Prochlorococcus, a tiny oxygenic photosynthetic picoplankton with unique pigment composition, has been found to be ubiquitous and abundant in the world oceans, and has been recognized to be closely related to living r...Prochlorococcus, a tiny oxygenic photosynthetic picoplankton with unique pigment composition, has been found to be ubiquitous and abundant in the world oceans, and has been recognized to be closely related to living resources and environmental issues. It has attracted the interest of marine biologists since its discovery, and field data on it over global oceans have accumulated rapidly in the past 10 years. In China, we have studied Prochlorococcus for 8 years, achieving a basic ecological understanding. The presence of Prochlorococcus in China seas, marginal seas of the west Pacific, was confirmed, and its distribution patterns were also brought to light. Prochlorococcus is very abundant in the South China Sea and the offshore regions of the East China Sea. It is seasonally present in the southeast part of the Yellow Sea and absent in the Bohai Sea. Temporal and spatial variations of the abundance of Prochlorococcus and their affecting factors, physiological and ecological characteristics of展开更多
The biomass and size fraction of phytoplankton in terms of chlorophyll a（Chl a） was measured during four cruises conducted in April, July, October 2013 and January 2014 in mariculture area, the Sanggou Bay, China.Re...The biomass and size fraction of phytoplankton in terms of chlorophyll a（Chl a） was measured during four cruises conducted in April, July, October 2013 and January 2014 in mariculture area, the Sanggou Bay, China.Results show that total Chl a levels in the surface seawater of the Sanggou Bay generally range from 0.10 to 20.46μg/L, with an average value of 2.13 μg/L. Nano-phytoplankton was the most important size-fraction and accounted for about 65.1% of total Chl a. In order to evaluate the importance of the ＂protozoan trophic link＂ for energy transfer from the microbial loop to filter-feeding feeders, Zhikong scallop Chlamys farreri was then offered a natural planktonic community as potential prey. Results show that scallops obtained carbon source from natural plankton with the rate of 11 033.05 μg/（g·d）. Protists（nanoflagellates and ciliates） were the dominant source of carbon retained by scallop（48.78%）. The microbial loop provided 58.45% of the carbon source for farmed scallops. These results indicate that the microbial loop represent a valuable trophic resource in mariculture system of the Sanggou Bay.展开更多
By using flow cytometry techniques, we investigated the abundance and composition of the heterotrophic prokaryotes, virioplankton and picophytoplankton community in the Pearl River Estuary and Daya Bay in the summer o...By using flow cytometry techniques, we investigated the abundance and composition of the heterotrophic prokaryotes, virioplankton and picophytoplankton community in the Pearl River Estuary and Daya Bay in the summer of 2012. We identified two subgroups of prokaryotes, high nucleic acid（HNA） and low nucleic acid（LNA）, characterized by different nucleic acid contents. HNA abundance was significantly correlated with larger phytoplankton and Synechococcus（Syn） abundance, which suggested the important role of organic substrates released from primary producers on bacterial growth. Although LNA did not show any association with environmental variables, it was a vital component of the microbial community. In contrast to previous studies, the total virioplankton concentration had a poor relationship with nutrient availability. The positive relationship between large-sized phytoplankton abundance and the V-I population confirmed that V-I was a phytoplankton-infecting viral subgroup. Although the V-II group（bacteriophages）was dominant in the virioplankton community, it was not related with prokaryotic abundance, which indicated factors other than hosts controlling V-II abundance or the uncertainty of virus-host coupling. With respect to the picophytoplankton community,our results implied that river input exerted a strong limitation to Syn distribution in the estuary, while picoeukaryotes（Euk） were numerically less abundant and showed a quite different distribution pattern from that of Syn, and hence presented ecological properties distinct from Syn in our two studied areas.展开更多
