Jellyfish outbreaks are severely exacerbated by coastal eutrophication,overfishing,and aquaculture.Jellyfish proliferation has been shown closely connected with larval populations during the early stages of their life...Jellyfish outbreaks are severely exacerbated by coastal eutrophication,overfishing,and aquaculture.Jellyfish proliferation has been shown closely connected with larval populations during the early stages of their life cycle.However,the factors affecting larval populations have not been fully explored.The changes in metabolites during the transition from planula larvae to polyps were analyzed using ultra-performance liquid chromatography coupled with a mass spectrometer.In jellyfish planula larvae and polyps,lipids and lipid-like molecules are the most abundant metabolites,followed by organic acids and their derivatives,organic heterocyclic compounds,and organic oxygen compounds.In comparison with planula larvae,13 metabolites were significantly increased while 212 were significantly decreased.Most of these metabolites are involved in lipid metabolism,amino acids metabolism,and nucleotide metabolism.Furthermore,during the jellyfish planula larvae metamorphosis and settlement,five differentially expressed metabolites were identified as candidate metabolites that facilitate larvae attachment and metamorphosis,including glycerol lactate pyruvate,N-stearoyl asparagine,4-methyl-umbelliferyl-N-acetyl-chitobiose,levetiracetam,and 4-amino-1-[(2 R,5 R)-5-(hydroxymethyl)-4-sulfanyloxolan-2-yl]pyrimidin-2-one.This study identified the metabolites and helped understand the metabolic mechanisms underlying the attachment and metamorphosis of jellyfish larvae,which expands our knowledge of jellyfish blooming at the early life stage.展开更多
Aurelia coerulea polyp is an important stage in the outbreaks of this species.To test the combined effects of salinity and temperature on the survival and asexual reproduction of polyps,we maintained 864 polyps at var...Aurelia coerulea polyp is an important stage in the outbreaks of this species.To test the combined effects of salinity and temperature on the survival and asexual reproduction of polyps,we maintained 864 polyps at various salinities(15,25,33,and 40)and temperatures(9,12,15,18,21,and 24℃).Polyps could mostly survive in all treatment combinations except in salinity 15 treatments with low temperatures(9-15℃).Budding occurred at all temperatures(9-24℃),while strobilation only occurred at the low temperatures(9-15℃).The range of 12-15℃was suitable for strobilation and ephyrae release.The optimal range of salinity for asexual reproduction was 25-33.Low(15)or high(40)salinity could significantly reduce the numbers of new buds or ephyrae,and low salinity of 15 retarded and even prevented strobilation at low temperatures.The optimal treatment for budding and strobilation was 21℃-salinity 25 and 12℃-salinity 33,respectively.Salinity had less of an impact than temperature on asexual reproduction,except for the polyps in high or low osmotic pressure conditions.展开更多
Mass occurrences of moon jellyfish have been observed in coastal waters. Strobilation directly determines the initial population size of adult jellyfish, but energy distribution during the strobilation process is not ...Mass occurrences of moon jellyfish have been observed in coastal waters. Strobilation directly determines the initial population size of adult jellyfish, but energy distribution during the strobilation process is not well understood. In this study, strobilation was induced in polyp of Aurelia coerulea by elevating temperature. The different stages in the strobilation process, including polyp budding, strobilation and body growth, were investigated at six temperature levels(8, 10, 13, 15, 17 and 19°C) and five food supply levels(0, 30, 60, 100 and 150 μg C/L). The results showed that the duration of strobilation preparation stage(SP) remarkably decreased with increasing temperature. Food level positively af fected the production of buds and ephyrae and the body growth of parent polyps. Of the six temperatures tested, 13°C was optimal for strobilation. At 13°C, strobilation activity was enhanced, and this treatment resulted in the greatest energy distribution, highest ephyrae production and longest duration of strobilation stage(SS). Polyps tended to allocate 6.58%–20.49% carbon to buds with sufficient food supply regardless of temperature. The body growth of parent polyps was highest at lower temperatures and higher food levels. This study is the first to provide information on carbon-based energy distribution strategy in the polyp strobilation process. We concluded that budding reproduction is a lower-risk strategy for A. coerulea polyps to increase populations. Even during strobilation season, polyps prioritize budding, but at the optimal strobilation temperature, polyps utilize a portion of the energy stored for budding to release ephyrae. The body carbon content of parent polyps may be considered as strategic energy reserves, which could help to support budding activities and strobilation during harsh conditions.展开更多
