The impacts of Prorocentrum donghaiense Lu and Alexandrium catenella Balech, causative species of the large-scale HAB in the East China Sea, were studied under laboratory conditions. According to bloom densities, the ...The impacts of Prorocentrum donghaiense Lu and Alexandrium catenella Balech, causative species of the large-scale HAB in the East China Sea, were studied under laboratory conditions. According to bloom densities, the effects of monoculture and mixture of the two species were examined on the egg-hatching success of Argopecten irradians Lamarck, and the population growth of Brachionus plicatilis Müller and Moina mongolica Daday. The results showed that monoculture of A. catenella had a significant inhibition on the egg hatching success of A. irradians, and the population growth of B. plicatilis and M. mongolica. The median effective densities (ED_50) inhibiting the egg hatching success of A. irradians for 24 h and the population growth of B. plicatilis and M. mongolica for 96 h were 800, 630, and 2 400 cells/cm3, respectively. Monoculture of P. donghaiense has no such inhibitory effect on the egg hatching success of A. irradians; P. donghaiense at lower suitable densities could sustain the population growth of B. plicatilis (1×104~3×104cells/cm3) and M. mongolica (2×104~5×104cells/cm3); P. donghaiense at higher densities had significantly adverse effect on the population growth of B. plicatilis (4×104~10×104cells/cm3) and M. mongolica (10×104cells/cm3). When the two algae were mixed according to bloom densities, P. donghaiense at suitable densities to some extent could decrease the toxicity of A. catenella to B. plicatilis and M. mongolica. The results indicated that the large-scale HAB in the East China Sea could have adverse effect on zooplankton, and might further influence the marine ecosystem, especially when there was also Alexandrium bloom.展开更多
The main objective of this study was to investigate toxic effects of the dinoflagellate Alexandrium species,on cladocera Moina mongolica in the laboratory.Ten strains of Alexandrium species,including Alexandrium tamar...The main objective of this study was to investigate toxic effects of the dinoflagellate Alexandrium species,on cladocera Moina mongolica in the laboratory.Ten strains of Alexandrium species,including Alexandrium tamarense(AT-6,ATHK,ATCI02,ATCI03 and AT5-1),A.catenella(ACDH),A.affine(AC-1 and AS-1),A.lusitanicum and A.minutum were tested.The results showed that A.tamarense(ATHK,ATCI02 and AT5-1) and A.affine(AC-1 and AS-1),but not A.tamarense(AT-6 and ATCI02),A.catenella(ACDH),A.lusitanicum and A.minutum had significantly negative effects on the survival of M.mongolica;when exposed to these ten strains of Alexandrium species in densities of 3 000 cells/cm 3 for 7 d,respecyively.M.mongolica could feed on A.tamarense(AT-6,ATHK,ATCI02,ATCI03 and AT5-1),A.catenella,A.lusitanicum and A.minutum,but exhibited little or no grazing on A.affine(AC-1 and AS-1),based on the changes in gut pigment after exposure to alga for 1 and 12 h.A.affine AC-1,which had the strongest toxicity on the survival of M.mongolica,was chosen to further study the negative effects on M.mongolica.The results showed that the effect of A.affine AC-1 on the survival of M.mongolica was density-dependent,and its lethal effects on one-day,two-day and three-day old M.mongolica were exacerbated with increasing age;The whole algal culture,re-suspended algal cells,cell fragments and cell contents all had adverse impacts on the survival of M.mongolica.Moreover,both juvenile numbers and life-span time of M.mongolica were decreased significantly when they were cultured in A.affine AC-1 of 10 and 50 cells/cm 3 ,combined with 3 × 10 6 cells/cm 3 of Chlorella spp.,respectively.As a non-PSP producer,A.affine may produce other toxins,responsible for the strong negative effects on M.mongolica.展开更多
Cladocera are filter feeders abundant in freshwaters,which consume phytoplankton particles in wide size and taxonomic ranges.The ability of cladocerans to control phytoplankton abundance by grazing is determined by va...Cladocera are filter feeders abundant in freshwaters,which consume phytoplankton particles in wide size and taxonomic ranges.The ability of cladocerans to control phytoplankton abundance by grazing is determined by various factors including the characteristics of phytoplankton.Freshwater salinization may reduce the strength of top-down grazing control of phytoplankton because of the detrimental effects of salinity on the grazing intensity of zooplankters.We performed grazing experiments with two species of Cladocera of different body lengths to test their ability to graze on phytoplankton in natural waters differing in salinity and size and taxonomic composition of food particles.Grazing experiments demonstrated that the grazing rate was mostly controlled by the abundance of phytoplankton in the medium.The grazing rate was reduced at salinity ca.above 3 g/L of NaCl in the medium.The lower grazing rate was observed in the medium with larger phytoplankton particles.Both species predominantly consumed phytoplankton particles with a diameter of 6-12μm,which may shift the size distribution of phytoplankton towards a larger average diameter of particles.The taxon-specific feeding was also observed,as both species predominantly consumed diatom algae.Thus,we found that because of grazing,the size and taxonomic characteristics of phytoplankton are shifted towards a less edible community.The detrimental effect of elevated salinity on grazing rate supports growing concern about freshwater salinization negatively affecting water quality,particularly reducing top-down grazing control of phytoplankton.展开更多
