The scyphozoan Aurelia aurita （Linnaeus） sp. 1., is a cosmopolitan species-complex which blooms seasonally in a variety of coastal and shelf sea environments around the world. The effects of different microalgal spe...The scyphozoan Aurelia aurita （Linnaeus） sp. 1., is a cosmopolitan species-complex which blooms seasonally in a variety of coastal and shelf sea environments around the world. The effects of different microalgal species on the growth of newly-released Aurelia sp. 1 ephyrae were studied under laboratory conditions. We fed ephyrae with four different microalgal species （diatom, autotrophic dinoflagellate, heterotrophic dinoflagellate, and chlorophyta） plus A rtemia nauplii for 12-24 d at 18℃. Results showed that the growth rate diverged significantly for Artemia nauplii compared to other food types. In addition, there was no sig- nificant variation between the growth rates for Skeletonema costatum and Prorocentrum donghaiense, and no significant variation was found in the growth rates for N. scintillans and P. subcordiformis. Artemia nauplii could support the energy requirement for the newly-released ephyrae to develop to meduase, and the ephyrae with Artemia nauplii showed a significant average growth rate of 25.85% d-1. Newly-released ephyrae could grow slightly with some species of microalgae in the earliest development stage. Chain diatom Skeletonema costatum and autotrophic dinoflagellate Prorocentrum donghaiense, could not support the growth of the ephyrae, while heterotrophic dinoflagellate Noctiluca scintillans and chlorophyta Platymonas subcordiformis could support the growth of the ephyrae. However, none of the ephyrae fed with the tested phytoplankton could mature to medusae.展开更多
Aurelia spp.ephyrae have been reported to form blooms in sea cucumber aquaculture ponds in the Bohai and Yellow Seas.To identify the species,we carried out a genetic analysis of Aurelia spp.ephyrae and medusae based o...Aurelia spp.ephyrae have been reported to form blooms in sea cucumber aquaculture ponds in the Bohai and Yellow Seas.To identify the species,we carried out a genetic analysis of Aurelia spp.ephyrae and medusae based on mitochondrial 16 S rRNA gene.Samples offour Aurelia sp.ephyrae populations were collected in sea cucumber aquaculture ponds and samples offour Aurelia sp.medusae populations were collected in coastal waters.Using a BLASTn search,we found that both the ephyrae collected in the aquaculture ponds and medusae collected in coastal waters belong to Aurelia coerulea.Seventeen haplotypes were recovered from the 16 S rRNA gene.The overall haplotype diversity and nucleotide diversity of the 166 A.coerulea individuals were 0.686%and 0.329%,respectively,indicating high haplotype diversity and low nucleotide diversity.Moreover,the haplotype diversity of ephyrae populations were generally lower than that of medusae populations with close sampling points.The genetic differentiation between ephyrae populations collected in the sea cucumber aquaculture ponds and A.coerulea medusae collected in coastal waters was not significant,suggesting the ephyrae populations in the sea cucumber culture ponds were part of the same genetic group as the medusae populations in the coastal waters.Phylogeographic analysis of the 16 S rRNA region revealed that there was no significant correlation between the haplotypes and the geographic distribution of populations.Pairwise fixation index values showed significant genetic differentiation and limited gene flow between A.coerulea population of Weifang and other locations.展开更多
Blooms of the scyphozoan jellyfish <i><span style="font-family:Verdana;">Aurelia aurita</span></i><span style="font-family:Verdana;"> are greatly regulated by the surv...Blooms of the scyphozoan jellyfish <i><span style="font-family:Verdana;">Aurelia aurita</span></i><span style="font-family:Verdana;"> are greatly regulated by the survival rate of planktonic ephyrae. The ecophysiology of ephyrae is poorly studied compared with polyps and medusae. As extremely strong starvation resistance and recovery capability of </span><i><span style="font-family:Verdana;">A. aurita</span></i><span style="font-family:Verdana;"> ephyrae may due to its low metabolic rate as well as starvation may reduce the swimming ability of ephyrae which may lead to the higher predation loss, the effects of temperature and starvation on their respiration and pulsation rates were examined. In this study, ephyrae under different starvation conditions were measured by a fluorescence-based DO meter after 72 h incubation. And the pulsation rates were measured at every 10-d interval in 1-liter plastic bottle by a hand-held counter. The results showed that the mean respiration rates of newly released ephyrae were 0.24, 0.24 and 0.19 μl O</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> ephyra</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> d</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> at 15°C, 12°C and 9°C, respectively, and the rates tended to decrease with increasing starvation duration. Carbon weight-specific respiration rates did not change significantly with starvation duration. The dry weight-specific respiration rates of newly released </span><i><span style="font-family:Verdana;">A. aurita</span></i><span style="font-family:Verdana;"> ephyrae (</span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;">, 11.7</span><span style="font-size:10pt;font-family:Verdana;">-</span><span style="font-size:10pt;font-family:;" "=""><span style="font-family:Verdana;">14.6 μl O</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> mg DW</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> d</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">) were nearly one order of magnitude lower than the rates for planktonic larvae of other taxa (e.g., molluscs, crustaceans and fish). The maximum pulsation rate taken by </span><i><span style="font-family:Verdana;">A. aurita</span></i><span style="font-family:Verdana;"> ephyrae was 49.2 beats min</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">, which represents the maximum swimming velocity to be 8.87 cm·min</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">. The pulsation rates were not affected by temperature over the range between 9°C and 15°C. However, they were influenced by starvation duration. Starvation-derived decrease in pulsation together with associated body shrinkage may lead to lower encounter rate of prey and lower escaping ability from predators, which may lead to higher predation loss in the field.</span></span>展开更多
基金supported by the National Basic Research Program of China(973 Program)(No.2011CB403603)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA0503 0401)the National Natural Science Founda-tion of Shandong Province,China(No.ZR2012DQ005)
文摘The scyphozoan Aurelia aurita （Linnaeus） sp. 1., is a cosmopolitan species-complex which blooms seasonally in a variety of coastal and shelf sea environments around the world. The effects of different microalgal species on the growth of newly-released Aurelia sp. 1 ephyrae were studied under laboratory conditions. We fed ephyrae with four different microalgal species （diatom, autotrophic dinoflagellate, heterotrophic dinoflagellate, and chlorophyta） plus A rtemia nauplii for 12-24 d at 18℃. Results showed that the growth rate diverged significantly for Artemia nauplii compared to other food types. In addition, there was no sig- nificant variation between the growth rates for Skeletonema costatum and Prorocentrum donghaiense, and no significant variation was found in the growth rates for N. scintillans and P. subcordiformis. Artemia nauplii could support the energy requirement for the newly-released ephyrae to develop to meduase, and the ephyrae with Artemia nauplii showed a significant average growth rate of 25.85% d-1. Newly-released ephyrae could grow slightly with some species of microalgae in the earliest development stage. Chain diatom Skeletonema costatum and autotrophic dinoflagellate Prorocentrum donghaiense, could not support the growth of the ephyrae, while heterotrophic dinoflagellate Noctiluca scintillans and chlorophyta Platymonas subcordiformis could support the growth of the ephyrae. However, none of the ephyrae fed with the tested phytoplankton could mature to medusae.
