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1.
The ratio of nitrogen/phosphorus (N/P) is known to affect cell proliferation of some marine micro algae. We evaluated the effect of N/P ratios on the proliferation and succession of phytoplankton using five marine micro algae species. We used two sources of nitrogen, NH4Cl (N1) and urea (N2), and a single source of phosphorous, NaH2PO4(P). The optimal N/P ratio that differed among the five species was affected by the source of nitrogen, being as follows (N1/P, N2/P in order): Thalassiosira sp. (30/1, 20/1),... 相似文献
2.
ＩＮＴＲＯＤＵＣＴＩＯＮＮａｎｄＰｉｎｐｕｔｔｅｄｉｎｔｏＪｉａｏｚｈｏｕＢａｙｂｙｒｉｖｅｒｓａｎｄｂｙｓｅｗａｇｅｅｆｆｌｕｅｎｔｓｏｆｃｉｔｉｅｓ ,ｈａｖｅｍａｄｅｔｈｅＢａｙｂｅｃｏｍｅｍｏｒｅａｎｄｍｏｒｅｅｕｔｒｏｐｈｉｃｄａｙｂｙｄａｙ .Ｓｈｅｎ ( 1994)ｔｈｏｕｇｈｔｔｈａｔｐｈｙｔｏｐｌａｎｋｔｏｎｇｒｏｗｔｈｗａｓｌｉｍｉｔｅｄｂｙｔｈｅｃｈａｎｇｅｆｒｏｍｎｉｔｒｏｇｅｎｔｏｐｈｏｓｐｈｏｒｏｕｓ ;ａｎｄｔｈａｔｔｈｅｓｉｌｉｃａｔｅｃｏｎｃｅｎｔｒａｔｉｏｎｉｎＪｉａｏｚｈ… 相似文献
3.
Dimethylsulfide(DMS) and dimethylsulfoniopropionate(DMSP) production by Scrippsiella trochoidea and Prorocentrum minimum was investigated to characterize the effects of physiological stage and salinity on DMS and DMSP pools of these two marine phytoplankton species.Axenic laboratory cultures of the two marine algae were tested for DMSP production and its conversion into DMS.The results demonstrated that both algal species could produce DMS,but the average concentration of DMS per cell in S.trochoidea(12.63 fmol/L) was about six times that in P.minimum(2.01 fmol/L).DMS and DMSP concentrations in algal cultures varied significantly at different growth stages,with high release during the late stationary growth phase and the senescent phase.DMS production induced by three salinities(22,28,34) showed that the DMS concentrations per cell in the two algal cultures increased with increasing salinity,which might result from intra-cellular DMSP up-regulation with the change of osmotic stress.Our study specifies the distinctive contributions of different physiological stages of marine phytoplankton on DMSP and DMS production,and clarifies the influence of salinity conditions on the release of DMS and DMSP.As S.trochoidea and P.minimum are harmful algal bloom species with high DMS production,they might play an additional significant role in the sulfur cycle when a red tide occurs. 相似文献
4.
Analysis and comparison of Jiaozhou Bay data collected from May 1991 to February 1994 (12 seasonal investigations) provided
by the Ecological Station of Jiaozhou Bay revealed the characteristic spatiotemporal variation of the ambient concentration
Si∶DIN and Si∶16P ratios and the seasonal variation of Jiaozhou Bay Si∶DIN and Si∶16P ratios showing that the Si∶DIN ratios
were <1 throughout the year in Jiaozhou Bay; and that the Si∶16P ratios were <1 throughout Jiaozhou Bay in spring, autumn
and winter. The results proved that silicate limited phytoplankton growth in spring, autumn and winter in Jiaozhou Bay. Analysis
of the Si∶DIN and Si∶P ratios showed that the nutrient Si has been limiting the growth of phytoplankton throughout the year
in some Jiaozhou Bay waters; and that the silicate deficiency changed the phytoplankton assemblage structure.
Analysis of discontinuous 1962 to 1998 nutrient data showed that there was no N or P limitation of phytoplankton growth in
that period. The authors consider that the annual cyclic change of silicate limits phytoplankton growth in spring, autumn
and winter every year in Jiaozhou Bay; and that in many Jiaozhou Bay waters where the phytoplankton as the predominant species
need a great amount of silicate, analysis of the nutrients N or P limitation of phytoplankton growth relying only on the N
and P nutrients and DIN∶P ratio could yield inaccurate conclusions. The results obtained by applying the rules of absolute
and relative limitation fully support this view.
