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舟山海区几种藤壶的食性分析 总被引：1，自引：0，他引：1
舟山海区五种藤壶的食性成分分析表明：其胃含物可分为浮游动物、浮游植物、有机碎屑及无机颗粒四类。浮游动物以挠足类为主，浮游植物以硅藻为主。不同大小个体的藤壶摄食偏向有所差别：大个体藤壶较多地摄食大型的烧足类等浮游动物，而小个体藤壶较多地摄食小型的硅藻等浮游植物和有机碎屑。藤壶食物成分种类与其生活海区中的浮游生物种类相一致，并随海区中浮游生物种类和数量变化而变化。通过测定发现，分布于外海的三角藤壶的食物颗粒度明显大于近海虾塘中的纹藤壶的食物颗粒度。 相似文献
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据2007年春季在南海西北部陆架区海域进行的网采浮游植物调查数据,分析了浮游植物群落的结构特征．此次共鉴定出浮游植物4门318种,其中硅藻类183种,甲藻类128种,蓝藻类5种,金藻类2种．大部分海域浮游植物种类数在40～70种之间,外海区域的种类数稍高于沿岸．浮游植物密度的变化范围为0．22×10。～3683．85×10。eells／m’,平均值（标准偏差）为97．49×10。（±437．38×10。）cel｜s／m。．其高值区主要位于粤西近岸海域,向外海呈递减趋势．调查海域硅藻类的平均密度（标准偏差）最高,为93．82×10。（±434．34×10。）cells／m’;甲藻类的次之,为3．65×10。（±9．08×10。）cells／m’．浮游植物优势种主要有拟旋链角毛藻（Chaetocerospseudocurvisetus）、细弱海链藻（Thalassiosirasubtilis）、中肋骨条藻（Skeletonemacostatum）、劳氏角毛藻（Chaetocerosloren—zianus）和菱形海线藻（Thalassionemanitzschioides）．该调查海域浮游植物多样性指数的变化范围为1．48～6．23,平均值（标准偏差）为4．70（±1．03）,其分布趋势与浮游植物密度的分布趋势大致相反．将站位依等深线划分为粤西近岸海区、琼东南近岸海区和外海海区,应用非度量多维标度（nMDS）和聚类分析法分析这3个海区的浮游植物群落结构差异,并通过ANOSIM和SIMPER进行检验．结果表明3个海区之间浮游植物群落结构具有显著性差异,且粤西近岸海区与外海海区之间差异性较高．近岸种拟旋链角毛藻和中肋骨条藻在粤西近岸海区为最主要的优势种,而外海海区优势种较多,且大部分为大洋暖水性种类． 相似文献
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于2013年8、10月及2014年2、5月对大鹏澳牡蛎养殖区及其邻近海域进行了采样调查。利用设置的3个站位(牡蛎养殖区S1、养殖区外S2、靠近湾口S3)的数据研究了牡蛎养殖对海区浮游植物种群结构和丰度的影响。本次考察共鉴定出大鹏澳浮游植物58属144种,丰度为6.15×103—5.94×106cells/L。其中,硅藻36属100种,占种类总数的69.4%,丰度在4.5×103—5.93×106cells/L之间;甲藻15属34种,占总种类的23.6%,丰度范围为1.5×102—4.53×104 cells/L;蓝藻、绿藻、隐藻等共7属10种。在牡蛎养殖期(8月至2月),养殖区内养殖水层浮游植物总丰度低于非养殖区,硅藻丰度占浮游植物总丰度的90%以上,硅藻丰度与总浮游植物细胞丰度的空间分布特征一致;与硅藻空间分布特点不同,养殖区内甲藻丰度显著低于非养殖区。牡蛎收获后的5月,养殖区内的甲藻丰度高于非养殖区。牡蛎养殖区站位S1浮游植物多样性指数平均值为1.35,明显低于非养殖区S2(2.68)和S3(2.69)。与此相似,养殖区内站位S1均匀度J(0.27)明显低于非养殖区站位S2(0.49)和S3(0.51)。本研究表明,大鹏澳牡蛎养殖对浮游植物群落结构造成了一定影响,能够显著降低浮游植物丰度、种类多样性和均匀度。 相似文献
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斑节对虾节水型养殖期间虾池硫化物含量的变化特征 总被引：4，自引：0，他引：4
在斑节对虾节水型养殖期间,观测了虾池底质和海水中硫化物含量的变化.结果表明,投放有益微生物的试验池与未投放有益微生物的对照池相比,底质硫化物含量波动较小,增高的速度较慢、增幅较小.在养殖后期试验池底质硫化物含量只增高了 68%,而对照池的增高了 252%.养殖过程中海水硫化物浓度呈阶段式和波浪式增高,在试验池中其浓度多数时间比对照池中的低.有益微生物能在一定程度上抑制水体和底质中硫化物的积累,但对老化虾池效果较差.由于节水型养殖模式利用有益微生物分解养殖过程中产生的有机物,采用单细胞藻类吸收利用营养盐,使养殖环境质量得到改善. 相似文献
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深圳湾浮游生物和底栖动物现状调查研究 总被引：10，自引：0，他引：10
对深圳湾浮游植物、浮游动物和底栖动物的种类、数量及分布现状进行了研究。结果表明 ,淡水种类占绝对优势 ,藻类5门32属45种 ,其中硅藻12属18种 ,绿藻1属15种 ,蓝藻7属10种 ,裸藻、金藻各1属1种 ;浮游动物共计37种 ,其中原生动物9种,轮虫14种 ,枝角类2种 ,桡足类8种 ,浮游幼虫及其它4种 ;底栖动物20种 ,分别为环节动物的多毛类7种 ,寡毛类2种 ,软体动物8种 ,甲壳动物2种 ,鱼类1种。浮游生物和底栖动物数量和分布的特征是 :藻类细胞密度为2.4×106～1.4×107个/L ,平均6.43×106 个/L。浮游动物为514.0～8049.2个/L,平均1690.8个/L。底栖动物个体数为180～8860个/m2,平均为2364个/m2。这三类生物的种类和数量分布与距深圳河河口的距离有密切关系。因此 ,三类生物多样性指数湾内段与湾口段差异明显,且平均值偏低 ,说明深圳湾水体有一定程度的污染 相似文献
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凡纳滨对虾高位池细菌数量变化及其与水环境因子的关系 总被引：2，自引：0，他引：2
对高位池细菌数量变化及其与水环境因子的关系进行了研究。结果表明,试验虾池水层细菌总数变化在2.31×106～87.2×106cfu/mL之间,平均为29.72×106cfu/mL。异氧菌数变化在0.48×104～61.2×104cfu/mL之间,平均为12.18×104cfu/mL。水层中细菌的水平和水层分布有一定的差异,但不十分显著,水层中细菌数量有明显的昼夜变化。水层细菌数量与水温、COD值之间呈显著的正相关,而与浮游植物生物量之间无明显的相关性。适合于虾池细菌生长的pH值(9.2)偏碱性。 相似文献
