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| Titel |
Flux and composition of settling particles across the continental margin of the Gulf of Lion: the role of dense shelf water cascading |
| VerfasserIn |
C. Pasqual, A. Sanchez-Vidal, D. Zúñiga, A. Calafat, M. Canals, X. Durrieu de Madron, P. Puig, S. Heussner, A. Palanques, N. Delsaut |
| 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 ; 7, no. 1 ; Nr. 7, no. 1 (2010-01-15), S.217-231 |
| Datensatznummer |
250004375
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| Publikation (Nr.) |
 copernicus.org/bg-7-217-2010.pdf |
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| Zusammenfassung |
| Settling particles were collected using sediment traps deployed along three
transects in the Lacaze-Duthiers and Cap de Creus canyons and the adjacent
southern open slope from October 2005 to October 2006. The settling material
was analyzed to obtain total mass fluxes and main constituent contents
(organic matter, opal, calcium carbonate, and siliciclastics). Cascades of
dense shelf water from the continental shelf edge to the lower continental
slope occurred from January to March 2006. They were traced through strong
negative near-bottom temperature anomalies and increased current speeds, and
generated two intense pulses of mass fluxes in January and March 2006. This
oceanographic phenomenon appeared as the major physical forcing of settling
particles at almost all stations, and caused both high seasonal variability
in mass fluxes and important qualitative changes in settling material.
Fluxes during the dense shelf water cascading (DSWC) event ranged from
90.1 g m−2 d−1 at the middle Cap de Creus canyon (1000 m) to
3.2 g m−2 d−1 at the canyon mouth (1900 m). Fractions of organic matter,
opal and calcium carbonate components increased seaward, thus diminishing
the siliciclastic fraction. Temporal variability of the major components was
larger in the canyon mouth and open slope sites, due to the mixed impact of
dense shelf water cascading processes and the pelagic biological production.
Results indicate that the cascading event remobilized and homogenized large
amounts of material down canyon and southwardly along the continental slope
contributing to a better understanding of the off-shelf particle transport
and the internal dynamics of DSWC events. |
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