The authors consider that the main function of nutrient silicon is to regulate and control the mechanism of the phytoplankton
growth process in the ecological system in estuaries, bays and the sea.
The authors consider that according to the evolution theory of Darwin, continuous environmental pressure gradually changes
the phytoplankton assemblage's structure and the physiology of diatoms. Diatoms requiring a great deal of silicon either constantly
decrease or reduce their requirement for silicon. This will cause a series of huge changes in the ecosystem so that the whole
ecosystem requires continuous renewal, change and balancing. Human beings have to reduce marine pollution and enhance the
capacity of continental sources to transport silicon to sustain the continuity and stability in the marine ecosystem.
This study was funded by the NSFC (No. 40036010) and subsidized by Special Funds from the National Key Basic Research Program
of P. R. China (G199990437), the Postdoctoral Foundation of Ocean University of Qingdao, the Director's Foundation of the
Beihai Monitoring Center of the State Oceanic Administration and the Foundation of Shanghai Fisheries University. 相似文献
5.
Carbonyl compounds,especially polyunsaturated aldehydes(PUAs),are increasingly reported as teratogenic to grazers and deleterious to phytoplankton.While PUAs have been considered to be mainly produced by diatoms after cell wounding,little is known about whether microalgae other than diatoms,particularly harmful algal bloom(HAB)-forming species,produce carbonyl compounds.In this study,we analyzed the carbonyl compounds from eight common HAB-forming species(Akashiwo sanguinea,Karenia mikimotoi,Karlodinium veneficum,Margalefidinium polykrikoides,Prorocentrum donghaiense,P.minimum,Scrippsiella trochoidea,and Heterosig,ma akashiwo)using gas chromatography-mass spectrometry in full scan and selected ion monitoring(SIM)modes.Our results show a ubiquitous presence of carbonyl colmpounds in both dissolved and particulate forms in all species we examined.In the full scan mode,133 chromatographic peaks were detected from 51 samples altogether.Both the varieties of carbonyl compounds and their quantities were algal species dependent,although most of the carbonyl compounds could not be fully identified according to the mass spectral database only due to the unavailability of enough standards for all analytes.Aided with nine standards in SIM mode,we further identified and quantified all nine aldehydes(2-methyl-2-pentenal,trans-2-nonenal,cis-6-nonenal,2,6-dimethyl-5-heptenal,trans-2-hexenal,trans-2-decenal,2,4-heptadienal,trans-trans-2,4-octadienal,and trans-trans-2,4-decadienal).Four of these nine aldehydes were detected in particulate form,which confirmed that trans-2-nonenal could be produced by K.mikimotoi,Karl.veneficum,P.donghaiense,P.minimum,S.trochoidea,and H.akashiwo,2,4-heptadienal and trans-trans-2,4-decadienal by A.sanguinea,M.polykrikoides,and S.trochoidea,and trans,trans-2,4-octadienal by S.trochoidea,respectively.We proved that some dinoflagellate and raphidophyte species could contribute to the pool of carbonyl compounds including PUAs in a marine ecosystem.Some carbonyl compounds,particularly those in high cell quota and/or dissolved concentration,may be related to fishkilling or allelopathy which needs further identification and quantification. 相似文献
6.
The ratio of nitrogen/phosphorus (N/P) is known to affect cell proliferation of some marine micro algae. We evaluated the
effect of N/P ratios on the proliferation and succession of phytoplankton using five marine micro algae species. We used two
sources of nitrogen, NH4Cl (N1) and urea (N2), and a single source of phosphorous, NaH2PO4(P). The optimal N/P ratio that differed among the five species was affected by the source of nitrogen, being as follows (N1/P, N2/P in order): Thalassiosira sp. (30/1, 20/1), Heterosigma akashiwo (30/1, 30/1), Chroomonas salina (20/1, 30/1), Chaetoceros gracilis (40/1, 60/1), and Alexandrium sp. (10/1, 30/1). Thus, the source of nitrogen must be considered when analyzing the N/P ratio. Our results provide insight
for predicting phytoplankton succession in coastal waters and may be used to forecast the potential risk of harmful algal
blooms. 相似文献
7.
