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1.
用高效液相色谱法对2010-10在胶州湾15个站位获取的表层海水样品中低分子量有机酸(LMWOAs)进行了定性、定量分析。结果表明,高效液相色谱法能够在胶州湾表层海水中检测到3种典型的低分子量有机酸,分别为乳酸、乙酸和甲酸,这3种酸的总浓度(TOA)的变化范围为18.02～24.66μmol.L-1,平均浓度为20.95±1.95μmol.L-1;乳酸、乙酸和甲酸浓度变化范围分别为1.72～11.11,4.47～17.98,2.89～6.04μmol.L-1,平均浓度分别为(3.25±2.25),(12.77±2.94),(4.90±1.27)μmol.L-1,乙酸的平均浓度显著高于甲酸和乳酸。总体而言,3种酸的分布呈现近岸高、远岸低的趋势,人类活动是胶州湾有机酸的主要来源并且对LMWOAs的分布有决定性的影响。分析了溶解有机碳(DOC)、叶绿素a(Chl-a)的浓度分布以及它们与LMWOAs之间的关系。DOC的浓度变化范围为140.25～197.50μmol.L-1,平均浓度为(161.22±17.67)μmol.L-1;Chl-a的浓度变化范围为0.70～1.45μmol.L-1,平均浓度为(0.91±0.28)μmol.L-1。发现TOA浓度与TOA/DOC之间存在一定的相关性,TOA浓度与Chl-a浓度缺少相关性,表明生物活动对胶州湾LMWOAs的影响不明显。  相似文献   

2.
大亚湾海域溶解游离氨基酸及其与环境的关系   总被引：4，自引：0，他引：4  
对大亚湾海域溶解游离氨基酸(DFAA)的分布特征及其影响因素进行了研究。现场采样调查分别于1995年5月、11月和2000年4月进行。结果表明 :(1)大亚湾海域DFAA的含量较高 ,在0.69～4.73μmol/L之间 ,平均2.16±0.87μmol/L,可能主要源于较为旺盛的生物活动 ;(2)DFAA含量在海域的平面分布变化较大 ,垂直分布和季节及年变化不明显 ;(3)DFAA与海水中的DOC呈正相关、与叶绿素呈负相关关系 ,与TIN的相关性则呈季节变化 ,生物效应可能是影响该海域DFAA含量的主要因素。  相似文献   

3.
基于中国第30次南极科学考察在南极半岛(60°~63°S)近岸海域获取的调查资料,分析了该海域生物化学要素中溶解有机碳(DOC)、总氮(TN)和总磷(TP)分布特征并讨论地形和水团对其的影响。结果表明:2014年夏季南极半岛近岸海域水体DOC浓度变化范围为40.5~78.1μmol/L,平均浓度为66.3μmol/L;TN浓度变化范围为4.2~29.5μmol/L,平均浓度为14.9μmol/L;TP浓度变化范围为0.8~2.9μmol/L,平均浓度为2.0μmol/L。表层DOC呈现研究海域西北部D1断面和东南部D5断面浓度较高,中部DOC浓度较低;表层TN与TP浓度高值区出现在研究海域西部D1断面北部以及南部,中部和东部浓度较低;DOC,TN和TP浓度的垂直分布与海底地形和水团交汇密切相关,水团运动受阻于地形致使生物化学要素在垂直方向再分布。DOC,TN和TP空间分布反映了南极半岛近岸海域生物化学要素复杂的流通,将为合理开发和利用南极资源及环境影响评价提供科学依据。  相似文献   

4.
秋季东海溶解态和颗粒态氨基酸的组成与分布   总被引：1，自引：0，他引：1  
本文对2012年秋季中国东海31个站位的海水样品中溶解态氨基酸(THAA)和颗粒态氨基酸(PAA)的组成与分布进行了研究。结果表明:表层海水中溶解游离氨基酸(DFAA)的平均浓度为(0.12±0.04)μmol/L(0.06—0.19μmol/L),溶解结合氨基酸(DCAA)的平均浓度为(0.61±0.51)μmol/L(0.15—1.79μmol/L),PAA的平均浓度为(0.11±0.06)μmol/L(0.02—0.27μmol/L)。THAA的水平分布特点大致为近岸高、远岸低;PAA的水平分布特点是近岸海域向远海海域分布呈现逐渐减小的趋势。THAA的垂直分布特点是由表层向底层逐渐降低。DCAA、PAA与chl a有很好的相关性,而DFAA与chl a的相关性不明显。东海表层海水中THAA的主要组分是天门冬氨酸、谷氨酸、丝氨酸、甘氨酸、苏氨酸及丙氨酸,PAA的主要组分是天门冬氨酸、谷氨酸、丝氨酸、甘氨酸、丙氨酸及亮氨酸。在表层海水中氨基酸是作为一个整体而对海洋生物地球化学过程产生影响的。  相似文献   