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA23050301)the Special Exchange Program from the Chinese Academy of Sciences,the National Natural Science Foundation of China(Nos.41576152,41876138)+1 种基金the Instrument Developing Project of the Chinese Academy of Sciences(No.YJKYYQ20180047)the Key Research and Development Program of Yantai(No.2018ZHGY073)。
文摘Aurelia spp.ephyrae have been reported to form blooms in sea cucumber aquaculture ponds in the Bohai and Yellow Seas.To identify the species,we carried out a genetic analysis of Aurelia spp.ephyrae and medusae based on mitochondrial 16 S rRNA gene.Samples offour Aurelia sp.ephyrae populations were collected in sea cucumber aquaculture ponds and samples offour Aurelia sp.medusae populations were collected in coastal waters.Using a BLASTn search,we found that both the ephyrae collected in the aquaculture ponds and medusae collected in coastal waters belong to Aurelia coerulea.Seventeen haplotypes were recovered from the 16 S rRNA gene.The overall haplotype diversity and nucleotide diversity of the 166 A.coerulea individuals were 0.686%and 0.329%,respectively,indicating high haplotype diversity and low nucleotide diversity.Moreover,the haplotype diversity of ephyrae populations were generally lower than that of medusae populations with close sampling points.The genetic differentiation between ephyrae populations collected in the sea cucumber aquaculture ponds and A.coerulea medusae collected in coastal waters was not significant,suggesting the ephyrae populations in the sea cucumber culture ponds were part of the same genetic group as the medusae populations in the coastal waters.Phylogeographic analysis of the 16 S rRNA region revealed that there was no significant correlation between the haplotypes and the geographic distribution of populations.Pairwise fixation index values showed significant genetic differentiation and limited gene flow between A.coerulea population of Weifang and other locations.
文摘Blooms of the scyphozoan jellyfish <i><span style="font-family:Verdana;">Aurelia aurita</span></i><span style="font-family:Verdana;"> are greatly regulated by the survival rate of planktonic ephyrae. The ecophysiology of ephyrae is poorly studied compared with polyps and medusae. As extremely strong starvation resistance and recovery capability of </span><i><span style="font-family:Verdana;">A. aurita</span></i><span style="font-family:Verdana;"> ephyrae may due to its low metabolic rate as well as starvation may reduce the swimming ability of ephyrae which may lead to the higher predation loss, the effects of temperature and starvation on their respiration and pulsation rates were examined. In this study, ephyrae under different starvation conditions were measured by a fluorescence-based DO meter after 72 h incubation. And the pulsation rates were measured at every 10-d interval in 1-liter plastic bottle by a hand-held counter. The results showed that the mean respiration rates of newly released ephyrae were 0.24, 0.24 and 0.19 μl O</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> ephyra</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> d</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> at 15°C, 12°C and 9°C, respectively, and the rates tended to decrease with increasing starvation duration. Carbon weight-specific respiration rates did not change significantly with starvation duration. The dry weight-specific respiration rates of newly released </span><i><span style="font-family:Verdana;">A. aurita</span></i><span style="font-family:Verdana;"> ephyrae (</span><i><span style="font-family:Verdana;">i.e.</span></i><span style="font-family:Verdana;">, 11.7</span><span style="font-size:10pt;font-family:Verdana;">-</span><span style="font-size:10pt;font-family:;" "=""><span style="font-family:Verdana;">14.6 μl O</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> mg DW</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;"> d</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">) were nearly one order of magnitude lower than the rates for planktonic larvae of other taxa (e.g., molluscs, crustaceans and fish). The maximum pulsation rate taken by </span><i><span style="font-family:Verdana;">A. aurita</span></i><span style="font-family:Verdana;"> ephyrae was 49.2 beats min</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">, which represents the maximum swimming velocity to be 8.87 cm·min</span><sup><span style="font-family:Verdana;">-1</span></sup><span style="font-family:Verdana;">. The pulsation rates were not affected by temperature over the range between 9°C and 15°C. However, they were influenced by starvation duration. Starvation-derived decrease in pulsation together with associated body shrinkage may lead to lower encounter rate of prey and lower escaping ability from predators, which may lead to higher predation loss in the field.</span></span>
