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1.
In the present study, we used catalyzed reporter deposition-fluorescence in situ hybridization to quantify the abundance of five bacterial (Alphaproteobacteria, SAR11, Gammaproteobacteria, SAR86, and Bacteroidetes) and two archaeal (Crenarchaeota and Euryarchaeota) phylotypes in the epipelagic layer (0–200 m) of the Central South Pacific Ocean along 170°W from 0° to 40°S. We found that the distribution patterns of these phylotypes differed from each other. All phylotypes except Gammaproteobacteria were particularly abundant at the surface water of the equatorial region, whereas Gammaproteobacteria was relatively abundant in the area from the southern part of the South Pacific Ocean. SAR11, affiliated with Alphaproteobacteria was the dominant phylotype at all depths, throughout the study area. The abundance of SAR11 significantly increased with chlorophyll a concentration, suggesting that phytoplankton could affect their distribution pattern. There was a positive correlation between Bacteroidetes abundance and water temperature, suggesting that the temperature gradient could be a critical factor determining their distribution in the South Pacific Ocean. Crenarchaeota and Euryarchaeota were more abundant at the equatorial region than in other study areas. Euryarchaeota abundance significantly decreased with depth, and increased with chlorophyll a concentration. This suggests that there was ecological interaction between Euryarchaeota and phytoplankton in the equatorial surface. Our data indicate that distinct hydrographic properties such as seawater temperature, salinity, and the concentrations of chlorophyll a and nutrients can principally control the basin-scale distribution of different prokaryotic phylotypes in the epipelagic layer of the Central South Pacific Ocean.  相似文献   

2.
Whereas diatoms (class Bacillariophyceae) often dominate phytoplankton taxa in the Amazon estuary and shelf, their contribution to phytoplankton dynamics and impacts on regional biogeochemistry are poorly understood further offshore in the western tropical Atlantic Ocean (WTAO). Thus, relative contribution of diatoms to phytoplankton biomass and primary production rates and associated environmental conditions were quantified during three month-long cruises in January–February 2001, July–August 2001, and April–May 2003. The upper water column was sampled at 6 light depths (100%, 50%, 25%, 10%, 1% and 0.1% of surface irradiance) at 64 stations between 3° and 14°N latitude and 41° and 58°W longitude. Each station was categorized as ‘oceanic’ or ‘plumewater’, based on principal component analysis of eight physical, chemical and biological variables. All stations were within the North Brazil Current, and plumewater stations were characterized by shallower mixed layers with lower surface salinities and higher dissolved silicon (dSi) concentrations than oceanic stations. The major finding was a much greater role of diatoms in phytoplankton biomass and productivity at plumewater stations relative to oceanic stations. Mean depth-integrated bSi concentrations at the plumewater and oceanic stations were 14.2 and 3.7 mmol m−2, respectively. Mean depth-integrated SiP rates at the plumewater and oceanic stations were 0.17 and 0.02 mmol m−2 h−1, respectively. Based on ratios of SiP and PP rates, and typical Si:C ratios, diatoms contributed on average 29% of primary productivity at plumewater stations and only 3% of primary productivity at oceanic stations. In contrast, phytoplankton biomass (as chlorophyll a concentrations) and primary production (PP) rates (as 14C uptake rates) integrated over the euphotic zone were not significantly different at plumewater and oceanic stations. Chlorophyll a concentrations ranged from 8.5 to 42.4 mg m−2 and 4.0 to 38.0 mg m−2 and PP rates ranged from 2.2 to 11.2 mmol m−2 h−2 and 1.8 to 10.8 mmol m−2 h−2 at plumewater and oceanic stations, respectively. A conservative estimate of annual integrated SiP in offshore waters of Amazon plume between April and August is 0.59 Tmol Si, based on mean SiP rates in plumewaters and satellite-derived estimates of the area of the Amazon plume. In conclusion, river plumewaters dramatically alter the silicon dynamics of the WTAO, forming extensive diatom-dominated phytoplankton blooms that may contribute significantly to the global Si budget as well as contributing to energy and matter flow off of the continental shelf.  相似文献   

