Document Detail

Phytoplankton, not allochthonous carbon, sustains herbivorous zooplankton production.
MedLine Citation:
PMID:  19934044     Owner:  NLM     Status:  MEDLINE    
Terrestrial organic matter inputs have long been thought to play an important role in aquatic food web dynamics. Results from recent whole lake (13)C addition experiments suggest terrestrial particulate organic carbon (t-POC) inputs account for a disproportionate portion of zooplankton production. For example, several studies concluded that although t-POC only represented approximately 20% of the flux of particulate carbon available to herbivorous zooplankton, this food source accounted for approximately 50% of the C incorporated by zooplankton. We tested the direct dietary impact of t-POC (from the leaves of riparian vegetation) and various phytoplankton on Daphnia magna somatic growth, reproduction, growth efficiency, and lipid composition. By itself, t-POC was a very poor quality resource compared to cryptophytes, diatoms, and chlorophytes, but t-POC had similar food quality compared to cyanobacteria. Small additions of high quality Cryptomonas ozolinii to t-POC-dominated diets greatly increased Daphnia growth and reproduction. When offered alone, t-POC resulted in a Daphnia growth efficiency of 5 +/- 1%, whereas 100% Cryptomonas and Scenedesmus obliquus diets resulted in growth efficiencies of 46 +/- 8% (+/- SD) and 36 +/- 3%, respectively. When offered in a 50:50 mixed diet with Cryptomonas or Scenedesmus, the t-POC fraction resulted in a partial growth efficiency of 22 +/- 9% and 15 +/- 6%, respectively. Daphnia that obtained 80% of their available food from t-POC assimilated 84% of their fatty acids from the phytoplankton component of their diet. Overall, our results suggest Daphnia selectively allocate phytoplankton-derived POC and lipids to enhance somatic growth and reproduction, while t-POC makes a minor contribution to zooplankton production.
Michael T Brett; Martin J Kainz; Sami J Taipale; Hari Seshan
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2009-11-23
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  106     ISSN:  1091-6490     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  2009 Dec 
Date Detail:
Created Date:  2009-12-18     Completed Date:  2010-02-12     Revised Date:  2010-09-27    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  United States    
Other Details:
Languages:  eng     Pagination:  21197-201     Citation Subset:  IM    
Department of Civil Engineering, Box 352700, University of Washington, Seattle, WA 98195-2700, USA.
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MeSH Terms
Carbon / metabolism*
Daphnia / growth & development,  metabolism*,  physiology
Food Chain*
Lipids / analysis
Phytoplankton / metabolism*
Plant Leaves / metabolism
Zooplankton / growth & development,  metabolism*,  physiology
Reg. No./Substance:
0/Lipids; 7440-44-0/Carbon

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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