Algal allelopathy is an ecological/physiological phenomenon that has focused attention on the interactions among algae and the production of algal toxins. We investigated the allelopathic interactions between the dinoflagellate genus Prorocentrum micans and diatom genus Skeletonema costatum and between P. micans and dinoflagellate genus Karenia mikimotoi using bi-algal cultures. Because the effects were species-specific and size-dependent, we evaluated the effect of different initial densities. At low densities of P. micans and high densities of S. costatum inoculated into the same medium, the growth of P. micans was weakly restrained, whereas the growth of S. costatum was significantly suppressed. S. costatum and K. mikimotoi were strongly inhibited by P. micans, in both the bi-algal cultures and enriched filtrates. Direct cell-to-cell contact was not necessary to gain a competitive advantage, thus, our results suggest that P. micans inhibited the growth of S. costatum and K. mikimotoi by the release of allelochemical(s). Last, a mathematical model was used to simulate growth and interactions between P. micans and S. costatum and between P. micans and K. mikimotoi in bi-algal cultures. 相似文献
8.
Interactions between Skeletonema costatum (S. costatum) and Prorocentrum donghaiense (P. donghaiiense) were inves-tigated using bi-algal cultures at different concentrations of phosphate (PO4-P) and nitrate/phosphate (N/P) ratios. Experiments were conducted under P-limited conditions and the Lotka-Volterra mathematical model was used to simulate the growth of S. costatum and P. donghaiense in the bi-algal cultures. Both of these two species were inhibited significantly in bi-algal culture. The results of the simulation showed that the inhibitory degree of S. costaum by P. donghaiense was high when the concentration of PO4-P was low (0.1μmolL-1/2 d), but that of P. donghaiense by S. costaum was high with increased PO4-P supply (0.6μmolL-1/2 d). At low concen-tration of PO4-P (0.1μmolL-1/2 d), or high concentration of PO4-P (0.6μmolL-1/2 d) with high N/P ratio (160), the interactions be-tween S. costatum and P. donghaiense were dependent on the initial cell densities of both species. At high concentration of PO4-P (0.6μmolL-1/2 d) with low N/P ratio (25 or 80), S. costatum exhibited a survival strategy superior to that of P. donghaiense. The de-gree of inhibition of P. donghaiense by S. costaum increased with elevated N/P ratio when the medium was supplemented with con-centration 0.1μmolL-1/2 d of PO4-P. The degree of inhibition to P. donghaiense by S. costaum increased with elevated N/P ratio at low concentration of PO4-P (0.1 μmolL-1/2 d). This trend was conversed at high concentration of PO4-P (0.6μmolL-1/2 d). However, the degree of inhibition of S. costaum by P. donghaiense increased with the increased N/P ratio at different PO4-P concentrations (0.1μmolL-1/2 d and 0.6μmolL-1/2 d). These results suggested that both phosphate concentration and N/P ratio affected the competition between S. costaum and P. donghaiense: P. donghaiense is more competitive in environments with low phosphate or high N/P ratio and the influence of N/P ratio on the competition was more significant with lower phosphate concentration. 相似文献
9.
This paper reports the photochemical degradation of Methylene Blue(MB)in natural seawater(NSW).The photodegradation reaction conformed to the first-order reaction kinetics with the rate constant 0.0158 min-1.MB was photochemically degradated faster under high-pressure mercury lamp(HPML)than under sunlight.When MB was in lower concentrations,salinity could inhibit the photoreaction whereas MB in higher concentration,salinity could accelerate the photoreaction.Humid acid could also inhibit the photoreactions.Toxicity tests with marine phytoplankton Skeletonema costatum(Sk)and Heterosigma akashiwo Hada (Ha)showed decreased acute toxicity after photodegradation. 相似文献
10.
The toxicity of seven major HAB (harmful algal bloom) species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense (AT-6, non-PSP producer), Alexandrium lusitanicum, Alexandrum tamarense (ATHK) and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6), or A. lusitanicum could maintain the individual survival and reproduction, as well as the population increase of the rotifer, but the individual reproduction would decrease when exposed to these five algae at higher densities for nine days; H. akashiwo could decrease the individual survival and reproduction, as well as population increase of the rotifer, which is similar to that of the starvation group, indicating that starvation might be its one lethal factor except for the algal toxins; A. tamarense (ATHK) has strong lethal effect on the rotifer with 48h LC50 at 800 cells/mL. The experiment on ingestion ability indicated by gut pigment change shows that P.donghaiense, P. globosa, P. micans, A. tamarense (AT-6) and A. lusitanicum can be taken by the rotifers as food, but A. tamarense (ATHK) or H. akashiwo can be ingested by the rotifers. The results indicate that all the indexes of individual survival and reproduction, population increase, gut pigment change of the rotifers are good and convenient to be used to reflect the toxicities of HAB species. Therefore, rotifer is suggested as one of the toxicity testing organisms in detecting the toxicity of harmful algae. 相似文献
11.
