1998年南极中山站海洋气溶胶的化学组成及其来源判别

从1998年3月7日至1999年3月2日历时12个月,在南极中山站连续采集52个海洋气溶胶样品,提供全部样品的13种化学元素铜、铅、锌、镉、铁、铝、锰、铬、钒、钾、钠、钙、镁含量的实测值.研究表明中山站气溶胶化学成分的含量具有季节性变化的特征.通过富集因子、相关分析、因子分析等方法判别中山站气溶胶化学成分的来源.     

西太平洋、东印度洋、南大洋和中山站海域气溶胶的化学组成及其来源判别

1999年11月至2000年4月，在中国第16次南极科学考察往返航线上的海域，采集了22个海洋气溶胶样品，用原子吸收分光法测定了样品中的Cu、Pb、Zn、Cd、Fe、A1、Mn、Cr、V、K、Na、Ca、Mg等13种元素的含量．研究表明气溶胶重金属微量元素的分布具有明显的地理区域性．应用元素富集因子、相关分析和因子分析等方法研究了西太平洋、东印度洋、南大洋、中国南极中山站邻近海域气溶胶中各元素的来源．     

台湾海峡大气微量金属的化学特征及其入海通量

2006～2007年,利用大容量气溶胶采样器在台湾海峡采集79个大气气溶胶样品．采用ICP—MS分析法测定了样品中Pb、Cu、Cd、V、Zn、Fe和Al等金属元素的含量．分析结果显示,台湾海峡大气微量金属含量呈现出明显的季节变化,对大部分元素而言,含量最低值出现在夏季,而最高值出现在冬季,气溶胶中微量金属的含量变化与海峡的气象条件等因素有关．通过富集因子、相关性分析和因子分析,对微量金属的来源进行了判别．台湾海峡大气微量金属的来源特征为：Cu、Pb、Cd、V主要来自污染源,而Al、Fe、Zn则主要来自地壳源．比较和分析了台湾海峡海域微量金属的大气与河流输入,Cu和Zn的大气输入低于九龙江和闽江的输入,而Pb、Cd的大气输入则超过了这2条河流的输入．     

中国沿海经济海藻化学成份的测定

于１９８８－１９９０年在中国沿海十几个省区采集大型经济海藻样品６０余种，应用高压液相色谱、电感耦合等离子体（ＩＣＰ）－米光栅摄谱仪等分析手段，全面系统地测定其化学成份。结果表明，其中的有效成份为碳水化合物，含氮化合物、维生素、脂肪酸、纤维素、矿物质及微量元素等。目前在于有效地开发利用各种海藻并建立数据库。     

海底沉积物样品的化学物相分析及碳酸钙的测定

海底沉积物中碳酸钙的测定属物相分析．基于化学原理，选用不同的溶剂可选择性地将样品分为六个相：碳酸盐相、金属相、硫化物相、氧化物相、碳酸盐相．酸不溶残余相．只要准确测定碳酸盐相中Ca^2 离子的难度，即可知样品中碳酸钙的含量．     

大气粉尘气溶胶中铁氧化物的光谱分析

首次利用浸反射光谱装置（DRS）对中国大气粉法气溶胶中铁氧化物进行了研究，结果表明，在可见光范围，粉尘样品反射光谱的一阶导数曲线，在435nm和560nm对样品中的针铁矿和赤铁矿有识别指示意义，样品中铁的含量与赤铁矿和针铁矿的一阶导数峰值相关性良好，同时发现，红、登、黄3种颜色的反射率随样品中铁含量的增加而增加，而紫、绿、蓝3种颜色的反射率随样品中铁含量的增加而减少，这表明铁氧化在粉尘气溶胶对可见光的散射和吸收效应中扮演着重要的角色。     

