Many marine dinoflagellates can form resting cysts as a part of their life cycle,and the cysts could be buried in sediment and remained viable for as long as over 150 years.However,only a very limited number of cyst s...Many marine dinoflagellates can form resting cysts as a part of their life cycle,and the cysts could be buried in sediment and remained viable for as long as over 150 years.However,only a very limited number of cyst species have been revived from long-buried sediments and investigated in regard to a possible shift in the intra-specific genetic structure of a species detected from the historical record at a particular location.Here,we report a successful germination of three species of resting cysts that were sampled from the depth dated back to 1941±18 AD from a 44-cm sediment core from the East China Sea.Seven isolates were established from germination of single cyst isolation or multi-cyst germinations.LSU rRNA gene or ITS sequences of these strains were obtained,then they were identified to be Biecheleria brevisulcata(five strains),Biecheleriopsis adriatica(one strain),and Scrippsiella donghaienis(one strain)in terms of morphology and rRNA gene sequence.Biecheleria brevisulcata strain 1,Bps.adriatica strain 21,and S.donghaienis strain 23 were examined in detail with light microscope(LM)and scanning electron microscope(SEM),and analyzed with high performance liquid chromatography(HPLC)for their pigment compositions,and genetic diversity.We also confirmed the presence of a resting cyst of Bps.adriatica in the field for the first time.The LSU rRNA gene-based genetic distances of Bps.adriatica from that obtained from water sample,single-cell PCR sequencing for the cysts isolated from the surface sediment of the same sea area and that reported from other regions during the recent years,and ITS-based genetic distances of S.donghaienis from that obtained from cysts isolated from the surface sediment of the same location and that reported from other regions during the recent years indicated that the intra-specific genetic structure of each species in the sampling area may have shifted during the last 70 years.Our work confirms that B.brevisulcata,Bps.adriatica,and S.donghaienis,all described as new species around 2010,have inhabited the East China Sea for about 70 years.The present work reports for the first time the revival of dinoflagellate resting cysts long-buried in the coastal sediments of China,which facilitates further study on the historical occurrences of other harmful dinoflagellates and their relevance to the regional climate and environmental changes in China.展开更多
Resting cysts are an important part of the life cycle for many harmful algal bloom-forming dinoflagellates, and play vital roles in the recurrence and geographical spread of harmful algal blooms. Numerous factors have...Resting cysts are an important part of the life cycle for many harmful algal bloom-forming dinoflagellates, and play vital roles in the recurrence and geographical spread of harmful algal blooms. Numerous factors have been suggested to regulate the formation of resting cysts, although only a few have been proven to be significant. Cyst formation can be induced by adverse environmental conditions such as drastic changes in temperature, light, salinity, and nutrient levels, and by biological interactions. In this study, we evaluated the ability of an artificial factor(fine sand particles) to enhance the formation of resting cysts. Fine sand particles were added to cultures of dinoflagellates that are known to produce cysts. The addition of fine sand particles significantly increased both the production rate and final yield of cysts in cultures of S crippsiella trochoidea, Biecheleria brevisulcata, and Levanderina fissa(= Gymnodinium fissum, Gyrodinium instriatum, Gyr odinium uncatenum). The largest increase in the final yield(107-fold) of cysts as a result of sand addition was in S. trochoidea. However, addition of fine sand particles did not induce cyst formation, or barely af fected cyst formation, in A kashiwo san guinea, Cochlodinium polykrikoides and Pheopolykrikos hartmannii, which are also known to be cyst-producing species. We speculated that addition of sand significantly increased the chances of cell collision, which triggered cyst formation. However, further research is required to test this idea. Importantly, our findings indicate that the addition of fine sand particles is a useful method to obtain a large quantity of cysts in a short time for laboratory studies or tests; for example, if a cyst viability test is being used to assess the eff ectiveness of ships' ballast water treatment.展开更多