XIE Zhihao） ） XIAO Hui） TANG Xuexi） CAI Hengjiang） ） Marine Ecology Laboratory Ocean University of China Qingdao P. R. China ） Faculty of Life Science Biotechnology Ningbo University Ningbo P. R. China 《中国海洋大学学报(英文版)》2009,8(2)
The interspecific interactions between the rotifer Brachionus plicatilis and two harmful algal blooms(HAB) species were investigated experimentally by single culture method. B. plicatilis population and the growth of the two algae were compared at different algal cell densities. The results demonstrated that the B. plicatilis obtained sufficient nutrition from Prorocentrum donghaiense to support net population increase. With exposure to 2.5×104 cells mL-1 of P. donghaiense,the number of B. plicatilis increa... 相似文献
12.
Microalgal lipids are regarded as main future feedstock of biofuels for its higher efficiency of accumulation and sustainable production.In order to investigate the effect of various nitrogen to phosphorus ratios on cells growth,chlorophyll content and accumulation of lipids in Dunaliella tertiolecta,experiments were carried out in modified microalgal medium with inorganic nitrogen(nitrate-nitrogen) or organic nitrogen(urea-nitrogen) as the sole nitrogen source at initial N:P ratios ranging from 1:1 to 32:1.The favorable N:P of 16:1 in the nitrate-N or urea-N medium yielded the maximum cell density and specific growth rate.Decrease in chlorophyll content were observed at the N:P of 4:1 in both nitrate-N and urea-N cultures.It was also observed that the maximum lipids concentration was obtained at the N:P of 4:1 in both nitrate and urea nutrient medium.The lipid productivity and lipid content of cultures in the urea-N medium at the N:P of 4:1were markedly higher than those from cultures with other N:P ratios(p 0.05).The results of this work illustrate the possibility that higher ratios of nitrogen to phosphorus have enhancing effect on cells growth of D.tertiolecta.Conversely,higher lipid accumulation is associated with a decrease in chlorophyll content under lower ratios of nitrogen to phosphorus.The results confirm the hypothesis of this study that a larger metabolic flux has been channeled to lipid accumulation in D.tertiolecta cells when the ratios of nitrogen to phosphorus drop below a critical level. 相似文献
13.
Liaodong Bay is one of the largest semi-enclosed bays located in Bohai Sea, in northeast China. It is an important feeding and spawning place, even wintering and breeding migration base for many marine organisms. The size structure of phytoplankton communities is a key feature of marine ecosystems and can be used as an indicator for algae disaster, but the methods to evalute is still challenging. Here, we compared the size-fractionated chlorophyll-a method with a high-throughout sequencing method in an evaluation of the size structure of phytoplankton assemblages in Liaodong Bay, China, in 2014. The proportion of picophytoplankton was estimated at just 19% according to the results based on size-fractionated chlorophyll-a, which likely represents a severe underestimation. The sequencing method confirmed that many kinds of phytoplankton species appeared in more than one size-fractionated filter membrane, with some even dominating where the filter membrane pore size was greater than the individual phytoplankton size. According to the sequencing method, the phytoplankton assemblages in Liaodong Bay were dominated by picophytoplankton(average proportion = 44%), followed by the nanophytoplankton(average 32%), a composition that is more consistent with other studies. The sequencing method provides a more robust way to assess the size structure and taxonomic diversity of marine phytoplankton communities. 相似文献
14.
Abundance,biomass and composition of the ice algal and phytoplank-ton communities were investigated in the southeastern Laptev Sea in spring 1999.Diatoms dominated the algal communities and pennate diatoms dominated the dia-tom population.12 dominant algal species occurred within sea ice and underlyingwater column,including Fragilariopsis oceanica,F.cylindrus,Nitzschiafrigida,N.promare,Achnanthes taeniata,Nitzschia neofrigida,Naviculapelagica,N.vanhoef fenii,N.septentrionalis,Melosira arctica,Clindrothecaclosterium and Pyrarnimonas sp.The algal abundance of bottom 10 cm sea icevaried between 14.6 and 1562.2×10~4 ceils l~(-1)with an average of 639.0×10~4cells l~(-1),and the algal biomass ranged from 7.89 to 2093.5μg C l~(-1)with an av-erage of 886.9μg C l~(-1),which were generally one order of magnitude higherthan those of sub-bottom ice and two orders of magnitude higher than those ofunderlying surface water.The integrated algal abundance and biomass of lower-most 20 cm ice column were averagely 7.7 and 12.2 times as those of upper 20 mwater column,respectively,suggesting that the ice algae might play an importantrole in maintaining the coastal marine ecosystem before the thawing of sea ice.Icealgae influenced the phytoplankton community of the underlying water column.However,the“seeding”of ice algae for phytoplankton bloom was negligible be-cause of the iow phytoplankton biomass within the underlying water column. 相似文献
15.
