A new planktonic dinoflagellate, Prorocentrum donghaiense Lu sp. nov., is described in the present paper. The water sample was collected from the Changjiang Estuary, the East China Sea. The species identification is b...A new planktonic dinoflagellate, Prorocentrum donghaiense Lu sp. nov., is described in the present paper. The water sample was collected from the Changjiang Estuary, the East China Sea. The species identification is based on shape, size, surface micro morphology, ornamentation of thecal plates and the architecture of the periflagellar area and the intercalary bands as seen by light and scanning electron microscope. Prorocentrum donghaiense Lu sp. nov. is compared with other prorocentrum species with respect to morphological characteristics and bloom behavior. It is not known whether Prorocentrum donghaiense Lu sp. nov produces phycotoxins like some other Prorocentrum species. Four other red tide species in the family Prorocentraceae (Dinophyceae), namely P. balticum , P. minimum, P. micans, P. triestinum , were examined and identified by light and scanning electron microscope. They have been recorded as bloom forming species. Some aggregates of Prorocentrum are observed at the end of blooms. An event of strong discoloration caused by P. donghaiense could be detected by satellite sensor in the East China Sea in the late spring of 1995.展开更多
Laboratory culture experiments showed that 【 100μmol/L nitrate, amonium or mixture of aminoacids promote the growth of the red tide organism Prorocentrum micans Ehrenb, but that 】100μmol/Lof ammonium, or mixture o...Laboratory culture experiments showed that 【 100μmol/L nitrate, amonium or mixture of aminoacids promote the growth of the red tide organism Prorocentrum micans Ehrenb, but that 】100μmol/Lof ammonium, or mixture of glycine and glutamate was harmful to growth, and that orthophosphatewas P. micrns’main phosphorous soruce in the ocean. Presence of 80μmol/L EDTA, 0.5 to 1μmol/LFe<sup>3+</sup>, 1.0 to 20.0 μmol/L Mn<sup>2+</sup> 0.1 to 0.4 μmol/L Co<sup>2+</sup> in the culture medium could improvethe growth of P. micans. Vitamin B<sub>1</sub> promoted growth, but vitamin B<sub>12</sub> and biotin did not. Theestimated minimum cell quotaS （q<sub>ο</sub>） for nitrogen and phosphorus being 0.74 pmole/cell and 0.045pmole/cell show that phosphorus （more than nitrogen） limits the growth of P. micans in the study area.展开更多
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 dino...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. mieans and high densities of S. costatum inoculated into the same medium, the growth of R rnieans 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. eostatum and between P. micans and K. mikimotoi in bi-algal cultures.展开更多
The effects of varying nitrogen （N）： phosphorus （P） ratios on the growth and N-uptake and assimilation of the harmful dinoflagellates Prorocentrum minimum and Prorocentrum donghaiense were examined in turbidistat...The effects of varying nitrogen （N）： phosphorus （P） ratios on the growth and N-uptake and assimilation of the harmful dinoflagellates Prorocentrum minimum and Prorocentrum donghaiense were examined in turbidistat culture experiments. Algal cultures were supplied with media containing PO4^3- in various concentrations to obtain a wide range of N：P ratios. Experiments to determine rates of N uptake and assimilation of different N sources （NO^3-, NH4^＋, urea and glycine by P. minimum and NO3^-, NH4^＋ by P. donghaiense） were conducted using ^15-N tracer techniques at each N：P ratio. The growth rates suggested nutrient limitation at both high and low N：P ratios relative to the Redfield ratio. On a diel basis, the growth of both species was regulated by the light-dark cycle, which may be a result of regulation of both lightdependent growth and light-independent nutrient uptake. Maximum growth rates of both species always occurred at the beginning of light phase. In P-rich medium （low N：P ratio）, both species had higher N assimilation rates, suggesting N limitation. Low assimilation coefficients at high N：P ratios suggested P limitation of N uptake and assimilation. NO3 ^-and NH4^＋ contributed more than 90% of the total N uptake of P. minimum. Reduced N sources were more quickly assimilated than NO3^-. Highest average daily growth rates were recorded near an N：P ratio of 12 for both species. The N uptake rates of cultures at N：P ratios near Redfield ratio were more balanced with growth rates. The linkage between growth rates and N uptake/assimilation rates were conceptually described by the variation of cell N quota. The N：P ratios affect the N uptake and growth of Prorocentrum spp., and may regulate their bloom progression in eutrophic ecosystems.展开更多
