The importance of phytoplankton cell death is being increasingly recognized,however,there are still no published reports on this in Xiamen Bay.In this study,the proportion of dead phytoplankton cells associated with e...The importance of phytoplankton cell death is being increasingly recognized,however,there are still no published reports on this in Xiamen Bay.In this study,the proportion of dead phytoplankton cells associated with environmental factors was assessed at a station in Xiamen Bay from December2012 to December 2013,using a cell digestion assay,which is an effective method to analyze dead/living cells in complex natural phytoplankton communities.The percentages of dead cells(%DC) in the total phytoplankton in summer(16%±6%) were lower than those in winter(27%±16%).Six groups of phytoplankton(G1-G6) were categorized by flow cytometry.These phytoplankton communities with diverse seasonal variations in%DC had different responses to environmental constraints.The main factors affecting mortality were temperature and salinity,while nutrient concentration showed little influence on phytoplankton death.Additionally,our results provide evidence that chlorophyll a concentrations had an inverse relationship with total phytoplankton%DC and viable cell abundance was more meaningful than total cells to explain variations in environmental parameters(such as Chl a).Moreover,the lowest mean%DC in total phytoplankton was 16%±6%at our sample site,which is in a subtropical area with high water temperatures,full solar radiation,and rich nutrients.This indicates that phytoplankton cell death is a process that cannot be ignored.In summary,phytoplankton cell death is important in understanding the dynamics of phytoplankton communities and the functioning of subtropical ecosystems.展开更多
Based on the data of the Jiaozhou Bay Ecosystem Dynamic Research, cell volume and sur face area of 87 common phytoplankton species in China sea waters were calculated with assignment of the similar geometric form. The...Based on the data of the Jiaozhou Bay Ecosystem Dynamic Research, cell volume and sur face area of 87 common phytoplankton species in China sea waters were calculated with assignment of the similar geometric form. The cell plasma volume, live weight, Carbon content and nitrogen content were also calculated with the methods of Mullin et al. (1966), Strathmann (1967), Eppley et al. (1970), and Taguchi (1976). After comparing these methods, we chase the method of Eppley et al. (1970) as the hot method for calculating phytoplankton carbon content in China sea waters.展开更多
Bioavailability of nitrogen (N) and phosphorus (P) is known to affect marine phytoplankton physiology, thus influencing their primary productivity;and it’s of general interest to see how the N or/and P additions affe...Bioavailability of nitrogen (N) and phosphorus (P) is known to affect marine phytoplankton physiology, thus influencing their primary productivity;and it’s of general interest to see how the N or/and P additions affect the differently cell-sized phytoplankton assemblages. Data from the northern South China Sea showed that P addition increased up to 6 times of total chl a content within 24 h in the estuarine water;and N+P addition increased more than 20 times of chl a within 144 h in the pelagic water. The P addition powered 18.0% and 149% increase in the carbon fixation of larger (>3 μm) and smaller (展开更多
Silver carp were introduced into the pre-sedimentation pond to control excessive phytoplankton in raw water. The effectiveness of the filter-feeding silver carp on phytoplankton control and the effect of silver carp o...Silver carp were introduced into the pre-sedimentation pond to control excessive phytoplankton in raw water. The effectiveness of the filter-feeding silver carp on phytoplankton control and the effect of silver carp on phytoplankton community were investigated. The results showed that Microcystis could be effectively removed by silver carp stocked in the pre-sedimentation pond, and simultaneously, the concentration of single-cell phytoplankton increased obviously. The difference in phytoplankton species and single- cell phytoplankton size between in the water and in the gut of silver carp indicated that phytoplankton smaller than 5 μm, such as Chamydomonas and Platymonas, were almost not be filtered by silver carp, phytoplankton with the size between 5 and 20μm could be partly filtered, and large size phytoplankton, mainly colony-forming Microcystis could be filtered almost completely. These filter- feeding characteristics directly caused the phytoplankton size distribution biased toward miniaturization. Therefore, this biological treatment using silver carp could be applied only to deal with groups of Microcystis-dominated eutrophic water, and was not appropriate in water bodies where single-cell micro phytoplankton were dominant. Especially when silver carp are used in water treatment, a cautious attitude should be taken based on the evaluation of phytoplankton biomass and species structure features in raw water.展开更多
