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| Titel |
Different carbon isotope fractionation patterns during the development of phototrophic freshwater and marine biofilms |
| VerfasserIn |
M. Staal, R. Thar, M. Kühl, M. C. M. Loosdrecht, G. Wolf, J. F. C. Brouwer, J. W. Rijstenbil |
| 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 ; 4, no. 4 ; Nr. 4, no. 4 (2007-08-08), S.613-626 |
| Datensatznummer |
250001857
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| Publikation (Nr.) |
 copernicus.org/bg-4-613-2007.pdf |
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| Zusammenfassung |
| Natural phototrophic biofilms are influenced by a broad array of abiotic and
biotic factors and vary over temporal and spatial scales. Different
developmental stages can be distinguished and growth rates will vary due to
the thickening of the biofilm, which is expected to lead to a limitation of
light or mass transport. This study shows that variation in CO2(aq)
availability leads to a fractionation shift and thereby affects δ13C
signatures during biofilm development. For phototrophic freshwater
biofilms it was found that the δ13C value became less negative
with the thickening of the biofilm, while the opposite trend was found in
marine biofilms. Modeling and pH profiling indicated that the trend in the
freshwater system was caused by an increase in CO2(aq) limitation
resulting in an increase of HCO3− as C-source. The opposite trend
in the marine system could be explained by a higher heterotrophic biomass
and activity causing a higher carbon recycling and thereby lower δ13C
values. We conclude that δ13C was more related to the
net areal photosynthesis rate and carbon recycling, rather than to the
growth rate of the biofilms. |
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