The complicated life cycle ofAurelia spp., comprising benthic asexually-reproducing polyps and sexually-reproducing medusae, makes it hard for researchers to identify and track them, especially for early stage individ...The complicated life cycle ofAurelia spp., comprising benthic asexually-reproducing polyps and sexually-reproducing medusae, makes it hard for researchers to identify and track them, especially for early stage individuals, such as planulae. To solve this problem, we developed a real-time PCR assay （SYBR Green I） to identify planulae in both cultured and natural seawater samples. Species-specific primers targeting Aurelia sp.1 mitochondrial 16S rDNA （mr 16S rDNA） regions were designed. Using a calibration curve constructed with plasmids containing the Aurelia sp. 1 mt 16S rDNA fragment and a standard curve for planulae, the absolute number of mt 16S rDNA copies per planula was determined and from that the total number ofplanulae per sample was estimated. For the field samples, a 100-fold dilution of the sample DNA combined with a final concentration of 0.2 μg/μL BSA in the PCR reaction mixture was used to remove real- time PCR inhibitors. Samples collected in Jiaozhou Bay from July to September 2012 were subsequently analyzed using this assay. Peak Aurelia sp.1 planula abundance occurred in July 2012 at stations near Hongdao Island and Qingdao offshore; abundances were very low in August and September. The real-time PCR assay （SYBR Green I） developed here negates the need for traditional microscopic identification, which is laborious and time-consuming, and can detect and quantify jellyfish planulae in field plankton samples rapidly and specifically.展开更多
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
Dietary studies of polyps and ephyrae are important to understand the formation and magnitude of jellyfish blooms and provide important insights into the marine food web.However,the diet of polyps and ephyrae in situ ...Dietary studies of polyps and ephyrae are important to understand the formation and magnitude of jellyfish blooms and provide important insights into the marine food web.However,the diet of polyps and ephyrae in situ is largely unknown.Here,prey species of the polyps and ephyrae of the moon jellyfish Aurelia coerulea in situ were identified using high-throughput DNA sequencing techniques.The results show that A.coerulea polyps and ephyrae consume a variety of prey items.The polyps consume both planktonic and benthic prey,including hydromedusae,copepods,ciliates,polychaetes,stauromedusae,and phytoplankton.A.coerulea ephyrae mainly feed on copepods and hydromedusae.Gelatinous zooplankton,including Rathkea octopunctata and Sarsia tubulosa,were frequently found as part of the diet of A.coerulea polyps and ephyrae.The utilization of highthroughput sequencing technique is a useful tool for studying the diet of polyps and ephyrae in the field,complementing the traditional techniques towards a better understanding of the complex role of gelatinous animals in marine ecosystems.展开更多
The moon jellyfi sh Aurelia spp.is a worldwide distributed scyphozoan species that seasonally blooms in coastal waters.Although the strobilation is directly responsible for the scale of jellyfi sh bloom,the underlying...The moon jellyfi sh Aurelia spp.is a worldwide distributed scyphozoan species that seasonally blooms in coastal waters.Although the strobilation is directly responsible for the scale of jellyfi sh bloom,the underlying mechanisms remain largely unknown.We exposed Aurelia coerulea polyps to 18 bioactive substances to test their ability to induce strobilation at the natural typically non-strobilation temperature of 21°C.Results revealed that A.coerulea polyps responded in four types.Type I—no change for estradiol,folic acid,iodine,retinoic acid,serotonin hydrochloride,and vitamin A.We suggested that 5-aza-2-deoxycytidine and N-acetyl-L-glutamic acid could not induce strobilation,since the percent of strobilated polyps in these two substances treatments was 3.3%and 1%,respectively.Type II—polyp body elongation for 3,5-diiodo-Ltyrosine,indole-3-acetic acid,L-dopamine,and noradrenaline treatments.Type III—transverse constrictions for L-thyroxine,progesterone,and melatonin treatments.Finally,Type IV—complete strobilation for 5-methoxy-2-methylindole,acetylcholine