3.
2001/2002年夏季南极普里兹湾及其邻近海域的浮游植物   总被引：15，自引：4，他引：15       下载免费PDF全文
报道了 2 0 0 1 /2 0 0 2年夏季南极普里兹湾邻近海域 3 7个大面测站浮游植物的调查结果。经初步鉴定共有浮游植物 3门 3 7属 86种 ,其中硅藻在种类和细胞丰度上占绝对优势 ,其次为甲藻。主要优势种为克格伦拟脆杆藻 (Fragilariopsiskerguelensis)、细条伪菱形藻 (Pseu do nitzschialineola)、短拟脆杆藻 (Fragilariopsiscurta)和赖氏束盒藻 (Trichotoxonreinboldii)等南极特有种类和常见种类。调查区浮游植物分为两个群集 ,分布在 6 7°S以南的普里兹湾内的群集主要以克格伦拟脆杆藻、短拟脆杆藻、胡克星脐藻 (Asteromphalushookeri)和南极弯角藻 (Eu campiaantarctica)等南极特有种类和常见种类为主 ;分布在 6 7°S以北的大洋海域的群集主要以细条伪菱形藻、赖氏束盒藻、拟膨胀伪菱形藻 (Pseudo nitzschiaturgiduloides)和羽状环毛藻(Corethronpennatum)等南极常见种为主。调查区浮游植物的平均细胞丰度为 (8796± 2 92 85 )ind/L ,细胞多分布于海水的表层 ,密集区分布在 6 7°S以南的普里兹湾内 ,浮游植物的细胞丰度同硝酸盐的浓度密切相关。调查区浮游植物的多样性程度是低的。  相似文献   

4.
To understand picocyanobacterial distribution patterns in the northwestern Pacific Ocean, their abundances and genetic diversity were studied using flow cytometry and a barcoded amplicon pyrosequencing approach. At open ocean stations affected by the North Equatorial Current, Prochlorococcus was the predominant picocyanobacteria, and a high-light-adapted ecotype (HLII) made up most of the population. In contrast, at stations in shelf areas of the East China Sea (ECS) and South Sea, Synechococcus was the predominant picocyanobacteria and clade II was dominant. At other ECS stations affected by the Kuroshio Current, both Prochlorococcus and Synechococcus made up similar proportions of the picocyanobacterial community. These results indicate that picocyanobacterial diversity differs among oceanic regions, and that physicochemical properties related to dominant water masses, seem to be important in determining picocyanobacterial diversity.  相似文献   

5.
黑潮入侵深刻影响东海生态环境,但对其如何影响浮游植物群落组成与分布仍知之甚少。为此,于2011年四季对东海(26°～33°N,121°～128°E)共164个站位进行浮游植物拖网采集和环境因子测定,分析了浮游植物丰度和优势种组成及其对黑潮入侵的响应。调查共检出浮游植物9门509种(含变种、变型和未定种),其中硅藻305种、甲藻154种,蓝藻、定鞭藻、金藻、裸藻、绿藻、隐藻和黄藻种类数较少。秋季浮游植物细胞丰度最高(30 496.91×103 cells/m3),高值区位于黑潮与长江冲淡水交汇形成的锋面处;夏季次之(28 911.28×103 cells/m3),高值区分布与秋季相似;春季较少(19 180.76×103 cells/m3),高值区位于舟山群岛东南部;冬季最低(472.36×103 cells/m3),高值区位于东海南部。冬季受黑潮表层水入侵影响,主要优势种为铁氏束毛藻(Trichodesmium thiebautii);春、夏季主要优势种为骨条藻(Skeleto...  相似文献   