5.
通过对长江口及其邻近海域2002-2006年13个航次的综合调查,研究了三峡水库蓄水前后长江口及其邻近海域浮游植物群落结构的变化,并应用相关性分析、典范对应分析(CCA)等方法对浮游植物群落结构变化的原因进行了探讨。结果表明:三峡水库蓄水后,长江口及其邻近海域的浮游植物群落结构、盐度及营养盐结构已发生显著变化。硅藻种类比例显著下降,由2002年秋季的77.09%下降至2006年秋季的71.43%;甲藻种类比例显著上升,由17.32%上升至22.45%。主要环境因子中,磷酸盐(DIP)、硅酸盐(DSi)、无机氮(DIN)浓度显著下降,盐度、N/P比值显著上升。DSi的降幅最大,从2002年秋季的83.14μmol/L下降至2006年秋季的42.83μmol/L;DIP从1.40μmol/L下降至0.89μmol/L;DIN从56.80μmol/L下降至49.18μmol/L。而N/P比值从39.86上升至81.27;盐度则从19.44上升至25.42。CCA及相关性分析表明,盐度、N/P比值的升高,DIP、DSi浓度的降低,均对浮游植物群落结构变化产生了显著的促进作用。三峡水库蓄水后,长江径流量、输沙量的减少以及径流季节分配的改变是造成长江口及其邻近海域浮游植物群落结构发生改变的根本原因。  相似文献   

6.
通过对2012—2016年5a来南排河海域无机氮环境质量跟踪监测数据进行的总结对比,分析了该海域春秋季无机氮质量浓度的变化及分布特征。结果表明:该海域无机氮质量浓度2012-10变化范围为201.5~403.7μg/L,平均值为(339.1±46.5)μg/L;2014-09变化范围为167.9~287.3μg/L,平均值为(246.6±31.3)μg/L;2015-09变化范围为259.1~290.8μg/L,平均值为(275.8±7.4)μg/L;2013-04变化范围为139.8~251.5μg/L,平均值为(213.9±26.7)μg/L,2016-06变化范围为203.9~256.4μg/L,平均值为(229.5±14.0)μg/L。从季节变化上看,该海域秋季无机氮质量浓度高于春季。从分布特征来看,秋季存在明显高值中心,主要集中于调查区域的近岸一侧,向西北、东南一侧降低;春季无机氮分布较均匀。基本呈现近岸浓度高,离岸远的浓度低的规律。  相似文献   

7.
测定了湛江湾海域20个站位表层沉积物中的酸可挥发性硫（AVS）、同步浸提重金属（SEM）、TOC含量和Eh值,对AVS、SEM含量的平面分布及AVS与SEM、TOC含量、Eh值的相互关系进行了分析.结果表明：该海域表层沉积物中AVS含量范围为0.004～0.547μmol/g,平均值为0.155μmol/g,SEM含量范围为2.10～4.27μmol/g,平均值为3.32μmol/g,相对其他海域湛江湾海域沉积物表现出AVS含量较低,SEM含量较高的特征.AVS与SEM含量平面分布较一致,湾顶的含量都较高,含量均值分别为0.361和3.52μmol/g,特呈岛以南到湾口呈逐渐减小的明显趋势.调查海域沉积物AVS与TOC含量呈显著正相关,与Eh值呈显著负相关,说明高有机质含量、低氧化还原电位沉积环境有利于AVS的生成.20个站位CSEM5-CAVS的差值均为0〈（CSEM5-CAVS）〈5,说明该海域可能存在重金属的中等毒性生态风险.  相似文献   

