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1.
全球河口海域屡屡爆发褐潮,但我们对致因种抑食金球藻和浮游桡足类之间的营养关系还不甚清楚。我们就浮游桡足类火腿伪镖水蚤摄食抑食金球藻中国株的单种或混合饵料时的摄食行为和生长、发育等表现进行了研究。研究发现:火腿伪镖水蚤的无节幼体、桡足幼体和成体摄食单种抑食金球藻饵料时,摄食率和食物浓度之间的关系符合米氏方程。较之桡足类幼体和成体,无节幼体摄食抑食金球藻时的Imax(最大摄食率)值最大,同时大于其摄食中肋骨条藻的Imax值。通常情况下,火腿伪镖水蚤在摄食抑食金球藻和中肋骨条藻的混合饵料时避食抑食金球藻,但于无节幼体,这种情况并不明显。无节幼体摄食单种抑食金球藻饵料在无节幼体期末期死亡,无法进入桡足类幼体期,与饥饿状态下的个体相似。但是,饵料中抑食金球藻的存在对桡足幼体的生长无明显效应,但却极大地减少了成体的生殖率。我们的研究表明火腿伪镖水蚤无节幼体,在褐潮的控制中有潜在作用,然而,这种潜在控制作用由于桡足类种群的衰落难以持续。  相似文献   

2.
Calanus sinicus is a calanoid copepod widely distributed in coastal waters of China and Japan, and oversummering strategies may have major impacts on their population dynamics which in turn affect local marine food web structure. The abundance, stage composition, and sex composition of the planktonic copepod C. sinicus were studied from August to October 2002 in the southern Yellow Sea to understand how its population recovers from the over-summering state. Results showed that C. sinicus had low reproduction in August due to high temperature, except in waters near the Cheju Island with rich food and moderate bottom temperature, but the reproduction rates here decreased in September–October as food availability declined. When temperature dropped in September–October, C. sinicus actively propagated in coastal shallow waters. However, reproduction rates of C. sinicus individuals inhabiting the Yellow Sea Cold Water Mass(YSCWM) remained low during the three months of the study. The percentage of C. sinicus females was high during the reproductive period, which suggests that the sex composition of adult C. sinicus may reflect whether or not the population is in the reproductive mode.Numerous fifth copepodite stage(CV) C. sinicus aggregated in the YSCWM in a suspended developmental stage during the three months of this study, and they potentially served as the parental individuals for population development when conditions became optimal for reproduction later in the year.  相似文献   

3.
The seasonal occurrence and reproductive strategy of the nemertean Tetrastemma fozensis, which inhabits the mantle cavity of the bivalve Scrobicularia plana, was studied through the analysis of the temporal diversity of a T. fozensis population. Bimonthly sampling was carried out from February 2001 to January 2002 at mudflats of Villaviciosa estuary (Asturias, Northern Spain). Nemerteans were found throughout the study period, but variations in their abundance were detected, with a maximum during winter months and a minimum during summer months. Moreover, variations in mean size of nemerteans were found, with maximal sizes at the end of the spring and the beginning of the summer and minimum size at early autumn. The annual variations in population parameters (decrease in abundance and complete disappearance of large individuals in summer) suggest that T. fozensis has a distinct reproductive season and a semelparous reproductive strategy.  相似文献   

4.
于2010年6月,以性状优良的白黄壳内面F2代菲律宾蛤仔二元杂交系(WO)与紫壳内面F2代选育系(P)为材料,进行了三元杂交研究,获得了三元正反交组合PWO、WOP,并且比较了各实验组子代在不同阶段生长、存活和变态的杂种优势。结果表明:(1)从生长上看。三元杂交子WOP生长始终最快,2个三元正反交组幼虫均表现出了不同程度的杂种优势,其生长主要受卵源与配对策略的交互作用影响。(2)从存活力上看。三元杂交子PWO幼虫及WOP稚贝表现出一定的杂种优势,卵源是浮游期幼虫存活的最主要影响因素。(3)从变态上看,三元杂交子PWO呈现出一定的变态优势为HmPWO=9.80,卵源、配对策略及交互作用均是影响变态主要因素。  相似文献   