6.
This study focuses on the comparison of oceanic and coastal cold-core eddies with inner-shelf and East Australian Current (EAC) waters at the time of the spring bloom (October 2008). The surface water was biologically characterised by the phytoplankton biomass, composition, photo-physiology, carbon fixation and by nutrient-enrichment experiments. Marked differences in phytoplankton biomass and composition were observed. Contrasted biomarker composition suggests that biomarkers could be used to track water masses in this area. Divinyl chlorophyll a, a biomarker for tropical Prochlorophytes, was found only in the EAC. Zeaxanthin a biomarker for Cyanophytes, was found only within the oceanic eddy and in the EAC, whereas chlorophyll b (Chlorophytes) was only present in the coastal eddy and at the front between the inner-shelf and EAC waters.This study showed that cold-core eddies can affect phytoplankton, biomass, biodiversity and productivity. Inside the oceanic eddy, greater phytoplankton biomass and a more complex phytoplankton community were observed relative to adjacent water masses (including the EAC). In fact, phytoplankton communities inside the oceanic eddy more closely resembled the community observed in the inner-shelf waters. At a light level close to half-saturation, phytoplankton carbon fixation (gC d−1) in the oceanic eddy was 13-times greater than at the frontal zone between the eddy and the EAC and 3-times greater than in the inner-shelf water. Nutrient-enrichment experiments demonstrated that nitrogen was the major macronutrient limiting phytoplankton growth in water masses associated with the oceanic eddy. Although the effective quantum yield values demonstrate healthy phytoplankton communities, the phytoplankton community bloomed and shifted in response to nitrogen enrichments inside the oceanic eddy and in the frontal zone between this eddy and the EAC. An effect of Si enrichment was only observed at the frontal zone between the eddy and the EAC. No response to nutrient enrichment was observed in the inner-shelf water where ambient NOx, Si and PO4 concentrations were up to 14, 4 and 3-times greater than in the EAC and oceanic eddy. Although results from the nutrient-enrichment experiments suggest that nutrients can affect biomass and the composition of the phytoplankton community, the comparison of all sites sampled showed no direct relationship between phytoplankton biomass, nutrients and the depth of the mixed layer. This is probably due to the different timeframe between the rapidly changing physical and chemical oceanography in the separation zone of the EAC.  相似文献   

7.
黄海和东海是西北太平洋重要的边缘海,复杂的海洋环流和丰富的陆源物质输入共同影响着海域环境和生态系统。为了解黄、东海浮游植物群落组成、分布状况及其影响因素,本研究于2015年8—9月期间,通过流式细胞仪和形态学观察等方法,调查了该海域微型真核藻类、微微型真核藻类、聚球藻（Synechococcus）、原绿球藻（Prochlorococcus）以及浮游植物优势种的组成、丰度与分布情况,并基于浮游植物种类和丰度状况进行了聚类分析。结果表明,黄、东海浮游植物群落组成存在明显差别,黄海海域微型浮游植物丰度高于东海,而微微型浮游植物丰度低于东海,原绿球藻主要分布在东海海域。黄、东海海域浮游植物群落组成及分布状况与海域环境特征密切相关。夏季黄海海域相对封闭,受黄海冷水团控制,表层海水中高丰度的微型真核藻类主要出现在冷水团西侧边缘锋面区。东海海域受到长江冲淡水和黑潮水向岸入侵的强烈影响,在长江口邻近海域出现硅藻赤潮,而原绿球藻呈现出自外海向近岸输送的分布态势。相关结果可望为进一步探讨陆源物质输入和邻近大洋对我国近海生态系统的影响及机理提供依据。  相似文献   

