孢囊及其与赤潮爆发关系的研究进展   总被引：2，自引：0，他引：2  

丁德文  刘胜浩  刘晨临  林学政  边际  黄晓航 《海洋科学进展》2005,23(1):1-10

某些藻类(特别是甲藻),在不适宜生长的恶劣环境条件下能形成休眠孢囊。孢囊下沉到海底,以渡过不良的生存条件。一旦环境条件适宜,孢囊就大量萌发形成浮游细胞和优势群体,从而诱导赤潮的形成。简述了当前国际上对孢囊研究的最新进展,从孢囊和营养细胞相互转化的角度探索了孢囊与赤潮形成的关系,以及分子生物学技术在赤潮生物及其孢囊的定性、定量及赤潮发生监测中的应用。  相似文献   

先天性胆管囊肿影像学诊断评价     

郑文龙  吴爱琴 《CT理论与应用研究》1998,7(4):16-18

本文目的在于评价先天性胆管囊肿影像学诊断的价值及首选检查方法。所用的材料与方法是搜集６８例术前经腹部平片、胃肠钡餐检查、静脉胆道造影、ＥＲＣＰ、ＰＴＣ、Ｂ超、ＣＴ检查并经手术证实的病例行回顾性分析。结果是Ｂ超简单,可重复检查,阳性率７４．６％;ＣＴ能清晰显示胆管囊肿的部位,大小,类型。对Ｃａｒｏｌｉｓ病有特别价值,ＥＲＣＰ检查痛苦,对小儿不适宜;ＰＴＣ为创伤性检查,静脉胆道造影显示病变不隹;腹部平片,胃肠钡餐造影仅能显示病变间接征象。结论得出：对胆管囊肿的检查诊断,首选ＣＴ和Ｂ超,ＥＲＣＰ和ＰＴＣ,应该做为补充检查方法  相似文献   

Sedimentary chrysophycean cyst assemblages as paleoindicators in acid sensitive lakes     

Mariusz Rybak  Izabela Rybak  Kenneth Nicholls 《Journal of Paleolimnology》1991,5(1):19-72

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A potential source of recruitment of Acartia pacifica nauplii: viable benthic resting eggs     

WANG Guizhong  JIANG Xiaodong  LI Shaojing  WU Lisheng  WU Dingxun 《海洋学报(英文版)》2005,24(2):151-158

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   

虾池中桡足类及其休眠卵携带对虾白斑综合症病毒的初步调查研究   总被引：2，自引：0，他引：2  

张家松  董双林  董云伟  闫冬春  田相利  刘相义 《中国海洋大学学报(自然科学版)》2007,37(3):405-408,412

探讨对虾白斑综合症(White Spot Syndrome WSS)与虾池中桡足类之间的关系,于2003年5~10月份,在暴发过对虾白斑综合症的池塘中采集桡足类样品共128个,并从冬季底泥样品分离出桡足类休眠卵样品20个,以及此种休眠卵孵化得来的桡足类幼体样品5个。利用PCR斑点杂交法以及巢式PCR法检测样品中对虾白斑综合症病毒(White Spot Syndrome Virus WSSV)携带情况。结果表明,5~10月份桡足类样品中均能检测到阳性样品,总的阳性率为56.3%;其中,5月份样品阳性率为37.5%,6,8,9,10月份各取样1次,每次样品中的阳性率均在60%以上。在20例桡足类休眠卵样品中有1例为阳性,阳性率为5%;并且实验室中孵化此种休眠卵得来的桡足类幼体样品中检测到阳性,阳性率为40%。本研究初步表明,桡足类是WSSV的携带者或传播媒介之一,且冬季池塘底泥中携带WSSV的桡足类休眠卵可萌发出带病毒的桡足类。  相似文献   

轮虫休眠卵研究进展   总被引：4，自引：0，他引：4  

闫冬春  董双林  黄倢 《海洋湖沼通报》2005,(3):95-102

综述了近年来国内外对轮虫休眠卵的研竞概况。重点介绍了轮虫休眠卵的形态、影响轮虫休眠卵形成的因素、轮虫休眠卵的萌发形式及影响其萌发的因素、自然水体中轮虫休眠卵的研究概况。  相似文献   

Fluctuations and Variations in Coastal Marine Environments   总被引：2，自引：0，他引：2  

Ferdinando  Boero 《Marine Ecology》1994,15(1):3-25

Abstract. The manifold aspects of variability of coastal marine ecosystems are reviewed, with special reference to the response of species and communities. Fluctuations are defined as recurrent modifications in community structure, for instance due to seasonality, whereas variations are defined as changes permanently leading from a given community to a different one. Both patterns are described and linked to the interaction between life history traits and environmental factors. Resting stages are proposed to play a still underestimated role in the dynamics of coastal communities, especially for plankton. Rare species are considered as an essential constant of communities, being the source of potential variation and alternance in the contribution to the standing biomass.  相似文献   

Modern Dinoflagellate Cysts Distribution off the Eastern Part of Geoje Island,Korea     

Hyeon Ho Shin  Yang Ho Yoon  Kazumi Matsuoka 《Ocean Science Journal》2007,42(1):31-39