Picoplankton distribution around the Zhangzi Island（northern Yellow Sea）was investigated by monthly observation from July 2009 to June 2010.Three picoplankton populations were discriminated by flow cytometry,namely ...Picoplankton distribution around the Zhangzi Island（northern Yellow Sea）was investigated by monthly observation from July 2009 to June 2010.Three picoplankton populations were discriminated by flow cytometry,namely Synechococcus,picoeukaryotes and heterotrophic prokaryotes.In summer（from July to September）,the edge of the northern Yellow Sea Cold Water Mass（NYSCWM）resulting from water column stratification was observed.In the NYSCWM,picoplankton（including Synechococcus,picoeukaryotes and heterotrophic prokaryotes）distributed synchronically with extremely high abundance in the thermocline（20 m）in July and August（especially in August）,whereas in the bottom zone of the NYSCWM（below 30 m）,picoplankton abundance was quite low.Synechococcus,picoeukaryotes and heterotrophic prokaryotes showed similar response to the NYSCWM,indicating they had similar regulating mechanism under the influence of NYSCWM.Whereas in the non-NYSCWM,Synechococcus,picoeukaryotes and heterotrophic prokaryotes exhibited different distribution patterns,suggesting they had different controlling mechanisms.Statistical analysis indicated that temperature,nutrients（NO3^and PO4^3-）and ciliate were important factors in regulating picoplankton distribution.The results in this study suggested that the physical event NYSCWM,had strong influence on picoplankton distribution around the Zhangzi Island in the northern Yellow Sea.展开更多
Variations of picoplankton groups were investigated over a one-month period in Daya Bay and Sanya Bay,in the northern South China Sea.The two coastal regions exhibited different variation patterns in physicochemical p...Variations of picoplankton groups were investigated over a one-month period in Daya Bay and Sanya Bay,in the northern South China Sea.The two coastal regions exhibited different variation patterns in physicochemical parameters.Moreover,the diel variations of picoplankton groups were different between the two bays.The abundance of the picoplankton in Sanya Bay displayed a pronounced diel variation,while it was not significant in Daya Bay.In addition,some similar patterns of picoplankton abundance were discovered.In the two bays,virioplankton exhibited the smallest fluctuation range,whereas picocyanobacteria fluctuated most markedly.The fluctuation range of picoplankton groups was larger in spring tide than in neap tide,especially in Sanya Bay.Random forest model analysis demonstrated that the variation of picoplankton groups was attributed to physical and chemical factors in Sanya Bay and Daya Bay,respectively.Therefore,our findings suggest that virioplankton abundance can persist more stably in response to changing environmental conditions compared to bacterioplankton and picophytoplankton.展开更多
Using a flow cytometer （FCM） onboard the R/V Xuelong during the 24th Chinese Antarctic cruise, picoplankton community structure and biomass in the surface water were examined along the latitude and around the Antarc...Using a flow cytometer （FCM） onboard the R/V Xuelong during the 24th Chinese Antarctic cruise, picoplankton community structure and biomass in the surface water were examined along the latitude and around the Antarctic Ocean. Salinity and temperature were automatically recorded and total Chl a was determined. Along the cruise, the abundance of Synechococcus, Prochlorococ- cus, pico-eukaryotes and heterotrophic bacteria ranged in 0.001-1.855~ 10s ind./L, 0.000-2.778×108 ind./L, 0.002-1.060×108 ind./L and 0.132-27.073×108 ind./L, respectively. Major oceanic distri- bution of Synechococcus and Prochlorococcus appeared between latitudes 30°N and 30°S. Prochlorococcus was mainly influenced by water temperature, water mass combination and freshwater inflow. Meanwhile, Synechococcus distribution was significantly associated with landing freshwater inflow. Pico-eukaryotes and heterotrophic bacteria were distributed all over the oceans, but with a relatively low abundance in the high latitudes of the Antarctic Ocean. Principal Component Analysis showed that at same latitude of Atlantic Ocean and Indian Ocean, picoplankton distribution and constitution were totally different, geographical location and different water masses combination would be main reasons.展开更多