Diatoms are widely distributed in many temperate areas and some species frequently form extensive blooms in spring. Hence, monitoring the variations of specific genera or species of diatoms is necessary for studying phytoplankton population dynamics in marine ecosystems. To test whether pigment ratios can be used to identify diatoms at a below-class taxonomic level, we analyzed 14 species/strains of diatoms isolated from Chinese seas using high performance liquid chromatography (HPLC). We normalized all pigment concentrations to total chlorophyll a to calculate the ratios of pigment to chlorophyll a, and calculated the ratios between accessory pigments (or pigment sums). Cluster analysis indicated that these diatoms could be classified into four clusters in terms of three accessory pigment ratios: chlorophyll c2: chlorophyll c1, fucoxanthin:total chlorophyll c and diadinoxanthin:diatoxanthin. The classification results matched well with those of biological taxonomy. To test the stability of the classification, pigment data from one species, cultured under different light intensities, and five new species/strains were calculated and used for discriminant analysis. The results show that the classification of diatom species using pigment ratio suites was stable for the variations of pigment ratios of species cultured in different light intensities. The introduction of new species, however, may confuse the classification within the current scheme. Classification of marine diatoms using pigment ratio suites is potentially valuable for the fine chemotaxonomy of phytoplankton at taxonomic levels below class and would advance studies on phytoplankton population dynamics and marine ecology. 相似文献
16.
We characterized variations in bacterioplankton community composition(BCC) in mesocosms subject to three different treatments. Two groups contained fish(group one: Cyprinus carpio; group two: Hypophthalmichthys molitrix); and group three, the untreated mesocosm, was the control. Samples were taken seven times over a 49-d period, and BCC was analyzed by PCR-denaturing gradient gel electrophoresis(DGGE) and real-time quantitative PCR(q PCR). Results revealed that introduction of C. carpio and H. molitrix had a remarkable impact on the composition of bacterioplankton communities, and the BCC was significantly diff erent between each treatment. Sequencing of DGGE bands revealed that the bacterioplankton community in the different treatment groups was consistent at a taxonomic level, but differed in its abundance. H. molitrix promoted the richness of Alphaproteobacteria and Actinobacteria, while more bands affiliated to Cyanobacteria were detected in C. carpio mesocosms. The redundancy analysis(RDA) result demonstrated that the BCC was closely related to the bottom-up(total phosphorus, chlorophyll a, phytoplankton biomass) and top-down forces(biomass of copepods and cladocera) in C. carpio and control mesocosms, respectively. We found no evidence for top-down regulation of BCC by zooplankton in H. molitrix mesocosms, while grazing by protozoa(heterotrophic nanoflagellates, ciliates) became the major way to regulate BCC. Total bacterioplankton abundances were significantly higher in C. carpio mesocosms because of high nutrient concentration and suspended solids. Our study provided insights into the relationship between fish and bacterioplankton at species level, leading to a deep understanding of the function of the microbial loop and the aquatic ecosystem. 相似文献
17.
《中国海洋湖沼学报》2021,(3)
The use of high alkaline medium is a feasible way to provide carbon source and prevent biological contamination for the outdoor cultivation of alkaliphilic microalgae and cyanobacteria. A novel cyanobacterial strain was isolated from the open pond of a marine green alga( Picochlorum sp. SCSIO-45015, Sanya, Hainan) and identified as Cyanobacterium sp. SCSIO-45682. The effects of initial sodium bicarbonate(NaHCO_3) concentrations on the growth and biochemical composition of Cyanobacterium sp. SCSIO-45682 were investigated. The results demonstrated that Cyanobacterium sp. SCSIO-45682 had good adaptation to 16.8-g/L NaHCO_3(the same concentration of NaHCO_3 used in Zarrouk medium for Spirulina). Moreover, the yields of biomass, polysaccharide, chlorophyll a(chl a), and phycocyanin increased under high NaHCO_3 concentrations. The maximum final biomass concentration of 2.5 g/L was observed at 8.4-g/L NaHCO_3, while the highest intracellular total saccharide content of 49.2% of dry weight(DW) and exopolysaccharide(EPS) concentration of 93 mg/L were achieved at the NaHCO_3 concentration of 16.8 g/L. The crude protein content declined under high NaHCO_3 concentrations, which provide a possible explanation for the accumulation of polysaccharide. This study shows a good potential of alkaliphilic Cyanobacterium sp. SCSIO-45682 as a polysaccharide feedstock. 相似文献
18.
