| Nitrogen isotope ratios and fatty acid composition as indicators of animal diets in belowground systems. | |
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MedLine Citation:
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PMID: 15007726 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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This study analyses trophic interactions between soil fungi, micro- and mesofauna in microcosm experiments. The trophic shift of 15N and fatty acids (FAs) was investigated in different food chains, which comprised either two (fungi and grazers) or three (fungi, nematodes and Collembola) levels. Contrary to the widely accepted assumption of 15N enrichment in trophic cascades the experiments revealed enrichment, depletion or no change in 15N of consumers compared to their diet. Factors responsible for this pattern were suggested to be: (1) the main metabolic pathway used for N excretion in ammonotelic nematodes to be similar or depleted in the heavier isotope, and uricotelic Collembola mostly enriched in the heavier isotope; (2) a higher shift in 15N with a high-protein diet (e.g. for predators); (3) compensation due to low-quality food altering the fractionation of 15N. Analysis of the lipid composition showed phospholipids to be generally unaffected and neutral lipids closely related to the FA pattern of the food source. Dietary routing of FAs into neutral lipids occurred, as evidenced by corresponding frequencies of FAs in host and consumer profiles. Additionally, several FAs were only detected in the grazer when present in the food source. Oleic acid showed a shift over three trophic levels, from fungi to nematodes to Collembola. The assimilation of dietary FAs resulted in a more diverse neutral lipid profile, i.e. animals higher in the food chain contained more individual FAs compared to animals lower in the food chain. The results indicate that monoenoic C18 and monoenoic C20 FAs have the potential to act as tools for the bioindication of feeding strategies in belowground systems. We suggest that primary consumers will have no or only trace amounts of monoenoic C20 acids in their neutral lipid profile, whereas consumers feeding on a eukaryote diet will show a considerably higher frequency. |
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Authors:
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Liliane Ruess; Max M Häggblom; Reinhard Langel; Stefan Scheu |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't Date: 2004-03-06 |
Journal Detail:
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Title: Oecologia Volume: 139 ISSN: 0029-8549 ISO Abbreviation: Oecologia Publication Date: 2004 May |
Date Detail:
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Created Date: 2005-10-17 Completed Date: 2006-03-10 Revised Date: 2006-11-15 |
Medline Journal Info:
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Nlm Unique ID: 0150372 Medline TA: Oecologia Country: Germany |
Other Details:
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Languages: eng Pagination: 336-46 Citation Subset: IM |
Affiliation:
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Institut für Zoologie, Technische Universität Darmstadt, Schnittspahnstrasse 3, 64287, Darmstadt, Germany. ruess@bio.tu-darmstadt.de |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Analysis of Variance Animals Diet* Fatty Acids / metabolism* Food Chain* Fungi / metabolism* Insects / metabolism* Mass Spectrometry Nematoda / metabolism* Nitrogen Isotopes / metabolism* Soil Microbiology* |
| Chemical | |
Reg. No./Substance:
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0/Fatty Acids; 0/Nitrogen Isotopes |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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