Phytoplankton cell density, biomass, chl-a concentration and their seasonal fluctuations at five stations in the channel between Dongting Lake and the Changjiang (Yangtze) River were studied from May 1995 to December ...Phytoplankton cell density, biomass, chl-a concentration and their seasonal fluctuations at five stations in the channel between Dongting Lake and the Changjiang (Yangtze) River were studied from May 1995 to December 1997. The seasonal fluctuations had two peaks in a year in general. The an- nual patterns of total cell density and biomass indicated that diatoms contributed more than 70 percent of the total biomass (except from June to October) during the investigation period. Twenty-one dominant species contributed about 60–80 percent of the biomass in various months. The cell density, biomass and seasonal fluctuation were similar at Stations 1–4, but at Station 5 connected directly with the Changjiang River, the annual mean values (127.34×104 cells/L and 0.46 mg/L in 1996, 41.98×104 cells/L and 0.2 mg/L in 1997 respectively) were lower than those (195.92×104 cells/L and 0.5 mg/L in 1996, 132.96×104 cells/L and 0.57 mg/L in 1997 respectively) at Station 1–4; and the curve of the seasonal fluctuation sometimes did not coincide with those at Stations 1–4. Based on criteria for evaluating trophic status, the dominant species, annual average cell density values of 114.86×104 –179.57×104 cells/L, biomass of 0.48–0.5 mg/L, chl-a concentration of 0.42–0.51 μg/L respectively recorded at five stations in 1996 and 1997, and values associated with the physico-chemical properties of the waterbody indicated that the water in the channel could be characterized as oligo-mesotrophic.展开更多
To better understand the spatial-temporal variation in phytoplankton community structure and its controlling factors in Jiaozhou Bay, Qingdao, North China, four seasonal sampling were carried out in 2017. The phytopla...To better understand the spatial-temporal variation in phytoplankton community structure and its controlling factors in Jiaozhou Bay, Qingdao, North China, four seasonal sampling were carried out in 2017. The phytoplankton community structure and various environmental parameters were examined. The phytoplankton community in the bay was composed of mainly diatoms and dinofl agellates, and several other species of Chrysophyta were also observed. Diatoms were the most dominant phytoplankton group throughout the year, except in spring and winter, when Noctiluca scintillans was co-dominant. High Si/N ratios in summer and fall refl ect the high dominance of diatoms in the two seasons. Temporally, the phytoplankton cell abundance peaked in summer, due mainly to the high temperatures and nutrient concentrations in summer. Spatially, the phytoplankton cell abundance was higher in the northern part of the bay than in the other parts of the bay in four seasons. The diatom cell abundances show signifi cant positive correlations with the nutrient concentrations, while the dinofl agellate cell abundances show no correlation or a negative correlation with the nutrient concentrations but a signifi cant positive correlation with the stratifi cation index. This discrepancy was mainly due to the diff erent survival strategies between diatoms and dinofl agellates. The Shannon-Wiener diversity index ( H′) values in the bay ranged from 0.08 to 4.18, which fell in the range reported in historical studies. The distribution pattern of H′ values was quite diff erent from that of chlorophyll a , indicating that the phytoplankton community structure might have high biomass with a low diversity index. Compared with historical studies, we believe that the dominant phytoplankton species have been changed in recent years due mainly to the changing environment in the Jiaozhou Bay in recent 30 years.展开更多
For compilation and comparison of desmids flora, the authors restudied the species composition, cell density and biomass of phytoplankton desmids collected at six stations in Donghu Lake at intervals of three months m...For compilation and comparison of desmids flora, the authors restudied the species composition, cell density and biomass of phytoplankton desmids collected at six stations in Donghu Lake at intervals of three months monitored from March of 1956 to February of 1957. A total of 122 taxa belonging to 16 genera were identified from qualitative and quantitative samples. Species of Cosmarium were the most popular ones occupy- ing about 41 % of the total species. Based on the observations, the annual mean values of the cell density and biomass were 132.11×102 cells/L and 0.09 mg/L. Cosmarium, Staurastrum, Staurodesmus and Closterium dominated and contributed more than 70 % of the total cell density and biomass at six stations in four seasons. The maximum species number, cell density and biomass in autumn revealed that the highest variety (64 taxa, 1296×102 cells/L and 0.889 mg/L respectively) occurred at Station 3 located in the southern part of Donghu Lake. From then on to the mid 1990s the desmids community decreased sharply in Donghu Lake, resulted clearly from eutrophication in the lake.展开更多
