苏北废黄河三角洲沉积物的时空变化特征

基于苏北废黄河三角洲近岸冬夏两季的表层沉积物粒度参数分析结果,研究了沉积物的时空变化特征。结果表明,沉积物分布具有显著的时空变化特征:空间上由岸向海、由北侧至南侧,沉积物粒度呈变粗的趋势;时间上,沉积物粒径冬季粗于夏季。沉积物分选普遍较差,偏态为正偏,峰态尖锐。受季节性风的影响,冬季沉积动力环境比夏季复杂,沉积物粒度参数变化幅度较夏季大,冬季样品粒度参数等值线梯度明显大于夏季。在粒级-标准偏差曲线上,高峰值在52.55～88.39μm,为敏感粒级。研究区在潮流和季风驱动的风浪作用下,沉积环境具有波-流联合作用复杂的特点。     

长江口泥质区垂向沉积结构及其环境指示意义

2006年4月在长江口泥质区获取了沉积物柱状样,进行了粒度分析及粒度分形计算,并从中提取沉积物环境变化敏感的粒度组分,结果表明,柱样的垂向沉积结构可分为两个部分:上部0~12cm是动力环境改造频繁的活动层,沉积物混合程度较高;自12cm以下沉积物有粗细旋回变化的特征,可能与长江入海泥沙的季节变化有关。本区沉积物主要含两个敏感粒度组分,标准偏差峰值为6.0~7.2μm的细组分与长江来源的悬沙粒径大致相当,而标准偏差峰值为40.7~57.5μm的粗组分则可能与风暴潮、波浪和潮流输沙、长江流域及河口区的水利工程的影响有关。沉积物粒度在0.9~20.3μm标度范围内的统计自相似程度很高,具有分形特征,粒度分维数的波动与沉积物粒度参数变化相吻合,表明沉积物粒度分维数具有一定的环境指示意义。     

江苏灌河口沉积物粒度组分特征及沉积速率研究

为了研究灌河口海区的沉积环境,利用激光粒度仪对位于灌河口的柱状样 GH-1孔进行了沉积物粒度分析,根据粒级-标准偏差方法对此柱状样的环境敏感粒级进行了计算,并结合对粒度概率曲线图的分析来对该区域进行沉积环境的研究,从而探讨了该环境敏感粒度组分的环境指示意义。在研究区内确定环境敏感粒度组分为250~32μm,32~16μm,代表沉积过程中的两种动力机制,分别是风暴流和沿岸流。通过该柱状样的210Pb测年可以得到沉积速率和沉积环境的变化,上段沉积速率较大为1.9 cm/a,下段20 cm沉积速率较低为0.4 cm/a。     

粒度分析中偏度系数的影响因素及其意义

利用粒度分析中的偏度系数对区分不同搬运动力和不同沉积环境下的沉积物具有重要的鉴定意义,通过对偏度系数内涵的深入分析和粒度分析不同方法的比较,研究表明:偏度是非正态粒度分布下的偏斜程度,可敏感地反映粒度分布两端的微量变化,正偏是沉积物粒度分布的细偏,负偏则是粗偏,偏度正负大小与多种因素有关,它主要受沉积物属性控制,既与沉积环境类型密切相关,又与环境能量是否对应平衡有关;偏度还受计算方法和测试方法等人为因素影响。筛析法结合图解法计算较适用于粒度粗、跨度大的沉积物粒度分析,激光粒度法结合矩法计算更适用于粉砂—黏土粒级沉积物的粒度分析。     

青岛近岸泥质区敏感粒级组分及对沉积记录的指示

通过对青岛南部近岸泥质区3个岩心(Z14、Z16、QDZ03)进行粒度分析和AMS14 C年龄测试,研究了沉积物粒度组成并提取了敏感粒级,探讨了敏感粒级的搬运机制及其环境指示意义。研究表明:研究区岩心沉积物以粉砂和黏土质粉砂为主,包含3个敏感粒级(敏感粒级1、敏感粒级2、敏感粒级3),分别对应粒度细端组分、中端组分和粗端组分,以悬浮和跳跃搬运为主,少量以滚动、推移方式搬运;沉积物主要受沿岸流输运的影响,粒度组分自东北向西南逐渐变细,反映了水动力条件自东北向西南逐渐减弱的趋势;其中,敏感粒级2对东亚冬季风增强事件具有较好的反映:利用QDZ03孔上部3.94m岩心沉积物敏感粒级获得了近3ka以来5个明显的东亚冬季风增强事件(230~370、1 050~1 180、1 400~1 550、1 850~1 950和2 250~2 350aBP),对古气候记录具有较好的指示作用。     