Responses of Prochlorococcus (Pro), Synechococcus (Syn), pico-eukaryotes (Euk) and heterotrophic bacteria (Bact) in pelagic marine ecosystems to external nutrient perturbations were examined using nitrogen- (N), phosp...Responses of Prochlorococcus (Pro), Synechococcus (Syn), pico-eukaryotes (Euk) and heterotrophic bacteria (Bact) in pelagic marine ecosystems to external nutrient perturbations were examined using nitrogen- (N), phosphorus- (P), iron- (Fe), and cobalt- (Co) enriched incubations in the South China Sea in November 1997. Variations in abundance of the 4 groups of microorganism and cellular pigment content of the autotrophs during incubation were followed by flow-cytometric measurements for seven days. During the incubation, Syn and Euk showed a relatively higher demand on Fe and N, while Pro required higher levels of Co and P. The Fe was inadequate for all the organisms in the deep euphotic zone (75 m) of the study area. The experimental results also implied that biological interaction among the organisms played a role in the community structure shift during the incubation. It seemed that besides the effects of temperature, there are some other physical and chemical limitations as well as impacts from biological interactions on Pro distribution in coast waters.展开更多
In order to understand the large-scale spatial distribution characteristics of picoplankton,nanophytoplankton and virio-plankton and their relationship with environmental variables in coastal and offshore waters,flow ...In order to understand the large-scale spatial distribution characteristics of picoplankton,nanophytoplankton and virio-plankton and their relationship with environmental variables in coastal and offshore waters,flow cytometry(FCM) was used to ana-lyze microbial abundance of samples collected in summer from four depths at 36 stations in the North Yellow Sea(NYS).The data revealed spatial heterogeneity in microbial populations in the offshore and near-shore waters of the NYS during the summer.For the surface layer,picoeukaryotes were abundant in the near-shore waters,Synechococcus was abundant in the offshore areas,and bacte-rial and viral abundances were high in the near-shore waters around the Liaodong peninsula.In the near-shore waters,no significant vertical variation of picophytoplankton(0.2-2μm) abundance was found.However,the nanophytoplankton abundance was higher in the upper layers(from the surface to 10 m depth) than in the bottom layer.For the offshore waters,both pico-and nanophytoplankton(2-20μm) abundance decreased sharply with depth in the North Yellow Sea Cold Water Mass(NYSCWM).But,for the vertical dis-tribution of virus and bacteria abundance,no significant variation was observed in both near-shore and offshore waters.Autotrophic microbes were more sensitive to environmental change than heterotrophic microbes and viruses.Viruses showed a positive correla-tion with bacterial abundance,suggesting that the bacteriophage might be prominent for virioplankton(about 0.45μm) in summer in the NYS and that viral abundance might play an important role in microbial loop functions.展开更多
Abundance, carbon biomass and composition of picoplankton along a transect (fromthe Pearl River estuary to Dongsha Island) in the northern South China Sea were measured by flow cytom-etry (FCM); and the vertical struc...Abundance, carbon biomass and composition of picoplankton along a transect (fromthe Pearl River estuary to Dongsha Island) in the northern South China Sea were measured by flow cytom-etry (FCM); and the vertical structure, composition variation, relationship between heterotrophic and au-totrophic picoplankton as well as the controlling mechanism of diel variation were studied. Results showedthat along the horizontal direction, both Synechococcus (SYN) and picoeukaryote (PEUK) were highest inabundance and dominated autotrophic picoplankton in the Pearl River estuary, but decreased展开更多