chloride,and indomethacin treatments,where the pre-strobilation periods were 2,4,and 2 days,and the mean numbers of ephyrae released per strobila were 4.7,5.7,and 5.7,respectively.The results reveal that indole derivatives,which contained methoxy or methyl pharmacophore,were the common strobilation inducer in the genus Aurelia.Iodinated organic compounds,catecholamine,acetylcholine chloride,and retinoic acid are species-specifi c strobilation inducer.Therefore,A.coerulea strobilation is regulated by neuronal and endocrine processes.Our fi ndings provide clues in understanding the mechanism of strobilation and contribute to developing specifi c strobilation antagonists in controlling moon jellyfi sh blooms.展开更多
The increasing amounts of artificial marine substrates, in many parts of the world have been proposed as a potential driver of Aurelia spp. blooms, on account of providing extra habitats for the settlement and the pro...The increasing amounts of artificial marine substrates, in many parts of the world have been proposed as a potential driver of Aurelia spp. blooms, on account of providing extra habitats for the settlement and the proliferation of the benthic stage(polyps). Previous experiments have mainly focused on the substrate choices of Aurelia spp. planulae. However, substrate preferences for the proliferation and immigration of polyps have not been reported. We monitored the propagation and immigration of Aurelia aurita(s. l.) polyps on two natural and nine artificial substrates at constant temperature(20±0.5°C) and salinity(30±0.5) in beakers and a glass aquarium in the laboratory, respectively. The results showed that, among artificial substrates, the highest number for polyp proliferation and immigration was found on nets, rigid polyvinyl chloride plates(RPVC), and wood. The lowest density of polyps was present on iron plates. Among natural substrates, the asexual reproduction rate of polyps on Patinopecten yessoensis(Jay, 1857) shells was significantly higher than Azumapecten farreri(Jones & Preston, 1904). On the account of the distinction in the roughness, chemical properties and biofilms of these material surfaces, bare artificial or natural substrates discriminatively affect the proliferation and the immigration of Aurelia spp. polyps at laboratory. These observations suggest that, even in the natural environment, different materials and texture may influence the composition and the abundance of the fouling communities and the assemblages of polyps and, indirectly, have effects on the amounts of released 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 <span style="font-family:Verdana;">Aurelia aurita<span style="font-family:Verdana;"> are greatly regulated by the survival rate of planktonic ephyrae....Blooms of the scyphozoan jellyfish <span style="font-family:Verdana;">Aurelia aurita<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 style="font-family:Verdana;">A. aurita<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<sub><span style="font-family:Verdana;">2</sub><span style="font-family:Verdana;"> ephyra<sup><span style="font-family:Verdana;">-1</sup><span style="font-family:Verdana;"> d<sup><span style="font-family:Verdana;">-1</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 style="font-family:Verdana;">A. aurita<span style="font-family:Verdana;"> ephyrae (<span style="font-family:Verdana;">i.e.<span style="font-family:Verdana;">, 11.7<span style="font-size:10pt;font-family:Verdana;">-<span style="font-size:10pt;font-family:;" "=""><span style="font-family:Verdana;">14.6 μl O<sub><span style="font-family:Verdana;">2</sub><span style="font-family:Verdana;"> mg DW<sup><span style="font-family:Verdana;">-1</sup><span style="font-family:Verdana;"> d<sup><span style="font-family:Verdana;">-1</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 style="font-family:Verdana;">A. aurita<span style="font-family:Verdana;"> ephyrae was 49.2 beats min<sup><span style="font-family:Verdana;">-1</sup><span style="font-family:Verdana;">, which represents the maximum swimming velocity to be 8.87 cm·min<sup><span style="font-family:Verdana;">-1</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.展开更多
基金Supported by the National Natural Science Foundation of China(NSFC)-Shandong Joint Fund(No.U 2106208)the NSFC(No.41976147)the Doctoral Fund of Yantai University(No.2222017)。
