粤东沿岸上升流的研究

在粤东沿岸的夏季存在风生上升流,中心位置在20m以浅,该上升流的年际变化较大,1982年8月碣石湾外上升流流速为1.2×10-3cm/s,活性磷酸盐的垂直通量为1.5 mmol/(m2·d),初级生产力为1558mg/(m2·d).在上升流靠岸内侧,5m以浅范围的底层存在着贫氧现象,在上升流的中心区外,有海水垂向逆温现象,上升流区海水的理化特征:温度为22.13℃,盐度为34.19,溶解氧为3.72cm3/dm3氧饱和度为74.6%,pH值为8.14,活性磷酸盐为1.10 mmol/m3.     

台湾海峡中北部夏季溶解氧饱和度分布与上升流的关系

本文据台湾海峡中北部1983年5月至1984年5月、1987年7,8月和1988年5～7月调查资料,讨论了该海域夏季溶解氧饱和度分布特征及其与上升流的关系,结果表明该海区夏季上升流的中心位置经常出现于海坛岛北侧至湄洲岛一带海域,西南季风是该区上升流产生的主要动力因子,该区上升流平均流速为4.4×10~(-3)cm/s。     

福建闽南沿海养殖贝类体中砷含量的分布

通过2003~2004年对福建闽南沿海5种养殖贝类体砷含量的调查监测,对养殖贝类体中砷含量的分布进行了探讨.福建闽南沿海5种养殖贝类体总砷含量为0.65×10-6~4.80×10-6,总平均值为2.09×10-6,其中有机砷和无机砷占总砷含量的百分比分别为61.6%~98.2%和2.3%~38.4%,平均值分别为88.8%和11.2%.在相同养殖区,养殖贝类体总砷平均含量的种间分布差异较小.滩涂养殖底栖贝类体内总砷平均含量总体上高于浅海筏式养殖贝类体的平均含量.福建闽南沿海5种养殖贝类体内总砷含量在泉州湾、湄州湾、东山湾和九龙江口高,在诏安湾和围头湾低,在其余各湾相近.5种养殖贝类体内无机砷的污染指数和总平均值分别为0.05~0.76和0.23,总砷的污染指数和总平均值分别为0.06~0.48和0.21,总体符合国家食品卫生质量标准.养殖贝类体中砷含量与体长之间总体成正相关.     

台湾海峡西部海域春季表观耗氧量的垂直分布及其极小值

根据1984年台湾海峡西部海域综合调查资料,分析了该海区春季表观耗氧量垂直分布的特征。结果表明,AOU垂直分布趋势为上低下高。表层均呈负值(-0.16×10~(-3)～-2.55×10~(-3)),底层1/2测站呈现负值(-0.04×10~(-3)～-2.42×10~(-3));而另1/2测站呈现正值(0～0.86×10~(-3))。AOU垂直分布有极小值的站位通常出现于不同水系的交汇带,其深度在密跃层下界附近。这是由于密跃层下界附近氧的涡动扩散进行得比热的涡动传导为慢的缘故。因而,逐渐增温时,氧来不及释放到大气中,即氧呈过饱和状态。浮游植物量对极小值的形成不起决定性作用,而只能影响极小值的大小。     

南海中部海区溶解氧垂直分布最小值

本文根据国家海洋局1983年9月—1985年1月在南海中部海区的综合调查资料,分析了该海区溶解氧的垂直结构特征和氧最小值的分布变化规律。结果表明,在水深500m至1000或1500m处终年存在着氧含量普遍小于2.0×10~(-3)的氧最小层,其厚度南部高于北部。氧最小值的含量在(1.65—2.10)×10~(-3)之间,其量值也明显地随着纬度而增加。文中还对氧最小层形成的机理作了初步探讨。     