5.
The trophic efficiency of the planktonic food web in the Phaeocystis-dominated ecosystem of the Belgian coastal waters was inferred from the analysis of the carbon flow network of the planktonic system subdivided into its different trophodynamic groups. A carbon budget was constructed on the basis of process-level field experiments conducted during the spring bloom period of 1998. Biomass and major metabolic activities of auto- and heterotrophic planktonic communities (primary production, bacterial production, nanoproto-, micro- and mesozooplankton feeding activities) were determined in nine field assemblages collected during spring at reference station 330. In 1998, the phytoplankton spring flowering was characterised by a moderate diatom bloom followed by a massive Phaeocystis colony bloom. Phaeocystis colonies, contributing 70% to the net primary production, escaped the linear food chain while the early spring diatom production supplied 74% of the mesozooplankton carbon uptake. The rest of mesozooplankton food requirement was, at the time of the Phaeocystis colony bloom, partially fulfilled by microzooplankton. Only one-third of the microzooplankton production, however, was controlled by mesozooplankton grazing pressure. Ungrazed Phaeocystis colonies were stimulating the establishment of a very active microbial network. On the one hand, the release of free-living cells from ungrazed colonies has been shown to stimulate the growth of microzooplankton, which was controlling 97% of the nanophytoplankton production. On the other hand, the disruption of ungrazed Phaeocystis colonies supplied the water column with large amounts of dissolved organic matter available for planktonic bacteria. The budget calculation suggests that ungrazed colonies contributed up to 60% to the bacterial carbon demand, while alternative sources (exudation, zooplankton egestion and lysis of other organisms) provided some 30% of bacterial carbon requirements. This suggests that the spring carbon demand of planktonic bacteria was satisfied largely by autogenic production. The trophic efficiency was defined as the ratio between mesozooplankton grazing on a given source and food production. In spite of its major contribution to mesozooplankton feeding, the trophic efficiency of the linear food chain, restricted to the grazing on diatoms, represented only 5.6% of the available net primary production. The trophic efficiency of the microbial food chain, the ratio between mesozooplankton grazing on microzooplankton and the resource inflow (the bacterial carbon demand plus the nanophytoplankton production) amounted to only 1.6%. These low trophic efficiencies together with the potential contribution of ungrazed Phaeocystis-derived production to the bacterial carbon demand suggest that during spring 1998 most of the Phaeocystis-derived production in the Belgian coastal area was remineralised in the water column.  相似文献   

6.
台湾以东副热带环流区大中型浮游桡足类的生态特征   总被引:1,自引:0,他引:1  
林景宏 《海洋学报》2007,29(1):92-97
根据1995~1997年期间在台湾岛以东副热带环流区进行4个季度月的综合调查资料,分析了该海域浮游桡足类的数量分布及其群落的生态特征,探讨其与环境因素的相关性.结果表明,本区大中型浮游桡足类呈低丰度(4个季度平均为6.75个/m3)、低优势度(Y<0.131)以及季节变化幅度小等特点.所记录的206种浮游桡足类中,5种生态类群共存.不同性质水系在测区间的动态制约着不同生态类群的配比,但丝毫左右不了热带大洋广布类群的主导地位.  相似文献   

7.
Many estuarine and coastal planktonic copepods depend on the hatching of benthic resting eggs for recruitment of nauplii to the water column population. The distribution and abundance of viable resting eggs of Acartia pacifica in the Xiamen Bay were determined by the presence of nauplii in the laboratory. The number of viable eggs varied temporally and spatially. The maximum number (9.2×104m-2) of viable eggs was in summer. In spring the average abundance of viable eggs was 5.6×104 m-2. The abundances of viable eggs in fall and winter were similar, respectively 2.7×104 and 3.3×104 m-2, which were the lowest in the year. The numbers of viable eggs inside the stations of the Xiamen Bay were higher than those outside the stations. The viable eggs were found at all depths (0~10 cm),although not in every station. The maximin number did not necessarily occur in the uppermost centimeter of the sediments but often occurred several centimeters below the water-sediment interface. The accumulation of viable eggs in the seabed of a subtropical bay constitutes a potential source of recruitment of nauplii into the pelagic population.  相似文献   