文摘Jellyfish outbreaks are severely exacerbated by coastal eutrophication,overfishing,and aquaculture.Jellyfish proliferation has been shown closely connected with larval populations during the early stages of their life cycle.However,the factors affecting larval populations have not been fully explored.The changes in metabolites during the transition from planula larvae to polyps were analyzed using ultra-performance liquid chromatography coupled with a mass spectrometer.In jellyfish planula larvae and polyps,lipids and lipid-like molecules are the most abundant metabolites,followed by organic acids and their derivatives,organic heterocyclic compounds,and organic oxygen compounds.In comparison with planula larvae,13 metabolites were significantly increased while 212 were significantly decreased.Most of these metabolites are involved in lipid metabolism,amino acids metabolism,and nucleotide metabolism.Furthermore,during the jellyfish planula larvae metamorphosis and settlement,five differentially expressed metabolites were identified as candidate metabolites that facilitate larvae attachment and metamorphosis,including glycerol lactate pyruvate,N-stearoyl asparagine,4-methyl-umbelliferyl-N-acetyl-chitobiose,levetiracetam,and 4-amino-1-[(2 R,5 R)-5-(hydroxymethyl)-4-sulfanyloxolan-2-yl]pyrimidin-2-one.This study identified the metabolites and helped understand the metabolic mechanisms underlying the attachment and metamorphosis of jellyfish larvae,which expands our knowledge of jellyfish blooming at the early life stage.
基金Supported by the National Key Research and Development Program of China(No.2017YFC1404402)the Scientific and Technological Innovation Project of the Qingdao National Laboratory for Marine Science and Technology(No.2016ASKJ02)the Basic Scientific Foundation of Guangxi Institute of Public Welfare Scientific Research(No.2019GMRC03)
文摘Aurelia coerulea polyp is an important stage in the outbreaks of this species.To test the combined effects of salinity and temperature on the survival and asexual reproduction of polyps,we maintained 864 polyps at various salinities(15,25,33,and 40)and temperatures(9,12,15,18,21,and 24℃).Polyps could mostly survive in all treatment combinations except in salinity 15 treatments with low temperatures(9-15℃).Budding occurred at all temperatures(9-24℃),while strobilation only occurred at the low temperatures(9-15℃).The range of 12-15℃was suitable for strobilation and ephyrae release.The optimal range of salinity for asexual reproduction was 25-33.Low(15)or high(40)salinity could significantly reduce the numbers of new buds or ephyrae,and low salinity of 15 retarded and even prevented strobilation at low temperatures.The optimal treatment for budding and strobilation was 21℃-salinity 25 and 12℃-salinity 33,respectively.Salinity had less of an impact than temperature on asexual reproduction,except for the polyps in high or low osmotic pressure conditions.
基金Supported by the National Key Research and Development Program of China(No.2017YFC1404400)the National Natural Science Foundation of China(Nos.41606127,41506144)the Aoshan Science and Technology Innovation Program of Qingdao National Laboratory for Marine Science and Technology(No.2016ASKJ02-2)
文摘Mass occurrences of moon jellyfish have been observed in coastal waters. Strobilation directly determines the initial population size of adult jellyfish, but energy distribution during the strobilation process is not well understood. In this study, strobilation was induced in polyp of Aurelia coerulea by elevating temperature. The different stages in the strobilation process, including polyp budding, strobilation and body growth, were investigated at six temperature levels(8, 10, 13, 15, 17 and 19°C) and five food supply levels(0, 30, 60, 100 and 150 μg C/L). The results showed that the duration of strobilation preparation stage(SP) remarkably decreased with increasing temperature. Food level positively af fected the production of buds and ephyrae and the body growth of parent polyps. Of the six temperatures tested, 13°C was optimal for strobilation. At 13°C, strobilation activity was enhanced, and this treatment resulted in the greatest energy distribution, highest ephyrae production and longest duration of strobilation stage(SS). Polyps tended to allocate 6.58%–20.49% carbon to buds with sufficient food supply regardless of temperature. The body growth of parent polyps was highest at lower temperatures and higher food levels. This study is the first to provide information on carbon-based energy distribution strategy in the polyp strobilation process. We concluded that budding reproduction is a lower-risk strategy for A. coerulea polyps to increase populations. Even during strobilation season, polyps prioritize budding, but at the optimal strobilation temperature, polyps utilize a portion of the energy stored for budding to release ephyrae. The body carbon content of parent polyps may be considered as strategic energy reserves, which could help to support budding activities and strobilation during harsh conditions.
