.18 mm,口和肛门张开,仔鱼开口摄食.     

鮸鱼胚胎发育的研究

研究了人工繁殖时鮸鱼(Miichthys miiuy)胚胎的发育过程。鮸鱼受精卵呈圆球形,浮性,卵径为0.99~1.15 mm,中央大多具有1个油球,少数为2~3个或较多个油球。在水温为24.5~24.7℃,盐度为24的天然海水中,鮸鱼胚胎发育历时约21h 48 min孵化出膜。整个胚胎发育分为5个阶段,共21个发育期。     

七带石斑鱼胚体和卵黄囊期仔鱼的发育

本实验对七带石斑鱼胚体、卵黄囊期仔鱼形态发育的过程进行观察,研究其发育特征.结果表明:(1)七带石斑鱼受精卵在水温会(27.77±1.05)℃,盐度32条件下,胚胎发育从胚体形成至孵出仔鱼历时约22h 10min.(2)仔鱼卵黄囊在孵化2d后消失,油球消失于孵化后第6 d,卵黄囊依照先卵黄、后油球的顺序被吸收.吸收速度为先快后慢.(3)初孵仔鱼在孵化后一天时间内生长迅速.之后速度减缓.(4)仔鱼的营养可概括为内源性营养一混合营养一外源性营养阶段.     

大西洋浪蛤繁殖生物学研究

于2002年1月至2003年1月 ,在浙江温州对引种养殖的大西洋浪蛤(Spisulasolidissima)的性腺发育、生殖周期、肥满度、胚胎发育、幼虫发育及变态等进行了研究。研究结果表明 ,大西洋浪蛤性腺发育过程分为增殖期、生长期、成熟期、排放期、休止期5个阶段。在浙南沿海的大西洋浪蛤繁殖期在4月下旬至6月上旬 (水温19.5～25℃ ) ,可大量产卵二次 ;肥满度最高出现在5月份,为10.37 % ,最低出现在2月份 ,为4.66 %。个体产卵量为14.1×104～111.1×104粒 ,卵沉性 ,卵径50～60μm ;受精卵在水温19.5～23℃ ,经16～20h孵化成D形幼虫 ;初孵D形幼虫平均大小为75μm×62μm ,浮游幼虫经12～13d培养进入壳顶后期 ,15～16d进入附着变态期 ,壳长为260～290μm ,发育变态为稚贝。     

驼背鲈的胚胎发育

对驼背鲈(Cromileptes altivelis)的胚胎发育过程进行了观察,描述其发育各期的形态特征及发育速度。驼背鲈成熟卵呈浮性,透明,平均卵径为810μm,油球一个。在水温25~27℃,盐度30条件下,胚胎发育时间为24 h 10 min。     

丝鳍圆天竺鲷的繁殖习性、胚胎发育和胚后发育观察

本文以丝鳍圆天竺鲷(Sphaeramia nematoptera)为研究对象,观察记录了其繁殖习性以及胚胎发育和胚后发育的过程。研究结果表明:丝鳍圆天竺鲷的繁殖活动由雌鱼主导,在凌晨1点至3点交配,产卵受精后由雄性口孵,产卵间隔期为11～18d,无季节性。雌鱼单次产卵3126～4882粒,受精卵近圆球形,卵径(720±10)μm,内有数颗油球;在水温(27.0±0.5)℃条件下,受精卵经过卵裂期、囊胚期、原肠期、神经胚期、器官形成期到出膜需187h。丝鳍圆天竺鲷胚后发育分为仔鱼期、稚鱼期、幼鱼期和成鱼期,初孵仔鱼全长(2.8±0.1)mm,口裂高度(0.202±18)mm,孵化后第二天仔鱼开口摄食;孵化后24d鳍条形成,身体出现两条黑色条带,结束浮游阶段,进入稚鱼期;孵化后50d鳞片完全形成,体色斑纹等外形特点与成鱼相同,进入幼鱼期;孵化后360d性腺发育成熟,具备生殖能力。     

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。     

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.     

Estimation of Sediment Properties during Benthic Impact Experiments

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.     