8.
Correlations between daily fish settlement and environmental and physical parameters were examined during two consecutive years in two labrid species (Symphodus roissali and Symphodus ocellatus) in the NW Mediterranean Sea. Both these species have a short planktonic larval duration (12±0.3 and 9±0.4 days, respectively) and limited offshore larval dispersal. Time-series analysis was used to compare the daily settlement patterns with various environmental variables, and non-linear generalized additive models (GAM) were used to examine the relationship between environmental conditions averaged over larval period and daily settlement patterns. Settlement was not uniform and took place as pulses of different length. Although the analyses detected a few significant correlations between day-to-day patterns in environmental variables and settlement (e.g. solar radiation, atmospheric pressure, daytime or nocturnal wind components), these were not consistent among years. In S. ocellatus, however, wind components (daytime or nighttime) explained part of the variance in settlement intensity. The correlations (GAM outputs) observed between settlement patterns and environmental variables (averaged during the whole planktonic period) suggest that calm weather during the planktonic period usually increases settlement success.  相似文献   

9.
One of the present concerns of fish biologists involves defining and identifying nursery habitats in the context of conservation and resource management strategies. Fish nursery studies usually report upon nursery occupation during the latter juvenile stages, despite the fact that recruitment to nurseries can start early in life, during the larval phase. Here we investigated the use of a temperate estuarine nursery area, the Lima estuary (NW Portugal), by initial development stages of flatfish species before and after metamorphosis, integrating the larval and juvenile phases. The Lima estuarine flatfish community comprised twelve taxa, seven of which were present as pelagic larvae, six as juveniles and three as adults. There was a general trend of increasing spring–summer abundance of both larvae and juveniles, followed by a sharp winter decrease, mainly of larval flatfishes. The Lima estuary was used by Solea senegalensis, Platichthys flesus and Solea solea as a nursery area, with direct settlement for the two first species. In contrast, indirect settlement was suggested for S. solea, with metamorphosis occurring outside the estuarine area. Estuarine recruitment of S. senegalensis varied between years, with young larvae occurring in the estuary throughout a prolonged period that lasted 6–9 months, corroborating the protracted spawning season. P. flesus, the second most abundant species, exhibited a typical spring estuarine recruitment, without inter-annual variations. Developed larvae arrived in the estuary during spring, whereas the 0-group juveniles emerged in the following summer period. The present study contributes new insight to our understanding of the economically important S. senegalensis, and highlights the importance of integrating the planktonic larval phase into traditional flatfish nursery studies.  相似文献   

10.
根据2006—2007年在舟山渔场渔业资源调查中采集的细点圆趾蟹样品,开展了生物学特性研究,对生物学特性的季节变化进行了分析,并将结果与以往报道进行了比较。结果表明,舟山渔场细点圆趾蟹甲长分布范围9—75mm,平均43.8mm,甲宽10—98mm,平均54.9mm。体重分布范围0.4—167.4g,平均40.4g。雄性...  相似文献   

11.
The materials were obtained from the survey conducted in the Kuroshio area of the East China Sea to the Southwest of Kyushu in Japan (29°30'-32°00', 128°00'-130°'00'E) on board the R. V. Yoko Maru of Seikai Regional Fisheries Lab, Fisheries Agency, Japan in June 15~28, 1988 during China-Japan Joint Research on the Kuroshio. Zoo-plankton was collected by means of the North Pacific Net with model TSK flowmeter through vertical haul from 50 -Om. Temperature and salinity were measured with CTD. 134 species (including 4 spp. ) of planktonic copepods were preliminarily identified in the survey area. Most of them belonged to the tropical and subtropical species and a few of them were the warm-temperate species and eurytopic species. The main dominant species vteieOncaea venusta, Oithona plumifera, Clausocalanus furcatus, C. Arcuicornis, Paracaianus dculeatus, Oithona similis, Temara turbinata, Oncaea media, Undinula danvinii, Acartia negligent, Corycaeus speciosus, Scolecithrix danae, etc. The total number  相似文献   

12.
Measurements of dry weight, carbon- and nitrogen contents together with the body length of important zooplankton from the Inland Sea of Japan were made using freshly caught specimens. The values of the former three parameters were found to be highly correlated to length, and species specific regression equations were calculated for 10 species of Copepoda (Calanus sinicus, Euchaeta plana, E. concinna, Centropages abdominalis, Sinocalanus tenellus, Acartia clausi, A. tsuensis, Tortanus forcipatus, Oithona brevicornis andO. similis), 3 species of Cladocera (Podon leuckarti, P. polyphemoides andPenilia avirostris), 1 species of each of Mysidacea (Neomysis japonica), and Natantia (Acetes japonicus), and two forms of Chaetognatha (Sagitta crassa andS. crassa f.naikaiensis).  相似文献   

