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1.
The toxicity of seven major HAB (harmful algal bloom) species/strains, Prorocentrum donghaiense, Phaeocystis globosa, Prorocentrum micans, Alexandrium tamarense (AT-6, non-PSP producer), Alexandrium lusitanicum, Alexandrum tamarense (ATHK) and Heterosigma akashiwo were studied against rotifer Brachionus plicatilis under laboratory conditions. The results show that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6), or A. lusitanicum could maintain the individual survival and reproduction, as well as the population increase of the rotifer, but the individual reproduction would decrease when exposed to these five algae at higher densities for nine days; H. akashiwo could decrease the individual survival and reproduction, as well as population increase of the rotifer, which is similar to that of the starvation group, indicating that starvation might be its one lethal factor except for the algal toxins; A. tamarense (ATHK) has strong lethal effect on the rotifer with 48h LC50 at 800 cells/mL. The experiment on ingestion ability indicated by gut pigment change shows that P. donghaiense, P. globosa, P. micans, A. tamarense (AT-6) and A. lusitanicum can be taken by the rotifers as food, but A. tamarense (ATHK) or H. akashiwo can be ingested by the rotifers. The results indicate that all the indexes of individual survival and reproduction, population increase, gut pigment change of the rotifers are good and convenient to be used to reflect the toxicities of HAB species. Therefore, rotifer is suggested as one of the toxicity testing organisms in detecting the toxicity of harmful algae. Supported by the Knowledge Innovation Program of Chinese Academy of Sciences (No. KZCX2-YW-208), National Natural Science Foundation of China (No. 40821004, U0733006) and National Basic Research Program of China (973 Program, No. 2001CB409700)  相似文献   

2.
The interspecific interactions between the rotifer Brachionus plicatilis and two harmful algal blooms(HAB) species were investigated experimentally by single culture method. B. plicatilis population and the growth of the two algae were compared at different algal cell densities. The results demonstrated that the B. plicatilis obtained sufficient nutrition from Prorocentrum donghaiense to support net population increase. With exposure to 2.5×104 cells mL-1 of P. donghaiense,the number of B. plicatilis increa...  相似文献   

3.
In recent years, harmful algal blooms (HABs) have occurred frequently along the coast of China, and have been exhibiting succession from diatom- to dinoflagellate-dominated blooms. To examine the effects of different diatom and dinoflagellate HABs, the life history parameters of rotifers (Brachionus plicatilis Müller) were measured after exposure to different concentrations of HAB species. The HAB species examined included a diatom (Skeletonema costatum) and four dinoflagellates (Prorocentrum donghaiense, Alexandrium catenella, Prorocentrum lima and Karlodinium veneficum). Compared with the control treatment (CT), the diatom S. costatum showed no adverse impacts on rotifers. Exposure to dinoflagellates at densities equivalent to those measured in the field resulted in a reduction in all the life history parameters measured. This included a reduction in: lifetime egg production (CT: 20.34 eggs/ind.) reduced to 10.11, 3.22, 4.17, 7.16 eggs/ind., life span (CT: 394.53 h) reduced to 261.11, 162.90, 203.67, 196 h, net reproductive rate (CT: 19.51/ind.) reduced to 3.01, 1.26, 3.53, 5.96/ind., finite rate of increase (CT: 1.47/d) reduced to 1.16, 1.03, 1.33, 1.38/d, and intrinsic rate of population increase (CT: 0.39/d) reduced to 0.15, 0.03, 0.28, 0.32/d, for the dinoflagellates P. donghaiense, A. catenella, P. lima and K. veneficum, respectively. The results showed that the diatom S. costatum had no detrimental consequences on the reproduction and growth of B. plicatilis, however, the four dinoflagellates tested did show adverse effects. This suggests that dinoflagellate HABs may suppress microzooplankton, resulting in an increase in algal numbers.  相似文献   

4.
1 INTRODUCTION In recent decades, red tides that induced by in- creasing eutrophication occur frequently in coastal areas worldwide. This has caused serious problems in marine environment, aquaculture industries and human health (Qi et al., 1993; Horner e…  相似文献   

