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1.
大亚湾温跃层形成及其对有关环境要素的影响   总被引:4,自引:0,他引:4  
温跃层是海洋环境中的一种重要物理现象,对海洋的环境生态系统有着重要的影响。大亚湾温跃层是受粤东上升流和夏季表层海水升温双重作用而形成的。通过对大亚湾海域水温、盐度、溶解氧等众多环境要素的长期调查取样分析显示,该海域温跃层是季节性温跃层,一般发生在每年的5—10月份,6月下旬到9月中旬分层现象比较显著,盐跃层和氧跃层会相伴发生。受核电站热排水的影响,湾西侧尤其是核电站前海域的温跃层较其它区域明显和持久。数据显示在温跃层发生期内,由于海水的分层效应,温度、盐度、pH值、DO、BOD5和COD、营养盐及叶绿素等都受到不同程度的影响,形成明显的表底层差异或层次梯度。  相似文献   

2.
厦门潘涂虾池及其附近内湾各态氮的季节性变化特征   总被引:9,自引:0,他引:9  
1996年6月至1997年2月,对厦门市潘涂垦区两口虾池及附近内湾不同形态氮的含量与动态进行调查。结果显示虾池的可溶性有机氮(DON)含量明显高于邻近内湾,颗粒有机氮(PN)多数时间也高于内湾,而邻近内湾可溶性无机氮(DIN)含量则明显比池内的高。虾池中的氮主要以DON形态存在(59.76%),DIN,PN含量较少(9.37%和20.87%);邻近内湾则是以DIN为主(59.97%),其次为DON(29.55%),PN所占比例最小(10.48%)。吓池与邻近内湾不同形态氮的季节变化也存在一定差异。  相似文献   

3.
渤海硝酸盐氮和亚硝酸盐氮季节循环分析   总被引:10,自引:1,他引:10  
根据1985-1987年期间19个月份的断面调查资料分析,莱州湾、渤海湾是硝酸盐氮浓度较高的海域,辽东湾、渤海湾是亚硝酸盐氮浓度较高的海域。硝酸盐氮浓度冬季最高,夏季最低;亚硝酸盐氮浓度秋季最高,春季最低。硝酸盐氮浓度的季节在莱州湾、渤海湾海域最大;亚硝酸盐氮浓度的季节变化在辽东湾最大。在分析海域,秋季硝酸盐氮浓度表、底层差异最大;夏季平均亚硝酸盐氮浓度表、底层差异最大。海洋生物化学过程是引起渤海硝酸盐氮和亚硝酸盐氮浓度季节变化的主要原因。渤海硝酸盐氮和亚硝酸盐氮基本维持着准平衡态季节循环,底层硝酸盐氮和亚硝酸盐氮准平衡态季节循环比较稳定,表层的季节循环容易受到其他因素的影响发生变异。  相似文献   

4.
厦门大学海洋与地球学院,近海海洋环境科学国家重点实验室。摘要:本文通过分析2016年春季航次在浙江中部海域3条断面的观测资料,结果表明:(1)在断面的10~25米层左右观测到了"中层冷水"现象以及在上层观测到微弱的上升流;(2)在浙江中部海域的上层观测到较弱的上升流;(3)春季,在浙江中部海域观测到了丰富的温跃层、逆温跃层以及盐跃层现象。(4)台湾暖流水向上爬坡对跃层的变化有一定的影响,使得跃层厚度变小,跃层强度加强,但是强度并不足以冲破跃层到达表层。  相似文献   

5.
台湾海峡南部灯光围网捕捞的水温选择及其季节变化   总被引:4,自引:0,他引:4  
对1989-1998年台湾海峡南部渔场生产记录资料分析结果表明:灯光围网捕捞主要捕捞年适宜水温16.1-30℃,年较佳水温20.1-30℃,年最佳选择水温21.2-29℃。环境水温过高或过低,不利于灯光围网生产。各季度的选择水温,冬季为21.2-24℃,春季为21.1-27℃,夏季为26.1-29℃,秋季为25.1-28℃;各月选择水温为该月环境水温的中间值至偏高2℃,多数比中间值偏高1-2℃。选择水温范围的宽幅3-5℃;随环境水温升高或降低,鱼类对水温选择发生同的、同步的变化,是一种渐进的过程;在环境水温上升或持续高温,温跃层存在、底层低温涌升水强盛的条件下,灯光围网的作业效率均受影响。  相似文献   

6.
南沙群岛海区毛颚动物的昼夜垂直移动   总被引:10,自引:2,他引:10  
对1997年11月和1999年4月、7月在南沙群岛海区3个昼夜连续测站采集的毛颚动物样品进行了研究。结果表明,这些水域的毛颚动物的昼夜垂直移动可以划分为3个类型:种类作显著移动,不作显著移动和仅在夜晚移动。作为昼夜垂直移动显著的种类,又可以把它们划分为:(1)种类在整个水柱移动;(2)种类在上层(0-60m)移动;(3)种类在中层(60-100m)移动。作为昼夜垂直移动不明显的种类,又可以把它们分为:(1)种类分布在于上层(0-60m)。(2)种类分布于底层(100-200m)。种类在白天下降或附着在海底物体上,仅在夜晚移动。光照,水温,食物和种类特征是影响本水域毛颚动物昼夜垂直移动的重要因素。  相似文献   