乳山湾邻近海域低氧现象及成因浅析

根据2009-06-2009-09及2010-05-2010-06在乳山湾及其毗邻海域的综合调查,分析了该海域溶解氧的变化,初步探讨了影响溶解氧变化及底层低氧形成的原因。结果表明,夏季乳山湾邻近海域存在季节性低溶解氧区,溶解氧在6,7月份相对较高,而在8,9月份相对较低,最低值出现在8月份,为3.21mg/L(饱和度为35.5%),表观耗氧量为5.82mg/L。乳山湾外邻近水域溶解氧略高于湾口和湾内。底层溶解氧水平受到潮汐的影响,具有较大的周日波动性,变化范围介于3.74～8.26mg/L;在落潮时质量浓度降低而在涨潮时质量浓度升高。在这一区域存在较为强烈的温、盐跃层,从而限制了表、底层溶解氧的交换,而COD质量浓度的升高为这一区域的耗氧过程提供了一定的物质基础。潮汐、黄海冷水团的顶托作用、有机物质在底层水域的氧化作用以及底泥耗氧过程导致底层溶解氧的亏损。     

湄洲湾表层沉积物中重金属的地球化学特征

根据1984年湄洲湾表层沉积物中重金属的分析资料,讨论了它们的地球化学特征和主要来源。沉积物中重金属的含量(Fe、Mn、Cu、Ni 的质量分数均值分别为3.21%、730×10~(-6)、19.4×10~(-6)、44×10~(-6)分布比较均匀,Pb、Zn 和Co 含量(质量分数均值分别为47.0×10~(-6)、25.8×10~(-6)和243×10~(-6))偏高,微量金属含量不受Fe-Mn 氧化物和有机物控制,本地区的金属来源受陆源输入的影响明显。     

三门湾微型浮游生物丰度的时空变化特征

粒径小于20 μm的微型浮游生物能迅速响应海洋环境变化,因而在海洋环境监测中起着重要作用。本文应用流式细胞技术研究了三门湾表层与底层海水中微型浮游生物（包括细菌、聚球藻、微型真核生物以及病毒）丰度的时空分布特征,探讨了微型浮游生物丰度与水体理化因子之间的关系。结果表明,三门湾海域微型浮游生物丰度范围:细菌,6.98×105~9.84×106 cells/mL;聚球藻,1.10×103~3.71×104 cells/mL;微型真核生物,1.04×103~3.75×104 cells/mL;病毒,1.01×106~3.47×107 mL-1。夏、秋两季表层微型浮游生物丰度均高于底层;秋季细菌、聚球藻和病毒丰度低于夏季,但微型真核生物丰度高于夏季;温度是造成微型浮游生物丰度季节差异的主要因素。微型浮游生物丰度的水平分布在夏季无显著规律,但秋季表底层均由内湾向外湾递减。秋季,除底层的细菌外,微型浮游生物丰度水平分布与pH和盐度呈显著负相关,同时与亚硝氮、硝氮、铵氮、叶绿素a呈显著正相关。     

渤海夏季底层氧亏损分布的年际差异分析

通过2014年和2019年观测资料分析了渤海夏季底层水体氧亏损空间分布的年际差异,同时首次揭示了黄河口东侧莱州湾 口区域的氧亏损现象,并利用三维物理生态耦合模式ROMS-CoSiNE探究了氧亏损分布年际差异的影响因素.2014年秦皇岛外氧亏损区(以溶解氧(dissolved oxygen,DO)饱和度小于70％为统计范...     

几种污染物对草鱼细胞SCE的影响

1987年10月—1988年6月期间,以草鱼(Ctenopharyngodon idellus)ZC-7901细胞株和1龄稚鱼作实验材料,选5种金属盐和4种农药作水体环境的污染物,对培养细胞和稚鱼进行处理,观察培养细胞和鱼体内肾细胞SCE的变化。结果表明:在每毫升培养基中分别含有104×10~(-7)mg的Cr~(6+),112×10~(-7)mg的Cd~(2+),74.9×10~(-7)mg的As~(3+),20l×l0~(-6)mg的Hg~(2+),207×10~(-4)mg的Pb~(2+)及216×10~(-4)mg的敌百虫等污染物,都能诱使培养细胞的SCE明显增加;稚鱼在每升分别含有15×10~(-7)g的Cr~(6+),15×10~(-7)g的Cd~(2+),13×10~(-7)g的Hg~(2+)的池水中喂养40天后,体内肾细胞的SCE也见增加;但是三环唑、甲胺磷、呋喃丹对细胞的SCE没有影响。本文认为,能够引起草鱼SCE变化的污染物的浓度,应该作为今后制定水质标准的参考;同时,草鱼培养细胞和体内肾细胞SCE的检测技术,可以发展成为一种监测水体环境污染的检测系统。     

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.     

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.     

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.