The Antarctic krill（Euphausia superba） is a key species in the Southern Ocean ecosystem and an important link in the food web of the Antarctic ecosystem. The trophic information for this species during the transitio...The Antarctic krill（Euphausia superba） is a key species in the Southern Ocean ecosystem and an important link in the food web of the Antarctic ecosystem. The trophic information for this species during the transition from the austral fall to the winter is important to understand its poorly known overwintering mechanisms. However, the few studies on the topic differ in their results, in terms of both spatial and temporal variables. We investigated the size dependence and monthly and regional variation in δ^（13） C and δ^（15） N values of adult krill in the Antarctic Peninsula, in the austral fall（April to May） and the early winter（June）. We aimed to examine the trophic variations of krill occurred during this period, and the relationship between krill and their feeding environment in the Antarctic marine ecosystem. The following results were obtained：（1） no significant relationship was observed between size and the δ13 C value of krill, but the δ15 N value of krill presented a remarkable association with size;（2）the δ13 C values of krill increased during the austral fall, but no remarkable variation existed at the onset of winter,and the δ15 N values were not significant different during this period;（3） mean δ15 N values of krill differed significantly between the Bransfield Strait and the South Shetland Islands. Our data imply that adult krill present size-, season-, and region-dependent trophic variation during the transition from austral fall to early winter in the Antarctic Peninsula.展开更多
Antarctic krill (Euphausia superba) were collected from the Prydz Bay region during the austral summer of 1999/2000. The sample - collection was made at 15 sites in 3 longitudinal transects. Although krill were encoun...Antarctic krill (Euphausia superba) were collected from the Prydz Bay region during the austral summer of 1999/2000. The sample - collection was made at 15 sites in 3 longitudinal transects. Although krill were encountered at 14 sites, the abundance was comparatively low in general. The main component of the krill population was of post -larval stages. The mean numerical and weight density of krill integrated for all sampling stations in the survey area were 16. 17 ind. 1000 m -3and 12.02 g 1000 m -3 , respectively. In the survey area, stations with larger krill density are mainly located in the slope zone, except that the largest sample was collected in the open sea zone. No krill occurred in the only station of the shelf zone during our investigation. Krill collected from the slope zone were under better growth condition than those from the open sea zone, but when the survey area is considered as a whole, the growth condition is normal. The results of the comprehensive analysis of the environmental factors show that the three large sample stations seem to be related with the cold water mass at 75 m depth and the confluence area between the high and low Chla centers at the depth of 25 m.展开更多
Sampling date and position are shown in Table 1. Complete E. superbasamples with fullstomach were usua1ly used. They were averagely 45 mm long and 1.5 g weight (wet). Beingconcentrated with filtered sea water, every f...Sampling date and position are shown in Table 1. Complete E. superbasamples with fullstomach were usua1ly used. They were averagely 45 mm long and 1.5 g weight (wet). Beingconcentrated with filtered sea water, every food species from krill stomach was observed andidentified under an optical microscope, and their size was measured. Food species in stomachcontent of E. superbawere divided into five classes, according to the presence of species indi-展开更多
Phospholipids are one of the major bioactive ingredients of Antarctic krill Euphausea superba. A feasible and effective extraction method of Antarctic krill oil was investigated and modified by orthogonal test which t...Phospholipids are one of the major bioactive ingredients of Antarctic krill Euphausea superba. A feasible and effective extraction method of Antarctic krill oil was investigated and modified by orthogonal test which the ratio of solid to liquid was 1:2.5, extraction time was 5 min, ratio of ethyl acetate (EA) and n-butanol (BuOH) was 1:1. With this method, the extract of krill oil has a higher phospholipids content of 27.7% - 42.3%, together with total oil yields of 4.15% - 6.18%.展开更多
The information of trophic relationship is important for studying the Southern Ocean ecosystems. In this study, three dominant krill species, Euphausia superba, Thysanoessa macrura and Euphausia crystallorophias, were...The information of trophic relationship is important for studying the Southern Ocean ecosystems. In this study, three dominant krill species, Euphausia superba, Thysanoessa macrura and Euphausia crystallorophias, were collected from Prydz Bay, Antarctica, during austral summer of 2009/2010. The composition of fatty acids in these species was studied. E. superba and T. macrura showed a similar fatty acid composition which was dominated by C140, C16：0, EPA （eicosapentenoic acid） and DHA （decosahexenoic acid） while E. crystallorophias showed higher contents of C 18：1（n-9）, C 18： 1 （n-7）, DHA and EPA than the former two. Higher fatty acid ratios of C 18：1（n-9）/18：1（n-7）, PUFA （polyunsaturated fatty acid）/SFA （saturated fatty acid）, and 18PUFA/16PUFA indicated that E. crystallorophias should be classified as a typical onmivore with a higher trophic position compared with E. superba and T. rnacrura.展开更多
