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A Circadian Clock in Antarctic krill: an endogenous timing system governs metabolic output rhythms in the Euphausid species Euphausia superba

Citation

Teschke, M and Wendt, S and Kawaguchi, S and Kramer, A and Meyer, B, A Circadian Clock in Antarctic krill: an endogenous timing system governs metabolic output rhythms in the Euphausid species Euphausia superba, PLoS ONE, 6, (10) Article e26090. ISSN 1932-6203 (2011) [Refereed Article]


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Licenced under Creative Commons Attribution 2.5 Generic (CC BY 2.5) http://creativecommons.org/licenses/by/2.5/

DOI: doi:10.1371/journal.pone.0026090

Abstract

Antarctic krill, Euphausia superba, shapes the structure of the Southern Ocean ecosystem. Its central position in the food web, the ongoing environmental changes due to climatic warming, and increasing commercial interest on this species emphasize the urgency of understanding the adaptability of krill to its environment. Krill has evolved rhythmic physiological and behavioral functions which are synchronized with the daily and seasonal cycles of the complex Southern Ocean ecosystem. The mechanisms, however, leading to these rhythms are essentially unknown. Here, we show that krill possesses an endogenous circadian clock that governs metabolic and physiological output rhythms. We found that expression of the canonical clock gene cry2 was highly rhythmic both in a light-dark cycle and in constant darkness. We detected a remarkable short circadian period, which we interpret as a special feature of the krill’s circadian clock that helps to entrain the circadian system to the extreme range of photoperiods krill is exposed to throughout the year. Furthermore, we found that important key metabolic enzymes of krill showed bimodal circadian oscillations (,9–12 h period) in transcript abundance and enzymatic activity. Oxygen consumption of krill showed ,9–12 h oscillations that correlated with the temporal activity profile of key enzymes of aerobic energy metabolism. Our results demonstrate the first report of an endogenous circadian timing system in Antarctic krill and its likely link to metabolic key processes. Krill’s circadian clock may not only be critical for synchronization to the solar day but also for the control of seasonal events. This study provides a powerful basis for the investigation into the mechanisms of temporal synchronization in this marine key species and will also lead to the first comprehensive analyses of the circadian clock of a polar marine organism through the entire photoperiodic cycle.

Item Details

Item Type:Refereed Article
Keywords:krill, Southern Ocean, ecosystem
Research Division:Biological Sciences
Research Group:Other Biological Sciences
Research Field:Global Change Biology
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Effects of Climate Change and Variability on Antarctic and Sub-Antarctic Environments (excl. Social Impacts)
Author:Kawaguchi, S (Dr So Kawaguchi)
ID Code:80558
Year Published:2011
Web of Science® Times Cited:24
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2012-11-02
Last Modified:2018-04-04
Downloads:222 View Download Statistics

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