5.
The dinoflagellates Alexandrium pacificum and Prorocentrum donghaiense are two wellknown harmful algal blooms(HABs)-forming species,both were usually found in the same sea areas in form of HABs in China.To date,there is no mechanistic model that can fully explain the occurrence of P.donghaiense blooms with A.pacificum.We found that different strains of P.donghaiense had different intrinsic growth rates of 0.107-0.215/d,and these strains exhibited different responses to the allelopathic action from A.pacificum.Some strains of P.donghaiense could grow well despite some degrees of inhibition in a short period,suggesting the two algal species P.donghaiense and A.pacificum could coexist,even if A.pacificum was allelopathic.Our findings may advance the understanding of phenotypes in P.donghaiense and provide a potential mechanism involved in the coexistence of P.donghaiense and A.pacificum in the same area.  相似文献   

6.
A new planktonic dinoflagellate, Prorocentrum donghaiense I_a 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 pel‘iflagellar area and the intercalary bands as seen by fight 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.  相似文献   

7.
Carbonyl compounds,especially polyunsaturated aldehydes(PUAs),are increasingly reported as teratogenic to grazers and deleterious to phytoplankton.While PUAs have been considered to be mainly produced by diatoms after cell wounding,little is known about whether microalgae other than diatoms,particularly harmful algal bloom(HAB)-forming species,produce carbonyl compounds.In this study,we analyzed the carbonyl compounds from eight common HAB-forming species(Akashiwo sanguinea,Karenia mikimotoi,Karlodinium veneficum,Margalefidinium polykrikoides,Prorocentrum donghaiense,P.minimum,Scrippsiella trochoidea,and Heterosig,ma akashiwo)using gas chromatography-mass spectrometry in full scan and selected ion monitoring(SIM)modes.Our results show a ubiquitous presence of carbonyl colmpounds in both dissolved and particulate forms in all species we examined.In the full scan mode,133 chromatographic peaks were detected from 51 samples altogether.Both the varieties of carbonyl compounds and their quantities were algal species dependent,although most of the carbonyl compounds could not be fully identified according to the mass spectral database only due to the unavailability of enough standards for all analytes.Aided with nine standards in SIM mode,we further identified and quantified all nine aldehydes(2-methyl-2-pentenal,trans-2-nonenal,cis-6-nonenal,2,6-dimethyl-5-heptenal,trans-2-hexenal,trans-2-decenal,2,4-heptadienal,trans-trans-2,4-octadienal,and trans-trans-2,4-decadienal).Four of these nine aldehydes were detected in particulate form,which confirmed that trans-2-nonenal could be produced by K.mikimotoi,Karl.veneficum,P.donghaiense,P.minimum,S.trochoidea,and H.akashiwo,2,4-heptadienal and trans-trans-2,4-decadienal by A.sanguinea,M.polykrikoides,and S.trochoidea,and trans,trans-2,4-octadienal by S.trochoidea,respectively.We proved that some dinoflagellate and raphidophyte species could contribute to the pool of carbonyl compounds including PUAs in a marine ecosystem.Some carbonyl compounds,particularly those in high cell quota and/or dissolved concentration,may be related to fishkilling or allelopathy which needs further identification and quantification.  相似文献   

8.
We investigated the allelopathic properties of Alexandrium tamarense (Laboar) Balech on the growth of Prorocentrum donghaiense Lu, Chattonella marina (Subrahmanyan) Hara et Chihara and Heterosigma akashiwo (Hada) Hada in a laboratory experiment. We examined the growth of A. tamarense, C. marina, P. donghaiense and H. Akashiwo in co-cultures and the effect of filtrates from A. tamarense cultures in various growth phases, on the three harmful algal bloom (HAB)-forming algae. In co-cultures with A. tamarense, both C. marina and H. akashiwo were dramatically suppressed at high cell densities; in contrast, the growth of P. donghaiense varied in different inoculative ratios of A. tamarense and P. donghaiense. When the ratio was 1:1 (P. donghaiense: A. tamarense), growth of P. donghaiense was inhibited considerably, while the growth of P. donghaiense was almost the same as that of the control when the ratio was 9:1. The growth difference of P. donghaiense, C. marina and H. akashiwo when co-cultured with A. tamarense indicated that the allelopathic effect may be one of the important factors in algal competition and phytoplankton succession involving A. tamarense. In addition, the filtrate from A. tamarense culture had negative impacts on these three HAB algae, and such inhibition varied with different growth phases of A. tamarense in parallel with reported values of PSP toxin content in Alexandrium cells. This implied that PSP toxin was possibly involved in allelopathy of A. tamarense. However, the rapid decomposition and inactivation of PSP toxin above pH 7 weakened this possibility. Further studies on the allelochemicals responsible for the allelopathy of A. tamarense need to be carried out in future.  相似文献   

