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| Titel |
Composition and sources of sedimentary organic matter in deep basins of the North-Eastern Mediterranean Sea |
| VerfasserIn |
Rut Pedrosa-Pàmies, Aleka Gogou, Anna Sanchez-Vidal, Costas Parinos, Antoni Calafat, Miquel Canals, Ioanna Bouloubassi, Nikos Lampadariou |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094643
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| Publikation (Nr.) |
 EGU/EGU2014-10069.pdf |
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| Zusammenfassung |
| The processes controlling the sources, and the composition, transport and transformation of
sedimentary organic matter (SOM) in the oligotrophic North-Eastern Mediterranean Sea
(NEMS) have been scarcely investigated so far. In this contribution we present the
results of the analysis of 29 surface sediment samples collected in the Ionian Sea,
the Southern Aegean Sea and the North-Western Levantine Sea, at depths from
1000 m to 4000 m, with the aim of characterizing the distribution and provenance
of SOM in different regions of the NEMS. Samples were analyzed for grain size
distribution, organic carbon (OC) content, total nitrogen (TN) and their stable isotopes
(δ13C, δ15N), together with selected lipid biomarkers, which allowed identifying the
marine vs. terrestrial sources of SOM, the later including anthropogenic aliphatic
hydrocarbons.
Marked variations were observed from one region to another. Concentrations of
clay-sized particles, and OC and TN contents varied significantly, ranging from
14 to 57%, 0.15 to 1.15% and 0.06 to 0.11%, respectively. The concentrations of
their stable isotopes, δ13C and δ15N, and the TN/OC ratio ranged from -24.74 to
-18.33 o 2.46 to 8.67oand 0.09 to 0.18, respectively. The sum of terrestrial (wax)
n-alkanes (defined as the sum of major homologues: n-C27 to n-C31) changed
between 80.7 and 1800 ng g-1, while the unresolved complex mixture of aliphatic
hydrocarbons (UCM), reflecting anthropogenic inputs, shifted from 0.73 to 36.7 μg
g-1.
The grain size characteristics and the geochemical composition of surface sediments in
each region seem to rely primarily on variable terrestrial inputs on the transport processes
driven by the mesoscale circulation in the study area and on the seafloor physiography
eventually easing advection. Our results show an enhanced contribution of terrestrial vs.
marine-derived organic matter in the deep Ionian Sea basins, which likely reflects the
oligotrophic character of the region and the degradation of the labile marine (planktonic)
SOM, along with its transport to the depth. Our data also show the influence of deep
Adriatic waters outflowing into the study area. A transfer of fine grained and OC-rich
SOM along the submarine canyons of the western Cretan Straits was also identified. |
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