Prorocentrum donghaiense is one of the most common red tide causative dinoflagellates in the Changjiang （Yangtze） River Estuary and the adjacent area of the East China Sea. It causes large-scale blooms in late sprin...Prorocentrum donghaiense is one of the most common red tide causative dinoflagellates in the Changjiang （Yangtze） River Estuary and the adjacent area of the East China Sea. It causes large-scale blooms in late spring and early summer that lead to widespread ecologic and economic damage. A means for distinguish- ing dinoflagellate blooms from diatom （Skeletonema costatum） blooms is desired. On the basis of measure- ments of remote sensing refectance [Rrs（λ）] and inherent optical parameters, the potential of using a mul- tispectral approach is assessed for discriminating the algal blooms due to P. donghaiense from those due to S. costatum. The behavior of two reflectance ratios [R1 = Rrs（560）/Rrs（532） and Re = Rrs（708）/Rrs（665）], suggests that differentiation of P. donghaiense blooms from diatom bloom types is possible from the current band setup of ocean color sensors. It is found that there are two reflectance ratio regimes that indicate a bloom is dominated by P. donghaiense; （1） R1 〉 1.55 and R2 〈 1.0 or （2） R1 〉 1.75 and R2 ≥ 1.0. Various sensitivity analyses are conducted to investigate the effects of the variation in varying levels of chlorophyll concentration and colored dissolved organic matter （CDOM） as well as changes in the backscattering ratio （bbp/bp） on the efficacy of this muitispectral approach. Results indicate that the intensity and inherent op- tical properties of the algal species explain much of the behavior of the two ratios. Although backscattering influences the amplitude of Rrs（λ）, especially in the 530 and 560 nm bands, the discrimination between P. donghaiense and diatoms is not significantly affected by the variation of bbp/bp. Since aCDOM （440） in coastal areas of the ECS is typically lower than 1.0 m-1 in most situations, the presence of CDOM does not interfere with this discrimination, even as SCDOM varies from 0.01 to 0.026 nm-1. Despite all of these effects, the dis- crimination of P. donghaiense blooms from diatom blooms based on multispectral measurements of Rrs（λ） is feasible.展开更多
The dinoflagellate Prorocentrum minimum,one of the most widespread red tide causing species,affects marine aquaculture and ecosystems worldwide.In this study,ridgetail white prawn Exopalaemon carinicauda were exposed ...The dinoflagellate Prorocentrum minimum,one of the most widespread red tide causing species,affects marine aquaculture and ecosystems worldwide.In this study,ridgetail white prawn Exopalaemon carinicauda were exposed to P.minimum cells(5 × 104 cells mL-1) to investigate its harmful effects on the shrimp.Antioxidant activities and histological changes were used as indicators of health status of the shrimp.In 72 hours,the mortality of E.carinicauda was not affected,but its antioxidant response and histology were statistically different from those of control.Elevated superoxide dismutase(SOD) and glutathione peroxidase(GPX) activities and depressed catalase(CAT) activity were observed in gill;while increased SOD,glutathione S-transferase(GST),CAT activities and modulated GPX activity were observed in hepatopancreas.Thus,antioxidant activities in gill and hepatopancreas seem to respond differentially to harmful alga exposure.Increased malondialdehyde(MDA) content in early a few hours indicates the damage of the antioxidant defense system.Although MDA content recovered to a low level thereafter,a series of histological abnormalities including accumulation or infiltration of hemocytes,tissue lesions and necrosis were discovered in gill and hepatopancreas.Exposure to P.minimum induced sublethal effects on E.carinicauda,including temporary oxidative damage and histological injury.展开更多