8.
《海洋通报》2021,40(5)
长江口外潮汐混合和低盐度羽流形成的泥沙锋和羽状锋对浮游植物与环境因子的空间分布具有重要控制作用。本研究依据2019年夏季长江口及邻近海域典型断面叶绿素a (Chl-a)浓度和环境因子的调查结果,以锋面为边界,探讨了不同区域Chl-a浓度与环境因子的分布特征及相互关系,以期深入了解锋面的生态效应。结果表明,在泥沙锋以内的近岸区域,水体垂直混合均匀;受长江径流输入和泥沙锋"屏障"作用影响,总悬浮物(TSM)和营养盐浓度最高,其中TSM为220.0±275.3 mg/L,溶解无机氮(DIN)、溶解无机磷(DIP)和溶解硅酸盐(DSi)分别可以达到94.7±21.2μmol/L、0.85±0.33μmol/L和95.3±22.6μmol/L;高浓度TSM引起显著的光限制效应,导致Chl-a浓度较低(1.7±0.5μg/L)。在羽状锋以外的区域,出现垂直层化现象;表层海水的TSM和营养盐显著降低,其中TSM为5.1 mg/L,DIN、DIP和DSi分别为1.0μmol/L、0.03μmol/L和2.4μmol/L;Chl-a浓度受到营养盐供应不足的影响,浓度仅为0.2μg/L。高浓度的Chl-a (7.5±4.1μg/L)主要出现在泥沙锋和羽状锋之间的过渡区域,该区域营养盐得到长江径流与上升流的补充;同时,由于大量TSM在泥沙锋快速沉降,缓解了水体的光限制效应,有利于浮游植物的生长和积累。研究结果验证了泥沙锋和羽状锋对TSM与营养盐的重要控制作用,这对于理解长江口及邻近海域藻类灾害高发区的成因具有科学参考价值。  相似文献   

9.
2021年3月对长江口及其邻近海域9个断面溶解氨基酸(THAA)、溶解有机碳(DOC)和溶解有机氮(DON)的分布和组成进行了调查研究。结果表明:THAA的浓度范围为1.24~4.71μmol/L,平均浓度为(2.61±0.85)μmol/L;DOC的浓度范围为118.17~450.58μmol/L,平均浓度为(149.73±33.34)μmol/L;DON的浓度范围为10.48~24.45μmol/L,平均浓度为(13.80±1.81)μmol/L。THAA、DOC和DON的水平分布表现出近岸高于远岸的特点,表明陆源输入对调查区域的THAA等分布有重要影响。而THAA与D-天门冬氨酸、D-谷氨酸、D-丝氨酸和D-丙氨酸的D/L比均呈显著负相关,与天门冬氨酸/β-丙氨酸(Asp/β-Ala)呈正相关,表明细菌活动是影响THAA浓度变化的重要因素。长江口及邻近海域的优势氨基酸为L型氨基酸,D型氨基酸和非蛋白型氨基酸的占比仅为7.34%。基于C/N比值分析,长江口及其邻近海域溶解有机物(DOM)的来源受到长江冲淡水和台湾暖流的共同影响。THAA-C%、THAA-N%、降解因子和反应活性指数表明:水平方向上盐度接近于0的淡水区域和盐度高于34的远海区域降解程度较高;垂直方向上随着深度的增加,有机物的降解程度逐渐升高。调查区域有机物的降解程度主要受到陆源输入和细菌活动的影响。  相似文献   

10.
本文根据2017年3、5、9月对苏北浅滩海域3个航次的调查数据,分析了调查海域溶解态营养盐的浓度与时空分布特征,并探讨了影响苏北浅滩营养盐分布变化的控制因素及其与浒苔暴发之间的关系。结果表明NO-3-N从3月至5月平均浓度略微降低,而9月NO-3-N平均浓度又降低至17.5μmol/L;PO43--P、SiO32--Si平均浓度从3月到5月再到9月均先降低后升高。NH+4-N平均浓度从3月的2.38μmol/L上升至5月的7.44μmol/L,整个调查海域浓度较高,尤其是南部海域,9月又下降至1.28μmol/L。5和9月DON平均浓度显著低于3月。苏北浅滩海域NO-3-N、PO43--P、SiO32--Si浓度均呈现由近岸向远岸梯度递减的...  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
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   

14.
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   

15.
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   

16.
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.  相似文献   

17.
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.  相似文献   

18.
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone.  相似文献   

19.
The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics.  相似文献   

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