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1.
庙岛群岛的光棘球海胆主要分布于北四岛(南、北隍城岛,大、小钦岛),砣矶岛及大、小竹山岛等,而南五岛极少分布。砣矶岛的海胆多是2~3年生壳径4~6cm的个体,海胆性腺成熟期为7月中旬至8月中旬,性腺发育与水温、栖息场和饵料等有关。海胆体重随季节而变化,繁殖季节体重W(g)与壳径D(cm)相关,W=2.582D2.034(r=0.87),性腺重GW(g)与壳径D(cm)关系为GW=0.0403D3.0828(r=0.8273),壳径D(cm)与壳高H(cm)呈线性关系H=0.5225D+0.0668(r=0.9078)。壳径生长随年龄而变慢,2.8cm的幼海胆年增长2.1cm;6.1cm的成海胆年增长0.43cm。光棘球海胆嗜食海带和裙带菜,平均日摄食量6.0cm的海胆为2.6g,4.0cm的为1.34g,3.1cm的为1.3g,幼海胆摄食率较高的原因是因其生长发育快速,活动强度和代谢水平高。  相似文献   

2.
南黄海浮游植物与水色透明度之间相关关系的研究   总被引:1,自引:0,他引:1  
本文根据 1995 年 9 月在南黄海获取的资料,分析和讨论了该水域浮游植物现存量(叶绿素 a ( C H ))、初级生产力( P P) 和海水光学参数(透明度( S T))、水色( W C)) 之间的相关关系。分析结果表明,夏末秋初南黄海 C H 与 P P, C H 与 W C 和 P P 与 W C 以及悬浮物( S S) 与 W C 之间均有良好的正相关关系。相关式分别为: P P = 22519ln( C H ) + 48891 或 P P = 5 E- 05 C H 16464( R2 = 07037); W C = 403ln( C H ) + 89768 或 W C = 71306 C H 04747 ( R2 =07921); C H = 15437ln( S S) + 13647 或 C H = 07499 S S1252( R2 = 07223); P P =33286ln S S+ 15222 或 P P = 33029 S S05694 ( R2 = 05476); P P = 42588ln( W C) - 37071或 P P = 66512 W C08665( R2 = 06731) 以 及 S S = 14019ln( W C) - 13363   相似文献   

3.
本文在σ坐标下建立了一个半诊断计算及预报计算的数值模式,应用于台湾海峡夏季时三维海流计算。计算结果表明,当t=2.5d时,密度场和速度场得到调整,即得到半诊断解,当t=40d以后,解已达到准稳定态;半诊断及预报计算的结果在定性上是与诊断计算结果一致。但它们在定量上有些变化,如表层台湾岛西岸附近的最大水平流速,在t=0时(诊断)为59.1cm/s,t=2.5d时(半诊断)为62.1cm/s,t=300d时(预报)为62.0cm/s.此外,在半诊断及预报计算中,上升流也主嵰⑸诟=ń兜龋魉偌忧浚段б灿兴┐蟆  相似文献   

4.
五阶斯托克斯波的简化解法及改进解   总被引:3,自引:0,他引:3  
付昱华 《海洋通报》1994,13(3):53-61
由于Skjelbreia导出的确定五阶斯托克斯波的二个方程不易求解,本文将其简化为确定d/L的一个方程:f(H,T,d,d/L)=0。根据这一简化解法,发现Skjelbreia方程组的解有3种情况;存在唯一的精确解精确解不止一个;不存在精确解(但存在满足Skjelbreia方程组方面的最佳近似解)。当精确解不止一个时,可应用变分原理的方法差别出合理的解,应用变分原理的方法还可将Skjeilbria  相似文献   

5.
厦门港湾沉积物中有机氯农药和多氯联苯的垂直分布特征   总被引:11,自引:0,他引:11  
从厦门港海区采集两根沉积柱样,研究有机氯农药六六六(HCHs),滴滴涕(DDTs)和多氯联苯(PCBs)在沉积物中的垂直分布,HCHs,DDTs及PCBs含量用GC法测定,取自厦门港湾口的1号柱样HCHs,DDTs和PCBs的含量范围分别为0.12~ 0.32ng/g,4.64~10.5ng/g和0.09~0.46ng/g取自厦门西港内湾的5号柱样采分别为0.17~0.31ng/g,3.65  相似文献   

6.
对海湾扇贝和太平洋牡蛎的呼吸和排泄进行了实验研究。结果表明,温度和贝的体重对两种贝类的耗氧率和氨排泄率都有明显的影响,且两因子间存在着交互作用。海湾扇贝的耗氧率(QO,mg/g·h)和氨排泄率(QN,μg/g·h)与温度(T,℃)和湿重(W,g)存在下列关系:QO=0.046W-0.2721.08T,QN=6.79W-0.3271.03T;太平洋牡蛎的耗氧和氨排泄率与温度、湿重存在下列关系:QO=0.085W-0.1301.06T,QN=2.66W-0.2361.01T。  相似文献   

7.
介绍我校海洋环境学院物理海洋实验室刚建成的二号平台的主要性能。其主要性能:转速范围0.2~25r/min;转速不均匀度小于0.3%,能在超低速(0.2~1r/min)下正常工作,转台平面度小于0.1mm/m,集流环能够传输各种信号。专家会检验确认:该转台能满足地球流体动力学,海洋和大气环流等模拟实验研究工作的要求。  相似文献   

8.
湄洲湾夏季的初级生产力   总被引:2,自引:3,他引:2  
王宪  李文权 《台湾海峡》1994,13(1):8-13
湄洲湾1992年夏季的叶绿素a,三磷酸腺苷,碳比积累速率,初级生产力的变化范围和均值分别为0.45-4.72,1.49mg/m^3;0.12-1.07,0.31μg/dm^3;0.06-0.58,0.34d^-1;0.07-0.34,0.21m/(m^2.d)。叶绿素a与三磷酸腺苷之间。初级生产力与碳比积累速率之间均呈正相关关系。叶绿素a三磷本能腺苷的比值为4.8,湄洲湾夏季浮游植物的生长受氮不足  相似文献   

9.
本文研究了如下的高阶奇异边值问题解的存在性y(n)+f(t,y,y',...,y(n-2))=0,n≥2,0<t<1,y(i)(0)=0,0≤i≤<n-2,y(n-1)(1)=0其中,f(t,y1,...,ym-1)在yi=0处有奇性,i=1,...,n-1。我们给出了该问题解存在的一个新的充分条件  相似文献   

10.
通过对东京湾两年度不同季节海水分光反射率与叶绿素浓度进行统计分析,结果表明,叶绿素浓度C与两谱段分光反射率之比Rw(λj)/Rw(λj)具有幂函关系C=A[Rw(λj)/Rw(λj)B。两者的对数显示出较好的线性关系,即logC=logA+Blog[Rw(λj)/Rw(λj)]。负相关系数达0.99。相关方程之一为C=3.329[Rw(520)/Rw(550)]-1.384(1987年6月初).在梅雨季节之后,相关方程为C=12.68[Rw(520)/Rw(550)]-2.010(1988年8月)。这表明了海湾或混浊的沿岸水质,在叶绿素浓度算法中,统计参数A和B的确立,要基于不同季节不同水质的现场观测资料。  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.
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   

16.
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   

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   

20.
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