This paper presents the identification and quantitative analysis of the phytoplankton samples collected in the Great Wall Bay, Antarctica from March 1988 to February 1989. The results indicate that the specific compos...This paper presents the identification and quantitative analysis of the phytoplankton samples collected in the Great Wall Bay, Antarctica from March 1988 to February 1989. The results indicate that the specific composition of phytoplankton clearly shows their ecological characteristics. That is the community mainly composed of cold-water species and neritic-eurythermal species. The dominant species altered with seasonal variation, their number showed the high-peak in the austral summer and the abundance of phytoplankton in each month mainly depended upon the dominant species. The distribution of phytoplankton is influenced by many environmental factors. Among them the hours of sunshine are the main factor.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.41330961,41406143)the Chinese Academy of Sciences Special Pilot Program(No.XDA10020103)+1 种基金the SOA Ocean Research Project,China(No.201105021-03)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20130121110031)
文摘The importance of phytoplankton cell death is being increasingly recognized,however,there are still no published reports on this in Xiamen Bay.In this study,the proportion of dead phytoplankton cells associated with environmental factors was assessed at a station in Xiamen Bay from December2012 to December 2013,using a cell digestion assay,which is an effective method to analyze dead/living cells in complex natural phytoplankton communities.The percentages of dead cells(%DC) in the total phytoplankton in summer(16%±6%) were lower than those in winter(27%±16%).Six groups of phytoplankton(G1-G6) were categorized by flow cytometry.These phytoplankton communities with diverse seasonal variations in%DC had different responses to environmental constraints.The main factors affecting mortality were temperature and salinity,while nutrient concentration showed little influence on phytoplankton death.Additionally,our results provide evidence that chlorophyll a concentrations had an inverse relationship with total phytoplankton%DC and viable cell abundance was more meaningful than total cells to explain variations in environmental parameters(such as Chl a).Moreover,the lowest mean%DC in total phytoplankton was 16%±6%at our sample site,which is in a subtropical area with high water temperatures,full solar radiation,and rich nutrients.This indicates that phytoplankton cell death is a process that cannot be ignored.In summary,phytoplankton cell death is important in understanding the dynamics of phytoplankton communities and the functioning of subtropical ecosystems.
文摘Based on the data of the Jiaozhou Bay Ecosystem Dynamic Research, cell volume and sur face area of 87 common phytoplankton species in China sea waters were calculated with assignment of the similar geometric form. The cell plasma volume, live weight, Carbon content and nitrogen content were also calculated with the methods of Mullin et al. (1966), Strathmann (1967), Eppley et al. (1970), and Taguchi (1976). After comparing these methods, we chase the method of Eppley et al. (1970) as the hot method for calculating phytoplankton carbon content in China sea waters.
文摘Bioavailability of nitrogen (N) and phosphorus (P) is known to affect marine phytoplankton physiology, thus influencing their primary productivity;and it’s of general interest to see how the N or/and P additions affect the differently cell-sized phytoplankton assemblages. Data from the northern South China Sea showed that P addition increased up to 6 times of total chl a content within 24 h in the estuarine water;and N+P addition increased more than 20 times of chl a within 144 h in the pelagic water. The P addition powered 18.0% and 149% increase in the carbon fixation of larger (>3 μm) and smaller (
基金supported by the National Natural Science Foundation of China (No.50778048)the National Key Technology R&D Program (No.2006BAJ08B02)
文摘Silver carp were introduced into the pre-sedimentation pond to control excessive phytoplankton in raw water. The effectiveness of the filter-feeding silver carp on phytoplankton control and the effect of silver carp on phytoplankton community were investigated. The results showed that Microcystis could be effectively removed by silver carp stocked in the pre-sedimentation pond, and simultaneously, the concentration of single-cell phytoplankton increased obviously. The difference in phytoplankton species and single- cell phytoplankton size between in the water and in the gut of silver carp indicated that phytoplankton smaller than 5 μm, such as Chamydomonas and Platymonas, were almost not be filtered by silver carp, phytoplankton with the size between 5 and 20μm could be partly filtered, and large size phytoplankton, mainly colony-forming Microcystis could be filtered almost completely. These filter- feeding characteristics directly caused the phytoplankton size distribution biased toward miniaturization. Therefore, this biological treatment using silver carp could be applied only to deal with groups of Microcystis-dominated eutrophic water, and was not appropriate in water bodies where single-cell micro phytoplankton were dominant. Especially when silver carp are used in water treatment, a cautious attitude should be taken based on the evaluation of phytoplankton biomass and species structure features in raw water.
基金Project 39670155 and 39430101 supported by NSFC.