9.
Qiu  Lixia  Yu  Zhiming  Cao  Xihua  Ji  Hena  Song  Xiuxian 《中国海洋湖沼学报》2020,38(4):1270-1282
Phaeocystis globosa is a harmful algal bloom(HAB) species worldwide.Using modified clay(MC) to control HAB s and to mitigate their adverse effects is currently a commonly used method in China.In this paper,the effects of oxidized composite modified clay(OXI-MC) on P.globosa were studied from different perspectives.The results show that the OXI-MC could effectively remove P.globosa and inhibit both the growth of residual algal cells and the formation of new colonies.The P.globosa algal biomass removal efficiencies after 3 h reached 90% at a dose of 0.1 g/L,and the number of colonies with different particle sizes was greatly reduced.Compared with those of the control,the superoxide dismutase(SOD)activity,catalase(CAT) activity,and malondialdehyde(MDA) content of the residual algae significantly increased,indicating that OXI-MC caused oxidative stress in the algal cells.In addition,we evaluated the effects of OXI-MC on the photo synthe sis of residual microalgae and found that the maximal photochemical efficiency of photosystem II(PSII) under dark adaptation(F_v/F_m) and actual photochemical efficiency of PSII(cDPSII) decreased,severely damaging the photosynthesis efficiency,implying that OXI-MC effected the photosynthesis system of P.globosa.The results of this study clarify that OXI-MC could remove the most of algal cells and break up the colonies of P.globosa by collision,flocculation,and releasing active substances,as well as inhibit effectively the growth and colony formation of residual P.globosa by causing oxidative stress,reducing photosynthesis activity,accelerating the degradation of polysaccharides,and inhibiting the formation of colonies.  相似文献   

10.
Algal allelopathy is an ecological/physiological phenomenon that has focused attention on the interactions among algae and the production of algal toxins. We investigated the allelopathic interactions between the dinoflagellate genus Prorocentrum micans and diatom genus Skeletonema costatum and between P. micans and dinoflagellate genus Karenia mikimotoi using bi-algal cultures. Because the effects were species-specific and size-dependent, we evaluated the effect of different initial densities. At low densities of P. micans and high densities of S. costatum inoculated into the same medium, the growth of P. micans was weakly restrained, whereas the growth of S. costatum was significantly suppressed. S. costatum and K. mikimotoi were strongly inhibited by P. micans, in both the bi-algal cultures and enriched filtrates. Direct cell-to-cell contact was not necessary to gain a competitive advantage, thus, our results suggest that P. micans inhibited the growth of S. costatum and K. mikimotoi by the release of allelochemical(s). Last, a mathematical model was used to simulate growth and interactions between P. micans and S. costatum and between P. micans and K. mikimotoi in bi-algal cultures.  相似文献   

11.
INTRODUCTIONFrequentoccurrenceofHAB (HarmfulAlgalBlooms)hasbeenobservedinChinasincethe1 970’s .ThegreatharmtothemarineecosystemandpotentialthreattohumanhealthcausedbyHABhavebecomeamajorconcern .However ,themechanismofHABformationisstillpoorlyunderstood .BothphysicalandchemicalfactorsareconsideredasmaincausesforHABformation ,becauseunderoptimaltemperature ,salinityandnutrientconditions,HABspeciesgrowfastandaremorelikelytoformblooms .Changesintheseenvironmentalfactorsmayleadtoashif…  相似文献   

12.
The interspecific interactions between the rotifer Brachionus plicatilis and two harmful algal blooms (HAB) species were investigated experimentally by single culture method. B. plicatilis population and the growth of the two algae were compared at different algal cell densities. The results demonstrated that the B. plicatilis obtained sufficient nutrition from Prorocentrum donghaiense to support net population increase. With exposure to 2.5×104 cells mL−1 of P. donghaiense, the number of B. plicatilis increased faster than it did when exposed to other four algal densities (5, 10, 15 and 20 ×104 cells mL−1), and the increase rate of B. plicatilis population (r) at this algal density was 0.104 ± 0.015 rd−1. Cell densities of P. donghaiense decreased due to the grazing of B. plicatilis. In contrast, Heterosigma akashiwo had an adverse effect on B. plicatilis population and its growth was largely unaffected by rotifer grazing. In this case, B. plicatilis population decreased and H. akashiwo grew at a rate similar to that of the control.  相似文献   

