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

Cited 9 time in WEB OF SCIENCE Cited 10 time in Scopus
Title
Trophodynamics of euphausiids in the Amundsen Sea during the austral summer by fatty acid and stable isotopic signatures
Author(s)
Ko, Ah-Ra; Yang, Eun Jin; Kim, Min-Seob; Ju, Se-Jong
Publication Year
2016-01
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 fishes, 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 significant 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. crystallorophias 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 difficult 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 specific FA ratios (18:1 omega 9/18:1 omega 7 and PUFA/SFA) and the nitrogen isotope ratio (delta N-15) 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. (C) 2015 Elsevier Ltd. All rights reserved.
ISSN
0967-0645
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/2287
DOI
10.1016/j.dsr2.2015.04.023
Bibliographic Citation
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY, v.123, pp.78 - 85, 2016
Publisher
PERGAMON-ELSEVIER SCIENCE LTD
Subject
ANTARCTIC KRILL; TROPHIC RELATIONSHIPS; DISTRIBUTION PATTERNS; COMMUNITY STRUCTURE; LIPID-METABOLISM; ENERGY BUDGETS; LARVAL KRILL; PRYDZ BAY; ICE-EDGE; FOOD-WEB
Keywords
Euphausia superb; Euphausia crystallorophias; Amundsen Sea Polynya; Fatty acid; Stable isotope
Type
Article
Language
English
Document Type
Article
Publisher
PERGAMON-ELSEVIER SCIENCE LTD
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