During spring and autumn of 2006, the investigations on abundance, carbon biomass and distri- bution of picoplankton were carried out in the southern Huanghai Sea （Yellow Sea, sHS）. Three groups of picoplankton-Syne...During spring and autumn of 2006, the investigations on abundance, carbon biomass and distri- bution of picoplankton were carried out in the southern Huanghai Sea （Yellow Sea, sHS）. Three groups of picoplankton-Synechococcus （Syn）, Picoeukaryotes （PEuk） and heterotrophic bacteria （BAC） were identified, but Prochlorococcus （Pro） was undetected. The average abundance of Syn and PEuk was lower in spring （5.0 and 1.3×10^3 cells/cm^3, respectively） than in autumn （92.4 and 2.7×0^3 cells/cm^3, respectively）, but it was opposite for BAC （1.3 and 0.7×10^6 cells/cm^3 in spring and autumn, respectively）. And the total carbon biomass of picoplankton was higher in spring （37.23×11.67） mg/m^3 than in autumn （21.29×13.75） mg/m^3. The ratios of the three cell abundance were 5：1：1 341 and 30：1：124 in spring and autumn, respectively. And the ratios of carbon biomass of them were 5：7：362 and 9：4：4 in spring and autumn, respectively. Seasonal distribution characteristics of Syn, PEuk, BAC were quite different from each other. In spring, Syn abundance decreased in turn in the central waters （where phytoplankton bloom in spring occurred）, the southern waters and inshore waters of the Shandong Peninsula （where even Syn was undetected）; the high values of PEuk abundance appeared in the central and southern waters and the inshore of the Shandong Peninsula; the abundance of BAC was nearly three order of magnitude higher than that of photosynthetic picoplankton, and high values appeared in the central waters. In autumn, Syn abundance in central waters was higher than that in surrounding waters, while for PEuk abundance, it decreased in turn in the inshore waters of the Shandong Peninsula, the southern waters and the central waters; BAC presented a complicated blocky type distribution. Sub-surface maximum of each group of picopalnkton appeared in both spring and autumn. Compared with the available lit- eratures concerning the studied area, the range of Syn abundance was l展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant Nos. 39625008 and 49876033) the National Basic Research Programme (Grant No. G2000078500).
文摘Prochlorococcus, a tiny oxygenic photosynthetic picoplankton with unique pigment composition, has been found to be ubiquitous and abundant in the world oceans, and has been recognized to be closely related to living resources and environmental issues. It has attracted the interest of marine biologists since its discovery, and field data on it over global oceans have accumulated rapidly in the past 10 years. In China, we have studied Prochlorococcus for 8 years, achieving a basic ecological understanding. The presence of Prochlorococcus in China seas, marginal seas of the west Pacific, was confirmed, and its distribution patterns were also brought to light. Prochlorococcus is very abundant in the South China Sea and the offshore regions of the East China Sea. It is seasonally present in the southeast part of the Yellow Sea and absent in the Bohai Sea. Temporal and spatial variations of the abundance of Prochlorococcus and their affecting factors, physiological and ecological characteristics of
基金The National Natural Science Foundation of China under contract Nos 41676147 and 41306117the Scientific and Technological Innovation Project Financially Supported by Qingdao National Laboratory for Marine Science and Technology under contract No.2016ASKJ02+1 种基金the earmarked fund for Modern Agro-industry Technology Research System under contract No.CARS-48the National Basic Research Program of China under contract No.2011CB409805
文摘The biomass and size fraction of phytoplankton in terms of chlorophyll a（Chl a） was measured during four cruises conducted in April, July, October 2013 and January 2014 in mariculture area, the Sanggou Bay, China.Results show that total Chl a levels in the surface seawater of the Sanggou Bay generally range from 0.10 to 20.46μg/L, with an average value of 2.13 μg/L. Nano-phytoplankton was the most important size-fraction and accounted for about 65.1% of total Chl a. In order to evaluate the importance of the ＂protozoan trophic link＂ for energy transfer from the microbial loop to filter-feeding feeders, Zhikong scallop Chlamys farreri was then offered a natural planktonic community as potential prey. Results show that scallops obtained carbon source from natural plankton with the rate of 11 033.05 μg/（g·d）. Protists（nanoflagellates and ciliates） were the dominant source of carbon retained by scallop（48.78%）. The microbial loop provided 58.45% of the carbon source for farmed scallops. These results indicate that the microbial loop represent a valuable trophic resource in mariculture system of the Sanggou Bay.