13.
Temporal variability and population structure of planktonic ostracods were investigated for the first time in the South Adriatic Sea during 1996. The maximal total ostracod abundance (1167 ind·100 m−3; 69% juveniles, 18% females and 13% males) was recorded in February. Thirteen species of marine planktonic ostracods were identified. Porroecia spinirostris and Archiconchoecia striata dominated the ostracod assemblage, accounting respectively for 62% and 18% of the total abundance. Their annual peaks were recorded during the cold season, which was the period of their intense reproduction, with favourable temperature conditions and lack of predators. The females surpassed the males in abundance in most species. The presence of the mesopelagic species indicated a strong influence of intermediate layer water masses from the Eastern Mediterranean Sea.  相似文献   

14.
吕红红  向荣 《海洋学报》2016,38(2):93-103
现代活体浮游有孔虫的生态研究是其古环境重建应用的重要基础。根据黄、东海陆架2011年秋季采集的20个垂直浮游拖网样品,分析了该海域浮游有孔虫的秋季生态分布特征。结果表明,黄海秋季基本上没有浮游有孔虫的出现。东海共发现13种活体浮游有孔虫,主要优势属种依次为Globigerinoides sacculifer、Pulleniatina obliquiloculata、Globigerina bulloides、Neogloboquadrina dutertrei和Globigerinoides ruber。浮游有孔虫丰度整体上呈现东南高,西北低的分布格局,这种分布格局反映了浮游有孔虫在黄、东海陆架区的分布主要受外海水影响强弱控制。浮游有孔虫主要属种在东海陆架呈现明显的区域分布差异:暖水种G. sacculifer是秋季陆架海区的主要优势种,其分布格局与总丰度基本一致,相对含量从南至北、从东至西逐渐降低,主要受区域表层海水温度变化的控制。G. bulloides与G. sacculifer呈相反的含量分布变化,其高含量主要出现在东海中陆架,从北往南逐渐降低,此外,在闽浙沿岸也有较高含量,表明了温度和生产力是影响G. bulloides在黄、东海陆架分布的主要因素。秋季P. obliquiloculata和N. dutertrei的高含量主要出现在东海南部中陆架区和济州岛西南黄海暖流影响区,可能受暖水与生产力的共同制约。  相似文献   

15.
本研究通过对线粒体控制区序列进行分析的技术手段,对中国宁德(ND)、厦门(XM)、漳浦(ZP)、南澳岛(NAD)、湛江(ZJ)、海口(HK)与北海(BH)的7个野生黄鳍棘鲷(Acanthopagrus latus)群体的遗传多样性和遗传分化进行比较分析。结果表明:中国东南沿海的野生黄鳍棘鲷群体呈现出中等以上的遗传多样性特征,48个黄鳍棘鲷样品的控制区序列长度为580 bp,单倍型数目为44个,总体的单倍型多样性指数(Hd)和核苷酸多样性指数(Pi)分别为0.996和0.017 30。7个野生黄鳍棘鲷群体间的遗传分化程度较低,各群体间的遗传距离为0.010 28~0.029 87。群体间的遗传分化系数(FST)为-0.068 41~0.545 86,北海群体和其他群体间存在一定程度的遗传分化。AMOVA分析显示群体内的遗传变异占比为83.34%,大部分遗传变异发生在组群内;但北海群体与其他6个群体分为两个组群后,组群间的遗传变异占比为42.66%,两个组群间存在较大程度的遗传变异。基于Kimrua距离法构建的系统进化树中显示北海群体聚为一个分支,另外6个群体聚为一支。基于TCS network构建的单倍型网络图中44个单倍型混杂在一起,未按照水系格局和地理距离进行分布,表明黄鳍棘鲷群体间未形成多个单系群。本研究可为中国东南沿海野生黄鳍棘鲷群体的种质资源利用和保护提供科学依据。  相似文献   

16.
应用显微技术观察了后刺才女虫(Polydora latispinosa)胚胎的发育过程及各发育阶段幼虫形态结构特点,以期为多毛类的发育生物学研究和分类学积累更多的资料。结果显示,后刺才女虫在魁蚶内表面形成瘤状突起,在外套膜上钻孔,导致外套膜溃疡发红。后刺才女虫受精卵在卵袋中发育至三刚节幼虫时,幼虫破袋而出开始营浮游生活...  相似文献   