A Tidal Flow Model for the Gulf of Kachchh, India

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.     

利用中国GF-3卫星SAR和HY-2A卫星微波散射计的首次台风联合定量观测

<正>The typhoon,as a mature tropical cyclone that develops in the western part of the North Pacific Ocean with high wind speed and heavy rainfall,is one of the most lethal and costly of natural disasters for the densely populated countries of East Asia.It can be easily detected by space-borne sensors operated at microwave,visible or infrared bands(Liu et al.,2014).Synthetic Aperture Radar(SAR)is     

离子交换—原子吸收光谱法测定海水中痕量铜、铅、锌、镉、铁、锰

本文介绍了用国产D401型螯合树脂分离富集海水中铜、铅、锌、镉、铁、锰等痕量元素,并用原子吸收光谱仪测定其含量的方法。讨论了各元素的分离条件选择及干扰元素的影响,并与溶剂萃取法的结果作了比较。各元素检测的定量下限为:铜0.5μg/L、铅0.1μg/L、锌1.0μg/L、镉0.01μg/L、铁2.0μg/L、锰2.0μg/L。方法精密度在4—8％之间,回收率为90—102％。     

Biogeochemistry of Mangrove Soil Organic Matter: a Comparison BetweenRhizophoraandAvicenniaSoils in South-eastern Brazil

Soil core samples fromRhizophora mangleL. andAvicennia schauerianaStapf & Leech forests from south-eastern Brazil were analysed for their total organic matter content and their sugars, amino acid and amino sugars composition. Organic carbon and nitrogen contents were higher inAvicenniathan inRhizophorasoils. The contribution of sugars and amino acids to the total organic carbon pool was constant with depth inRhizophorasoils whereas inAvicenniasoils it increased. Spectral distribution of sugars and amino acids showed a dominance of Ca-affine monomers, particularly acidic amino acids, and the sugar arabinose. Biogeochemical indicators derived from ratios of individual sugar and amino acid monomers confirm previous studies which showed that organic matter in both soils is mainly of mangrove origin. The results further suggest accumulation of organic matter inRhizophorasoils and a continuing degradation of organic matter inAvicenniasoils. The latter may thus release more nutrients to adjacent ecosystems thanRhizophorasoils.     

A review of orange roughy Hoplostethus atlanticus fisheries,estimation methods,biology and stock structure

Orange roughy Hoplostethus atlanticus are unusual fish. They form dense aggregations that have fuelled lucrative fisheries at great depths (600–1 400 m), especially off Namibia, New Zealand and Australia. They are thought to be very long-lived (>100 years, maturity at 22 – 40 years), and to have exceptionally low natural mortality (M = 0.045–0.064 year^?1) and slow growth rates (K = 0.055–0.070 year^?1). In addition, they spawn large eggs and have low fecundity. These factors combine to make orange roughy highly susceptible to overfishing; most stocks are below 30% of pristine levels. Assessments are obtained from indices of catch rate and trawl, acoustic and egg surveys. Acoustic estimates are the most direct, but are confounded by the species' low target strength (?50 to ?53 dB)–attributable to the wax-filled swim bladder. Extracellular wax esters are stored in abundance and comprise mostly mono-unsaturated fatty acids, with low concentrations of the ω-3 fatty acid family. This unusual composition (resultant from the species' diet) ensures neutral buoyancy. Stock separation has been inferred mainly from biological studies, but genetic studies have also found differences among stocks within New Zealand and Australia. Deep-water habitat may be damaged by trawling operations and may take many years to recover, so in some quarters there is a call for a portion of suitable habitat to be set aside for preservation. Although Namibian orange roughy are shallower, smaller and younger than those in other stocks, the Namibian fishery sustained high catches for only a few years before quotas were reduced, from 12 000 to 1 875 tons. Three management lessons are suggested for developing orange roughy fisheries based on the Namibian experience: (1) imposition of catch limits during exploratory fishing; (2) starting the acoustic surveys earlier in the fishery, if possible; (3) greater reliance on trends in catch rate until a survey series has been established.