8.
Little is known about the effects of iron enrichment in high-nitrate low-chlorophyll (HNLC) waters on the community composition of heterotrophic bacteria, which are crucial to nutrient recycling and microbial food webs. Using denaturing gradient gel electrophoresis (DGGE) of 16S rDNA fragments, we investigated the heterotrophic eubacterial community composition in surface waters during an in situ iron-enrichment experiment (SEEDS-II) in the western subarctic Pacific in the summer of 2004. DGGE fingerprints representing the community composition of eubacteria differed inside and outside the iron-enriched patch. Sequencing of DGGE bands revealed that at least five phylotypes of α-proteobacteria including Roseobacter, Cytophaga-Flavobacteria-Bacteroides (CFB), γ-proteobacteria, and Actinobacteria occurred in almost all samples from the iron-enriched patch. Diatoms did not bloom during SEEDS-II, but the eubacterial composition in the iron-enriched patch was similar to that in diatom blooms observed previously. Although dissolved organic carbon (DOC) accumulation was not detected in surface waters during SEEDS-II, growth of the Roseobacter clade might have been particularly stimulated after iron additions. Two identified phylotypes of CFB were closely related to the genus Saprospira, whose algicidal activity might degrade the phytoplankton assemblages increased by iron enrichment. These results suggest that the responses of heterotrophic bacteria to iron enrichment could differ among phylotypes during SEEDS-II.  相似文献   

9.
The influences of the hydrological features and environmental conditions in the phytoplankton community found in the Campos Basin area in the Atlantic Ocean (20° to 25°S; 42° to 38°W) were studied using HPLC/CHEMTAX pigment analysis. Samples were collected at 72 stations distributed along the 25–3000 m isobaths at two depths during two seasonal periods (rainy and dry). Seven taxonomic groups of phytoplankton were detected (diatoms, dinoflagellates, prasinophytes, cryptophytes, haptophytes, pelagophytes and cyanobacteria). Redundancy analysis showed that the spatial and temporal patterns observed in the distribution of the phytoplanktonic groups were primarily related to variations in the availability of light and nutrients. Nutrient variations were caused by South Atlantic Central Water seasonal intrusions over the continental shelf region. Cyanobacteria predominated in the rainy season, while diatoms, Haptophyceae and Prasinophyceae, were associated with higher nutrient availability in the dry season. In the inner shelf region, diatoms dominated and were associated with increased conditions of turbulence and nutrient availability. Haptophytes and prasinophytes were predominant on the outer shelf and shelf-break regions associated with high nutrient concentrations and availability of light. Prochlorococcus was related to oceanic waters (in both dry and rainy periods) or to low nutrient/strongly stratified shelf waters (rainy period). In contrast, Synechococcus was widely distributed in both the shelf and oceanic regions. Variation in the quality of light between coastal and oceanic waters was probably responsible for the distributions observed. Through HPLC/CHEMTAX pigment analysis we have developed a detailed picture of the influence of hydrological regime on the dynamics of the phytoplankton community in an under-studied shelf/ocean system in the tropical southern Atlantic Ocean.  相似文献   

10.
Spring phytoplankton bloom in the fronts of the East China Sea   总被引：2，自引：0，他引：2  
Frontal areas between warm and saline waters of the Kuroshio currents and colder and diluted waters of the East China Sea (ECS) influenced by the Changjiang River were identified from the satellite thermal imagery and hydrological data obtained from the Coastal Ocean Process Experiment (COPEX) cruise during the period between March 1st and 10th, 1997. High chlorophyll concentrations appeared in the fronts of the East China Seas with the highest chlorophyll-a concentration in the southwestern area of Jeju Island (~2.9 mg/m3) and the eastern area of the Changjiang River Mouth (~2.8 mg/m3). Vertical structures of temperature, salinity and density were similar, showing the fronts between ECS and Kuroshio waters. The water column was well mixed in the shelf waters and was stratified around the fronts. It is inferred that the optimal condition for light utilization and nutrients induced both from the coastal and deep waters enhances the high phytoplankton productivity in the fronts of the ECS. In addition, the high chlorophyll-a in the fronts seems to have been associated with the water column stability as well.  相似文献   