13.
A fragment of a large sub-unit ribosomal DNA (LrDNA) of 12 strains of Prorocentrum species was amplified by polymerase chain reaction (PCR). The PCR products were digested by 3 restriction endonucleases (Cfo Ⅰ, Hae Ⅲ, and RSA Ⅰ) and then resolved in agarose gels. Results show that different species had different RFLP patterns, except for P arcuatum (ME 131), which had the same pattern to P. micans (ME 160 and 04).The same fragment of 19 strains of the genus was also amplified and subjected to denaturing gradient gel electrophoresis (DGGE). 11 different patterns were resolved. Different cultures of a same species had the same pattern. The results of RFLP and DGGE analyses showed that eight newly isolated epibenthic Prorocentrum species were different from each other, and also from other cultured ones examined in this study. P arcuatum(MEI32) could not be differentiated from P. micans (MEI60 and 04), it was probably mis-identified, since they are quite different morphologically. P. redfieldii (MEI38) could also not be distinguished form P. triestinium(MEI32), it should be regarded as a synonym ofP. triestinium. Unexpectedly, a restriction site was found in P.micans, compared with previous sequence data.  相似文献   

14.
Growth interactions between the dinoflagellate Levanderina fissa(=Gyrodinium instriatum) and the other three algal bloom species Skeletonema costatum(Bacillariophyceae), Prorocentrum micans(Dinophyceae), and Chattonella marina(Raphidophyceae) were studied using bi-or tri-algal co-cultures under laboratory conditions. The Lotka-Volterra model was applied to estimate the interspecific competition between them. Results showed that the growth of L. fissa was significantly suppressed in both bi-algal and tri-algal cultures, and the maximum cell densities in co-cultures were only between 21% and 69% of that in mono-culture. L. fissa outcompeted P. micans; however, its effects on S. costatum and C. marina were generally less than the effects of their intraspecific competitions based on the competition coefficients. Contrarily, the inhibitory effects of S. costatum and C. marina on L. fissa were much greater. S. costatum outcompeted the other three species in all co-cultures, and its competition coefficients on the other species were more than 10000 times higher than the opposite. The growth of C. marina was suppressed by S. costatum; however, it outcompeted L. fissa and P. micans. The growth of P. micans was most strongly inhibited in co-cultures, and the maximum cell densities in co-cultures were less than 15% of that in mono-species culture. The results suggested that L. fissa had few advantages in the interspecific competition. The adaptation to low salinity and the utilization of organic phosphorus might be the important reasons for L. fissa to take the competitive predominance in brackish estuarine environments.  相似文献   

15.
16.
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 PO34? 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 (NO3?, NH4+, urea and glycine by P. minimum and NO3?, NH4+ by P. donghaiense) were conducted using 15N 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 light- dependent 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.  相似文献   

17.
Miao  Fengping  Zuo  Jincheng  Liu  Xianghong  Ji  Naiyun 《中国海洋湖沼学报》2019,37(1):112-121
Red tide occurrs frequently and causes signi?cant damage to the environment and human health. As a result, development of new effcient and environment friendly red-tide microalgae inhibitors has gained increasing attention in recent times. Algicolous endophytic fungi with unique habitats are promising sources for active agents owing to their abundant secondary metabolites and distinguished activities. In this study, the algicidal activities of 49 marine macroalgal-derived endophytic fungi against phytoplankton Alexandrium tamarense, Prorocentrum donghaiense, Heterosigma akashiwo, and Chattonella marina were examined using 96-well microplate. Four fungal strains, including Aspergillus wentii(pt-1), A. ustus(cf-42),and A. versicolor(dl-29, pt-20), exhibited potent algicidal activities. A total of 32 pure compounds isolated from these fungi were noted to possess dif ferent degrees of algicidal activities. Of those, 11 compounds comprising ?ve anthraquinones, two terpenoids, and four steroids showed high 24-h inhibition rates for the four red tide algae, with 24 h EC_(50) values ranging from 0.01 to 14.29 μg/mL. Among them, compound1(1,5-dihydroxy-3-methoxy-7-methylanthraquinone) presented the strongest activity against H. akashiwo,and could decrease its chlorophyll a(Chl a) and superoxide dismutase contents and increase the soluble protein, malondialdehyde, and peroxidase contents. These results suggested that the identi?ed anti-algal compound might inhibit the growth of red tide algae by weakening photosynthesis(reducing Chl a content),destroying cell membrane, and damaging the antioxidant system.  相似文献   

