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1.
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 总被引：2，自引：1，他引：1
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。 相似文献
2.
南极考察航线跨越全球多个大洋,对认识超微型浮游生物在全球尺度分布及变化具有重要意义。依托中国第33次南极考察,利用流式细胞仪对航线海表水样中的超微型浮游生物进行了现场测定。结果表明,在热带与温带海域,超微型浮游生物量可占总叶绿素a浓度的60%以上,在南大洋则集中在15%～40%;原绿球藻主要分布在40°S以北海域,聚球藻主要分布在50°S以北海域,而超微型真核藻类和异养细菌则在沿线各海域均有明显分布。在纬向上,原绿球藻、聚球藻、超微型真核藻类和异养细菌的平均丰度分别为(5.50±9.09)×103 cells/mL、(13.56±20.33)×103 cells/mL、(3.87±3.08)×103 cells/mL和(6.39±4.78)×105 cells/mL;南大洋海域,超微型真核藻类和异养细菌的平均丰度分别为(3.31±1.46)×103 cells/mL和(4.68±4.39)×105 cells/mL,在少数站位检测到较低丰度的聚球藻,平均值... 相似文献
3.
本研究自2006年7月至2007年10月,分4个季节调查了辽东湾海域的微微型浮游生物的丰度。结果表明:夏季辽东湾的聚球藻(Synechococcus)丰度最高,平均丰度为1.89×104 cell/mL。秋季次之,冬季居第三位,春季最低。夏季比其他3个季节的聚球藻丰度要高一个数量级。夏季辽东湾的微微型真核藻类(Picoeukaryote)丰度最高,平均丰度为3.79×103cell/mL,秋季次之,冬季与春季相差不大。夏季比其他3个季节的微微型真核藻类丰度要高一个数量级。 相似文献
4.
2017年6月和8月，通过对秦皇岛海域的超微型浮游植物进行现场调查和流式细胞仪分析，发现了聚球藻(Synechococcus)和超微型真核藻类(picoeukaryotes)两大类群，其中聚球藻又分为聚球藻Ⅰ和聚球藻Ⅱ两个亚群。调研期间，正处于秦皇岛海域褐潮高发期。通过分析超微型浮游植物细胞丰度、碳生物量及分布特点，研究了秦皇岛海域在褐潮高发期超微型浮游植物分布及相关环境因子影响。结果表明，6月份超微型真核藻、聚球藻Ⅰ和聚球藻Ⅱ平均丰度分别为1.14×104 个/mL、4.02×104 个/mL和1.04×104 个/mL，碳生物量均值分别为27.22 μg/L、8.49 μg/L和2.27 μg/L；在8月份超微型真核藻、聚球藻Ⅰ和聚球藻Ⅱ平均丰度分别为3.27×103 个/mL、5.79×104 个/mL 和2.58×104个/mL，碳生物量均值分别为6.35 μg/L、13.41 μg/L和5.83 μg/L。超微型真核藻、聚球藻Ⅰ和聚球藻Ⅱ在6月份和8月份表现出不同的分布特征。超微型真核藻的细胞丰度从6月到8月明显降低一个数量级，说明8月份过高的水体温度与低浓度的营养物质等因素限制了超微型真核藻中褐潮种的生长。聚球藻Ⅰ和聚球藻Ⅱ细胞丰度在6月份呈现从河口到近岸逐渐升高的分布趋势，而超微型真核藻呈现下降的分布趋势。与6月份聚球藻Ⅰ和聚球藻Ⅱ细胞丰度分布相反，超微型真核藻和聚球藻Ⅰ细胞丰度则在8月份呈现从河口到近岸逐渐降低的分布趋势，而聚球藻Ⅱ细胞丰度的区域分布趋势不明显，主要分布在水体表层。通过对超微型真核藻、聚球藻Ⅰ和聚球藻Ⅱ与环境因子相关性分析表明，6月份硝酸盐与铵盐是聚球藻Ⅰ细胞生长的主要控制因子，而聚球藻Ⅱ与环境因子没有明显的相关性，超微型真核藻的细胞丰度与硅酸盐浓度呈正相关。在8月份，超微型真核藻细胞的生长受到多种环境因子(硝酸盐、亚硝酸盐、硅酸盐、磷酸盐、温度以及光照)的共同作用的影响，聚球藻Ⅰ细胞丰度与硝酸盐呈正相关，温度与光照则是影响聚球藻Ⅱ细胞分布的关键因素。 相似文献
5.
