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| Titel |
Lack of 13C-label incorporation suggests low turnover rates of thaumarchaeal intact polar tetraether lipids in sediments from the Iceland shelf |
| VerfasserIn |
S. K. Lengger, Y. A. Lipsewers, H. de Haas, J. S. Sinninghe Damsté, S. Schouten |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 2 ; Nr. 11, no. 2 (2014-01-17), S.201-216 |
| Datensatznummer |
250117136
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| Publikation (Nr.) |
 copernicus.org/bg-11-201-2014.pdf |
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| Zusammenfassung |
| Thaumarchaeota are amongst the most abundant microorganisms in aquatic
environments, however, their metabolism in marine sediments is still
debated. Labeling studies in marine sediments have previously been
undertaken, but focused on complex organic carbon substrates which
Thaumarchaeota have not yet been shown to take up. In this study, we
investigated the activity of Thaumarchaeota in sediments by supplying
different 13C-labeled substrates which have previously been shown to be
incorporated into archaeal cells in water incubations and/or enrichment
cultures. We determined the incorporation of 13C-label from
bicarbonate, pyruvate, glucose and amino acids into thaumarchaeal intact
polar lipid-glycerol dibiphytanyl glycerol tetraethers (IPL-GDGTs) during
4–6 day incubations of marine sediment cores from three sites on the Iceland
shelf. Thaumarchaeal intact polar lipids, in particular crenarchaeol, were
detected at all stations and concentrations remained constant or decreased
slightly upon incubation. No 13C incorporation in any IPL-GDGT was
observed at stations 2 (clay-rich sediment) and 3 (organic-rich sediment).
In bacterial/eukaryotic IPL-derived fatty acids at station 3, contrastingly,
a large uptake of 13C label (up to + 80‰ ) was
found. 13C was also respired during the experiment as shown by a
substantial increase in the 13C content of the dissolved inorganic
carbon. In IPL-GDGTs recovered from the sandy sediments at station 1,
however, some enrichment in δ13C (1–4‰ )
was detected after incubation with bicarbonate and pyruvate. The low
incorporation rates suggest a low activity of Thaumarchaeota in marine
sediments and/or a low turnover rate of thaumarchaeal IPL-GDGTs due to their
low degradation rates. Cell numbers and activity of sedimentary
Thaumarchaeota based on IPL-GDGT measurements may thus have previously been
overestimated. |
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