18.
Fractal dimensions of flocs between clay particles and HAB organisms   总被引:1,自引:0,他引:1  
The impact of harmful algal blooms (HABs) on public health and related economics have been increasing in many coastal regions of the world. Sedimentation of algal cells through flocculation with clay particles is a promising strategy for controlling HABs. Previous studies found that removal efficiency (RE) was influenced by many factors, including clay type and concentration, algal growth stage, and physiological aspects of HAB cells. To estimate the effect of morphological characteristics of the aggregates on HAB cell removal, fractal dimensions were measured and the RE of three species of HAB organism, Heterosigma akashiwo, Alexandrium tamarense, and Skeletonema costatum, by original clay and modified clay, was determined. For all HAB species, the modified clay had a higher RE than original clay. For the original clay, the two-dimensional fractal dimension (D2) was 1.92 and three-dimensional fractal dimension (D3) 2.81, while for the modified clay, D2 was 1.84 and D3 was 2.50. The addition of polyaluminum chloride (PACl) lead to a decrease of the repulsive barrier between clay particles, and resulted in lower D2 and D3. Due to the decrease of D3, and the increase of the effective sticking coefficient, the flocculation rate between modified clay particles and HAB organisms increased, and thus resulted in a high RE. The fractal dimensions of flocs differed in HAB species with different cell morphologies. For example, Alexandrium tamarense cells are ellipsoidal, and the D3 and D2 of flocs were the highest, while for Skeletonema costatum, which has filamentous cells, the D3 and D2 of flocs were the lowest.  相似文献   

19.
Harmful algal blooms(HABs),caused by the overgrowth of certain phytoplankton species,have negative effects on marine environments and coastal fisheries.In addition to cell-counting methods using phytoplankton nets,a hydroacoustic technique based on acoustic backscattering has been proposed for the detection of phytoplankton blooms.However,little is known of the acoustic properties of HAB species.In this study,as essential data to support this technique,we measured the acoustic properties of two HAB species,Akashiwo sanguinea and Alexandrium affine,which occur in the South Sea off the coast of Korea.Due to the small size of the target,we used ultrasound for the measurements.Experiments were conducted under laboratory and field conditions.In the laboratory experiment,the acoustic signal received from each species was directly proportional to the cell abundance.We derived a relationship between the cell abundance and acoustic signal received for each species.The measured signals were compared to predictions of a fluid sphere scattering model.When A.sanguinea blooms appeared at an abundance greater than 3 500 cells/mL,the acoustic signals varied with cell abundance,showing a good correlation.These results confirm that acoustic measurements can be used to detect HAB species.  相似文献   

20.
Blooms of Akashiwo sanguinea frequently break out around the world, causing huge economic losses to the aquaculture industry and seriously damaging coastal ecosystems. However, the formation mechanisms of A. sanguinea blooms remain unclear. We investigated the allelopathic effects of A. sanguinea on multiple phytoplankton species, explored the mode of allelochemicals action and the way of nutrient factors regulation of the allelopathic activity. Results show that strains of A. sanguinea could inhibit the growth of co-occurring phytoplankton including Scrippsiella trochoidea, Phaeocystis globosa, and Rhodomonas salina, but inhibition of Prorocentrum micans was not obvious. The inhibition rates on phytoplankton were positively correlated with the cell densities of A. sanguinea. The highest inhibition rate of 94% on R. salina was for A. sanguinea CCMA256 culture of 2 000 cells/mL at 72 h. We observed that cells of S. trochoidea, Ph. g lobosa, and R. sali na were lysed when co-cultured with A. sanguinea, with the shortest time for S. trochoidea. Additionally, the growth rates of A. sanguinea were promoted by coculturing with S. trochoidea, Ph. globosa, and R. salina. Four components of A. sanguinea culture were all able to inhibit growth of R. salina:the strongest inhibitory effect was found in the sonicated culture, followed by whole-cell culture, filtrates of sonicated culture, and filtrate culture. The crude extract of A. sanguinea culture also lysed cells of R. salina, and the inhibition rates on R. salina increased with the increasing dose of crude extract. It was shown that both nutrient enrichment and nitrogen:phosphorus ratio imbalance enhanced remarkably the allelopathic activity of A. sanguinea. The highest inhibition rate on R. salina of 70% occurred in A. sanguinea JX13 treatment at 2 000 cells/mL under high nutrient condition in 48 h. In JX14 treatment at 2 000 cells/mL for N:P of 10:1, the inhibition rate increased by 1.7 times of that for N:P of 20:1. In addition, the allelopathy of A. sanguinea could not only be a competitive strategy but also a nutrition strategy, playing an important role in formation and/or maintenance of blooms of the mixotrophic dinoflagellate A. sanguinea.  相似文献   

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