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福建沿岸不同海区夏季浮游植物的组成与分布 总被引：3，自引：0，他引：3
结合福建省“908专项”，于2006年7～8月对福建省沿岸海域水采浮游植物的种属组成、数量分布、生物量进行了大面积科学调查．结果表明，福建沿岸海域浮游植物隶属于6门57属127种，其中硅藻47属107种，甲藻5属15种，蓝藻1属1种，金藻2属2种，隐藻1属1种，裸藻1属1种．硅藻类在种类和数量上均占主导地位，优势种主要是柔弱伪菱形藻（Pseudo—nitzschia delicatissima）、中肋骨条藻（Skeletonema costatum）、旋链角毛藻（Chaetoceros curvisetus）、菱形海线藻（Thalassionema nitzschioides）等．硅藻类广布，甲藻类在闽东海域及东山沿岸分布较多，蓝藻类检出率降低，裸藻类和金藻类检出率增高．表层浮游植物平均细胞密度为3222．59×10^4ind／dm^3，数量分布态势为近岸高、外海低，阂东和闽南高、闽中低．叶绿素a及优势类群的分布与数量分布基本一致．福建沿岸海域赤潮生物种类较多，是引发赤潮的潜在生物因素，一些赤潮生物已在闽南、闽东沿岸局部海域成为优势种． 相似文献
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大亚湾人工鱼礁区浮游植物的种类组成和生物量研究 总被引：2，自引：0，他引：2
于2005年11月、2006年5月及2006年12月,对大亚湾人工鱼礁投放区、拟投放区和对照区浮游植物的种类组成及生物量进行了研究.合计观察到藻类种类67种.主要由硅藻门(48种)和甲藻门(13种)组成,同时还有少量蓝藻、绿藻和着色鞭毛藻门等其他藻类(6种).优势种类主要有尖刺拟菱形藻、菱形海线藻、尖刺菱形藻等硅藻类和又状甲藻、海洋原甲藻及海洋原多甲藻等甲藻类,这些优势种类均为可能引发赤潮的赤潮生物.人工鱼礁区的藻类数量和叶绿素含量均比对照区高,说明人工鱼礁的投放促进了藻类的生长:人工鱼礁区和拟投放区的Shannonweaver多样性指数高于对照区,进一步表明人工鱼礁的投放增加了藻类的生物多样性.综合浮游植物的种类组成、生物量及多样性指数的结果表明:人工鱼礁的投放促进了浮游植物的生长,增加了生物多样性,但藻类的优势类群是可引发赤潮的赤潮生物,对海洋水环境具有极大的潜在威胁. 相似文献
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浮游动物在贝类筏式养殖区内,外生态特征研究 总被引：6，自引：0，他引：6
１９９６年６月～１０月对大李家湾贝类筏式养殖区内,外浮游动物进行了生态调查研究,结果表明,浮游动物种类类组成以小型挠足类为主,浮游动物数量在养殖区内,外具有相同的分布趋势,７月最高,９月次之,１０月最低,浮游动物在养殖区外的数量明显高于养殖区内,前者是后者的１．６～２．３倍,优势种小拟哲水蚤和鸟喙尖头蚤数量分布明显反映出浮游动物数量分布特征,而近缘大眼剑水蚤在养殖区内,外的数量则差异不大。 相似文献
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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
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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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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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《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
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The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a ‘ critical level ’. The critical level is determined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern England. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance. 相似文献
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Rahul Sharma 《Marine Georesources & Geotechnology》2000,18(3):237-250
Observations on seafloor features from subbottom profiling and seabed photography data show that the undisturbed and natural conditions before the benthic disturbance undergo a substantial change after operation of the disturber. The effects can be seen in the form of deep trenches and grooves, formed by the action of the sleds and the pumping of the sediment along its path, as well as sediment piles on either side of the track. Biological traces such as fecal coils, casts, tubes, burrows, and trails get obliterated in the areas of disturbance and resedimentation. The smooth, uniform nature of the seafloor observed in predisturbance phase shows microtopographic changes in and around the disturbed area as a result of sediment excavation and resettlement. Vertical mixing as well as lateral transport of sediment alter the geological, biological, physical, and chemical conditions on the seafloor, which need to be monitored over time to assess the process and the time taken for restoration of environmental conditions. 相似文献