11.
The effects on the structure of the phytoplankton community of in situ environmental gradients concerning water qualities, formed during the mixing process of coastal with oceanic waters, were investigated on macro scale over a wide area of the Seto Inland Sea, Japan.The community structure of the phytoplankton varied almost constantly along the in situ environmental gradients in the community, which was shown by use of the diversity index rather than a mere listing of the phytoplankton community. These observations were considered to be the result of the direct or indirect response of the phytoplankton community to environmental gradients which occur in situ, which mean a series of variations of the habitat of the phytoplankton community. Their effects were reflected not in biomass but in the structure of the phytoplankton community. It was difficult to establish quantitatively the extent of their effects because of the variability in the degree of the environmental gradients which occur in situ.  相似文献   

12.
2010年胶州湾网采浮游植物种类组成与数量的周年变化   总被引：2，自引：1，他引：1  
为了研究胶州湾网采浮游植物的种类组成与数量变化,作者根据2010年的胶州湾调查资料,对调查区浮游植物丰度、优势种类和季节变化进行分析研究。结果表明,胶州湾浮游植物主要由硅藻和甲藻两大类组成,硅藻占据绝对优势地位。除了7月以外,甲藻/硅藻比均0.2。生态类型主要以近岸广布种和暖温带种为主,在不同季节也出现了少数暖水种和外洋种。浮游植物丰度表现为明显的"双周期",冬、春两季较高,夏、秋两季较低。2月为全年最高峰,数量为1108×104个/m3,10月为夏、秋两季的高峰,数量为458.7×104个/m3。浮游植物群落的多样性指数平均为1.9。  相似文献   

13.
Pre-metamorphic leptocephali of Pisodonophis sangjuensis (n = 91, 10.4?90.2 mm in total length, TL) were collected in the East China Sea for the first time. Pre-metamorphic leptocephali of P. sangjuensis, which were identified using mitochondrial DNA cytochrome c oxidase subunit I gene (mtDNA COI), are characterized by various combinations of morphological characters: 8 moderate to pronounced gut loops with the kidney terminating on the 6-7th loops; and 8 subcutaneous pigment patches on the tail just ventral to the notochord. Pisodonophis sangjuensis leptocephali were more numerously collected offshore than inshore around Jeju Island. The smallest leptocephali (< 15.0 mm TL) were collected from the south far from Jeju Island, and the largest leptocephali (> 100.0 mm TL) were collected from around Jeju Island and the southern coast of Korea. Our findings indicate that P. sangjuensis spawns offshore south of Jeju Island that is an area associated with high water temperature, and then the hatched leptocephali are transported to Jeju Island or the southern coast of Korea by the Tsushima Warm Current.  相似文献   

14.
Phytoplankton growth and microzooplankton grazing were studied during the 2007 spring bloom in Central Yellow Sea. The surveyed stations were divided to pre-bloom phase (Chl a concentration less than 2 μg L−1), and bloom phase (Chl a concentration greater than 2 μg L−1). Shipboard dilution incubation experiments were carried out at 19 stations to determine the phytoplankton specific growth rates and the specific grazing rates of microzooplankton on phytoplankton. Diatoms dominated in the phytoplankton community in surface waters at most stations. For microzooplankton, Myrionecta rubra and tintinnids were dominant, and heterotrophic dinoflagellate was also important in the community. Phytoplankton-specific growth rates, with an average of 0.60±0.19 d−1, were higher at pre-bloom stations (average 0.62±0.17 d−1), and lower at the bloom stations (average 0.59±0.21 d−1), but the difference of growth rates between bloom and pre-bloom stations was not statistically significant (t test, p=0.77). The phytoplankton mortality rate by microzooplankton grazing averaged 0.41±0.23 d−1 at pre-bloom stations, and 0.58±0.31 d−1 during the blooms. In contrast to the growth rates, the statistic difference of grazing rates between bloom and pre-bloom stations was significant (after removal of outliers, t test, p=0.04), indicating the importance of the top-down control in the phytoplankton bloom processes. Average potential grazing efficiency on primary productivity was 66% at pre-bloom stations and 98% at bloom stations, respectively. Based on our results, the biomass maximum phase (bloom phase) was not the maximum growth rate phase. Both phytoplankton specific growth rate and net growth rate were higher in the pre-bloom phase than during the bloom phase. Microzooplankton grazing mortality rate was positively correlated with phytoplankton growth rate during both phases, but growth and grazing were highly coupled during the booming phase. There was no correlation between phytoplankton growth rate and cell size during the blooms, but they were positive correlated during the pre-bloom phase. Our results indicate that microzooplankton grazing is an important process controlling the growth of phytoplankton in spring bloom period in the Central Yellow Sea, particularly in the “blooming” phase.  相似文献   

