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| Titel |
External forcings, oceanographic processes and particle flux dynamics in Cap de Creus submarine canyon, NW Mediterranean Sea |
| VerfasserIn |
A. Rumín-Caparrós, A. Sanchez-Vidal, A. Calafat, M. Canals, J. Martin, P. Puig, R. Pedrosa-Pàmies |
| 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 ; 10, no. 6 ; Nr. 10, no. 6 (2013-06-03), S.3493-3505 |
| Datensatznummer |
250018265
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| Publikation (Nr.) |
 copernicus.org/bg-10-3493-2013.pdf |
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| Zusammenfassung |
| Particle fluxes (including major components and grain size), and
oceanographic parameters (near-bottom water temperature, current speed and
suspended sediment concentration) were measured along the Cap de Creus
submarine canyon in the Gulf of Lions (GoL; NW Mediterranean Sea) during two
consecutive winter-spring periods (2009–2010 and 2010–2011). The comparison of
data obtained with the measurements of meteorological and hydrological
parameters (wind speed, turbulent heat flux, river discharge) have shown the
important role of atmospheric forcings in transporting particulate matter
through the submarine canyon and towards the deep sea.
Indeed, atmospheric forcing during 2009–2010 and 2010–2011 winter
months showed differences in both intensity and persistence that led to
distinct oceanographic responses. Persistent dry northern winds caused strong
heat losses (14.2 × 103 W m−2) in winter 2009–2010 that
triggered a pronounced sea surface cooling compared to winter
2010–2011 (1.6 × 103 W m−2 lower). As a
consequence, a large volume of dense shelf water formed in winter 2009–2010,
which cascaded at high speed (up to ∼1 m s−1) down Cap de Creus
Canyon as measured by a current-meter in the head of the canyon. The lower
heat losses recorded in winter 2010–2011, together with an increased
river discharge, resulted in lowered density waters over the shelf, thus
preventing the formation and downslope transport of dense shelf water.
High total mass fluxes (up to 84.9 g m−2 d−1) recorded in
winter-spring 2009–2010 indicate that dense shelf water cascading
resuspended and transported sediments at least down to the middle canyon.
Sediment fluxes were lower (28.9 g m−2 d−1) under the quieter
conditions of winter 2010–2011. The dominance of the lithogenic fraction in
mass fluxes during the two winter-spring periods points to a resuspension
origin for most of the particles transported down canyon. The variability in
organic matter and opal contents relates to seasonally controlled inputs
associated with the plankton spring bloom during March and April of both years. |
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