文摘Phytoplankton cell density, biomass, chl-a concentration and their seasonal fluctuations at five stations in the channel between Dongting Lake and the Changjiang (Yangtze) River were studied from May 1995 to December 1997. The seasonal fluctuations had two peaks in a year in general. The an- nual patterns of total cell density and biomass indicated that diatoms contributed more than 70 percent of the total biomass (except from June to October) during the investigation period. Twenty-one dominant species contributed about 60–80 percent of the biomass in various months. The cell density, biomass and seasonal fluctuation were similar at Stations 1–4, but at Station 5 connected directly with the Changjiang River, the annual mean values (127.34×104 cells/L and 0.46 mg/L in 1996, 41.98×104 cells/L and 0.2 mg/L in 1997 respectively) were lower than those (195.92×104 cells/L and 0.5 mg/L in 1996, 132.96×104 cells/L and 0.57 mg/L in 1997 respectively) at Station 1–4; and the curve of the seasonal fluctuation sometimes did not coincide with those at Stations 1–4. Based on criteria for evaluating trophic status, the dominant species, annual average cell density values of 114.86×104 –179.57×104 cells/L, biomass of 0.48–0.5 mg/L, chl-a concentration of 0.42–0.51 μg/L respectively recorded at five stations in 1996 and 1997, and values associated with the physico-chemical properties of the waterbody indicated that the water in the channel could be characterized as oligo-mesotrophic.
基金Supported by the National Natural Science Foundation of China(Nos.31700425,91751202)the Innovation Plan of Science and Technology for Aoshan(No.2016ASKJ02)the Health Assessment and Decision Support System for Coastal Ecosystem(No.XDA19060204)
文摘To better understand the spatial-temporal variation in phytoplankton community structure and its controlling factors in Jiaozhou Bay, Qingdao, North China, four seasonal sampling were carried out in 2017. The phytoplankton community structure and various environmental parameters were examined. The phytoplankton community in the bay was composed of mainly diatoms and dinofl agellates, and several other species of Chrysophyta were also observed. Diatoms were the most dominant phytoplankton group throughout the year, except in spring and winter, when Noctiluca scintillans was co-dominant. High Si/N ratios in summer and fall refl ect the high dominance of diatoms in the two seasons. Temporally, the phytoplankton cell abundance peaked in summer, due mainly to the high temperatures and nutrient concentrations in summer. Spatially, the phytoplankton cell abundance was higher in the northern part of the bay than in the other parts of the bay in four seasons. The diatom cell abundances show signifi cant positive correlations with the nutrient concentrations, while the dinofl agellate cell abundances show no correlation or a negative correlation with the nutrient concentrations but a signifi cant positive correlation with the stratifi cation index. This discrepancy was mainly due to the diff erent survival strategies between diatoms and dinofl agellates. The Shannon-Wiener diversity index ( H′) values in the bay ranged from 0.08 to 4.18, which fell in the range reported in historical studies. The distribution pattern of H′ values was quite diff erent from that of chlorophyll a , indicating that the phytoplankton community structure might have high biomass with a low diversity index. Compared with historical studies, we believe that the dominant phytoplankton species have been changed in recent years due mainly to the changing environment in the Jiaozhou Bay in recent 30 years.
文摘For compilation and comparison of desmids flora, the authors restudied the species composition, cell density and biomass of phytoplankton desmids collected at six stations in Donghu Lake at intervals of three months monitored from March of 1956 to February of 1957. A total of 122 taxa belonging to 16 genera were identified from qualitative and quantitative samples. Species of Cosmarium were the most popular ones occupy- ing about 41 % of the total species. Based on the observations, the annual mean values of the cell density and biomass were 132.11×102 cells/L and 0.09 mg/L. Cosmarium, Staurastrum, Staurodesmus and Closterium dominated and contributed more than 70 % of the total cell density and biomass at six stations in four seasons. The maximum species number, cell density and biomass in autumn revealed that the highest variety (64 taxa, 1296×102 cells/L and 0.889 mg/L respectively) occurred at Station 3 located in the southern part of Donghu Lake. From then on to the mid 1990s the desmids community decreased sharply in Donghu Lake, resulted clearly from eutrophication in the lake.
文摘This paper presents the identification and quantitative analysis of the phytoplankton samples collected in the Great Wall Bay, Antarctica from March 1988 to February 1989. The results indicate that the specific composition of phytoplankton clearly shows their ecological characteristics. That is the community mainly composed of cold-water species and neritic-eurythermal species. The dominant species altered with seasonal variation, their number showed the high-peak in the austral summer and the abundance of phytoplankton in each month mainly depended upon the dominant species. The distribution of phytoplankton is influenced by many environmental factors. Among them the hours of sunshine are the main factor.
