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Trophodynamics of euphausiids in the Amundsen Sea during the austral summer by fatty acid and stable isotopic signatures

Cited 9 time in wos
Cited 11 time in scopus
Title
Trophodynamics of euphausiids in the Amundsen Sea during the austral summer by fatty acid and stable isotopic signatures
Authors
Ko, Ah-Ra
Ju, Se-Jong
Kim, Min-Seob
Yang, Eun Jin
Keywords
Amundsen SeaPolynyaEuphausia crystallorophiasEuphausia superbFatty acidStable isotope
Issue Date
2016
Citation
Ko, Ah-Ra, et al. 2016. "Trophodynamics of euphausiids in the Amundsen Sea during the austral summer by fatty acid and stable isotopic signatures". DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY, 123(1): 78-85.
Abstract
The Amundsen Sea is characterized by a continental shelf, long-term sea ice, and many coastal polynyas with high biological productivity. Euphausia superba and Euphausia crystallorophias, which are dominant Antarctic krill, are major prey for most predators, such as ?shes, birds, and marine mammals. An understanding of the feeding ecology of krill may provide the information for the structure and function of the Amundsen Sea ecosystem. Thus, we applied two biochemical approaches (fatty acids and stable isotopes) to determine the trophodynamics of adult krill in the Amundsen Sea. There were no signi?cant differences in lipid contents between the two species, but the dominant storage lipids were different. Triacylglycerol (TAG) was dominant in E. superba, but wax esters (WE) were dominant in E. crystal- lorophias due to their different living strategies. Furthermore, the lipid content of E. crystallorophias displayed a spatial variation, being highest on the glacial edge. It was dif?cult to understand the feeding strategy and food source using only the fatty acid compositions of krill and in situ particulate organic matter. However, we found that speci?c FA ratios (18:1ω9/18:1ω7 and PUFA/SFA) and the nitrogen isotope ratio (δ 15 N) provide more insight into the feeding ecology of krill, such as feeding strategy and trophic position. These ratios suggest that E. crystallorophias consistently showed a higher degree of carnivorous feeding than E. superba in the Amundsen Sea during the austral summer. In conclusion, adult E. superba might more directly obtain their energy from in situ primary producers in the open sea, but, in the Amundsen Sea Polynya, adult E. crystallorophias seems to obtain their energy mainly through the microbial loop (microzooplankton). If so, E. crystallolophias would be a key player not only to transfer the energy from microbes to higher trophic levels but also to control the carbon and nitrogen cycle in the Amundsen Sea Polynya.
URI
https://repository.kopri.re.kr/handle/201206/7422
DOI
http://dx.doi.org/10.1016/j.dsr2.2015.04.023
Type
Article
Indexed
SCI
Appears in Collections  
2014-2016, Physical and Bio-Geochemical Processes in the Amundsen Sea / Lee; Sang H. (PP15020; PP16020; PP14020)
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