近年来，北部湾海域连年暴发球形棕囊藻（Phaeocystis globosa）赤潮，对近海生态环境构成了潜在威胁。为了解北部湾海域球形棕囊藻赤潮生消过程及其与其他浮游植物类群的关系，自2016年9月至2017年8月期间，在北部湾海域开展了9个航次的调查，并应用流式细胞仪分析了微型真核藻类、微微型真核藻类、原绿球藻（Prochlorococcus spp.）和聚球藻（Synechococcus spp.）等4类浮游植物类群的变化情况。结果表明，北部湾海域各浮游植物类群主要分布在调查区北部钦州湾外侧海域和雷州半岛西侧近岸海域，其丰度有明显的季节变化。微微型真核藻类在春、秋两季丰度较高，而冬、夏季较低。微型真核藻类、聚球藻和原绿球藻的丰度均呈现夏季高、冬季低的特点，其中聚球藻丰度的季节变化最为显著，与水温变化密切相关。结合对球形棕囊藻赤潮生消过程以及调查海域水文条件的分析可以看出，北部湾海域球形棕囊藻赤潮发生过程中，海水温度下降至20℃左右，并且聚球藻和原绿球藻丰度具有明显变化，有望作为棕囊藻赤潮的预警指标，为该海域棕囊藻赤潮的预测和防控提供依据。 相似文献
6.
2004年秋季在菲律宾海取得了微微型生物颗粒样品和光衰减剖面资料,然后对三种常见的微微型颗粒(原绿球藻,聚球藻和自养真核细胞)丰度及其光学性质做了初步分析和估算。研究结果表明,菲律宾海原绿球藻的丰度最高,其次为聚球藻,自养真核细胞的丰度最低。3种微微型颗粒的光散射系数同水体剖面的光衰减系数(cp)具有明显的相关关系。3种微微型颗粒的散射作用仅占总光衰减系数的5.1%,其中原绿球藻、自养真核细胞和聚球藻分别占2.6%,2.2%和0.3%。 相似文献
7.
黑潮源区及其邻近海域叶绿素a浓度的季节分布 总被引：6，自引：0，他引：6
2001年冬季、2002年春季和秋季在琉球群岛、台湾岛和吕宋岛以东的西北太平洋黑潮源区及其邻近海域观测叶绿素a浓度季节分布及其粒级结构。结果表明,冬季表层平均叶绿素a浓度高于春季和秋季,台湾岛及以北岛链东南部的北部测区叶绿素a浓度高于巴士海峡及吕宋岛以东的南部海区。叶绿素a垂直分布呈真光层内随垂直深度增加而浓度增大,真光层下至水深200m随垂直深度增加而浓度降低的分布趋势。春季和秋季叶绿素a浓度粒级结构表明,微微型光合浮游生物(Pico级份)对总叶绿素a的贡献占优势,微型(Nano级份)次之,小型(Micro级份)所占比例最小。表层水光合浮游植物细胞丰度在(1.3~13.5)×103cells/dm3,以小粒径的硅藻占优势。呈现出微微型光合浮游生物在观测海区的重要性。 相似文献
8.
热带西太平洋Y3和M2海山微食物网主要类群生态分布与比较 总被引：2，自引：0，他引：2
2014年12月和2016年3月分别对热带西太平洋Y3海山(中层海山)和M2海山(浅海山)微食物网主要类群(包括聚球藻、原绿球藻、微微型真核浮游生物、异养细菌和浮游纤毛虫)丰度和生物量垂直分布进行了研究。结果表明,Y3和M2海山水文环境比较相似但略有区别,叶绿素最大值层(DCM)分别在75—100m和110m水层,微食物网各主要类群在垂直尺度上的分布与叶绿素a浓度紧密相关。其中浮游纤毛虫呈现"双峰型"模式,即丰度高值出现在表层和DCM层;原绿球藻和微微型真核浮游生物呈现"单峰型"模式,丰度高值出现在DCM层;聚球藻和异养细菌峰型相对不显著,DCM层以浅丰度较高,DCM层以深丰度明显降低。分析其原因,可能是受到温度、光照和营养盐的共同影响。Y3和M2海山微食物网结构的垂直变化不完全一致。其中,Y3海山30m以浅和150m以深异养细菌生物量占绝对优势,75—100m水层自养型生物(原绿球藻和微微型真核浮游生物)占绝对优势;M2海山75m以浅和200m以深异养细菌占绝对优势,110—150m自养型生物占绝对优势。M2海山自养型生物占优势的水层要明显深于Y3海山,可能与它们的海山类型和采样季节不同有关。 相似文献
9.
