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Seasonal differences in citrate synthase and digestive enzyme activity in larval and postlarval Antarctic krill, Euphausia superba

Meyer, B.; Saborowski, R.; Atkinson, A.; Buchholz, F.; Bathmann, U.. 2002 Seasonal differences in citrate synthase and digestive enzyme activity in larval and postlarval Antarctic krill, Euphausia superba. Marine Biology, 141 (5). 855-862. 10.1007/s00227-002-0877-7

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Abstract/Summary

Antarctic krill maintain large population sizes despite dramatic seasonal fluctuations in food availability, but the mechanisms for this are still debated. The aim of this study was to compare seasonal differences in enzyme activity and respiration rates of larval and postlarval krill to provide insights into their overwintering strategies. Respiration rates, activity of the metabolic enzyme citrate synthase (CS), and those of the digestive enzymes laminarinase and total proteinase were measured in austral summer west of the Antarctic Peninsula, and in autumn in the southwestern Lazarev Sea. The 100-fold difference in chlorophyll a concentrations between the two studies is representative of the classic transition from a summer bloom to sparse winter conditions. Correspondingly, adult krill showed reduced respiration rates and CS activity in autumn. However, their digestive enzyme activity was significantly higher, suggesting more efficient assimilation of food, at low food levels. Similar-sized larvae showed no summer-autumn differences in respiration rates and enzyme activity, supporting suggestions that they need to feed and grow year-round. However, trends in enzymatic activity varied between the larval stages measured, implying ontogenetic changes in body structure and function.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1007/s00227-002-0877-7
Programmes: BAS Programmes > Antarctic Science in the Global Context (2000-2005) > Dynamics and Management of Ocean Ecosystems
ISSN: 00253162
NORA Subject Terms: Marine Sciences
Biology and Microbiology
Ecology and Environment
Date made live: 04 Aug 2010 10:45
URI: http://nora.nerc.ac.uk/id/eprint/10204

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