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Young-Ok Kim Eun Jin Yang Jung-Hoon Kang Kyoungsoon Shin Man Chang Cheol Soo Myung 《Ocean Science Journal》2007,42(1):9-17
The summer distributions of planktonic microbial communities (heterotrophic and phtosynthetic bacteria, phtosynthetic and
heterotrophic nanoflagellates, ciliate plankton, and microphytoplankton) were compared between inner and outer areas of Lake
Sihwa, divided by an artificial breakwater, located on the western coast of Korea, in September 2003. The semienclosed, inner
area was characterized by hyposaline surface water (<17 psu), and by low concentrations of dissolved oxygen (avg. 0.4 mg L1) and high concentrations of inorganic nutrients (nitrogenous nutrients >36 μM, phosphate <4 μM) in the bottom layer. Higher
densities of heterotrophic bacteria and nanoflagellates also occurred in the inner area than did in the outer area, while
microphytoplankton (mainly diatoms) occurred abundantly in the outer area. A tiny tintinnid ciliate, Tintinnopsis nana, bloomed
into more than 106 cells L1 at the surface layer of the inner area, while its abundance was much lower (103-104 cells L1) in the outer area of the breakwater. Ciliate abundance was highly correlated with heterotrophic bacteria (r = 0.886, p <
0.001) and heterotrophic flagellates (r = 0.962, p < 0.001), indicating that rich food availability may have led to theT. nana bloom. These results suggest that the breakwater causes the eutrophic environment in artificial lakes with limited flushing
of enriched water and develops into abundant bacteria, nanoflagellates, and ciliates. 相似文献
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桑沟湾浮游纤毛虫丰度和生物量分布的季节变化 总被引：1，自引：0，他引：1
于2011年4、8、10月及2012年1月对桑沟湾进行了浮游纤毛虫丰度和生物量的季节调查。纤毛虫的平均丰度为(7 552±10 979)个/L,范围为408~61 667个/L;纤毛虫的平均生物量(以碳计)为(4.79±5.77)μg/L,范围为0.35~33.09 μg/L。无壳纤毛虫丰度和生物量主要分布在湾内,湾中和湾外丰度相对较低;砂壳纤毛虫丰度和生物量在盐度较高的海区总体较高,呈现朝向外海分布的趋势。纤毛虫丰度和生物量的高值区春季主要出现在湾的西北,夏季向湾中部迁移,秋季主要出现在湾的西南,冬季主要出现在湾的西部,高值区随季节大致呈顺时针迁移的趋势。纤毛虫的丰度春季最高,冬季最低;生物量夏季最高,冬季最低。无壳纤毛虫夏季粒级较大,冬季粒级较小;砂壳纤毛虫壳的平均口径夏季较大,秋季较小。共鉴定出砂壳纤毛虫8属27种,其中拟铃虫属(Tintinnopsis)种数最多。砂壳纤毛虫在纤毛虫总丰度中的比例平均为16.3%±21.9%,夏季最高(36.3%±27.8%),冬季最低(4.9%±5.9%)。纤毛虫丰度与温度、盐度、Chl a浓度及微微型真核浮游生物丰度均没有明显的相关性,但与蓝细菌及异养细菌丰度呈显著的正相关关系。 相似文献
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《Deep Sea Research Part I: Oceanographic Research Papers》2002,49(7):1217-1232
We examined tintinnid (loricate ciliate microzooplankton) diversity using data from 11 stations between the Moroccan upwelling system and the oligotrophic Eastern Mediterranean. Taxonomic and morphological diversity of tintinnids was compared to phytoplankton distribution and size-structure, to the abundance of competitors in the form of oligotrich ciliates, and predators as copepods. Tintinnid taxonomic diversity was estimated as numbers of species and the Shannon Index, H′; morphological diversity was quantified by substituting size classes of lorica dimensions for species. Total chlorophyll was partitioned into micro-, nano- and pico-fractions using pigment data and a size-diversity was estimated by considering the 3 size classes as 3 species. Along a west-to-east gradient, average water column concentrations of most organism groups declined approximately an order of magnitude yielding tight correlations. However, tintinnid diversity, both taxonomic and morphological, increased from the Atlantic upwelling station into the western basin of the Mediterranean, and declined slightly towards the Eastern Mediterranean, paralleling shifts in the chlorophyll size-diversity estimate. Diversity varied with absolute or relative abundance of oligotrich or copepods, but different diversity metrics were significantly correlated only with phytoplankton size-diversity. We conclude that tintinnid diversity more closely reflects resource diversity than competitive interactions or predation. 相似文献
