南黄海秋季浮游病毒丰度分布及其与宿主和环境因子的相关性研究

利用流式细胞仪对南黄海秋季浮游病毒丰度在水平分布和垂直分布上的特征进行了研究,并分析了浮游病毒丰度与异养细菌、微微型浮游植物等宿主丰度以及环境因子的相关性.结果表明,该海区秋季浮游病毒丰度在(2.22×106)-(1.60× 107)ind/ml之间,平均值8.32×106ind/ml.病毒丰度在调查海域的东北和中南部海域出现高值区,在西南部出现低值区,且浮游病毒丰度与异养细菌丰度的平面分布趋势较一致.在表层、中层和底层水体,浮游病毒丰度平均值分别为8.63×106、7.83×106、8.49×106ind/ml,表层和底层丰度无显著差异,但均高于中层(P＜0.05).相关性分析表明,浮游病毒丰度与异养细菌丰度、VBR呈显著正相关(P＜0.01),与微微型真核浮游植物丰度呈显著负相关(P＜0.05),与聚球藻、水深、水温、盐度、溶氧、叶绿素a浓度无明显相关性(P＞0.05).     

胶州湾冬季异养细菌与营养盐分布特征及关系研究

2003年12月、2004年1月和2月下旬进行了3个航次的现场调查,对胶州湾冬季异养浮游细菌和无机营养盐分布特征、相互关系及影响因素进行了探讨。胶州湾冬季异养浮游细菌数量的月变化与水温的变化趋势基本一致,分布特征为近岸高,离岸逐渐减少,最大值出现在湾东北部,为7.55×109个/dm3,最小值位于湾中央,为1.89×109个/dm3。水体PO3-,NO-和NH+等营养盐的分布同样具有近岸较高,离岸逐渐减少的特点,异养细菌数量分布与氨盐浓度呈高度显著性正相关,相关系数为0.73(P<0.01),与硝酸盐和磷酸盐浓度呈显著性正相关关系,相关系数分别为0.50和0.48(P≤0.05)。水温是影响胶州湾细菌季节变化的主要因素之一,冬季营养盐水平分布可能与异养浮游细菌矿化有机质产生营养盐有关。     

2009年冬、夏季南海北部超微型浮游生物的分布特征及其环境相关分析

2009年2月(冬季)和8月(夏季)在南海北部海域(nSCS)采用流式细胞术对聚球藻、原绿球藻、超微型光合真核生物3类超微型光合浮游生物和异养浮游细菌的丰度和碳生物量的时空分布特征进行了研究,并分析了其与环境因子之间的关系。结果表明,夏季聚球藻和原绿球藻的平均丰度高于冬季,超微型光合真核生物和异养浮游细菌的丰度反之,为冬季高于夏季。聚球藻、超微型光合真核生物和异养浮游细菌在富营养的近岸陆架海域丰度较高,而原绿球藻高丰度则出现在陆坡开阔海域。在垂直分布上,聚球藻主要分布在跃层以上,跃层以下丰度迅速降低;原绿球藻高丰度主要出现在真光层底部;超微型光合真核生物在水层中的高值同样出现在真光层底部,且与Pico级份叶绿素a浓度分布一致;异养浮游细菌在水体中的分布与聚球藻类似。这些分布格局的差异,取决于环境条件的变化和4类超微型浮游生物生态生理适应性的差异。在超微型光合浮游生物群落中,各类群碳生物量的贡献因季节和海域类型的不同而发生变化:聚球藻在夏季近岸陆架区占超微型光合浮游生物总碳生物量的41%,原绿球藻在陆坡开阔海成为主要贡献者(50%),超微型光合真核生物碳生物量以冬季为高(在近岸陆架区占比68%)。冬、夏季异养浮游细菌碳生物量均高于超微型光合浮游生物碳生物量。     

春秋季山东南部近岸浮游细菌生态分布

分别于2007年4月(春季)和10月(秋季),对山东南部近岸海域进行了现场调查,研究了该海区浮游细菌丰度、生物量分布特征,探讨了它们与温度、溶解氧(DO)、总氮(N)、总磷(P)、硝酸盐(NO-3)、铵盐(NH+2)及活性磷酸盐(PO4-P)的相关性.结果表明:浮游细菌生物量具有一定的时间、空间分布特征,春季浮游细菌丰度及生物量要高于秋季,2个季节近岸细菌数量高于远岸区域;浮游细菌丰度及生物量与温度、DO、总P、NO-3、NH+2及PO4-P均呈显著相关关系(P<0.01),表明上述因子可能是该海域浮游细菌数量分布的主要限制因子.     

南海南部海域异养浮游细菌生长对外源营养物的响应

于2012年8月利用现场调查结合现场培养的方法研究了南海南部海域异养浮游细菌的生物量、呼吸速率、比生长速率和生长效率对外源营养物的响应。结果表明,南海南部海域异养细菌生物量低于北部海域;外源营养物可显著影响南海南部异养细菌生物量、比生长速率和细菌呼吸速率。在海盆区域S1站,异养细菌生长主要受DOC和氮限制,同时添加DOC、氮和磷会使细菌生物量、比生长速率和细菌呼吸速率明显增加;而在近海陆架S2站主要受磷限制,DOC和磷的添加会极大地促进异养细菌生长。分析发现,外源营养物在促进异养细菌生长的也同时也提高了异养细菌的物质转换效率,使异养细菌的异养程度进一步加大。     

