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
The Patagonian Shelf is a very productive region with dif ferent ecosystem structures. A long history of fishing in the Southwestern Atlantic Ocean combined with a complex hydrographic structure, with a permanent fron...The Patagonian Shelf is a very productive region with dif ferent ecosystem structures. A long history of fishing in the Southwestern Atlantic Ocean combined with a complex hydrographic structure, with a permanent front over the shelf-break and dif ferent coastal frontal regions, and a wide non-frontal area in between have made the food web in this area more complex and have resulted in changes to the spatialtemporal scale. Stable isotopes of carbon and nitrogen were used to determine the trophic structure of the Patagonian shelf break which was previously poorly understood. The results indicated that the average δ^(15)N value of pelagic guild(I llex argentinus) was remarkable lower than those of the other guilds. The δ^(13)C values of almost all species ranged from-17‰ to-18‰, but S tromateus brasiliensis had a significant lower δ^(13)C value. Compared with the southern Patagonian shelf, short food chain length also occurred. The impact of complex oceanographic structures has resulted in food web structure change to the temporal-spatial scale on the Patagonian shelf. The Patagonian shelf break can be considered as a separated ecosystem structure with lower δ^(15)N values.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Supported by the National Key Technology R&D Program of China(No.2013BAD13B03)the National Natural Science Foundation of China(No.41776185)the Special Fund for Agro-Scientifi c Research in the Public Interest of China(No.201203018)
文摘The Patagonian Shelf is a very productive region with dif ferent ecosystem structures. A long history of fishing in the Southwestern Atlantic Ocean combined with a complex hydrographic structure, with a permanent front over the shelf-break and dif ferent coastal frontal regions, and a wide non-frontal area in between have made the food web in this area more complex and have resulted in changes to the spatialtemporal scale. Stable isotopes of carbon and nitrogen were used to determine the trophic structure of the Patagonian shelf break which was previously poorly understood. The results indicated that the average δ^(15)N value of pelagic guild(I llex argentinus) was remarkable lower than those of the other guilds. The δ^(13)C values of almost all species ranged from-17‰ to-18‰, but S tromateus brasiliensis had a significant lower δ^(13)C value. Compared with the southern Patagonian shelf, short food chain length also occurred. The impact of complex oceanographic structures has resulted in food web structure change to the temporal-spatial scale on the Patagonian shelf. The Patagonian shelf break can be considered as a separated ecosystem structure with lower δ^(15)N values.