17.
Surveys of the abundance and size composition of the ctenophore Bolinopsis mikado were conducted in Tokyo Bay over a 5-year period from 1990 to 1994. B. mikado appeared throughout the year, and its mass occurrence was observed between August and November; annual maximum abundance ranged from 19 to 91 ind. m–2. Water temperature seems to influence the seasonal variation of B. mikado abundance. Environmental conditions (e.g. rough waters due to a typhoon) and predation by the beroid ctenophore Beroe cucumis appear to affect annual variations of B. mikado abundance. Size frequency distributions of B. mikado indicated that its reproduction was most active in summer and fall but occurred throughout the year in Tokyo Bay. A sharp decline of the copepod population in August 1990 was probably due to predation by B. mikado which was very abundant at that time; its predatory impact was estimated to be 24 % day–1.  相似文献   

18.
The vertical and temporal distribution of two calycophoran siphonophores, Chelophyes appendiculata (Eschscholtz, 1829) and Abylopsis tetragona (Otto, 1823) in the Bay of Villefranche (northwestern Mediterranean) was investigated by an analysis of three different planktonic time series. A daily series (1993–1995) showed seasonal peaks of the nectophores of C. appendiculata during spring and particularly in late summer, while the abundance of A. tetragona remained similar throughout the year. A weekly series (1994–1995) showed that C. appendiculata (nectophores and eudoxids) became concentrated above the thermal discontinuity, in the most stratified and warm waters, whereas A. tetragona was collected in large numbers below this discontinuity. A 27-year survey (1966–1993) showed long-term fluctuations of these siphonophore populations, which became abundant in the Bay starting from 1980 and especially after 1984, when the water column grew warm and hypersaline, corresponding to a less rainy period. Temporal (seasonal and long-term) and bathymetric (between 10 and 60 m depth) successions of these two siphonophores were noted in this shallow coastal bay.  相似文献   

19.
本研究利用形态学方法和基于线粒体细胞色素氧化酶亚基Ⅰ(COⅠ)的遗传学方法分析了中国沿海青蚶(Barbatia virescens)6个地理群体的形态差异、遗传多样性、遗传结构及其种群历史动态。单因素方差分析(ANOVA)和Tukey检验表明,青蚶不同地理种群间表现出显著形态差异(P0.05)。经PCR扩增测序获得长度为587bp的COⅠ基因片段,112个个体共检测到18个多态性位点、17个单倍型,每个群体均有特有单倍型。青蚶群体的遗传多样性水平较低,总群体的平均单倍型多样度为0.5472,平均核苷酸多样度为0.000974。AMOVA分析表明,群体内个体间的遗传分化是青蚶群体遗传变异的主要原因,占87.40%。阳江群体与其他群体之间存在显著的低程度的遗传分化,而其他群体间的遗传分化不显著。单倍型网络关系图呈典型的星状拓扑结构,没有表现出显著的地理谱系结构。单倍型邻接树结果也没有明显分支,未呈现出地域性差异。中性检验和核苷酸不配对分析结果揭示青蚶种群历史上经历了群体扩事件,扩张时间约为26万年前。研究结果为青蚶资源的保护和可持续利用提供了基础资料。  相似文献   

20.
Geographical variations in prosome length and body weight of Neocalanus copepods (N. cristatus, N. plumchrus and N. flemingeri) were investigated on samples from North-South and East-West transects in the North Pacific during spring to early summer in 1998 and 1999. Southward and eastward increasing patterns were pronounced for water temperature, although no significant pattern was observed for chlorophyll a concentrations. All Neocalanus species showed large geographical variations in prosome length and body weight, being smaller in the southern and eastern waters. Comparing the relationship between prosome length and body weight, large deviations (lower body weight at a given prosome length) were evident for the eastern specimens of N. cristatus and N. plumchrus. In stepwise regression analysis, the geographical variations of prosome length and body weight revealed a significantly negative correlation with temperature variations. These results suggest that temperature is a more important environmental factor than chlorophyll a concentration in its effect on geographical variations in prosome length and body weight of Neocalanus copepods in the North Pacific. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

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