基金Supported by the National Basic Research Program of China(973 Program)(No.2011CB403602)the National Natural Science Foundation of China(No.41076085)the National Special Research Fund for Non-Profit Marine Sector(No.201205031)
文摘The complicated life cycle ofAurelia spp., comprising benthic asexually-reproducing polyps and sexually-reproducing medusae, makes it hard for researchers to identify and track them, especially for early stage individuals, such as planulae. To solve this problem, we developed a real-time PCR assay （SYBR Green I） to identify planulae in both cultured and natural seawater samples. Species-specific primers targeting Aurelia sp.1 mitochondrial 16S rDNA （mr 16S rDNA） regions were designed. Using a calibration curve constructed with plasmids containing the Aurelia sp. 1 mt 16S rDNA fragment and a standard curve for planulae, the absolute number of mt 16S rDNA copies per planula was determined and from that the total number ofplanulae per sample was estimated. For the field samples, a 100-fold dilution of the sample DNA combined with a final concentration of 0.2 μg/μL BSA in the PCR reaction mixture was used to remove real- time PCR inhibitors. Samples collected in Jiaozhou Bay from July to September 2012 were subsequently analyzed using this assay. Peak Aurelia sp.1 planula abundance occurred in July 2012 at stations near Hongdao Island and Qingdao offshore; abundances were very low in August and September. The real-time PCR assay （SYBR Green I） developed here negates the need for traditional microscopic identification, which is laborious and time-consuming, and can detect and quantify jellyfish planulae in field plankton samples rapidly and specifically.
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The National Key Research and Development Program of China under contract No.2018YFC1406501the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA23050301+2 种基金the National Natural Science Foundation of China under contract No.41876138the Instrument Developing Project of the Chinese Academy of Sciences under contract No.YJKYYQ20180047the Key Research and Development Program of Yantai under contract No.2018ZHGY073。
文摘Dietary studies of polyps and ephyrae are important to understand the formation and magnitude of jellyfish blooms and provide important insights into the marine food web.However,the diet of polyps and ephyrae in situ is largely unknown.Here,prey species of the polyps and ephyrae of the moon jellyfish Aurelia coerulea in situ were identified using high-throughput DNA sequencing techniques.The results show that A.coerulea polyps and ephyrae consume a variety of prey items.The polyps consume both planktonic and benthic prey,including hydromedusae,copepods,ciliates,polychaetes,stauromedusae,and phytoplankton.A.coerulea ephyrae mainly feed on copepods and hydromedusae.Gelatinous zooplankton,including Rathkea octopunctata and Sarsia tubulosa,were frequently found as part of the diet of A.coerulea polyps and ephyrae.The utilization of highthroughput sequencing technique is a useful tool for studying the diet of polyps and ephyrae in the field,complementing the traditional techniques towards a better understanding of the complex role of gelatinous animals in marine ecosystems.