15.
秦皇岛海域浮游植物的群落结构特征   总被引：1，自引：0，他引：1  
2014年4~9月对秦皇岛海域进行了调查,共鉴定出浮游植物3门33属70种,以硅藻门为主,7、8月份浮游植物种类数最多,约40种。在整个调查期间,浮游植物丰度在不同站位和月份之间差异较大,平均值为2.42×108个/m3,浮游植物优势种有北方娄氏藻、尖刺拟菱形藻、丹麦细柱藻、微小原甲藻等,优势种种类数9月最多,6月最少。浮游植物多样性指数为1.27~3.6,均匀度为0.31~0.73,6月份群落结构较单一,其他月份群落结构较稳定。  相似文献   

16.
2010年秋季南海北部浮游植物群落结构研究   总被引：5，自引：0，他引：5  
2010年10月26日-11月24日在南海北部进行了浮游植物群落结构的调查,共鉴定浮游植物4门70属204种(包括未定种12种),浮游植物以硅藻为主,其物种数为146种,其细胞丰度占总浮游植物细胞丰度的93.17%;甲藻次之,其物种数为51种,占总浮游植物细胞丰度的0.63%;金藻门3属4种及蓝藻门2属3种;蓝藻门中以红海束毛藻(Trichodesmium erythraeum)为主。调查区浮游植物的细胞丰度介于0.06×103~107.50×103 cells/L之间,平均值为5.00×103 cells/L。海南岛东北部和粤东近岸表层浮游植物丰度较高。垂直分布上,表层和25 m层的浮游植物细胞丰度较高。浮游植物主要优势种类有菱形海线藻(Thalassionema nitzschioides)、舟形藻(Navicula spp.)、中肋骨条藻(Skeletonema costatum)、旋链角毛藻(Chaetoceros curvisetus)、斯氏几内亚藻(Guinardia stolterforthii)、具槽帕拉藻(Paralia sulcata)等。调查区表层和5 m层Shannon-Wiener多样性指数平均值分别为3.14和2.83,Pielou均匀度指数平均值分别为0.73和0.77;两种指数在表层和5 m层均表现出较高的一致性。环境分析表明除硅酸盐外,浮游植物细胞丰度与其他环境因子均呈极显著性的相关性,主要受到氮元素及磷酸盐的共同限制作用。  相似文献   

17.
This is the first attempt to examine the relationship between the spatial distribution of siphonophores and mesoscale hydrographic features in the waters around Taiwan in summer. A total of 59 species of siphonophores, consisting of 12 Physonectae and 47 Calycophorae, were identified from our samples. The most abundant species were Lensia subtiloides (49.7 % of the total collection by number), Diphyes chamissonis (12.1 %), Chelophyes appendiculata (9.3 %), C. contorta (8.1 %), and Bassia bassensis (5.2 %). Two clear assemblages were associated with shelf waters (influenced by the South China Sea Surface Current) and oceanic waters (influenced by the Kuroshio Current), respectively. The shelf water assemblage was characterized by low diversity and high abundance of L. subtiloides, whereas the oceanic assemblage showed greater diversity and was dominated by C. appendiculata, C. contorta, and B. bassensis. We discovered strong correlations between temperature and zooplankton and siphonophore abundances, suggesting that temperature and prey concentration are important in determining the spatial distribution of siphonophores. In addition, lower abundance and higher species diversity of siphonophores were observed after the passage of typhoons. This study provides basic knowledge on the distributional patterns of siphonophores, which is essential information to further understand the ecological roles played by siphonophores and their responses to the hydrological conditions in the waters surrounding Taiwan.  相似文献   