东海、黄海浮游病毒及异养细菌的分布研究

采用流式细胞仪对2009年春季东海、黄海浮游病毒和异养细菌的丰度进行了大尺度(119.5°—129°E, 25°—39°N)研究, 并分析了浮游病毒丰度、异养细菌丰度以及其与环境因子之间的相关性。结果表明, 研究海域浮游病毒、异养细菌的丰度范围分别为3.38×105—2.26×107个/mL(平均6.24×106个/mL)、5.83×103—1.23×106个/mL(平均1.22×105个/mL)。在水平分布上, 浮游病毒与异养细菌的变化趋势基本一致, 且均在山东半岛周边养殖海域、浙江东南沿海养殖区及舟山渔场北部形成明显的高值区; 黄海浮游病毒与异养细菌的丰度平均值均高于东海。在垂直分布上, 东海浮游病毒与异养细菌丰度值随水深呈明显下降趋势, 表层丰度值与30m以下各层差异显著(P<0.05); 在黄海, 二者丰度随水深降低趋势不明显。Pearson相关性分析显示: 调查海域浮游病毒丰度与异养细菌丰度显著正相关(r =0.288, P<0.01), 浮游病毒丰度与温度显著负相关(r = -0.243, P<0.05), 异养细菌丰度与盐度显著负相关(r = -0.245, P<0.05)。     

渤海湾海域硝化、亚硝化细菌的生态研究

于2004年8月和10月对渤海湾海域进行了两次硝化菌群的生态学调查。结果显示,在渤海湾水体中,8月份硝化细菌的数量在(1.6~300)×104个/L之间,10月份硝化细菌的数量在(0.5~30)×104个/L之间;8月份亚硝化细菌的数量在(1.1~160)×104个/L之间,10月份亚硝化细菌的数量在(0.5~30)×104个/L之间。8月份硝化细菌与磷酸盐有高度明显的相关性(0.01水平),与氨氮、水温、溶氧量都有较明显的相关性(0.05水平);10月份细菌数仅与溶氧量有较明显的相关性(0.05水平)。8月份亚硝化细菌数与各环境因子相关性不明显;10月份亚硝化细菌数与磷酸盐、pH值及溶氧量的相关性都是在0.01水平上;而且与亚硝酸盐、硝酸盐、氨氮有明显的相关性,都在0.05水平上。     

粤东深澳湾养殖区域异养细菌和弧菌的动态分布

调查于2007年1月至2008年12月进行,对异养细菌和弧菌丰度的时间和空间分布开展了相关的研究,结果显示深澳养殖海湾水体中以上2种被调查菌类的丰度全年变化范围分别为1.20×105―1.27×108cfu·L-1和1.00×103―3.90×105cfu·L-1;底质中的丰度变化范围分别为2.73×104―4.06×107cfu·g-1和3.25×102―7.23×104cfu·g-1.从时间上来看,营养盐类与异养细菌的相关性要强于温度、盐度、pH值和溶氧等物理因素的相关性;而弧菌与物理因素的相关性要强于与营养盐类的相关性.从空间分布来看水体环境的变化要比底质的大,水体中经常出现异养细菌和弧菌丰度的剧烈变化,变化程度也远远高于底质中细菌的变化.而且不同的养殖活动也会很明显地影响异养细菌和弧菌的丰度:S3站位水体中异养细菌的丰度比底质中的高;S5站位的底质中异养细菌和弧菌的丰度都是较高的.龙须菜的养殖可以很明显地改善底质环境,特别是降低底质中对养殖和水质环境有很大负面影响的生物和非生物因子如硫化物和弧菌等.     

秋季东、黄海异养细菌(Heterotrophic Bacteria)的分布特点

2000年10-11月,乘"北斗号"考察船进行秋季"东、黄海生态系统动力学与生物资源可持续利用"大面调查,研究秋季东、黄海异养细菌的分布.结果表明,异养细菌在黄海和东海的丰度分别在(2.37-13.33)×108 cell/L和(3.05-13.62)×108 cell/L之间.细菌丰度最高值出现在长江口附近,且断面E和断面F各站位的细菌丰度明显高于其他断面.异养细菌丰度大小以长江口为中心向外海依次递减.东、黄海水体异养细菌生物量分别在244.45-1812.90mgC/m2和100.60-940.87mgC/m2之间.东、黄海异养细菌丰度无显著差异,但是东海海域水体异养细菌生物量高于黄海海域.异养细菌空间分布与浮游植物叶绿素在东海有一定的相关性,黄海异养细菌与硝酸盐浓度的相关性极显著.     

渤海湾天津近岸表层沉积物中细菌丰度及其与环境因子的相关性研究

于2003年7月—2004年5月间,4个航次测定了渤海湾近岸表层沉积物中的可培养异养菌数、总菌数和活菌数,并分析了其与10项环境因子之间的相关性。结果表明,异养菌数变化范围为(1.1~470.0)×103CFU/g湿泥;总菌数和活菌数分别为(2.6~25.0)×107/g湿泥和(1.6~14.6)×107/g湿泥。异养菌数的季节分布为夏季最高,春季次之,冬季最低;站位间分布为最高值基本在沿岸或排污口附近的站位,最小值基本在远岸或远排污口的站位。沉积物中总菌数和活菌数最高值均出现在秋季,最低值出现在冬季,但次高值有所不同;各站点间的分布没有明显规律。此外,沉积物中仅异养菌数与总有机碳(Total organic carbon,TOC)和总氮(Total nitrogen,TN)之间有着显著的相关性,相关系数分别为0.568和0.598(P0.05);活菌数与铅(Pb)浓度显著负相关,相关系数为-0.751(P0.05)。     

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.     

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.     

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.     

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.     

Interannual Sea Level Variations and Annual Tides in the Northwestern Pacific

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.     

Flow Cytometric Analysis of Coastal Lagoon Bacterioplankton and Picophytoplankton: Fixation and Storage Effects

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.