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Christine Dupuy Agathe Talarmin Hans J. Hartmann Daniel Delmas C. Courties Elise Marquis 《Estuarine, Coastal and Shelf Science》2011
In order to investigate the parameters controlling the heterotrophic protists (nano-microzooplankton) on the continental shelf of the southern Bay of Biscay, plankton communities and their physico-chemical environment were studied 4 times in February, April, June and September–October 2004 at three stations in the euphotic zone in the Bay of Biscay. The abundance and carbon biomass of heterotrophic protists (ciliates, heterotrophic dinoflagellates and nanoflagellates) as well as all the others groups of plankton (picoplankton, nanophytoplankton, diatoms, autotrophic dinoflagellates, metazoan microzooplankton and mesozooplankton), the environmental parameters and the primary and bacteria production were evaluated at each sampling period. Microzooplankton grazing experiments were undertaken at the same time. Ciliates and heterotrophic dinoflagellates accounted for the main major component of nano- and microzooplankton communities in term of biomass. The total carbon biomass of heterotrophic protists was highest in spring and lowest at the end of summer. The development of heterotrophic protists started after a winter microphytoplankton bloom (principally large diatoms), the biomass was lower in June and was low in September (through inappropriate prey). The carbon requirement of microzooplankton ranged from 50 to more than 100% of daily primary, bacterial and nanoflagellate production. The heterotrophic protist community was predominantly constrained by bottom-up control in spring and at the end of summer via food availability and quality. 相似文献
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《Deep Sea Research Part I: Oceanographic Research Papers》2000,47(3):479-503
The composition and vertical distribution of planktonic ciliates within the surface layer was monitored over four diel cycles in May 95, during the JGOFS-France DYNAPROC cruise in the Ligurian Sea (NW Mediterranean). Ciliates were placed into size and trophic categories: micro- and nano-heterotrophic ciliates, mixotrophic ciliates, tintinnids and the autotrophic Mesodinium rubrum. Mixotrophic ciliates (micro and nano) represented an average of 46% of oligotrich abundance and 39% of oligotrich biomass; nano-ciliates (hetero and mixotrophic) were abundant, representing about 60 and 17% of oligotrich abundance and biomass, respectively. Tintinnid ciliates were a minor part of heterotrophic ciliates. The estimated contribution of mixotrophs to chlorophyll a concentration was modest, never exceeding 9% in discrete samples. Vertical profiles of ciliates showed that chlorophyll-containing ciliates (mixotrophs and autotrophs) were mainly concentrated and remained at the chlorophyll a maximum depth. In contrast, among heterotrophic ciliates, a portion of the population appeared to migrate from 20–30 m depth during the day to the surface at night or in the early morning. Correlation analyses of ciliate groups and phytoplankton pigments showed a strong relationship between nano-ciliates and zeaxanthin, and between chlorophyll-containing ciliates and chlorophyll a, as well as other pigments that were maximal at the chlorophyll a maximum depth. Total surface layer concentrations showed minima of ciliates during nightime/early morning hours. 相似文献