Distributional characteristics of dinoflagellate cysts in surface sediments were investigated in relation to environmental factors in the eastern part of Geoje Island, Korea. Samples were collected from 10 stations in February of 2004 and water temperature and salinity were measured in February, May, September and November of 2004. Total 30 taxa of dinoflagellate cysts were identified representing 19 genera, 28 species and 2 unidentified species. Among these dinoflagellate cysts,Brigantedinium spp. of which relative proportion in the total dinoflagellate cysts was 23.5%, was the most abundant at all stations except St. 1, and was followed bySpiniferites bulloideus (8.6%),Lingulodinium machaerophorum (8.2%) andDiplopsalis lenticula (6.7%). In addition, ellipsoidal cysts of the genusAlexandrium (Alexandrium catenella - tamarense type) andGymnodinium catenatum, known to be causative organisms for PSP, occurred with high concentrations.Scrippsiella trochoidea was also found; however, its cyst concentration was low. Generally, species composition in the study area was similar to these reported from Jinhae Bay and Busan Harbor and several dinoflagellate cysts reflected the eutrophic condition. Cyst distribution in the eastern part of Geoje Island seems to be influenced by the Tsushima Warm Current flowing from the southwest. The mean water temperature was 12.0°C in February, 14.7°C in May, 20.9°C in September and 17.2°C in November, which was most favorable forAlexandrium spp. growth. The abundances of dinoflagellate cysts ranged from 528 to 2,834 cysts/g dry sediment. Higher concentrations were recognized in sediments of west area of the Jisimdo than at other stations. The cyst composition of this area was closely related to these of Jinhae Bay and Busan Harbor from which currents flow into this area. Higher cyst concentration in the west area of Jisimdo might be due to formation of the gyre.  相似文献   

Disentangling late-Holocene climate and land use impacts on an Austrian alpine lake using seasonal temperature anomalies,ice-cover,sedimentology, and pollen tracers   总被引：1，自引：0，他引：1  

Roland Schmidt  Monika Roth  Richard Tessadri  Kaarina Weckström 《Journal of Paleolimnology》2008,40(1):453-469

Major and trace elements, minerals and grain-size were analysed from a sediment core covering the last 4,000 years of an Austrian Alpine lake (Oberer Landschitzsee, ObLAN, 2,076 m a.s.l.). These analyses were combined with autumn and spring temperature anomalies and ice-cover estimated from a diatom and chrysophyte cyst, thermistor-based regional calibration dataset and selected pollen markers published previously. Diatom-inferred pH (Di-pH) and DOC (Di-DOC) completed the multi-proxy approach, which, together with ordination techniques (PCA and RDA), helped (1) to confirm proposed climatic patterns and hypotheses, and (2) to disentangle the complex interactions between climatic and anthropogenic impacts. Shifts in chemical and physical weathering, erosion, production, lake stratification, redox potentials and air pollution were the major processes that have affected Oberer Landschitzsee in relation to climate, lake/catchment interactions, and human impact. Geochemistry supported the finding that the four waves of high-altitude land use (Early to Middle Bronze, ca. 1,800–1,300 B.C.; Late Bronze to Hallstatt, ca. 1,000–500 B.C.; Celtic to Roman, ca. 300 B.C.–400 A.D.; and Medieval, ca. 1,000–1,600 A.D.) were coupled mainly with warm periods. Increased production, onset of lake stratification, and the deterioration of hypolimnetic oxygen conditions were the major changes governing in-lake processes during climate warming. They resulted in specific element assemblages associated with organic matter accumulation (Br), oxygen depletion (As, Ga, Cu, S), and changes in redox (Fe/Mn). The Se/Di-DOC ratio was introduced to track shifts between in-lake production and allochthonous sources. Nutrient loading from pastures, coupled with climate warming, could explain that in-lake production was highest during Roman and Medieval land use. Lithogenic elements mainly originated from chemical weathering of silicate bedrock and they increased when intense land-use was coupled with climate deterioration and/or increased humidity. These perturbations were highest during a High Medieval climate fluctuation around 1,000 A.D. The association of sand with LOI and C/N and the decoupling of sand from quartz and feldspar separates erosion from physical weathering. Di-DOC, S, and C/N showed hybrid characters in relation to climate and human impact. The mineral proportions indicated gradients in relation to weathering, snow-cover and running waters, as well as vegetation. Air pollution by metallurgic industries, starting during the High Medieval and culminating during the Late Medieval, caused lead accumulation and could have contributed to As and S enrichment. Corresponding features in the distribution of selected elements and pollen tracers, as well as changes in mineral proportions, supported the hypotheses of shifts in seasonal climate and an overall trend towards more continental climate conditions since Medieval times.  相似文献   

Resting cells of microorganisms in the 20–100 μm fraction of marine sediments in an Antarctic coastal area     

Mutsuo Ichinomiya  Miwa Nakamachi  Mitsuo Fukuchi  Akira Taniguchi 《Polar Science》2008,2(1):27-32

We investigated the morphological features, vertical sinking fluxes, and number densities of the resting cells of ice-associated microorganisms in the 20–100 μm fraction of natural marine sediments collected from ice-covered and ice-free areas around Syowa Station, Lützow-Holm Bay, East Antarctica. We identified the resting cells of various taxonomic groups, including the spores of a diatom, cysts of three dinoflagellates, cysts of five oligotrich ciliates, and the eggs of a mesozooplankton. This is the first report of oligotrich ciliate cysts from Antarctic waters. The resting spores of Thalassiosira australis (diatom), cysts of Polarella glacialis (dinoflagellate), and egg type 1 sink to the bottom sediment during summer. Our results suggest that some planktonic and ice-associated microorganisms in Antarctic coastal areas send their resting cells to the bottom sediments as seed populations for the following generation.  相似文献