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| Titel |
Composition and sources of sedimentary organic matter in the deep eastern Mediterranean Sea |
| VerfasserIn |
R. Pedrosa-Pàmies, C. Parinos, A. Sanchez-Vidal, A. Gogou, A. Calafat, M. Canals, I. Bouloubassi, N. Lampadariou |
| 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. 24 ; Nr. 12, no. 24 (2015-12-16), S.7379-7402 |
| Datensatznummer |
250118216
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| Publikation (Nr.) |
 copernicus.org/bg-12-7379-2015.pdf |
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| Zusammenfassung |
| Surface sediments collected from deep slopes and basins (1018–4087 m depth)
of the oligotrophic eastern Mediterranean Sea have been analysed for bulk
elemental and isotopic composition of organic carbon, total nitrogen and
selected lipid biomarkers, jointly with grain size distribution and other
geochemical proxies. The distribution and sources of sedimentary organic
matter (OM) have been subsequently assessed and general environmental
variables, such as water column depth and physical circulation patterns, have
been examined as causative factors of deep-sea sediment characteristics.
Lithogenic and biogenic carbonates are the dominant sedimentary fractions,
accounting for up to 85.4 and 66.5 % of the total weight respectively.
The low OC and TN contents in the surface sediments of the study area, which
ranged from 0.15 to 1.15 % and 0.06 to 0.11 % respectively, reflect
the oligotrophic character of the eastern Mediterranean Sea. Both bulk and
molecular organic tracers reflect a mixed contribution from autochthonous and
allochthonous sources for the sedimentary OM, as indicated by relatively
degraded marine OM, terrestrial plant waxes and anthropogenic OM (e.g.
degraded petroleum by-products) respectively. Wide regional variations have
been observed amongst the studied proxies, which reflect the multiple factors
controlling sedimentation in the deep eastern Mediterranean Sea. Our findings
highlight the role of deep eastern Mediterranean basins as depocentres of
organic-rich fine-grained sediments (mean 5.4 ± 2.4 μm), with OM
accumulation and burial being attributed to aggregation mechanisms and
hydrodynamic sorting. A multi-proxy approach is applied aiming to investigate
the biogeochemical composition of sediment samples, which sheds new light on
the sources and transport mechanisms along with the impact of preservation
vs. diagenetic processes on the composition of sedimentary OM in the deep
basins of the oligotrophic eastern Mediterranean Sea. |
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