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Vance P. Vicente 《Marine Ecology》1989,10(2):179-191
Abstract. Long-term changes in the distributional patterns of commercial sponges ( Spongia spp. and Hippospongia spp.) within the West Indian Region indicates that: 1) commercial sponges had a widespread distribution throughout the whole West Indian Region and were ubiquitous in very shallow water until about the first half of the present century; 2) they were fished commercially not only in the traditional northern Caribbean sites (Florida, Gulf of Mexico, Bahamas) but also in the Greater ( e. g. , Hispaniola, Jamaica) and Lesser Antilles; and 3) they became extinct throughout most of the Lesser Antilles ( e. g. , Puerto Rico, Vieques, St. Thomas) sometime during the first half of this century. Mortalities of spongiids within the Antilles were found to differ from other marine mortalities in that: 1) species disappeared from a large region; 2) species vanished from different habitats and depths; and 3) natural populations never recovered. Species richness patterns suggest that commercial sponge genera ( Spongia and Hippospongia ) evolved under slightly cooler elimatic conditions than those found at present, and that these extinctions occurred as a direct or indirect effect of positive thermal anomalies in sea surface and atmospheric temperatures between 1900–1950. The concept that species diversity is stable on a regional scale is questioned. 相似文献
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The behaviour of an axially pre-loaded cylindrical member of an offshore structure, hit by a supply ship, has been investigated. The effects of axial pre-loading on the dynamic properties of members, the extent of damage and propagation of dynamic instability in the tubular members have also been investigated. Numerical models have been validated using available experimental data from the literature although these are mostly static with no pre-loading. Axial pre-loading was found to change the dynamic characteristics of some cylindrical members quite dramatically while it had no significant effect on others. The study examined whether there was any change in the behaviour between local and global modes when the loading was dynamic rather than static. The effect of damping on the dynamic instability of axially pre-loaded tubes under lateral dynamic loads was also studied. It was observed that for some geometries the quasi-static response can be used to define the boundary between bounded and unbounded dynamic responses. The main contribution of this study, compared with previous investigations reported in the literature, is that both pre-loading and dynamic effects have been included. 相似文献