基金supported by the National Basic Research Program (973 Program) of China (Nos. 2015CB452905, 2015CB452903)the Strategic Priority Research Program of the Chinese Academy of Sciences (No. XDA11020205)+1 种基金Fund of Key Laboratory of Global Change and Marine-Atmospheric Chemistry, SOA, (GCMAC1209)Public science and technology research funds projects of ocean (201105015-06)
文摘By using flow cytometry techniques, we investigated the abundance and composition of the heterotrophic prokaryotes, virioplankton and picophytoplankton community in the Pearl River Estuary and Daya Bay in the summer of 2012. We identified two subgroups of prokaryotes, high nucleic acid（HNA） and low nucleic acid（LNA）, characterized by different nucleic acid contents. HNA abundance was significantly correlated with larger phytoplankton and Synechococcus（Syn） abundance, which suggested the important role of organic substrates released from primary producers on bacterial growth. Although LNA did not show any association with environmental variables, it was a vital component of the microbial community. In contrast to previous studies, the total virioplankton concentration had a poor relationship with nutrient availability. The positive relationship between large-sized phytoplankton abundance and the V-I population confirmed that V-I was a phytoplankton-infecting viral subgroup. Although the V-II group（bacteriophages）was dominant in the virioplankton community, it was not related with prokaryotic abundance, which indicated factors other than hosts controlling V-II abundance or the uncertainty of virus-host coupling. With respect to the picophytoplankton community,our results implied that river input exerted a strong limitation to Syn distribution in the estuary, while picoeukaryotes（Euk） were numerically less abundant and showed a quite different distribution pattern from that of Syn, and hence presented ecological properties distinct from Syn in our two studied areas.
基金The National Natural Science Foundation of China under contract Nos 41306160the NSFC-Shandong Joint Fund for Marine Science Research Centers under contract No.U1606404the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA11020103.1
文摘Picoplankton distribution around the Zhangzi Island（northern Yellow Sea）was investigated by monthly observation from July 2009 to June 2010.Three picoplankton populations were discriminated by flow cytometry,namely Synechococcus,picoeukaryotes and heterotrophic prokaryotes.In summer（from July to September）,the edge of the northern Yellow Sea Cold Water Mass（NYSCWM）resulting from water column stratification was observed.In the NYSCWM,picoplankton（including Synechococcus,picoeukaryotes and heterotrophic prokaryotes）distributed synchronically with extremely high abundance in the thermocline（20 m）in July and August（especially in August）,whereas in the bottom zone of the NYSCWM（below 30 m）,picoplankton abundance was quite low.Synechococcus,picoeukaryotes and heterotrophic prokaryotes showed similar response to the NYSCWM,indicating they had similar regulating mechanism under the influence of NYSCWM.Whereas in the non-NYSCWM,Synechococcus,picoeukaryotes and heterotrophic prokaryotes exhibited different distribution patterns,suggesting they had different controlling mechanisms.Statistical analysis indicated that temperature,nutrients（NO3^and PO4^3-）and ciliate were important factors in regulating picoplankton distribution.The results in this study suggested that the physical event NYSCWM,had strong influence on picoplankton distribution around the Zhangzi Island in the northern Yellow Sea.