ＩＮＴＲＯＤＵＣＴＩＯＮＰｈｏｓｐｈｏｒｕｓｉｓａｋｅｙｎｕｔｒｉｔｉｖｅｅｌｅｍｅｎｔｆｏｒｔｈｅｇｒｏｗｔｈｏｆｍａｒｉｎｅｐｈｙｔｏｐｌａｎｋｔｏｎ .Ｒｅｃｅｎｔｌｙ ,ｂｅ ｃａｕｓｅｏｆｅｎｖｉｒｏｎｍｅｎｔａｌｐｏｌｌｕｔｉｏｎ ,ｔｈｅｅｕｔｒｏｐｈｉｃａｔｉｏｎｐｒｏｂｌｅｍｓｉｎｃｏａｓｔａｌａｎｄｏｃｅａｎｉｃｗａｔｅｒｓｈａｖｅｂｅ ｃｏｍｅｍｏｒｅａｎｄｍｏｒｅｓｅｒｉｏｕｓ.Ｔｈｅｅｎｖｉｒｏｎｍｅｎｔｅｃｏｌｏｇｉｃａｌｒｅｓｐｏｎｓｅｉｎｔｈｅｌｏｎｇ ｔｅｒｍｔｏｔｈｅｆ… 相似文献
19.
根据 1998年的现场调查资料 ,分析考洲洋海水无机营养盐与浮游植物生物量的平面分布及其相互关系。结果表明二者的关系很密切 :浮游植物量在枯水期 (2月 )与无机氮、无机磷、硅酸盐显著正相关 ,相关系数分别为 0 779、0 94 6和 0 876 (n =12 ) ;在丰水期 (8月 )与无机氮和硅酸盐负相关、与磷酸盐正相关 ,相关系数分别为 - 0 6 5 5、- 0 84 5和 0 5 84 (n =11)。从浮游植物对营养盐的一般需要量和N、P、Si的原子比分析 ,2月N、P显得紧缺 ,8月N、P、Si均过量 相似文献
20.
Shu Yang Xiurong Han Chuansong Zhang Baiye Sun Xiulin Wang Xiaoyong Shi 《中国海洋大学学报(英文版)》2014,13(6):926-934
The characteristics of seasonal variation in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas were discussed based on field investigation data from 1959 to 2009. The field data from 1981 to 2004 showed that the Chlorophyll-a concentration in surface seawater was between 0.4 and 8.5 μg dm-3. The seasonal changes generally presented a bimodal trend, with the biomass peaks occurring in May and August, and Chlorophyll-a concentration was the lowest in winter. Seasonal biomass changes were mainly controlled by temperature and nutrient levels. From the end of autumn to the next early spring, phytoplankton biomass was mainly influenced by temperature, and in other seasons, nutrient level(including the nutrient supply from the terrestrial runoffs) was the major influence factor. Field investigation data from 1959 to 2009 demonstrated that diatoms were the main phytoplankton in this area, and Skeletonema costatum, Pseudo-nitzschia pungens, Coscinodiscus oculus-iridis, Thalassinoema nitzschioides, Paralia sulcata, Chaetoceros lorenzianus, Chaetoceros curvisetus, and Prorocentrum donghaiense Lu were common dominant species. The seasonal variations in major dominant phytoplankton species presented the following trends: 1) Skeletonema(mainly S. costatum) was dominant throughout the year; and 2) seasonal succession trends were Coscinodiscus(spring) →Chaetoceros(summer and autumn) → Coscinodiscus(winter). The annual dominance of S. costatum was attributed to its environmental eurytopicity and long standing time in surface waters. The seasonal succession of Coscinodiscus and Chaetoceros was associated with the seasonal variation in water stability and nutrient level in this area. On the other hand, long-term field data also indicated obvious interannual variation of phytoplankton biomass and community structure in the Changjiang River Estuary and adjacent seas: average annual phytoplankton biomass and dinoflagellate proportion both presented increased trends during the 1950 s-2000 s. 相似文献