Two species of jellyfish, Cyanea nozakii Kishinouye and Nemopilema nomurai Kishinouye, have occurred offcoastal areas of the northeastern China Sea, Yellow Sea, and Bohai Sea in recent years. They influence marine eco...Two species of jellyfish, Cyanea nozakii Kishinouye and Nemopilema nomurai Kishinouye, have occurred offcoastal areas of the northeastern China Sea, Yellow Sea, and Bohai Sea in recent years. They influence marine ecosystem safety and fishery production, and also pose a risk to human health. The current study examined the hemolytic and cytotoxic activities of crude venoms extracted from the nematocysts of C. nozakii and N. nomurai. The results showed that there were more nematocysts on tentacles from C. nozakii than on tentacles of the same length from N. nomurai. The protein concentration per nematocyst extracted from N. nomurai was higher than that from C. nozakii. Both nematocyst venoms showed dose-and timedependent hemolytic activity on erythrocytes from chicken, pigeon, and sheep, with sheep erythrocytes being the most sensitive, with EC 50 values of 69.69 and 63.62 μg/m L over a 30-min exposure with N. nomurai and C. nozakii nematocyst venoms, respectively. A cytotoxic assay of both jellyfish venoms on A431 human epidermal carcinoma cells resulted in IC 50 values of 68.6 and 40.9 μg/mL after 24-h incubation, respectively, with venom from C. nozakii showing stronger cytotoxic activity than that from N. nomurai. The results of current study indicate that nematocyst venom from C. nozakii had stronger hemolytic and cytotoxic activities than that from N. nomurai and, thus, C. nozakii might be more harmful to the health of humans and other species than are N. nomurai when they appear in coastal waters.展开更多
The aim of this study was to investigate nitrogen and phosphorus released in the process of the decomposition of giant jellyfish in the laboratory and found the evidence to verify the influence of nutrients released b...The aim of this study was to investigate nitrogen and phosphorus released in the process of the decomposition of giant jellyfish in the laboratory and found the evidence to verify the influence of nutrients released by the decomposition of jellyfish on the ecosystem in the field. The release of nitrogen and phosphorus from the decomposition of Nernopilerna nomurai was examined in a series of experiments under different incubation conditions such as different pH values, salinity values, temperatures and nitrogen and phosphorus concentrations. The results showed that the complete decomposition of Nemopilema nomurai generally took about 4-8 d. The release of nitrogen and phosphorus from the decomposition of Nemopilema nomurai could be divided into two stages： the early stage and the later stage, although the efflux rate of nitrogen was one order more than phosphorus. In the early stage of the decomposition of Nemopilema nomurai, the concentrations of dissolved nitrogen, dissolved phosphorus, total nitrogen and total phosphorus in seawater increased rapidly, and the concentration of nitrogen could reach the highest level in the whole degradation process. In the later stage of the decomposition, the concentrations of dissolved nitrogen and total nitrogen declined slowly, while the concentration of phosphorus in water could reach a maximum in the degradation process. High pH, low salinity, high temperature and N/P will promote the release of nitrogen; low pH is unfavorable to the release of nitrogen but favorable to the release of phosphorus. In addition, we found the concentrations of ammonium and phosphate in the bottom water were higher than those in the surface water during the period of jellyfish bloom in the ]iaozhou Bay, proving that nutrients released by the decomposition of jellyfish have significant influence on nitrogen and phosphorus in the field. For the whole Yellow Sea, nutrients released by jellyfish carcasses may reach up to （2.63±2.98）x10^7 mol/d of dissolved nitrogen （DN） and （0.74±0.84）x10^8 mol/d of dissolved phosphorus （DP） during the period of jellyfish bloom. The values are comparable to riverine inputs in a day, but much higher than sediment-water exchange flux in the Yellow Sea. The great amounts of nutrients must have significant influence on the nutrients balance of the Yellow Sea during the period of jellyfish dead and decomposition. Both the experimental data and field observations proved that the decomposition of jellyfish may release a great amount of nutrient to the surrounding environment during the period of jellyfish decomposition.展开更多
Bacterial abundance, phytoplankton community structure and environmental parameters were investigated to study the relationships between bacteria and phytoplankton during giant jellyfish Nemopilema nomurai blooms in t...Bacterial abundance, phytoplankton community structure and environmental parameters were investigated to study the relationships between bacteria and phytoplankton during giant jellyfish Nemopilema nomurai blooms in the central Yellow Sea during 2013. N. nomurai appeared in June, increased in August, reached a peak and began to degrade in September 2013. Results showed that phosphate was possible a key nutrient for both phytoplankton and bacteria in June, but it changed to nitrate in August and September. Phytoplankton composition significantly changed that pico-phytoplankton relative biomass significantly increased, whereas other size phytoplankton significantly decreased during jellyfish bloom. In June, a significantly positive correlation was observed between chlorophyll a concentration and bacterial abundance（r=0.67, P0.001, n=34）.During jellyfish outbreak in August, there was no significant correlation between phytoplankton and bacteria（r=0.11, P0.05, n=25）, but the relationship（r=0.71, P0.001, n=31） was rebuilt with jellyfish degradation in September. In August, small size phytoplankton occupied the mixed layer in offshore stations, while bacteria almost distributed evenly in vertical. Chlorophyll a concentration significantly increased from（0.42±0.056） μg/L in June to（0.74±0.174） μg/L in August, while bacterial abundance just slightly increased. Additionally, the negative net community production indicated that community respiration was not entirely determined by the local primary productivity in August. These results indicated that jellyfish blooms potentially affect coupling of phytoplankton and bacteria in marine ecosystems.展开更多