基金Supported by the National Natural Science Foundation of China(Nos.42176116,41576126,41890851,U21A6001)the Natural Science Foundation of Guangdong Province(No.2017A030306020)+4 种基金the Guangdong Major Project of Basic and Applied Basic Research(No.2019B030302004)the Rising Star Foundation of the South China Sea Institute of Oceanology(No.NHXX2019ST0101)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2018377)the Science and Technology Planning Project of Guangdong Province of China(No.2021B1212050023)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA19060503)。
文摘Variations of picoplankton groups were investigated over a one-month period in Daya Bay and Sanya Bay,in the northern South China Sea.The two coastal regions exhibited different variation patterns in physicochemical parameters.Moreover,the diel variations of picoplankton groups were different between the two bays.The abundance of the picoplankton in Sanya Bay displayed a pronounced diel variation,while it was not significant in Daya Bay.In addition,some similar patterns of picoplankton abundance were discovered.In the two bays,virioplankton exhibited the smallest fluctuation range,whereas picocyanobacteria fluctuated most markedly.The fluctuation range of picoplankton groups was larger in spring tide than in neap tide,especially in Sanya Bay.Random forest model analysis demonstrated that the variation of picoplankton groups was attributed to physical and chemical factors in Sanya Bay and Daya Bay,respectively.Therefore,our findings suggest that virioplankton abundance can persist more stably in response to changing environmental conditions compared to bacterioplankton and picophytoplankton.
基金The National Natural Science Foundation of China under contract Nos 40576002 and 40006010the Key International S & T Cooperation Projects under contract No.2008DFA20420+3 种基金the Youth Scientific and Technological Innovation Foundation of Polar Research Institute of China under contract No.JDQ200802the Polar Strategic Research Foundation under contract No.2008209the LMEB Open Research Foundation under contract No.LMEB200902the PhD Program Scholarship Fund of ECNU under contract No.2010041
文摘Using a flow cytometer （FCM） onboard the R/V Xuelong during the 24th Chinese Antarctic cruise, picoplankton community structure and biomass in the surface water were examined along the latitude and around the Antarctic Ocean. Salinity and temperature were automatically recorded and total Chl a was determined. Along the cruise, the abundance of Synechococcus, Prochlorococ- cus, pico-eukaryotes and heterotrophic bacteria ranged in 0.001-1.855~ 10s ind./L, 0.000-2.778×108 ind./L, 0.002-1.060×108 ind./L and 0.132-27.073×108 ind./L, respectively. Major oceanic distri- bution of Synechococcus and Prochlorococcus appeared between latitudes 30°N and 30°S. Prochlorococcus was mainly influenced by water temperature, water mass combination and freshwater inflow. Meanwhile, Synechococcus distribution was significantly associated with landing freshwater inflow. Pico-eukaryotes and heterotrophic bacteria were distributed all over the oceans, but with a relatively low abundance in the high latitudes of the Antarctic Ocean. Principal Component Analysis showed that at same latitude of Atlantic Ocean and Indian Ocean, picoplankton distribution and constitution were totally different, geographical location and different water masses combination would be main reasons.
文摘Responses of Prochlorococcus (Pro), Synechococcus (Syn), pico-eukaryotes (Euk) and heterotrophic bacteria (Bact) in pelagic marine ecosystems to external nutrient perturbations were examined using nitrogen- (N), phosphorus- (P), iron- (Fe), and cobalt- (Co) enriched incubations in the South China Sea in November 1997. Variations in abundance of the 4 groups of microorganism and cellular pigment content of the autotrophs during incubation were followed by flow-cytometric measurements for seven days. During the incubation, Syn and Euk showed a relatively higher demand on Fe and N, while Pro required higher levels of Co and P. The Fe was inadequate for all the organisms in the deep euphotic zone (75 m) of the study area. The experimental results also implied that biological interaction among the organisms played a role in the community structure shift during the incubation. It seemed that besides the effects of temperature, there are some other physical and chemical limitations as well as impacts from biological interactions on Pro distribution in coast waters.