Prorocentrum minimum is a bloom-forming, planktonic mixotrophic dinoflagellate, and can cause stress in shrimp ponds. In this study, healthy Exopalaemon carinicauda were exposed to 5 × 10^4 cells mL^-1 P. minimum...Prorocentrum minimum is a bloom-forming, planktonic mixotrophic dinoflagellate, and can cause stress in shrimp ponds. In this study, healthy Exopalaemon carinicauda were exposed to 5 × 10^4 cells mL^-1 P. minimum for 72 hours to investigate the adverse effect of P. minimum on shrimps. Elevated superoxide dismutase(SOD) activity and malondialdehyde(MDA) content, reduced total antioxidant capacity(T-AOC) and catalase(CAT) activity, and regulatory glutathione peroxidase(GPX) activity were found in the hemolymph of E. carinicauda after exposure to P. minimum. In this study, P. minimum exposure induced oxidative stress and caused significant oxidative damage to E. carinicauda. P. minimum exposure increased the expression of HSP70 gene in the hemocyte, gills and hepatopancreas. Compared with the enhanced level of caspase-3 gene mR NA in the hemocyte and gills, the up-regulation of caspase-3 gene in the hepatopancreas was only observed from 3 to 6 h, and then the mRNA level of glutathione-S-transferase(GST) gene increased. These results indicated that GST might be involved in the shrimp hepatopancreas’ defense against P. minimum exposure. The present study demonstrates that exposure to P. minimum could induce oxidative stress and apoptosis in E. carinicauda. The SOD activity, HSP70 and GST(in the hepatopancreas) were evoked to protect cells from oxidative stress and apoptosis. This study will provide new insights into the toxic mechanism of P. minimum on shrimps.展开更多
In this paper, we examined the detailed morphology of two strains of Prorocentrum isolated from the coastal waters of Zhejiang (Wenling area), China, and Masan Bay of Korea. A taxonomic comparison was made among strai...In this paper, we examined the detailed morphology of two strains of Prorocentrum isolated from the coastal waters of Zhejiang (Wenling area), China, and Masan Bay of Korea. A taxonomic comparison was made among strains on the basis of morphological and molecular data. The cellular dimensions of the Chinese Wenling strain (LAMB090508) and Korean strain (PDKS0206) were similar and the cells of both strains were of asymmetric and elongated shape. The posterior end of most cells was rounded. Megacytic zones of aged cells were broader with dense tiny knobs. The roundish nucleus was located in the posterior part of the cell. A few irregular shaped chloroplasts were distributed within the cell. The nucleotide similarity of the two strains, determined from the 5.8S rDNA-ITS sequences, was 99.83%. The comparative results of morphology and molecular analysis suggest that both strains isolated from China and Korea were the identical species, Prorocentrum donghaiense Lu.展开更多
The ecological processes and interrelationships between protists,either autotrophic or heterotrophic,and environmental factors in mariculture ponds are largely unknown.This study investigated the temporal dynamics of ...The ecological processes and interrelationships between protists,either autotrophic or heterotrophic,and environmental factors in mariculture ponds are largely unknown.This study investigated the temporal dynamics of potentially harmful dinoflagellate,Prorocentrum minimum (Pavillard) Schiller,and its relationship to physico-chemical factors and protozoan grazers over a complete cycle in a semi-enclosed shrimp-farming pond near Qingdao,Northern China.P.minimum occurred frequently in low numbers from June to August,followed by a sharp increase from the middle of August,reaching a single maximum peak value of 2.2×105 cells L-1 in October.Temporal variation in abundance was positively correlated with dissolved nitrogen,but showed a significant inverse relationship to abundance of the dominant ciliates,Tintinnopsis lohmanni and Askenasia stellaris.The results provide statistical evidence that the number of P.minimum increased with increasing nitrogen,and the suppression or shortening of algal bloom may be associated with protozoan grazers,such as Tintinnopsis lohmanni,in mariculture ponds.展开更多