珠江口海域气溶胶中重金属含量的时间变化特征及入海通量初步估算

采用2009～2011年珠江口海域获取的代表春、夏、秋、冬4个季节的240个气溶胶样品,分析重金属（Cu、Pb、Zn、ca）质量浓度和大气干沉降通量的年、季变化特征．结果表明：气溶胶中zn的质量浓度最高,其次是Pb和Cu,Cd的质量浓度最低,年平均质量浓度依次为69,2、31．2、12．6和0．58ng／m3．Cu、Pb和Zn的年平均质量浓度和入海通量表现为2009年〉2011年〉2010年．Cd的年平均质量浓度和入海通量呈现逐年递减的变化趋势．各金属质量浓度及大气干沉降通量均为秋季最高,冬春季次之,夏季最低,这种季节性差异主要与季风和雨水冲刷作用有关．气溶胶中Cu、Ph、Cd和Zn平均质量浓度的较低值出现在2010年夏季．Pb在4个季节的平均质量浓度低值均出现在2010年,平均质量浓度依次为18．9、3．8、56．7、20．2ng／m3,表明加强人为污染物排放的控制,可有效地降低气溶胶中重金属的含量,提高环境空气质量．通过评估金属元素分别从大气和河流进入珠江口海域的输入量,该海域金属物质输送入海仍以河流输入为主,但大气中Pb对该海域的输入具有重要作用．     

利用火试金-ICP质谱分析地质样品中低于ppb级的Au、Pt和Pd

利用火试金—ＩＣＰ质谱分析地质样品中低于ｐｐｂ级的Ａｕ、Ｐｔ和ＰｄＧ．Ｅ．Ｍ．Ｈａｌｌ等回顾工业实验室分析地质样品中Ａｕ、Ｐｔ和Ｐｄ通常所采用的方法，显然，Ｐｔ和较小含量Ｐｄ的检出限，不足以保证这些元素的地球化学勘查计划。北美７个主要实验室关于Ａｕ、...     

西北太平洋及中国东部近海秋季海洋气溶胶分布特征

2015年9月,分两个航次同时对西北太平洋及中国东部近海上空海洋气溶胶进行采集.对样品中的Na~+、K~+、Ca~(2+)、Mg~(2+)、Cl~-、NH~+_4、NO~-_3、SO~(2-)_4、甲基磺酸(MSA)等9种组分进行了分析,结合数理统计方法探究两个海域上空海洋气溶胶的来源.结果表明西北太平洋及中国东部近海海域气溶胶来源具有显著差异,西北太平洋海域气溶胶以海盐来源为主,中国东部近海海域则受陆源气溶胶影响较大,K~+、Ca~(2+)及二次气溶胶含量明显高于西北太平洋;此外,中国东部近海海域气溶胶中MSA含量平均值高于西北太平洋.本研究还估算了NH~+_4、NO~-_3、SO~(2-)_4在两个海域的干沉降通量,中国东部近海营养盐气溶胶干沉降通量远大于西北太平洋,营养盐的输入有利于海洋初级生产力的提高,也会促进生物来源气溶胶的产生.     

西太平洋降水化学的研究

本文根据TOGA(热带海洋与全球大气)第二航次中采集的36个雨水样品,对西太平洋降水化学特征及其影响因素进行研究。结果表明,海洋降水与大陆污染地区降水化学组成上差异显著,海洋降水基本未受人为排放的影响,但化学组成相当程度上受海洋气溶胶的支配,其中Cl-、Na+、Mg2+、Ca2+等离子主要来自降水对海盐气溶胶的淋洗和冲刷,海洋生物代谢过程排放的NO和有机硫化物使降水中NO₃-,SO₄2-得到富集,在赤道附近富集效应更为突出。     

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.     

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.     

Assessing the Validity of Seismo-Acoustic Predictor Equations for Obtaining Seabed and Sub-Surface Sediment Physical Properties

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.     

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.     

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。     

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.     

《Acta Oceanologica Sinica》Vol. 33(2014) contents

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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,