基金supported by the General Oceano-graphic Survey Project(908 Project)the Special Fund forPublic Welfare Industry(Oceanography)(Grant No.20080511)the CAS Hundred Talents Project‘The response mechanism of the typical gulf ecosystem to the environmental changes’
文摘In order to understand the large-scale spatial distribution characteristics of picoplankton,nanophytoplankton and virio-plankton and their relationship with environmental variables in coastal and offshore waters,flow cytometry(FCM) was used to ana-lyze microbial abundance of samples collected in summer from four depths at 36 stations in the North Yellow Sea(NYS).The data revealed spatial heterogeneity in microbial populations in the offshore and near-shore waters of the NYS during the summer.For the surface layer,picoeukaryotes were abundant in the near-shore waters,Synechococcus was abundant in the offshore areas,and bacte-rial and viral abundances were high in the near-shore waters around the Liaodong peninsula.In the near-shore waters,no significant vertical variation of picophytoplankton(0.2-2μm) abundance was found.However,the nanophytoplankton abundance was higher in the upper layers(from the surface to 10 m depth) than in the bottom layer.For the offshore waters,both pico-and nanophytoplankton(2-20μm) abundance decreased sharply with depth in the North Yellow Sea Cold Water Mass(NYSCWM).But,for the vertical dis-tribution of virus and bacteria abundance,no significant variation was observed in both near-shore and offshore waters.Autotrophic microbes were more sensitive to environmental change than heterotrophic microbes and viruses.Viruses showed a positive correla-tion with bacterial abundance,suggesting that the bacteriophage might be prominent for virioplankton(about 0.45μm) in summer in the NYS and that viral abundance might play an important role in microbial loop functions.
基金This work was supported by a grant from NSFC(No.40076031,49825162)and"973"fund(Grant No.G2000078504)
文摘Abundance, carbon biomass and composition of picoplankton along a transect (fromthe Pearl River estuary to Dongsha Island) in the northern South China Sea were measured by flow cytom-etry (FCM); and the vertical structure, composition variation, relationship between heterotrophic and au-totrophic picoplankton as well as the controlling mechanism of diel variation were studied. Results showedthat along the horizontal direction, both Synechococcus (SYN) and picoeukaryote (PEUK) were highest inabundance and dominated autotrophic picoplankton in the Pearl River estuary, but decreased
基金The National Basic Research Program of China under contract No. 2006CB400605the scientific research fund of the Second Institute of Oceanography,SOA under contract No. JG0919
文摘During spring and autumn of 2006, the investigations on abundance, carbon biomass and distri- bution of picoplankton were carried out in the southern Huanghai Sea （Yellow Sea, sHS）. Three groups of picoplankton-Synechococcus （Syn）, Picoeukaryotes （PEuk） and heterotrophic bacteria （BAC） were identified, but Prochlorococcus （Pro） was undetected. The average abundance of Syn and PEuk was lower in spring （5.0 and 1.3×10^3 cells/cm^3, respectively） than in autumn （92.4 and 2.7×0^3 cells/cm^3, respectively）, but it was opposite for BAC （1.3 and 0.7×10^6 cells/cm^3 in spring and autumn, respectively）. And the total carbon biomass of picoplankton was higher in spring （37.23×11.67） mg/m^3 than in autumn （21.29×13.75） mg/m^3. The ratios of the three cell abundance were 5：1：1 341 and 30：1：124 in spring and autumn, respectively. And the ratios of carbon biomass of them were 5：7：362 and 9：4：4 in spring and autumn, respectively. Seasonal distribution characteristics of Syn, PEuk, BAC were quite different from each other. In spring, Syn abundance decreased in turn in the central waters （where phytoplankton bloom in spring occurred）, the southern waters and inshore waters of the Shandong Peninsula （where even Syn was undetected）; the high values of PEuk abundance appeared in the central and southern waters and the inshore of the Shandong Peninsula; the abundance of BAC was nearly three order of magnitude higher than that of photosynthetic picoplankton, and high values appeared in the central waters. In autumn, Syn abundance in central waters was higher than that in surrounding waters, while for PEuk abundance, it decreased in turn in the inshore waters of the Shandong Peninsula, the southern waters and the central waters; BAC presented a complicated blocky type distribution. Sub-surface maximum of each group of picopalnkton appeared in both spring and autumn. Compared with the available lit- eratures concerning the studied area, the range of Syn abundance was l
