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| Titel |
Stable carbon isotope biogeochemistry of lakes along a trophic gradient |
| VerfasserIn |
A. de Kluijver, P. L. Schoon, J. A. Downing, S. Schouten, J. J. Middelburg |
| 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. 22 ; Nr. 11, no. 22 (2014-11-20), S.6265-6276 |
| Datensatznummer |
250117681
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| Publikation (Nr.) |
 copernicus.org/bg-11-6265-2014.pdf |
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| Zusammenfassung |
| The stable carbon (C) isotope variability of dissolved inorganic and organic
C (DIC and DOC), particulate organic carbon (POC), glucose and polar-lipid
derived fatty acids (PLFAs) was studied in a survey of 22 North American
oligotrophic to eutrophic lakes. The δ13C of different PLFAs were
used as proxy for phytoplankton producers and bacterial consumers. Lake
pCO2 was primarily determined by autochthonous production
(phytoplankton biomass), especially in eutrophic lakes, and governed the
δ13C of DIC. All organic-carbon pools showed overall higher
isotopic variability in eutrophic lakes (n = 11) compared to
oligo-mesotrophic lakes (n = 11) because of the high variability in
δ13C at the base of the food web (both autochthonous and
allochthonous carbon). Phytoplankton δ13C was negatively related to
lake pCO2 over all lakes and positively related to phytoplankton
biomass in eutrophic lakes, which was also reflected in a large range in
photosynthetic isotope fractionation (ϵCO2-phyto,
8–25‰). The carbon isotope ratio of
allochthonous carbon in oligo-mesotrophic lakes was rather constant, while it
varied in eutrophic lakes because of maize cultivation in the watershed. |
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