基金Supported by the National Key R&D Program of China(No.2017YFC1404401)the National Natural Science Foundation of China(Nos.41606127,41976135)the Youth Talent Support Program of the Laboratory for Marine Ecology and Environmental Science,Pilot National Laboratory for Marine Science and Technology(Qingdao)(No.LMEESYTSP-2018-01-10)。
文摘The moon jellyfi sh Aurelia spp.is a worldwide distributed scyphozoan species that seasonally blooms in coastal waters.Although the strobilation is directly responsible for the scale of jellyfi sh bloom,the underlying mechanisms remain largely unknown.We exposed Aurelia coerulea polyps to 18 bioactive substances to test their ability to induce strobilation at the natural typically non-strobilation temperature of 21°C.Results revealed that A.coerulea polyps responded in four types.Type I—no change for estradiol,folic acid,iodine,retinoic acid,serotonin hydrochloride,and vitamin A.We suggested that 5-aza-2-deoxycytidine and N-acetyl-L-glutamic acid could not induce strobilation,since the percent of strobilated polyps in these two substances treatments was 3.3%and 1%,respectively.Type II—polyp body elongation for 3,5-diiodo-Ltyrosine,indole-3-acetic acid,L-dopamine,and noradrenaline treatments.Type III—transverse constrictions for L-thyroxine,progesterone,and melatonin treatments.Finally,Type IV—complete strobilation for 5-methoxy-2-methylindole,acetylcholine chloride,and indomethacin treatments,where the pre-strobilation periods were 2,4,and 2 days,and the mean numbers of ephyrae released per strobila were 4.7,5.7,and 5.7,respectively.The results reveal that indole derivatives,which contained methoxy or methyl pharmacophore,were the common strobilation inducer in the genus Aurelia.Iodinated organic compounds,catecholamine,acetylcholine chloride,and retinoic acid are species-specifi c strobilation inducer.Therefore,A.coerulea strobilation is regulated by neuronal and endocrine processes.Our fi ndings provide clues in understanding the mechanism of strobilation and contribute to developing specifi c strobilation antagonists in controlling moon jellyfi sh blooms.
基金Supported by the State Key Program of National Natural Science of China(No.41230963)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA11020305)+1 种基金the Shandong Joint Fund for Marine Ecology and Environmental Sciences(No.U1406403)the National Natural Science Foundation of China(No.41506144)
文摘The increasing amounts of artificial marine substrates, in many parts of the world have been proposed as a potential driver of Aurelia spp. blooms, on account of providing extra habitats for the settlement and the proliferation of the benthic stage(polyps). Previous experiments have mainly focused on the substrate choices of Aurelia spp. planulae. However, substrate preferences for the proliferation and immigration of polyps have not been reported. We monitored the propagation and immigration of Aurelia aurita(s. l.) polyps on two natural and nine artificial substrates at constant temperature(20±0.5°C) and salinity(30±0.5) in beakers and a glass aquarium in the laboratory, respectively. The results showed that, among artificial substrates, the highest number for polyp proliferation and immigration was found on nets, rigid polyvinyl chloride plates(RPVC), and wood. The lowest density of polyps was present on iron plates. Among natural substrates, the asexual reproduction rate of polyps on Patinopecten yessoensis(Jay, 1857) shells was significantly higher than Azumapecten farreri(Jones & Preston, 1904). On the account of the distinction in the roughness, chemical properties and biofilms of these material surfaces, bare artificial or natural substrates discriminatively affect the proliferation and the immigration of Aurelia spp. polyps at laboratory. These observations suggest that, even in the natural environment, different materials and texture may influence the composition and the abundance of the fouling communities and the assemblages of polyps and, indirectly, have effects on the amounts of released 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 <span style="font-family:Verdana;">Aurelia aurita<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 style="font-family:Verdana;">A. aurita<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<sub><span style="font-family:Verdana;">2</sub><span style="font-family:Verdana;"> ephyra<sup><span style="font-family:Verdana;">-1</sup><span style="font-family:Verdana;"> d<sup><span style="font-family:Verdana;">-1</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 style="font-family:Verdana;">A. aurita<span style="font-family:Verdana;"> ephyrae (<span style="font-family:Verdana;">i.e.<span style="font-family:Verdana;">, 11.7<span style="font-size:10pt;font-family:Verdana;">-<span style="font-size:10pt;font-family:;" "=""><span style="font-family:Verdana;">14.6 μl O<sub><span style="font-family:Verdana;">2</sub><span style="font-family:Verdana;"> mg DW<sup><span style="font-family:Verdana;">-1</sup><span style="font-family:Verdana;"> d<sup><span style="font-family:Verdana;">-1</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 style="font-family:Verdana;">A. aurita<span style="font-family:Verdana;"> ephyrae was 49.2 beats min<sup><span style="font-family:Verdana;">-1</sup><span style="font-family:Verdana;">, which represents the maximum swimming velocity to be 8.87 cm·min<sup><span style="font-family:Verdana;">-1</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.