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Ciliates are important components in planktonic food webs,but our understanding of their community structures in different oceanic water masses is limited.We report pelagic ciliate community characteristics in three seas:the tropical West Pacific,the Bering Sea and the Arctic Ocean.Planktonic ciliate abundance had"bimodal-peak","surface-peak"and"DCM(deep chlorophyll a maximum layer)-peak"vertical distribution patterns in the tropical West Pacific,the Bering Sea and the Arctic Ocean,respectively.The abundance proportion of tintinnid to total ciliate in the Bering Sea(42.6%)was higher than both the tropical West Pacific(7.8%)and the Arctic Ocean(2.0%).The abundance proportion of small aloricate ciliates(10–20μm size-fraction)in the tropical West Pacific was highest in these three seas.The Arctic Ocean had higher abundance proportion of tintinnids in larger LOD(lorica oral diameter)size-class.Proportion of redundant species increased from the Arctic Ocean to the tropical West Pacific.Our result provided useful data to further understand ecology roles of planktonic ciliates in different marine habitats. 相似文献
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台湾海峡小型浮游动物的摄食对夏季藻华演替的影响 总被引：3，自引：2，他引：3
于2004年8月1~6日对台湾海峡南部近岸的藻华过程进行了定点连续跟踪观测,用稀释法研究了浮游植物的生长率和小型浮游动物对浮游植物的摄食死亡率,同时运用高效液相色谱(HPLC)技术,分析了浮游植物不同光合色素类群的生长率和摄食死亡率.结果表明,观测期间处于藻华的消退期.8月1日时,浮游植物生物量(叶绿素a)和丰度分别为2.04μg/dm3和2.99×105个/dm3,主要优势种为尖刺伪菱形藻(Pseudo-nitzschia pungens)、冰河拟星杆藻(Asterionellopsis glacialis)和中肋骨条藻(Skeletonema costatum),8月6日时,浮游植物生物量和丰度分别减为0.37μg/dm3和1.54×104个/dm3;而蓝藻和甲藻的丰度和比例则呈现出逐渐增加的趋势,所占的比重分别从1日的0.04%和0.85%增加到6日的9.59%和41.97%.小型浮游动物主要由无壳纤毛虫、砂壳纤毛虫、红色中缢虫(Mesodinium rubrum)和异养甲藻等类群组成,总丰度于8月2日达到最大值,为3640个/dm3,之后逐渐减少,6日时,仅为436个/dm3.观测期间,小型浮游动物在群落组成上虽一直以无壳纤毛虫和异养甲藻为主,但在具体的类群结构上却表现出了一定的差异,30μm以下的无壳纤毛虫和异养甲藻总体呈下降的趋势,而红色中缢虫、砂壳纤毛虫和大于50μm的无壳纤毛虫总体呈增加的趋势.观测期间,浮游植物的生长率为0.40~0.91d-1,小型浮游动物的摄食率为0.26~1.34d-1,摄食率和生长率总体呈逐渐下降的趋势.结果还表明,小型浮游动物的摄食率与叶绿素a具有很好的相关性(R2=0.89),对各光合色素类群的现存量和初级生产力均具有较高的摄食压力(分别为37.97%~82.24%和70.71%~281.33%),是藻华消亡的重要原因之一;此外,小型浮游动物对甲藻和蓝藻的避食行为,可能是观测期间由“硅藻”水华向“硅藻-甲藻”水华转变的重要原因之一. 相似文献
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春、秋季南黄海浮游纤毛虫丰度及生物量的分布差异 总被引：1，自引：0，他引：1
Seasonal variation of marine plankton spatial distribution is important in understanding the biological processes in the ocean.In this study,we studied spatial distribution of planktonic ciliate abundance and biomass in the central deep area(station depth greater than 60 m) and the coastal shallow area(station depth less than 60 m) of the southern Yellow Sea(32°–36.5°N,121°–125°E) in spring(April) and autumn(October–November) of 2006.Our results showed that both ciliate abundance and biomass in the surface waters were higher in spring((1 490±2 336)ind./L;(4.11±7.81) μg/L) than in autumn((972±823) ind./L;(1.11±1.18) μg/L,calculated by carbon).Ciliate abundance and biomass in the surface waters of the coastal shallow area were similar in spring and autumn.However,in the central deep area,those values were much higher in spring((1 878±2 893) ind./L;(5.99±10.10)μg/L) than in autumn((738±373) ind./L;(0.74±0.76) μg/L).High values of ciliate abundance and biomass occurred in the central deep area in spring and in the coastal shallow area in autumn.Mixotrophic ciliate Laboea strobila was abundant in the central deep area in spring,when a phytoplankton bloom occurred.However,in autumn,L.strobila was abundant in the coastal shallow area.Boreal tintinnid Ptychocyli obtusa was found in spring.Both L.strobila and P.obtusa were concentrated in the surface waters when their abundance was more than 1 000 ind./L.Peaks of these species were in the subsurface waters when their abundance was less than 400 ind./L.This study showed that both high abundance and biomass of ciliates occurred in different areas in southern Yellow Sea seasonally. 相似文献