Algal blooms caused by Prorocentrum donghaiense occurred frequently in the East China Sea （ECS） during spring in recent years. In this study, a coupled biophysical model was used to hindcast a massive P. donghaiense...Algal blooms caused by Prorocentrum donghaiense occurred frequently in the East China Sea （ECS） during spring in recent years. In this study, a coupled biophysical model was used to hindcast a massive P. donghaiense bloom that occurred in 2005 and to determine the factors influencing bloom initiation and development. The model comprised the Regional Ocean Modeling System tailored for the ECS that utilized a multi-nested configuration and a population dynamics model for 19. donghaiense. Comparisons between simulations and observations revealed that the biological model is capable of reproducing the characteristics of 19. donghaiense growth under different irradiances and phosphorus limitation scenarios. The variation of intracellular phosphorus and the effects of 19. donghaiense on ambient nutrients conditions were also reproduced. The biophysical model hindcasted the hydrodynamics and spatiotemporal distributions of the P. donghaiense bloom reasonably well. Bloom development was consistent with observations reported in earlier studies. The results demonstrate the capability of the model in capturing subsurface incubation during bloom initiation. Then model＇s hindcast solutions were further used to diagnose the factors controlling the vertical distribution. Phosphate appeared to be one of the factors controlling the subsurface incubation, whereas surface wind fields played an important role in determining P. donghaiense distribution. The results highlight the importance of nutrient-limitation as a mechanism in the formation of P. donghaiense subsurface layers and the dispersing of P. donghaiense blooms. This coupled biophysical model should be improved and used to investigate 19. donghaiense blooms occurring in different scenarios.展开更多
文摘A new planktonic dinoflagellate, Prorocentrum donghaiense Lu sp. nov., is described in the present paper. The water sample was collected from the Changjiang Estuary, the East China Sea. The species identification is based on shape, size, surface micro morphology, ornamentation of thecal plates and the architecture of the periflagellar area and the intercalary bands as seen by light and scanning electron microscope. Prorocentrum donghaiense Lu sp. nov. is compared with other prorocentrum species with respect to morphological characteristics and bloom behavior. It is not known whether Prorocentrum donghaiense Lu sp. nov produces phycotoxins like some other Prorocentrum species. Four other red tide species in the family Prorocentraceae (Dinophyceae), namely P. balticum , P. minimum, P. micans, P. triestinum , were examined and identified by light and scanning electron microscope. They have been recorded as bloom forming species. Some aggregates of Prorocentrum are observed at the end of blooms. An event of strong discoloration caused by P. donghaiense could be detected by satellite sensor in the East China Sea in the late spring of 1995.
基金This project was supported by the Natural Science Foundation of Zhejiang Province
文摘Laboratory culture experiments showed that 【 100μmol/L nitrate, amonium or mixture of aminoacids promote the growth of the red tide organism Prorocentrum micans Ehrenb, but that 】100μmol/Lof ammonium, or mixture of glycine and glutamate was harmful to growth, and that orthophosphatewas P. micrns’main phosphorous soruce in the ocean. Presence of 80μmol/L EDTA, 0.5 to 1μmol/LFe<sup>3+</sup>, 1.0 to 20.0 μmol/L Mn<sup>2+</sup> 0.1 to 0.4 μmol/L Co<sup>2+</sup> in the culture medium could improvethe growth of P. micans. Vitamin B<sub>1</sub> promoted growth, but vitamin B<sub>12</sub> and biotin did not. Theestimated minimum cell quotaS （q<sub>ο</sub>） for nitrogen and phosphorus being 0.74 pmole/cell and 0.045pmole/cell show that phosphorus （more than nitrogen） limits the growth of P. micans in the study area.