7.
长江口上升流海区的生态环境特征   总被引:36,自引:4,他引:36  
根据 1 985年 8月的调查资料 ,讨论了长江口上升流海区的生态环境特征。研究表明 ,在长江口外 ,大约在 1 2 2°2 0′— 1 2 3°1 0′E、31°0 0′— 32°0 0′N海区存在着明显的下层高盐冷水的抬升现象 ;伴随这种上升运动 ,于 5— 1 0m层 ,在上述高盐冷水区明显地存在一个低溶解氧、高营养盐区。资料表明 ,该低氧、高营养盐海水不是直接来自表层的长江冲淡水 ,而是来自深底层的变性后的台湾暖流水。分析表明 ,长江口外的浮游植物高值区的分布位置与上升流区基本一致 ,两者比较浮游植物高值区略向东南方向偏移约 1 5— 2 0km。作者认为形成这种偏离现象的原因可能与上升流中心区水温偏低有关  相似文献   

8.
2014年与2015年夏季琼东上升流的年际变化及其成因分析   总被引:1,自引:1,他引:0  
本文通过2014年与2015年7月琼东海域的现场调查资料,结合卫星遥感数据,对ENSO影响下琼东上升流的变化进行研究分析,结果表明:2015年为强厄尔尼诺年,2015年7月低温高盐水总体上离表层较深,大约为20~30 m(24.5℃等温线和34等盐线),但在近岸处(离岸20 km以内)却相对较浅,24.5℃等温线和34等盐线在整个断面抬升15~25 m,上升流的爬升现象更为明显;受西南季风影响,表层海水离岸运动,低温高盐水沿地形爬升进行补充,是典型的风生上升流。2014年为正常年份,2014年7月,整个断面低温高盐水更接近表层(近岸例外),大约为10~20 m,同等深度低温高盐现象比2015年明显,但上升流爬升现象不明显,24.5℃等温线和34等盐线在整个断面抬升不到10 m;盛行风为东南风、向岸风,对上升流的形成起抑制作用,低温高盐水使整个断面的抬升,不符合风生上升流的特征规律,表明该年琼东上升流的形成可能与外海环流变化导致的温跃层抬升有关。  相似文献   

9.
温度对褐牙鲆资源补充特征的生态效应   总被引:10,自引:2,他引:8  
根据1980-1995年让湾和渤海不记学调查资料,采用自然生态学与实验生态学相结合的方法,综合分析温度对褐牙鲆补充阶段生活史特征及其资源补充过程的影响。结果表明,随地理纬度的增加,褐牙鲆产卵期滞后,生殖季节缩短,在水温从9.62℃增至19.89℃的过程中褐芽鲆的性腺 育指数(GSI)出现单一峰值,7月至翌年3月间此值均小于1.0;在实验水温范围(7-27℃)内,受精卵孵化时数(t)随水温(T)变化  相似文献   

10.
根据1980-06,1980-07,1980-09,1980-10的胶州湾水域调查资料,通过石油烃(PHC)在胶州湾水域的质量浓度变化、表、底层水平分布、垂直分布和季节变化的分析,研究结果表明:在胶州湾水体中,PHC的质量浓度达到了三类海水水质标准的水域有:6和9月份,在整个湾内的水域;7月份,在海泊河、李村河、娄山河和大沽河的入海口以及他们之间的近岸水域;10月份,在海泊河、李村河和娄山河的入海口水域及其他们之间的近岸水域。除了上述水域外,在湾内的其它水域,PHC的质量浓度达到了二类海水水质标准。在空间和时间尺度上表明,胶州湾东部和东北部的海泊河、李村河和娄山河,还有北部的大沽河,都是胶州湾PHC污染的主要来源。通过PHC的陆地迁移过程,展示了从湾的东部、东北部和北部近岸水域到湾的其他水域包括湾中心、湾口和湾外,PHC的质量浓度从大到小的下降趋势。通过PHC的水域迁移过程,展示了PHC表层质量浓度迅速下降的过程及结果。通过表层PHC的水平分布和质量浓度变化,进一步说明了河流对PHC的大量输送和表层PHC质量浓度的迅速下降。于是,在胶州湾水体中,PHC表、底层质量浓度没有明显的季节变化,PHC质量浓度完全依赖于河流对PHC的大量输送。同时将河流输送的强度分为4个阶段,展示了河流输送PHC质量浓度的强度变化过程。  相似文献   

11.
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。  相似文献   

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14.
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.  相似文献   

15.
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.  相似文献   

16.
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.  相似文献   

17.
<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  相似文献   

18.
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.  相似文献   

19.
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.  相似文献   

20.
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%。  相似文献   

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