The giant jellyfish Nemopilema nomurai is the largest and most dangerous jellyfish species in East Asian waters,and the N.nomurai bloom causes serious problem in coastal industries,fisheries,and tourism.In the previou...The giant jellyfish Nemopilema nomurai is the largest and most dangerous jellyfish species in East Asian waters,and the N.nomurai bloom causes serious problem in coastal industries,fisheries,and tourism.In the previous surveys,we found N.nomurai could not be observed in the south of 30°N.In this paper,we analyzed the mechanism of this phenomenon.After exploring the possible impacts of different environmental factors,we found that physical processes are essential to the distribution pattern of N.nomurai rather than biological or chemical factors in the East China Sea.The combination of the location of the initial breeding places of N.nomurai and the current system determine the distribution pattern.This study could provide important insights to the potential control of the giant jellyfish in the Chinese coastal waters.展开更多
Information on the dietary composition and food preferences of the giant jellyfish Nemopilema nomurai is important for understanding the trophic drivers of jellyfish outbreaks and their ecological consequences.We used...Information on the dietary composition and food preferences of the giant jellyfish Nemopilema nomurai is important for understanding the trophic drivers of jellyfish outbreaks and their ecological consequences.We used fatty acid(FA)and stable isotope(SI)biomarkers to analyze the diet of N.nomurai from the Yellow Sea in August 2016.N.nomurai was found at all sampling stations,with abundances ranging from 59 inds./km^(2) to 1651 inds./km^(2).There were no significant differences between large(>80 cm in diameter)and small(20–30 cm in diameter)medusae,either in FA compositions or in SI values,which suggests that large and small jellyfi sh have the same food composition and similar trophic levels.Compared to other zooplanktons,the relatively high levels of C20꞉4n-6 in total FAs(~12%)indicates that organic detritus contributes considerably to the food composition of the jellyfish.The mixed model Stable Isotope Analysis in R(SIAR)revealed that N.nomurai tended to prey on smaller organisms(<1000μm in diameter)which comprised about 70%of its diet.This means the N.nomurai blooms will put high feeding pressure on the small plankton.The similar SI values and FA composition indicates that krill may share the same food resources with N.nomurai,which suggests that the jellyfi sh blooms may affect krill populations as a result of food competition.展开更多
The northern East China Sea and Yellow Sea are highly dynamic marginal seas,serving as important fishing grounds and primary areas for aquaculture.The zooplankton community structure,including abundance,biovolume,and ...The northern East China Sea and Yellow Sea are highly dynamic marginal seas,serving as important fishing grounds and primary areas for aquaculture.The zooplankton community structure,including abundance,biovolume,and normalized biovolume size spectra(NBSS)within this ecosystem in summers 2021 and 2022 was assessed through ZooScan digital imaging system.The abundances of zooplankton in summers 2021 and 2022 were 3364.22±2190.53 and 4435.52±2520.06 inds./m^(3),respectively,whereas the corresponding biovolumes were 649.10±519.63 and 1064.86±1254.87 mm^(3)/m^(3),respectively.Small copepods as the dominant zooplankton functional group in terms of abundance in both years,while chaetognath and medusae were the dominant groups in terms of biovolume.The dominance of medusae and chaetognath in terms of biovolume,along with the flatter slopes of NBSS compared to a stable community,indicated that more energy accumulated in gelatinous organisms within the study area.There were significant positive relationships between temperature and tunicates or medusae,with a significantly higher population size observed in summer 2022 than in 2021.The lower abundance and biovolume of zooplankton,mainly of small copepods,in summer 2021 may be related to the larger population size of the large jellyfish and the proliferation of green tides.The investigation provided basic data and fundamental insights for achieving a comprehensive understanding of zooplankton community structure and their long-term dynamics.展开更多
基金Supported by the NSFC-Shandong Joint Funds Project(No.U1606404)the National Natural Science Foundation of China(No.41606140)the National Special Research Fund for Non-Profit Marine Sector(No.201005018)