基金Supported by the National Basic Research Program of China (973 Program) (Nos. 2011CB200901, 2010CB428706)the National Natural Science Foundation of China (No.40806053)
文摘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. mieans and high densities of S. costatum inoculated into the same medium, the growth of R rnieans 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. eostatum and between P. micans and K. mikimotoi in bi-algal cultures.
基金supported by the University of Maryland Center for Environmental Science (UMCES), Horn Point Laboratory. This is UMCES contribution number 4503
文摘The effects of varying nitrogen （N）： phosphorus （P） ratios on the growth and N-uptake and assimilation of the harmful dinoflagellates Prorocentrum minimum and Prorocentrum donghaiense were examined in turbidistat culture experiments. Algal cultures were supplied with media containing PO4^3- in various concentrations to obtain a wide range of N：P ratios. Experiments to determine rates of N uptake and assimilation of different N sources （NO^3-, NH4^＋, urea and glycine by P. minimum and NO3^-, NH4^＋ by P. donghaiense） were conducted using ^15-N tracer techniques at each N：P ratio. The growth rates suggested nutrient limitation at both high and low N：P ratios relative to the Redfield ratio. On a diel basis, the growth of both species was regulated by the light-dark cycle, which may be a result of regulation of both lightdependent growth and light-independent nutrient uptake. Maximum growth rates of both species always occurred at the beginning of light phase. In P-rich medium （low N：P ratio）, both species had higher N assimilation rates, suggesting N limitation. Low assimilation coefficients at high N：P ratios suggested P limitation of N uptake and assimilation. NO3 ^-and NH4^＋ contributed more than 90% of the total N uptake of P. minimum. Reduced N sources were more quickly assimilated than NO3^-. Highest average daily growth rates were recorded near an N：P ratio of 12 for both species. The N uptake rates of cultures at N：P ratios near Redfield ratio were more balanced with growth rates. The linkage between growth rates and N uptake/assimilation rates were conceptually described by the variation of cell N quota. The N：P ratios affect the N uptake and growth of Prorocentrum spp., and may regulate their bloom progression in eutrophic ecosystems.
基金The National Basic Research Program of China (973 Program) under contract No.2013CB430302the National High Technology Research and Development Program of China (863 Program) under contract No.2007AA092002+2 种基金the National Natural Science Foundation of China under contract No.41206170the public science and technology research funds projects of the ocean under contract No.201005030scientific research fund of the Second Institute of Oceanography,SOA under contract No.JG1212
文摘Prorocentrum donghaiense is one of the most common red tide causative dinoflagellates in the Changjiang （Yangtze） River Estuary and the adjacent area of the East China Sea. It causes large-scale blooms in late spring and early summer that lead to widespread ecologic and economic damage. A means for distinguish- ing dinoflagellate blooms from diatom （Skeletonema costatum） blooms is desired. On the basis of measure- ments of remote sensing refectance [Rrs（λ）] and inherent optical parameters, the potential of using a mul- tispectral approach is assessed for discriminating the algal blooms due to P. donghaiense from those due to S. costatum. The behavior of two reflectance ratios [R1 = Rrs（560）/Rrs（532） and Re = Rrs（708）/Rrs（665）], suggests that differentiation of P. donghaiense blooms from diatom bloom types is possible from the current band setup of ocean color sensors. It is found that there are two reflectance ratio regimes that indicate a bloom is dominated by P. donghaiense; （1） R1 〉 1.55 and R2 〈 1.0 or （2） R1 〉 1.75 and R2 ≥ 1.0. Various sensitivity analyses are conducted to investigate the effects of the variation in varying levels of chlorophyll concentration and colored dissolved organic matter （CDOM） as well as changes in the backscattering ratio （bbp/bp） on the efficacy of this