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| Titel |
Seasonal survey of the composition and degradation state of particulate organic matter in the Rhône River using lipid tracers |
| VerfasserIn |
M.-A. Galeron, R. Amiraux, B. Charrière, O. Radakovitch, P. Raimbault, N. Garcia, V. Lagadec, F. Vaultier, J.-F. Rontani |
| 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 ; 12, no. 5 ; Nr. 12, no. 5 (2015-03-05), S.1431-1446 |
| Datensatznummer |
250117846
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| Publikation (Nr.) |
 copernicus.org/bg-12-1431-2015.pdf |
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| Zusammenfassung |
Lipid tracers including fatty acids, hydroxyacids, n-alkanols, sterols and
triterpenoids were used to determine the origin and fate of suspended
particulate organic matter (POM) collected in the Rhône River (France). This
seasonal survey (April 2011 to May 2013) revealed a year-round strong
terrestrial higher-plant contribution to the particulate organic matter
(POM), with significant algal inputs observed in March and attributed to
phytoplanktonic blooms likely dominated by diatoms. Major terrigenous
contributors to our samples are gymnosperms, and more precisely their roots
and stems, as evidenced by the presence of high proportions of ω-hydroxydocosanoic acid (a suberin biomarker). The high amounts of
coprostanol detected clearly show that the Rhône River is significantly
affected by sewage waters.
Specific sterol degradation products were quantified and used to assess the
part of biotic and abiotic degradation of POM within the river.
Higher-plant-derived organic matter appears to be mainly affected by
photo-oxidation and autoxidation (free radical oxidation), while organic
matter of mammal or human origin, evidenced by the presence of coprostanol,
is clearly more prone to bacterial degradation. Despite the involvement of
an intense autoxidation-inducing homolytic cleavage of peroxy bonds, a
significant proportion of hydroperoxides is still intact in higher plant
debris. These compounds could affect the degradation of terrestrial material
by inducing an intense autoxidation upon its arrival at sea. |
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