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黄海水母旺发区浮游鞭毛虫和纤毛虫群落结构分布及其与水母发生关系初探 总被引：2，自引：2，他引：0
鞭毛虫和纤毛虫在海洋微食物环和经典食物链间的能量流动中起着重要的枢纽作用,但其在水母暴发过程中的作用仍然不明。本研究基于2011年春季以及水母旺发的夏季黄海专项航次,通过荧光染色技术和定量蛋白银法研究了南黄海水母频发海域3个断面(E:33°N,G:34°N,I:35°N)的鞭毛虫和纤毛虫的群落结构和时空分布特点,对其与水母的发生关系进行了初步探讨。结果表明,春夏两季的微型鞭毛虫丰度均以近岸水域为最高,向外海递减,高值区大多出现在水体表层及底层附近。夏季总微型鞭毛虫的丰度和生物量较春季略高,且异养微型鞭毛虫比例升高。纤毛虫丰度的水平分布与鞭毛虫正相反,以近岸较低,向外海递增,主要分布在表层及10m水层。在水母出现的E和G断面,夏季纤毛虫数量显著降低,丰度仅为春季的30%—40%;而未见水母的I断面夏季较春季的数量升高了一个数量级。推测夏季水母发生的E、G断面纤毛虫丰度明显降低系因水母的捕食压力所致,纤毛虫数量的减少导致对鞭毛虫的摄食压力降低,鞭毛虫数量增加;而未见水母的I断面纤毛虫则维持较高的丰度值。本研究表明,水母作为浮游生态系统的顶级捕食者,可通过营养级联效应对微小型浮游动物群落产生影响。 相似文献
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To investigate the seasonal variation and community structure of nano- and microzooplankton in Gyeonggi Bay of the Yellow Sea, the abundance and carbon biomass of nano- and microzooplankton were evaluated at 10-day intervals from January 1997 to December 1999. Four major groups of nano- and microzooplankton communities were classified: heterotrophic ciliates, heterotrophic dinoflagellates (HDF), heterotrophic nanoflagellates (HNF), and copepod nauplii. The total carbon biomass of nano- and microzooplankton ranged from 10.2 to 168.8 μg C L−1 and was highest during or after phytoplankton blooms. Nano- and microzooplankton communities were composed of heterotrophic ciliates (7.4–81.4%; average 41.7% of total biomass), HDF (0.1–70.3%; average 26.1% of total biomass), copepod nauplii (1.6–70.6%; average 20.7% of total biomass), and HNF (0.8–59.5%; average 11.5% of total biomass). The relative contribution of individual components in the nano- and microzooplankton communities appeared to differ by seasons. Ciliates accounted for the most major component of nano- and microzooplankton communities, except during summer and phytoplankton blooming seasons, whereas HDF were more dominant during the phytoplankton blooming seasons. The abundance and biomass of nano- and microzooplankton generally followed the seasonal dynamics of phytoplankton. The size and community distribution of nano- and microzooplankton was positively correlated with size-fractionated phytoplankton. The carbon requirement of microzooplankton ranged from 60 to 83% of daily primary production, and was relatively high when phytoplankton biomass was high. Therefore, our result suggests that the seasonal variation in the community and size composition of nano- and microzooplankton appears to be primarily governed by phytoplankton size and concentration as a food source, and their abundance may greatly affect trophic dynamics by controlling the seasonal abundance of phytoplankton. 相似文献
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采用密度梯度离心结合定量蛋白银染色(Ludox-QPS)方法,对2010年7月和11月获自黄海海域沉积物中的底栖纤毛虫进行了群落结构研究,并结合环境因子进行了分析。结果表明:7月浒苔暴发期间,纤毛虫现存量以北黄海、南黄海近岸和长江口外海域较高,南黄海离岸站位较低;11月的纤毛虫丰度和生物量均明显高于7月,南黄海近岸站位的丰度和生物量较高,且向外海随水深增大呈减少的趋势。11月丰度和生物量前三位的类群与7月一致,前口类丰度所占比例最高,核残迹类生物量所占比例最高。肉食性纤毛虫均是两个月份的最优势摄食类群。11月纤毛虫的物种数、Margalef指数和香农-威纳指数均高于7月,且均以南黄海近岸海域较高,而离岸海域较低;纤毛虫丰度、生物量、物种数、Margalef和香农-威纳指数与底层水温度和沉积物中值粒径呈显著正相关。冷水团对底栖纤毛虫群落结构和分布有一定的影响,且是多个环境因子的共同影响。两个月份纤毛虫群落间的Jaccard相似系数值高于单个月份南北黄海和冷水团内外的系数值,表明黄海底栖纤毛虫的物种组成在季节间的差异可能小于不同海域之间的差异。7月南黄海近岸较高的纤毛虫现存量和多样性表明,浒苔的死亡和降解可能通过级联效应促进了近岸站位纤毛虫的生长。 相似文献
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Chang-Rae Lee Keun-Hyung Choi Hyung-Ku Kang Eun Jin Yang Jae Hoon Noh Dong Han Choi 《Journal of Oceanography》2012,68(3):473-482