muitispectral approach. Results indicate that the intensity and inherent op- tical properties of the algal species explain much of the behavior of the two ratios. Although backscattering influences the amplitude of Rrs（λ）, especially in the 530 and 560 nm bands, the discrimination between P. donghaiense and diatoms is not significantly affected by the variation of bbp/bp. Since aCDOM （440） in coastal areas of the ECS is typically lower than 1.0 m-1 in most situations, the presence of CDOM does not interfere with this discrimination, even as SCDOM varies from 0.01 to 0.026 nm-1. Despite all of these effects, the dis- crimination of P. donghaiense blooms from diatom blooms based on multispectral measurements of Rrs（λ） is feasible.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest of China(No.2060302201515013)the Scientific and Technological Innovation Project Financially Supported by Qingdao National Laboratory for Marine Science and Technology(No.2015ASKJ02)
文摘The dinoflagellate Prorocentrum minimum,one of the most widespread red tide causing species,affects marine aquaculture and ecosystems worldwide.In this study,ridgetail white prawn Exopalaemon carinicauda were exposed to P.minimum cells(5 × 104 cells mL-1) to investigate its harmful effects on the shrimp.Antioxidant activities and histological changes were used as indicators of health status of the shrimp.In 72 hours,the mortality of E.carinicauda was not affected,but its antioxidant response and histology were statistically different from those of control.Elevated superoxide dismutase(SOD) and glutathione peroxidase(GPX) activities and depressed catalase(CAT) activity were observed in gill;while increased SOD,glutathione S-transferase(GST),CAT activities and modulated GPX activity were observed in hepatopancreas.Thus,antioxidant activities in gill and hepatopancreas seem to respond differentially to harmful alga exposure.Increased malondialdehyde(MDA) content in early a few hours indicates the damage of the antioxidant defense system.Although MDA content recovered to a low level thereafter,a series of histological abnormalities including accumulation or infiltration of hemocytes,tissue lesions and necrosis were discovered in gill and hepatopancreas.Exposure to P.minimum induced sublethal effects on E.carinicauda,including temporary oxidative damage and histological injury.
基金supported by the Program of Shandong Leading Talent (No. LNJY2015002)the Scientific and Technological Innovation Project Financially Supported by Qingdao National Laboratory for Marine Science and Technology (No. 2015ASKJ02)the Qingdao Planned Projects for Postdoctoral Research Funds (No. ZQ 5120 1617013)
文摘Prorocentrum minimum is a bloom-forming, planktonic mixotrophic dinoflagellate, and can cause stress in shrimp ponds. In this study, healthy Exopalaemon carinicauda were exposed to 5 × 10^4 cells mL^-1 P. minimum for 72 hours to investigate the adverse effect of P. minimum on shrimps. Elevated superoxide dismutase(SOD) activity and malondialdehyde(MDA) content, reduced total antioxidant capacity(T-AOC) and catalase(CAT) activity, and regulatory glutathione peroxidase(GPX) activity were found in the hemolymph of E. carinicauda after exposure to P. minimum. In this study, P. minimum exposure induced oxidative stress and caused significant oxidative damage to E. carinicauda. P. minimum exposure increased the expression of HSP70 gene in the hemocyte, gills and hepatopancreas. Compared with the enhanced level of caspase-3 gene mR NA in the hemocyte and gills, the up-regulation of caspase-3 gene in the hepatopancreas was only observed from 3 to 6 h, and then the mRNA level of glutathione-S-transferase(GST) gene increased. These results indicated that GST might be involved in the shrimp hepatopancreas’ defense against P. minimum exposure. The present study demonstrates that exposure to P. minimum could induce oxidative stress and apoptosis in E. carinicauda. The SOD activity, HSP70 and GST(in the hepatopancreas) were evoked to protect cells from oxidative stress and apoptosis. This study will provide new insights into the toxic mechanism of P. minimum on shrimps.
