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| Titel |
Organic carbon production, mineralisation and preservation on the Peruvian margin |
| VerfasserIn |
A. W. Dale, S. Sommer, U. Lomnitz, I. Montes, T. Treude, V. Liebetrau, J. Gier, C. Hensen, M. Dengler, K. Stolpovsky, L. D. Bryant, K. Wallmann |
| 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 (2015-03-11), S.1537-1559 |
| Datensatznummer |
250117852
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| Publikation (Nr.) |
 copernicus.org/bg-12-1537-2015.pdf |
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| Zusammenfassung |
| Carbon cycling in Peruvian margin sediments (11 and 12° S) was
examined at 16 stations, from 74 m water depth on the middle shelf down to
1024 m, using a combination of in situ flux measurements, sedimentary
geochemistry and modelling. Bottom water oxygen was below detection limit
down to ca. 400 m and increased to 53 μM at the deepest station.
Sediment accumulation rates decreased sharply seaward of the middle shelf and
subsequently increased at the deep stations. The organic carbon burial
efficiency (CBE) was unusually low on the middle shelf (<20%) when
compared to an existing global database, for reasons which may be linked to
episodic ventilation of the bottom waters by oceanographic anomalies.
Deposition of reworked, degraded material originating from sites higher up on
the slope is proposed to explain unusually high sedimentation rates and CBE
(>60%) at the deep oxygenated sites. In line with other studies, CBE
was elevated under oxygen-deficient waters in the mid-water oxygen minimum
zone. Organic carbon rain rates calculated from the benthic fluxes alluded to
efficient mineralisation of organic matter in the water column compared to
other oxygen-deficient environments. The observations at the Peruvian margin
suggest that a lack of oxygen does not greatly affect the degradation of
organic matter in the water column but promotes the preservation of organic
matter in sediments. |
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