This study examined the biomass structure of autotrophic and heterotrophic plankton along a trophic gradient in the northwestern Pacific Ocean in an attempt to understand planktonic food web structure. Autotrophic biomass exceeded that of heterotrophic organisms in all sampling regions, but with lesser contribution to total planktonic biomass at stations of higher phytoplankton biomass, including the northern East China Sea, compared to the regions of lower phytoplankton biomass. The proportion of the biomass of heterotrophic bacteria, nanoflagellates (HNF), and dinoflagellates (HDF) relative to that of phytoplankton was all inversely related to phytoplankton biomass, but positive relationships were observed for both ciliates and mesozooplankton. Mesozooplankton biomass inclined greater than phytoplankton along the gradient of phytoplankton biomass, with biomass rise being most closely associated with ciliate and HDF biomass and, to a lesser degree, with large phytoplankton (>3?μm). Both bacteria and picophytoplankton were significantly and positively related to the biomass ratio of mesozooplankton to the sum of HDF and ciliates (i.e., proxy of mesozooplankton predation on protozoans), but no positive relationship was apparent either for HNF or for large phytoplankton. Such relationships may result from predation relief on lower food webs associated with mesozooplankton feeding on protistan plankton. 相似文献
14.
Seasonal dynamics of ciliated protozoa and their potential food in an eutrophic estuary (Bay of Biscay) 总被引：2，自引：0，他引：2
Iaki Urrutxurtu Emma Orive Alejandro de la Sota 《Estuarine, Coastal and Shelf Science》2003,57(5-6):1169-1182
Ciliate assemblages, together with phytoplankton and heterotrophic nanoflagellates (HNF) as their potential food, have been surveyed monthly along the salinity gradient of the Nervión River estuary from March 2000 to March 2002. A total of 135 taxa of ciliate have been identified corresponding to 20 orders. Scuticociliates, naked choreotrichs and oligotrichs were the most abundant groups, distributed throughout a broad range of salinity. In addition to these groups, which were the dominant taxa in the middle estuary, tintinnids were characteristic of the ciliate assemblages of the outer estuary whereas in the innermost part naked choreotrichs and oligotrichs decreased in number, being substituted by sessilids, hymenostomatids, peniculids and cyrtophorids. Total ciliate concentrations were among the highest reported in the literature for other estuaries and coastal waters, frequently reaching 105 cells l−1. Meanwhile, tintinnid concentrations were comparable with those of other estuarine and coastal waters. Based on a principal component analysis (PCA) three main groups were delineated, with ciliates and their potential food sources as variables. One was that constituted by freshwater ciliate such as sessilids, hymenostomatids, cyrtophorids and pleurostomatids, which appear in low numbers in the innermost part, mainly in winter. Another group contained diatoms, chlorophytes, flagellates, euplotids and scuticociliates, all of them broadly distributed along the estuary and reaching their maximum density in late spring–summer. The third group was made up of taxa mainly appearing at the seaward end such as dinoflagellates, cyanobacteria, haptorids, tintinnids, naked choreotrichs and oligotrichs, which reached the highest densities in summer and early autumn. Ciliates do not seem to be food limited in the Nervión River estuary or much controlled by metazoan grazing. 相似文献
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16.