文摘Two species of jellyfish, Cyanea nozakii Kishinouye and Nemopilema nomurai Kishinouye, have occurred offcoastal areas of the northeastern China Sea, Yellow Sea, and Bohai Sea in recent years. They influence marine ecosystem safety and fishery production, and also pose a risk to human health. The current study examined the hemolytic and cytotoxic activities of crude venoms extracted from the nematocysts of C. nozakii and N. nomurai. The results showed that there were more nematocysts on tentacles from C. nozakii than on tentacles of the same length from N. nomurai. The protein concentration per nematocyst extracted from N. nomurai was higher than that from C. nozakii. Both nematocyst venoms showed dose-and timedependent hemolytic activity on erythrocytes from chicken, pigeon, and sheep, with sheep erythrocytes being the most sensitive, with EC 50 values of 69.69 and 63.62 μg/m L over a 30-min exposure with N. nomurai and C. nozakii nematocyst venoms, respectively. A cytotoxic assay of both jellyfish venoms on A431 human epidermal carcinoma cells resulted in IC 50 values of 68.6 and 40.9 μg/mL after 24-h incubation, respectively, with venom from C. nozakii showing stronger cytotoxic activity than that from N. nomurai. The results of current study indicate that nematocyst venom from C. nozakii had stronger hemolytic and cytotoxic activities than that from N. nomurai and, thus, C. nozakii might be more harmful to the health of humans and other species than are N. nomurai when they appear in coastal waters.
基金The National Natural Science Foundation of China under contract No.41376092the National Key Project for Basic Research of China under contract No.2011CB403602the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA11030202
文摘The aim of this study was to investigate nitrogen and phosphorus released in the process of the decomposition of giant jellyfish in the laboratory and found the evidence to verify the influence of nutrients released by the decomposition of jellyfish on the ecosystem in the field. The release of nitrogen and phosphorus from the decomposition of Nernopilerna nomurai was examined in a series of experiments under different incubation conditions such as different pH values, salinity values, temperatures and nitrogen and phosphorus concentrations. The results showed that the complete decomposition of Nemopilema nomurai generally took about 4-8 d. The release of nitrogen and phosphorus from the decomposition of Nemopilema nomurai could be divided into two stages： the early stage and the later stage, although the efflux rate of nitrogen was one order more than phosphorus. In the early stage of the decomposition of Nemopilema nomurai, the concentrations of dissolved nitrogen, dissolved phosphorus, total nitrogen and total phosphorus in seawater increased rapidly, and the concentration of nitrogen could reach the highest level in the whole degradation process. In the later stage of the decomposition, the concentrations of dissolved nitrogen and total nitrogen declined slowly, while the concentration of phosphorus in water could reach a maximum in the degradation process. High pH, low salinity, high temperature and N/P will promote the release of nitrogen; low pH is unfavorable to the release of nitrogen but favorable to the release of phosphorus. In addition, we found the concentrations of ammonium and phosphate in the bottom water were higher than those in the surface water during the period of jellyfish bloom in the ]iaozhou Bay, proving that nutrients released by the decomposition of jellyfish have significant influence on nitrogen and phosphorus in the field. For the whole Yellow Sea, nutrients released by jellyfish carcasses may reach up to （2.63±2.98）x10^7 mol/d of dissolved nitrogen （DN） and （0.74±0.84）x10^8 mol/d of dissolved phosphorus （DP） during the period of jellyfish bloom. The values are comparable to riverine inputs in a day, but much higher than sediment-water exchange flux in the Yellow Sea. The great amounts of nutrients must have significant influence on the nutrients balance of the Yellow Sea during the period of jellyfish dead and decomposition. Both the experimental data and field observations proved that the decomposition of jellyfish may release a great amount of nutrient to the surrounding environment during the period of jellyfish decomposition.
基金The National Natural Science Foundation of China under contract Nos U1406403 and 41176112the Chinese Academy of Science Project under contract No.XDA11020103the National Basic Research Program of China under contract No.2011CB403603
文摘Bacterial abundance, phytoplankton community structure and environmental parameters were investigated to study the relationships between bacteria and phytoplankton during giant jellyfish Nemopilema nomurai blooms in the central Yellow Sea during 2013. N. nomurai appeared in June, increased in August, reached a peak and began to degrade in September 2013. Results showed that phosphate was possible a key nutrient for both phytoplankton and bacteria in June, but it changed to nitrate in August and September. Phytoplankton composition significantly changed that pico-phytoplankton relative biomass significantly increased, whereas other size phytoplankton significantly decreased during jellyfish bloom. In June, a significantly positive correlation was observed between chlorophyll a concentration and bacterial abundance（r=0.67, P0.001, n=34）.During jellyfish outbreak in August, there was no significant correlation between phytoplankton and bacteria（r=0.11, P0.05, n=25）, but the relationship（r=0.71, P0.001, n=31） was rebuilt with jellyfish degradation in September. In August, small size phytoplankton occupied the mixed layer in offshore stations, while bacteria almost distributed evenly in vertical. Chlorophyll a concentration significantly increased from（0.42±0.056） μg/L in June to（0.74±0.174） μg/L in August, while bacterial abundance just slightly increased. Additionally, the negative net community production indicated that community respiration was not entirely determined by the local primary productivity in August. These results indicated that jellyfish blooms potentially affect coupling of phytoplankton and bacteria in marine ecosystems.