This study investigates the composition,abundance,and basic biological parameters of krill in Prydz Bay,Antarctic Peninsula and Amundsen Sea by analyzing samples and environmental data from the Chinese National Antarc...This study investigates the composition,abundance,and basic biological parameters of krill in Prydz Bay,Antarctic Peninsula and Amundsen Sea by analyzing samples and environmental data from the Chinese National Antarctic Research Expeditions conducted between 2009/2010 and 2019/2020.The predominant krill species observed were Euphausia superba,Euphausia crystallorophias,and Thysanoessa macrura.T.macrura,although the most widespread,exhibited the lowest mean abundance 9.96 ind:(1000 m^(-3))and biomass 0.31 g(1000 m^(-3)),predominantly found in low-latitude regions of the Amundsen Sea while E.crystallorophias was most concentrated in polynyas of Prydz Bay.E.superba,with an average abundance of 34.05 ind(1000 m^(-3))and biomass of 11.80 g:(1000 m^(-3)),was mainly distributed in the Antarctic Peninsula and Prydz Bay.This study also identified regional variations in mean body length and frequency distributions of kril.The relationship between krill body length and wet weight followed a power-law pattern.Regional differences were observed in the relationship between krill abundance,biomass,and environmental factors with varying correlations.In the Amundsen Sea,no significant correlation was found between krill abundance and environmental factors.Notably,E.crystallorophias in Prydz Bay demonstrated a significant positive correlation with chlorophyll a concentration,while T.macrura abundance and biomass in the Antarctic Peninsula exhibited a significant negative correlation with ice-free days.The findings contribute valuable regional data on krll distribution,abundance,and biomass in the Southern Ocean,serving as foundational information for the conservation of the Southern Ocean ecosystem and Antarctic krill fishery management on a circumpolar scale.展开更多
基金The National Natural Science Fundation of China under contract Nos 41776185 and 41606210the National Key Technology R&D Program of China under contract No.2013BAD13B03the Special Fund for Agro-scientific Research in the Public Interest of China under contract No.201203018
文摘The Antarctic krill（Euphausia superba） is a key species in the Southern Ocean ecosystem and an important link in the food web of the Antarctic ecosystem. The trophic information for this species during the transition from the austral fall to the winter is important to understand its poorly known overwintering mechanisms. However, the few studies on the topic differ in their results, in terms of both spatial and temporal variables. We investigated the size dependence and monthly and regional variation in δ^（13） C and δ^（15） N values of adult krill in the Antarctic Peninsula, in the austral fall（April to May） and the early winter（June）. We aimed to examine the trophic variations of krill occurred during this period, and the relationship between krill and their feeding environment in the Antarctic marine ecosystem. The following results were obtained：（1） no significant relationship was observed between size and the δ13 C value of krill, but the δ15 N value of krill presented a remarkable association with size;（2）the δ13 C values of krill increased during the austral fall, but no remarkable variation existed at the onset of winter,and the δ15 N values were not significant different during this period;（3） mean δ15 N values of krill differed significantly between the Bransfield Strait and the South Shetland Islands. Our data imply that adult krill present size-, season-, and region-dependent trophic variation during the transition from austral fall to early winter in the Antarctic Peninsula.
基金This study was supported by the CAS know ledge innov ation program KZCX2-303.
文摘Antarctic krill (Euphausia superba) were collected from the Prydz Bay region during the austral summer of 1999/2000. The sample - collection was made at 15 sites in 3 longitudinal transects. Although krill were encountered at 14 sites, the abundance was comparatively low in general. The main component of the krill population was of post -larval stages. The mean numerical and weight density of krill integrated for all sampling stations in the survey area were 16. 17 ind. 1000 m -3and 12.02 g 1000 m -3 , respectively. In the survey area, stations with larger krill density are mainly located in the slope zone, except that the largest sample was collected in the open sea zone. No krill occurred in the only station of the shelf zone during our investigation. Krill collected from the slope zone were under better growth condition than those from the open sea zone, but when the survey area is considered as a whole, the growth condition is normal. The results of the comprehensive analysis of the environmental factors show that the three large sample stations seem to be related with the cold water mass at 75 m depth and the confluence area between the high and low Chla centers at the depth of 25 m.