九龙江口春季微型浮游生物数量变动及其与小型水母消长的关系 总被引：2，自引：0，他引：2
通过2011年春季对九龙江口的生态调查,对浮游植物、微型浮游动物以及小型水母的种类组成和数量变动特征并对分粒级叶绿素进行了研究,同时还分析了营养盐、温度和盐度等环境参数。调查共记录浮游植物种类45种,以硅藻门的中肋骨条藻(Skeletonema costatum)、颗粒直链藻(Melosira granulate)、针杆藻(Synedra spp.),以及绿藻门的斜生栅藻(Scenedesmus obliquus)、甲藻门的微小亚历山大藻(Alexandrium minutum),蓝藻门的优美平裂藻(Merismopedia elegans)具有较高的检出率;微型浮游动物分为4大类,红色中缢虫(Mesodinium rubrum)占有最大的比例为55.5%-79.8%,无壳纤毛虫次之,砂壳纤毛虫和无节幼体所占的比例均不足10%;小型水母种类组成中主要以弗洲指突水母(Blackfordia virginica)、球型侧腕水母(Pleurobrachia globosa)、厦门和平水母(Eirene xiamenensis)以及水螅水母幼体(Hydroidomedusae larvae)为主要优势类群,占小型水母总量的85%以上。小型水母数量在4月底和5月初达到丰度最高值(69.49±29.4)ind/L,此时微型浮游动物数量从小型水母出现初期的峰值(1085±574.66)ind/L下降为(526±152.93)ind/L,同时micro级叶绿素占总叶绿素比例达到最大值(42.26±12.94)%。小型水母数量下降后,微型浮游动物的数量回升。在小型水母数量消长过程中,浮游植物、微型浮游动物和小型水母数量间处于动态平衡。 相似文献
17.
研究了2005年4个季度用浅海Ⅲ型网在长江口40个站位采集的浮游生物样品,发现砂壳纤毛虫11种:Codonellopsis ostenfeldi,C.parva,Eutintinnus tenuis,Favella panamensis,Leprotintinnus nordqvisti,Leprotintinnus sp.,Tintinnopsis japonica,T. karajacensis,T. mortensenii,T. radix,T. schotti.Leprotintinnus sp.,最大丰度可达32 400个/m3,有的种的最大丰度不足200个/m3,如Codonellopsis parva,E. tenuis和T.mortensenii.冬季T.japonica主要分布于长江口外,Leprotintinnus sp.在春、夏、秋季都主要分布于长江口外,其他种的分布没有明显规律.在4个季度长江口内都没有发现砂壳纤毛虫. 相似文献
18.