基金Supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Nos.XDA19060204,XDA23050502)the State Key Program of National Natural Science of China(No.42130411)+4 种基金the Key Deployment Project of Centre for Ocean Mega-Research of ScienceChinese Academy of Sciences(CAS)(No.COMS2019J03)the International Science Partnership Program of the Chinese Academy of Sciences(Nos.121311KYSB20190029,133137KYSB20200002)the Laoshan Laboratory(No.LSKJ202204005)the Aoshan Science and Technology Innovation Program(No.2016ASKJ02-4)。
文摘The giant jellyfish Nemopilema nomurai is the largest and most dangerous jellyfish species in East Asian waters,and the N.nomurai bloom causes serious problem in coastal industries,fisheries,and tourism.In the previous surveys,we found N.nomurai could not be observed in the south of 30°N.In this paper,we analyzed the mechanism of this phenomenon.After exploring the possible impacts of different environmental factors,we found that physical processes are essential to the distribution pattern of N.nomurai rather than biological or chemical factors in the East China Sea.The combination of the location of the initial breeding places of N.nomurai and the current system determine the distribution pattern.This study could provide important insights to the potential control of the giant jellyfish in the Chinese coastal waters.
基金Supported by the National Key Research and Development Program of China(Nos.2017YFC1404401,2017YFC1404402)the National Natural Science Foundation of China(No.41706189)。
文摘Information on the dietary composition and food preferences of the giant jellyfish Nemopilema nomurai is important for understanding the trophic drivers of jellyfish outbreaks and their ecological consequences.We used fatty acid(FA)and stable isotope(SI)biomarkers to analyze the diet of N.nomurai from the Yellow Sea in August 2016.N.nomurai was found at all sampling stations,with abundances ranging from 59 inds./km^(2) to 1651 inds./km^(2).There were no significant differences between large(>80 cm in diameter)and small(20–30 cm in diameter)medusae,either in FA compositions or in SI values,which suggests that large and small jellyfi sh have the same food composition and similar trophic levels.Compared to other zooplanktons,the relatively high levels of C20꞉4n-6 in total FAs(~12%)indicates that organic detritus contributes considerably to the food composition of the jellyfish.The mixed model Stable Isotope Analysis in R(SIAR)revealed that N.nomurai tended to prey on smaller organisms(<1000μm in diameter)which comprised about 70%of its diet.This means the N.nomurai blooms will put high feeding pressure on the small plankton.The similar SI values and FA composition indicates that krill may share the same food resources with N.nomurai,which suggests that the jellyfi sh blooms may affect krill populations as a result of food competition.
基金Supported by the National Natural Science Foundation of China(Nos.42076166,42130411)the NSFC Ship Time Sharing Project(No.42149901)+2 种基金the Laoshan Laboratory(Nos.LSKJ202203700(or LSKJ202203704)LSKJ202204005)the National Key R&D Program of China(No.2023YFC3108202)。
文摘The northern East China Sea and Yellow Sea are highly dynamic marginal seas,serving as important fishing grounds and primary areas for aquaculture.The zooplankton community structure,including abundance,biovolume,and normalized biovolume size spectra(NBSS)within this ecosystem in summers 2021 and 2022 was assessed through ZooScan digital imaging system.The abundances of zooplankton in summers 2021 and 2022 were 3364.22±2190.53 and 4435.52±2520.06 inds./m^(3),respectively,whereas the corresponding biovolumes were 649.10±519.63 and 1064.86±1254.87 mm^(3)/m^(3),respectively.Small copepods as the dominant zooplankton functional group in terms of abundance in both years,while chaetognath and medusae were the dominant groups in terms of biovolume.The dominance of medusae and chaetognath in terms of biovolume,along with the flatter slopes of NBSS compared to a stable community,indicated that more energy accumulated in gelatinous organisms within the study area.There were significant positive relationships between temperature and tunicates or medusae,with a significantly higher population size observed in summer 2022 than in 2021.The lower abundance and biovolume of zooplankton,mainly of small copepods,in summer 2021 may be related to the larger population size of the large jellyfish and the proliferation of green tides.The investigation provided basic data and fundamental insights for achieving a comprehensive understanding of zooplankton community structure and their long-term dynamics.