文摘The impacts of Prorocentrum donghaiense Lu and Alexandrium catenella Balech, causative species of the large-scale HAB in the East China Sea, were studied under laboratory conditions. According to bloom densities, the effects of monoculture and mixture of the two species were examined on the egg-hatching success of Argopecten irradians Lamarck, and the population growth of Brachionus plicatilis Müller and Moina mongolica Daday. The results showed that monoculture of A. catenella had a significant inhibition on the egg hatching success of A. irradians, and the population growth of B. plicatilis and M. mongolica. The median effective densities (ED_50) inhibiting the egg hatching success of A. irradians for 24 h and the population growth of B. plicatilis and M. mongolica for 96 h were 800, 630, and 2 400 cells/cm3, respectively. Monoculture of P. donghaiense has no such inhibitory effect on the egg hatching success of A. irradians; P. donghaiense at lower suitable densities could sustain the population growth of B. plicatilis (1×104~3×104cells/cm3) and M. mongolica (2×104~5×104cells/cm3); P. donghaiense at higher densities had significantly adverse effect on the population growth of B. plicatilis (4×104~10×104cells/cm3) and M. mongolica (10×104cells/cm3). When the two algae were mixed according to bloom densities, P. donghaiense at suitable densities to some extent could decrease the toxicity of A. catenella to B. plicatilis and M. mongolica. The results indicated that the large-scale HAB in the East China Sea could have adverse effect on zooplankton, and might further influence the marine ecosystem, especially when there was also Alexandrium bloom.
基金The Chinese Academy of Sciences Innovation Project under contract No. KZCX2-YW-208the National Nature Science Foundation of China under contract No. U0733006+1 种基金the National Basic Research Priorities Programme under contract No.2010CB428700the Leading Academic Discipline Project of Shanghai Municipal Education Commission under contract No. J50701(Marine Biology)
文摘The main objective of this study was to investigate toxic effects of the dinoflagellate Alexandrium species,on cladocera Moina mongolica in the laboratory.Ten strains of Alexandrium species,including Alexandrium tamarense(AT-6,ATHK,ATCI02,ATCI03 and AT5-1),A.catenella(ACDH),A.affine(AC-1 and AS-1),A.lusitanicum and A.minutum were tested.The results showed that A.tamarense(ATHK,ATCI02 and AT5-1) and A.affine(AC-1 and AS-1),but not A.tamarense(AT-6 and ATCI02),A.catenella(ACDH),A.lusitanicum and A.minutum had significantly negative effects on the survival of M.mongolica;when exposed to these ten strains of Alexandrium species in densities of 3 000 cells/cm 3 for 7 d,respecyively.M.mongolica could feed on A.tamarense(AT-6,ATHK,ATCI02,ATCI03 and AT5-1),A.catenella,A.lusitanicum and A.minutum,but exhibited little or no grazing on A.affine(AC-1 and AS-1),based on the changes in gut pigment after exposure to alga for 1 and 12 h.A.affine AC-1,which had the strongest toxicity on the survival of M.mongolica,was chosen to further study the negative effects on M.mongolica.The results showed that the effect of A.affine AC-1 on the survival of M.mongolica was density-dependent,and its lethal effects on one-day,two-day and three-day old M.mongolica were exacerbated with increasing age;The whole algal culture,re-suspended algal cells,cell fragments and cell contents all had adverse impacts on the survival of M.mongolica.Moreover,both juvenile numbers and life-span time of M.mongolica were decreased significantly when they were cultured in A.affine AC-1 of 10 and 50 cells/cm 3 ,combined with 3 × 10 6 cells/cm 3 of Chlorella spp.,respectively.As a non-PSP producer,A.affine may produce other toxins,responsible for the strong negative effects on M.mongolica.
基金supported by the State Assignment of the Ministry of Science and Higher Education of the RF(No.0287-2021-0019).
文摘Cladocera are filter feeders abundant in freshwaters,which consume phytoplankton particles in wide size and taxonomic ranges.The ability of cladocerans to control phytoplankton abundance by grazing is determined by various factors including the characteristics of phytoplankton.Freshwater salinization may reduce the strength of top-down grazing control of phytoplankton because of the detrimental effects of salinity on the grazing intensity of zooplankters.We performed grazing experiments with two species of Cladocera of different body lengths to test their ability to graze on phytoplankton in natural waters differing in salinity and size and taxonomic composition of food particles.Grazing experiments demonstrated that the grazing rate was mostly controlled by the abundance of phytoplankton in the medium.The grazing rate was reduced at salinity ca.above 3 g/L of NaCl in the medium.The lower grazing rate was observed in the medium with larger phytoplankton particles.Both species predominantly consumed phytoplankton particles with a diameter of 6-12μm,which may shift the size distribution of phytoplankton towards a larger average diameter of particles.The taxon-specific feeding was also observed,as both species predominantly consumed diatom algae.Thus,we found that because of grazing,the size and taxonomic characteristics of phytoplankton are shifted towards a less edible community.The detrimental effect of elevated salinity on grazing rate supports growing concern about freshwater salinization negatively affecting water quality,particularly reducing top-down grazing control of phytoplankton.