大亚湾大鹏澳海域表层沉积物中浮游植物休眠体集群的季节变化 总被引：2，自引：0，他引：2
于2007年4月至2008年3月对大亚湾大鹏澳海域表层沉积物中浮游植物休眠体进行了每月1次的周年调查.本调查分析鉴定出浮游植物休眠体79种,包括甲藻孢囊50种,硅藻休眠体26种.浮游植物休眠体丰度没有明显的季节变化规律,变化范围为217～6 764 cells/cm3,平均为1 376 cells/cm3;鱼类养殖区休眠体丰度较高,平均丰度为1 999 cells/cm3.浮游植物休眠体在数量上以硅藻为主,甲藻次之,而在鱼类养殖区也出现了较高的蓝藻休眠体.硅藻休眠体的平均丰度为783 cells/cm3,百分比含量为56.9%,从而反映了该海域硅藻型浮游植物群落结构.甲藻孢囊丰度的变化范围在79～1 237 cells/cm3,位于湾口对照区丰度较高,年平均为733 cells/cm3,而鱼类养殖区和贝类养殖区平均值分别为502、388 cells/cm3.异养型甲藻孢囊的种类和数量均比较丰富,其百分比含量为26.7%～82.4%.研究结果显示,在富营养化程度较高的养殖区海域,硅藻休眠体和异养型甲藻孢囊百分率均较高,而鱼类养殖区还出现了较高蓝藻孢子丰度.本次调查中还出现了易碎藻和艉杆藻等在本海域浮游植物调查中未记录种类的孢囊,有毒有害赤潮生物的休眠体如亚历山大藻、链状裸甲藻、旋沟藻、巴哈马梨甲藻孢囊等也在此次调查中频繁出现,说明大亚湾海域存在较大的有毒有害赤潮发生的风险. 相似文献
19.
An-Yi Tsai Gwo-Ching Gong Robert W. Sanders Ciou-Jyu Wang Kuo-Ping Chiang 《Estuarine, Coastal and Shelf Science》2010
Variation in the summer nanoflagellate community on the continental shelf ecosystem of East China Sea (ECS) is closely coupled with environmental variation due to extension of the Changjiang River plume. Spatial patterns of nanoflagellate abundance were studied in June and August 2003, June 2006 and July 2007 over the ECS shelf. The Changjiang River plume was smaller during the August 2003 and July 2007 cruises than during the rest other 2 cruises. Total nanoflagellates densities varied between 1 and 120 × 102 cells ml−1 with the highest abundances occurring within the Changjiang River plume during large plume periods. In the small plume periods, the range of nanoflagellates abundance was 3–33 × 102 cells ml−1 and the highest abundances were observed during these periods either within the Changjiang River plume or the Yellow Sea Coastal Water (YSCW). During large plume periods, nanoflagellate abundance closely related to changes in salinity and during the small period, abundance was most related to water temperature. The pigmented nanoflagellate community (PNF) within Changjiang River plume, especially in the <3 μm size class, appears to increase in response to terrestrial or anthropogenic inorganic nutrient loading in the discharge of fresh water from the Changjiang River. The PNF abundance pronounced increase caused the variation of nanoflagellate community of ECS in summer. We suggest that the discharge of fresh water from Changjiang River has significant ecological impacts on spatial variations in nanoflagellate community in the ECS. 相似文献
20.
夜光藻是全球广泛分布的藻华种之一, 其摄食作用对浮游生物的群落结构有着重要影响。利用环境DNA技术和Spearman相关性分析, 文章研究了2021年1月中旬大亚湾夜光藻高丰度站位浮游生物的群落结构与生物相关性。结果显示, 夜光藻高丰度站位的海水温盐条件为温度 14.4~18.3℃、盐度 32.52‰~33.14‰。夜光藻丰度较高的站位中, 卡顿藻科、海链藻科等浮游植物类群的相对丰度均值为2.41%和2.23%, 明显高于其他站位的0.75%和0.62%; 同时拟哲水蚤科与长腹剑水蚤科等类群的相对丰度均值为8.22%和4.46%, 明显低于其他站位的64.13%和11.12%。结合Spearman相关性分析表明, 夜光藻丰度增加可能导致其对拟哲水蚤科等类群摄食压力增加, 拟哲水蚤科类群丰度减少降低了卡顿藻科、海链藻科、原甲藻科、隐芽藻科等浮游植物类群的摄食压力, 使其生物丰度增加; 同时夜光藻摄食压力增加使得裸甲藻科、圆筛藻科等浮游植物丰度下降。因此, 夜光藻丰度增加影响了水域中真核浮游生物群落结构。综上结果表明, 环境DNA技术有助于认识夜光藻在浮游生物群落中的生态地位, 可用于浮游生物各类群之间的关系分析。 相似文献