文摘Sampling date and position are shown in Table 1. Complete E. superbasamples with fullstomach were usua1ly used. They were averagely 45 mm long and 1.5 g weight (wet). Beingconcentrated with filtered sea water, every food species from krill stomach was observed andidentified under an optical microscope, and their size was measured. Food species in stomachcontent of E. superbawere divided into five classes, according to the presence of species indi-
文摘Phospholipids are one of the major bioactive ingredients of Antarctic krill Euphausea superba. A feasible and effective extraction method of Antarctic krill oil was investigated and modified by orthogonal test which the ratio of solid to liquid was 1:2.5, extraction time was 5 min, ratio of ethyl acetate (EA) and n-butanol (BuOH) was 1:1. With this method, the extract of krill oil has a higher phospholipids content of 27.7% - 42.3%, together with total oil yields of 4.15% - 6.18%.
基金supported by Polar Project of State Oceanic Administration,China (CHINARE2013-01-05-02 and CHINARE2013-04-01-05)the National Natural Science Foundation of China (41206180)
文摘The information of trophic relationship is important for studying the Southern Ocean ecosystems. In this study, three dominant krill species, Euphausia superba, Thysanoessa macrura and Euphausia crystallorophias, were collected from Prydz Bay, Antarctica, during austral summer of 2009/2010. The composition of fatty acids in these species was studied. E. superba and T. macrura showed a similar fatty acid composition which was dominated by C140, C16：0, EPA （eicosapentenoic acid） and DHA （decosahexenoic acid） while E. crystallorophias showed higher contents of C 18：1（n-9）, C 18： 1 （n-7）, DHA and EPA than the former two. Higher fatty acid ratios of C 18：1（n-9）/18：1（n-7）, PUFA （polyunsaturated fatty acid）/SFA （saturated fatty acid）, and 18PUFA/16PUFA indicated that E. crystallorophias should be classified as a typical onmivore with a higher trophic position compared with E. superba and T. rnacrura.
基金supported by Marine S&T Fund of Shandong Province for Qingdao Marine Science and Technology Center(Grant no.2022QNLM030002-1)National Natural Science Foundation of China(Grant no.42276238)National Polar Special Program“Impact and Response of Antarctic Seas to Climate Change”(Grant no.IRASCC 01-02-01D)and Taishan Scholars Program.
文摘This study investigates the composition,abundance,and basic biological parameters of krill in Prydz Bay,Antarctic Peninsula and Amundsen Sea by analyzing samples and environmental data from the Chinese National Antarctic Research Expeditions conducted between 2009/2010 and 2019/2020.The predominant krill species observed were Euphausia superba,Euphausia crystallorophias,and Thysanoessa macrura.T.macrura,although the most widespread,exhibited the lowest mean abundance 9.96 ind:(1000 m^(-3))and biomass 0.31 g(1000 m^(-3)),predominantly found in low-latitude regions of the Amundsen Sea while E.crystallorophias was most concentrated in polynyas of Prydz Bay.E.superba,with an average abundance of 34.05 ind(1000 m^(-3))and biomass of 11.80 g:(1000 m^(-3)),was mainly distributed in the Antarctic Peninsula and Prydz Bay.This study also identified regional variations in mean body length and frequency distributions of kril.The relationship between krill body length and wet weight followed a power-law pattern.Regional differences were observed in the relationship between krill abundance,biomass,and environmental factors with varying correlations.In the Amundsen Sea,no significant correlation was found between krill abundance and environmental factors.Notably,E.crystallorophias in Prydz Bay demonstrated a significant positive correlation with chlorophyll a concentration,while T.macrura abundance and biomass in the Antarctic Peninsula exhibited a significant negative correlation with ice-free days.The findings contribute valuable regional data on krll distribution,abundance,and biomass in the Southern Ocean,serving as foundational information for the conservation of the Southern Ocean ecosystem and Antarctic krill fishery management on a circumpolar scale.
