Publication Details |
| Reference Category | Journals |
| DOI / URL | link |
| Title (Primary) | Carbon stable isotope fractionation and trophic transfer of fatty acids in fungal based soil food chains |
| Author | Ruess, L.; Tiunov, A.; Haubert, D.; Richnow, H.H.; Häggblom, M.M.; Scheu, S. |
| Journal | Soil Biology & Biochemistry |
| Year | 2005 |
| Department | ISOBIO |
| Volume | 37 |
| Issue | 5 |
| Page From | 945 |
| Page To | 953 |
| Language | englisch |
| Abstract | Stable isotope analysis has been used as a powerful tool in food web studies in
terrestrial ecosystems. In addition the occurrence and abundance of fatty acids
may serve as indicator for feeding strategies of soil animals. Here we combine
both approaches and investigate the fatty acid composition, delta C-13 values of
bulk tissues and individual fatty acids in soil organisms. The fungi Chaetomium
globosum and Cladosporium cladosporioides were isotopically labelled by fructose
derived from either C-3 or C-4 plants, and the fungal-feeding nematode
Aphelenchoides sp. was reared on C. globosum. Fungi and nematodes were used as
diet for the Collembolan Protaphorura fimata. The sugar source was fractionated
differently by fungal lipid metabolism in a species-specific manner that points
to a sensitivity of physiological processing to the non-random distribution of
C-13/C-12 isotopes in the molecule. As a general trend stearic acid (18:0) was
depleted in C-13 compared to the precursor palmitic acid (16:0), whereas its
desaturation to oleic acid (18:1 omega 9) favoured the C-13-rich substrate.
Fatty acid profiles of P. fimata varied due to food source, indicating incorporation of dietary fatty acids into Collembolan tissue. Individuals feeding on fungi had lower amounts in C20 fatty acids, with monoenoic C20 forms not present. This pattern likely separates primary consumers (fungivores) from predators (nematode feeders). The isotopic discrimination in C-13 for bulk Collembola ranged between -2.6 and 1.4 parts per thousand and was dependent on fungal species and C-3/C-4 system, suggesting differences at metabolic branch points and/or isotope discrimination of enzymes. Comparison of delta C-13 values in individual fatty acids between consumer and diet generally showed depletion (i.e. de novo synthesis) or no changes (i.e. dietary routing), but the fractionation was not uniform and affected by the type of ingested food. Fatty acid carbon isotopes were more variable than those of bulk tissues, likely due to both the distrimination by enzymes and the different lipid origin (i.e. neutral or polar fraction). |
| Persistent UFZ Identifier | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=3742 |
| Ruess, L., Tiunov, A., Haubert, D., Richnow, H.H., Häggblom, M.M., Scheu, S. (2005): Carbon stable isotope fractionation and trophic transfer of fatty acids in fungal based soil food chains Soil Biol. Biochem. 37 (5), 945 - 953 |
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