沉积物粒度参数和频率曲线对粒级划分的响应

以Φ、Φ/2、Φ/4为粒级间距,分别采用Folk-Ward图解法和Mc Manus矩法计算了粉砂质砂、黏土质粉砂、砂-粉砂-黏土等3类沉积物共136个底质样品的粒度参数,并引用统计学中的单因素方差分析法对每一类沉积物的每一个粒度参数进行分间距计算结果对比。结果表明,各类沉积物在各种计算方法中粒级划分对粒度参数表征粒度分布特征均不构成影响。但粒度频率曲线形态随粒级间距的不同会有变化,同一粒径所对应的频率值在不同粒级间距下有较大差异。因此,在进行动力条件和沉积环境等研究时,必须对粒级间距在粒度分析中的影响给予足够重视。在进行粒度分析时,如果只求粒度参数,采用Φ间距即可,这样可以减小工作量;如果研究沉积环境,建议采用Φ/4间距。     

胶州湾沉积物的时空分异特征及运移趋势

2006年6月在胶州湾采集柱状岩芯并对沉积物进行粒度分析,结果表明,胶州湾沉积物存在显著的空间和时间分异.从平面分布上看,由南往北表层沉积物颗粒逐渐变粗,分选变差;粉砂含量逐渐减少,砂含量逐渐增加.粒径趋势分析亦显示了胶州湾内沉积物输运的空间分异特征:内湾西北部浅水区的沉积物存在向南偏东方向的净输运,外湾浅水区沉积物则向黄岛前湾内运移,与10 a前的沉积物运移趋势基本一致;青岛近岸海域沉积物沿沧口水道向湾顶输运.从垂向上看,柱状岩芯的沉积层具有互层层理和多个粒级的环境敏感组分,并且早期(底部)的沉积物颗粒偏粗.根据本文柱状岩芯的210Pb测年结果并与10 a或数十年前的分析数据相比,胶州湾的平均沉积速率有所降低.胶州湾柱状岩芯呈现出的平面与垂向上的时空分异特征不但与局地的水动力变化、沉积物输运有关,还与物源供应、沉积环境的演化和人类活动的影响有关.     

碳酸盐含量对莱州湾南岸钻孔沉积物粒度测试结果的影响

采用2种不同的前处理方法对莱州湾南岸钻孔沉积物样品进行粒度测量。通过比较沉积物粒度的粒级组成发现,未去除碳酸盐颗粒的测量结果,黏土粒级含量显著增加,粉砂粒级的变化主要受到黏土粒级含量增加的影响而降低,砂粒级未见明显的变化规律。应用2参数Weibull分布,对沉积物粒度分布进行拟合,发现测量样品的粒度分布以3峰态和4峰态为主,是否去除碳酸盐不改变粒度分布的基本形态,但对各组分的相对含量影响明显。通过实验对比,我们认为,粒度测量的前处理过程中去除碳酸盐是必要的。     

埕岛海域CBG4a孔岩芯粒度特征与古环境

对埕岛海域CBG4a孔岩芯进行粒度分析，划分出海滩、三角洲支流河口滨线、海滩附近沙丘、黄河三角洲河口沙坝、黄河三角洲水下三角洲前缘隆起、水下天然堤、河流等7种沉积环境。对样品进行Q型聚类分析，识别出分辨力及代表性更强的一组分类统计量：各粒组百分含量及相关的粒度参数（C，Md，Mφ，δ1，Sk，Kg，Q1，Q3）。Mφ-δ1，Kg-Sk等结构参数散点图与沉积环境有很好的相关性，河流、海滩、沙丘等沉积物有较明确的界线。粒度象图反映了沉积物分布总体特征，其中水下天然堤、三角洲支流河口滨线沉积、海滩及其附近沙丘沉积等亚相易于在F-M图中区分，而黄河水下三角洲前缘隆起沉积、黄河三角洲河口沙坝沉积、河流沉积等在L-M图和A-M图中均易于区分。     

苏北潮滩不同生态带沉积物分布特征

利用2004年1月3日在江苏盐城珍禽国家级自然保护区核心区新洋港采集到的表层和柱状沉积物样品,采用矩值法对该潮滩沉积物粒度和粒度参数进行了分析和计算,并对潮滩沉积物的水平和垂向分布特征以及不同植被对沉积物分布的影响进行了研究,结果表明:(1)自海向陆,光滩、互花米草滩、互花米草盐蒿混合滩、盐蒿滩和芦苇地5个亚带中,光滩沉积物的粒径明显较其它4个亚带处的粒径大,在接近互花米草滩时沉积物的粒径迅速变小,而互花米草滩等其它4个亚带处的沉积物粒径则变化不大。较低部位光滩沉积物的频率分布曲线呈不明显双峰分布,而较高部位的光滩及其它生态带内的沉积物频率分布曲线均为单峰,显示出物源较为单一的特点。(2)沉积物自海向陆粒度特征的变化规律反映了潮滩水动力条件对沉积物分布的影响,尤其是反映了盐沼植物在潮滩的发育过程中所起的重要作用。(3)周期性变化的潮动力作用、潮流不对称作用、植被以及潮滩不同部位淤积演化差异的影响造成了潮滩不同部位沉积物敏感组分粒度垂向变化的差异。     

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.