18.
Manila clam Ruditapes philippinarum is one of the most important benthic animals in the coastal north Pacific region, where clam populations have been mixed genetically through trade and aquaculture activities. Accordingly, identification of the genetically different clam populations has become one of the most important issues to manage interbreeding of the local and introduced clam populations. To identify genetically different populations of clam populations, we developed 11 expressed sequence tag (EST)-microsatellite loci (i.e., simple sequence repeat, SSR) from 1,128 clam hemocyte cDNA clones challenged by the protozoan parasite Perkinsus olseni. Genotype analysis using the markers developed in this study demonstrated that clams from a tidal flat on the west coast contained 6 to 19 alleles per locus, and a population from Jeju Island had 4 to 20 alleles per locus. The expected heterozygosity of the 2 clam populations ranged from 0.472 to 0.919 for clams from the west coast, and 0.494 to 0.919 for clams from Jeju Island, respectively. Among the 11 loci discovered in this study, 7 loci significantly deviated from the Hardy-Weinberg equilibrium after Bonferroni correction. The 5 loci developed in this study also successfully amplified the SSRs of R. variegatus, a clam species taxonomically very close to R. philippinarum, from Hong Kong and Jeju Island. We believe that the 11 novel polymorphic SSR developed in this study can be utilized successfully in Manila clam genetic diversity analysis, as well as in genetic discrimination of different clam populations.  相似文献   

19.
In order to characterize the distribution and community structure of phytoplankton, chlorophyll and carotenoid pigments, nutrients, and hydrographic variables were measured in the coastal waters off Jeju Island, Korea, during 11–13 May 2005. The photosynthetic pigments were analyzed using a high-performance liquid chromatograph (HPLC), and were used to calculate the algal class abundances using the CHEMTAX program. There was a distinct difference in phytoplankton abundance and community composition between the northern coastal water (NCW) and the southern coastal water (SCW) of this island. The chlorophyll a concentrations were ～26% higher in NCW than in SCW. Diatoms were predominant (> 50%) in NCW, while the phytoplankton composition was more diverse in SCW. Considering the hydrographic conditions and nutrient distributions in the study region, the sharp structural change in phytoplankton community seems to be mainly due to the slight difference in the origin of NCW and SCW. This study shows that HPLC-pigment measurements are useful for identifying sharp structural changes in phytoplankton communities in dynamic coastal environments.  相似文献   

20.
This study examined seasonal and annual occurrences of warm oceanic tintinnid species in southern Korea coastal waters. The indicative species of tintinnids was monitored using three approaches: monitoring from cruises traveling from the warm pool in the western North Pacific to the Korea Strait; biweekly or monthly monitoring in the Korea Strait; and daily monitoring in the nearshore water. Annual pulses of warm oceanic indicator species were regularly observed in the Korea Strait. In September 2008 recorded a maximum species number of warm water indicators, a representative species for warm oceanic waters, Climacocylis scalaroides was simultaneously detected in the nearshore water as well as the Korea Strait. The result indicates that the greater warm water extension into Korean coastal areas was in September 2008. Sharp declines in species diversity were observed in the transitional area between neritic and Kuroshio zone in East China Sea (ECS). Epiplocyloides reticulata, reported previously as a Kuroshio indicator, was considered an ECS indicator species, as it was undetected in the western North Pacific central zone but was found abundantly in the ECS. Tintinnid species can be used as biological indicators to detect the inflow of warm oceanic waters into Korean coastal waters.  相似文献   

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