基金Supported by the Science and Technology Basic Resources Investigation Program of China(No.2018FY100200)the National Natural Science Foundation of China(No.41976134)+2 种基金the Youth Talent Support Program of the Laboratory for Marine Ecology and Environmental SciencePilot National Laboratory for Marine Science and Technology(Qingdao)(No.LMEES-YTSP-2018-01-04)the Program for Scientific Research Start-up Funds of Guangdong Ocean University(No.060302022201)。
文摘Many marine dinoflagellates can form resting cysts as a part of their life cycle,and the cysts could be buried in sediment and remained viable for as long as over 150 years.However,only a very limited number of cyst species have been revived from long-buried sediments and investigated in regard to a possible shift in the intra-specific genetic structure of a species detected from the historical record at a particular location.Here,we report a successful germination of three species of resting cysts that were sampled from the depth dated back to 1941±18 AD from a 44-cm sediment core from the East China Sea.Seven isolates were established from germination of single cyst isolation or multi-cyst germinations.LSU rRNA gene or ITS sequences of these strains were obtained,then they were identified to be Biecheleria brevisulcata(five strains),Biecheleriopsis adriatica(one strain),and Scrippsiella donghaienis(one strain)in terms of morphology and rRNA gene sequence.Biecheleria brevisulcata strain 1,Bps.adriatica strain 21,and S.donghaienis strain 23 were examined in detail with light microscope(LM)and scanning electron microscope(SEM),and analyzed with high performance liquid chromatography(HPLC)for their pigment compositions,and genetic diversity.We also confirmed the presence of a resting cyst of Bps.adriatica in the field for the first time.The LSU rRNA gene-based genetic distances of Bps.adriatica from that obtained from water sample,single-cell PCR sequencing for the cysts isolated from the surface sediment of the same sea area and that reported from other regions during the recent years,and ITS-based genetic distances of S.donghaienis from that obtained from cysts isolated from the surface sediment of the same location and that reported from other regions during the recent years indicated that the intra-specific genetic structure of each species in the sampling area may have shifted during the last 70 years.Our work confirms that B.brevisulcata,Bps.adriatica,and S.donghaienis,all described as new species around 2010,have inhabited the East China Sea for about 70 years.The present work reports for the first time the revival of dinoflagellate resting cysts long-buried in the coastal sediments of China,which facilitates further study on the historical occurrences of other harmful dinoflagellates and their relevance to the regional climate and environmental changes in China.
基金Supported by the NSFC-Shandong Joint Fund for Marine Ecology and Environmental Sciences(No.U1606404)the National Natural Science Foundation of China(Nos.41476142,61533011,41506143)+1 种基金the Scientific and Technological Innovation Project supported by the Qingdao National Laboratory for Marine Science(No.2016ASKJ02)the NSFCGuangdong Joint Fund(No.U1301235)
文摘Resting cysts are an important part of the life cycle for many harmful algal bloom-forming dinoflagellates, and play vital roles in the recurrence and geographical spread of harmful algal blooms. Numerous factors have been suggested to regulate the formation of resting cysts, although only a few have been proven to be significant. Cyst formation can be induced by adverse environmental conditions such as drastic changes in temperature, light, salinity, and nutrient levels, and by biological interactions. In this study, we evaluated the ability of an artificial factor(fine sand particles) to enhance the formation of resting cysts. Fine sand particles were added to cultures of dinoflagellates that are known to produce cysts. The addition of fine sand particles significantly increased both the production rate and final yield of cysts in cultures of S crippsiella trochoidea, Biecheleria brevisulcata, and Levanderina fissa(= Gymnodinium fissum, Gyrodinium instriatum, Gyr odinium uncatenum). The largest increase in the final yield(107-fold) of cysts as a result of sand addition was in S. trochoidea. However, addition of fine sand particles did not induce cyst formation, or barely af fected cyst formation, in A kashiwo san guinea, Cochlodinium polykrikoides and Pheopolykrikos hartmannii, which are also known to be cyst-producing species. We speculated that addition of sand significantly increased the chances of cell collision, which triggered cyst formation. However, further research is required to test this idea. Importantly, our findings indicate that the addition of fine sand particles is a useful method to obtain a large quantity of cysts in a short time for laboratory studies or tests; for example, if a cyst viability test is being used to assess the eff ectiveness of ships' ballast water treatment.