基金Supported by the National High Technology Research and Development Program of China (863 Program) (No. 2007AA09Z110)the National Basic Research Program of China (973 Program) (No. 2010CB428702)+2 种基金Foundation of SOA (Nos. 201005031, 2009123)the Basic Research Fund of SIO (No. JG200818)Joint Project between Germany and China supported by International Bureau of BMBF at DLR (No. CHN 06/009)
文摘In this paper, we examined the detailed morphology of two strains of Prorocentrum isolated from the coastal waters of Zhejiang (Wenling area), China, and Masan Bay of Korea. A taxonomic comparison was made among strains on the basis of morphological and molecular data. The cellular dimensions of the Chinese Wenling strain (LAMB090508) and Korean strain (PDKS0206) were similar and the cells of both strains were of asymmetric and elongated shape. The posterior end of most cells was rounded. Megacytic zones of aged cells were broader with dense tiny knobs. The roundish nucleus was located in the posterior part of the cell. A few irregular shaped chloroplasts were distributed within the cell. The nucleotide similarity of the two strains, determined from the 5.8S rDNA-ITS sequences, was 99.83%. The comparative results of morphology and molecular analysis suggest that both strains isolated from China and Korea were the identical species, Prorocentrum donghaiense Lu.
基金Supported by the National Natural Science Foundation of China (No. 40976075)a Post-Doctoral Fellowship of Inha University,a Grant from the Center of Excellence in Biodiversity Research,King Saud University and 111 project of China (No. B08049)
文摘The ecological processes and interrelationships between protists,either autotrophic or heterotrophic,and environmental factors in mariculture ponds are largely unknown.This study investigated the temporal dynamics of potentially harmful dinoflagellate,Prorocentrum minimum (Pavillard) Schiller,and its relationship to physico-chemical factors and protozoan grazers over a complete cycle in a semi-enclosed shrimp-farming pond near Qingdao,Northern China.P.minimum occurred frequently in low numbers from June to August,followed by a sharp increase from the middle of August,reaching a single maximum peak value of 2.2×105 cells L-1 in October.Temporal variation in abundance was positively correlated with dissolved nitrogen,but showed a significant inverse relationship to abundance of the dominant ciliates,Tintinnopsis lohmanni and Askenasia stellaris.The results provide statistical evidence that the number of P.minimum increased with increasing nitrogen,and the suppression or shortening of algal bloom may be associated with protozoan grazers,such as Tintinnopsis lohmanni,in mariculture ponds.
基金The National Natural Science Foundation of China(NSFC)under contract Nos 41276186,41506015 and 41606038the NSFC-Shandong Joint Fund for Marine Science Research Centers under contract No.U1606405the Postdoctoral Innovation Foundation of Shandong Province under contract No.201502031
文摘Algal blooms caused by Prorocentrum donghaiense occurred frequently in the East China Sea （ECS） during spring in recent years. In this study, a coupled biophysical model was used to hindcast a massive P. donghaiense bloom that occurred in 2005 and to determine the factors influencing bloom initiation and development. The model comprised the Regional Ocean Modeling System tailored for the ECS that utilized a multi-nested configuration and a population dynamics model for 19. donghaiense. Comparisons between simulations and observations revealed that the biological model is capable of reproducing the characteristics of 19. donghaiense growth under different irradiances and phosphorus limitation scenarios. The variation of intracellular phosphorus and the effects of 19. donghaiense on ambient nutrients conditions were also reproduced. The biophysical model hindcasted the hydrodynamics and spatiotemporal distributions of the P. donghaiense bloom reasonably well. Bloom development was consistent with observations reported in earlier studies. The results demonstrate the capability of the model in capturing subsurface incubation during bloom initiation. Then model＇s hindcast solutions were further used to diagnose the factors controlling the vertical distribution. Phosphate appeared to be one of the factors controlling the subsurface incubation, whereas surface wind fields played an important role in determining P. donghaiense distribution. The results highlight the importance of nutrient-limitation as a mechanism in the formation of P. donghaiense subsurface layers and the dispersing of P. donghaiense blooms. This coupled biophysical model should be improved and used to investigate 19. donghaiense blooms occurring in different scenarios.