2014年夏季南海北部超微型浮游植物分布及环境因子影响 总被引：3，自引：1，他引：2
利用流式细胞仪BD Accuri C6对2014年夏季南海北部超微型浮游植物进行了现场的观测研究,发现了3类超微型光合自养浮游植物,聚球藻(Synechococcus,Syn)、原绿球藻(Prochlorococcus,Pro)和超微型真核藻类(pico-eukaryotes,Euk),并对其丰度与分布以及环境因子影响进行了研究。结果表明,Syn、Pro和Euk丰度总平均值分别为5.13×103个/mL,3.27×104个/mL和1.85×103个/mL,碳生物量均值分别为1.19μg/L,1.86μg/L和4.51μg/L。Syn、Pro和Euk的丰度表现出不同的分布特征。Syn、Pro和Euk丰度分布趋势呈现近海低而外海高,Syn和Euk丰度高值区分别出现在沿岸带与陆架和上升流影响海域,Pro丰度高值区出现在沿岸带与陆架,低值区出现在上升流影响海域。Syn、Euk丰度高值区主要分布在次表层,Pro丰度高值区主要分布在真光层底部,Euk丰度垂直变化差异相对Syn和Pro较小。超微型浮游植物与环境因子的相关性分析结果表明,Syn、Pro和Euk的碳生物量均与硝酸盐、硅酸盐浓度和深度呈现负相关关系,Pro的碳生物量与磷酸盐浓度呈现正相关关系。 相似文献
10.
获取并分析了2017年8月热带西太平洋M4海山水体中的超微型浮游生物样品,根据流式细胞术的散射光和荧光信号,检测到M4海山各水层中普遍存在四个超微型自养浮游生物类群(聚球藻、原绿球藻、微微型真核浮游生物、微型真核浮游生物)和两个超微型异养原核生物类群(低核酸含量和高核酸含量异养原核生物)。聚球藻丰度高值出现在100m以浅;原绿球藻和微微型真核浮游生物丰度高值区在深层叶绿素最大值附近(75—150m);微型真核浮游生物和异养原核生物分布范围较广,150m以浅丰度较高。异养原核生物的生物量(1.68—11.25μgC/L)高于自养浮游生物(0.05—6.02μgC/L)的生物量。在超微型自养浮游生物中,原绿球藻生物量在100—150m水层占优势(53.83%±6.32%),微型真核浮游生物的生物量在75m以浅(58.62%±8.53%)和200—300m水层占优势(46.18%±7.82%)。在异养原核生物中,高核酸含量异养原核生物的生物量所占百分比(61.05%±3.98%)高于低核酸含量异养原核生物(38.95%±3.98%),然而在海山附近DCM层低核酸含量异养原核生物比例最高可达58.64%。冗余分析表明,超微型浮游生物的丰度与温度呈正相关,与深度和营养盐呈负相关关系。在M4海山超微型自养浮游生物分布没有明显的"海山效应",但海山的存在会对异养原核生物两个类群生物量的比例产生影响。 相似文献
11.
Chandralata Raghukumar G. Sheelu P. A. Loka Bharathi Shanta Nair C. Mohandass 《Marine Georesources & Geotechnology》2001,19(1):1-16
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.
Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
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.
Derek V. Ellis 《Marine Georesources & Geotechnology》2001,19(1):51-63
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.
G. Parthiban 《Marine Georesources & Geotechnology》2000,18(3):223-235
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
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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. 相似文献
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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.
Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
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
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