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| Titel |
Distribution and fluxes of aggregates >100 μm in the upper kilometer of the South-Eastern Pacific |
| VerfasserIn |
L. Guidi, G. Gorsky, H. Claustre, J. C. Miquel, M. Picheral, L. Stemmann |
| 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 ; 5, no. 5 ; Nr. 5, no. 5 (2008-09-29), S.1361-1372 |
| Datensatznummer |
250002832
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| Publikation (Nr.) |
 copernicus.org/bg-5-1361-2008.pdf |
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| Zusammenfassung |
| Large sinking particles transport organic and inorganic matter into the
deeper layers of the oceans. Between 70 and 90% of the aggregates
exported from the surface mixed layer are disaggregated within the upper
1000 m. This decrease with depth indicates that fragmentation and
remineralization processes are intense during sedimentation. Generally, the
estimates of vertical flux rely on sediment trap data but difficulties
inherent in their design limit the reliability of this information. During
the BIOSOPE study in the south-eastern Pacific, 76 vertical casts using the
Underwater Video Profiler (UVP) and deployments of drifting sediment traps
provided an opportunity to fit the UVP data to sediment trap flux
measurements. We applied the calculated UVP flux in the upper 1000 m to the
whole 8000 km BIOSOPE transect. Comparison between the large particulate
material (LPM) abundance and the estimated fluxes from both UVP and sediment
traps showed different patterns in different regions. On the western end of
the BIOSOPE section the standing stock of particles in the surface layer was
high but the export between 150 and 250 m was low. Below this layer the flux
values increased. High values of about 30% of the calculated UVP maximum
surface zone flux were observed below 900 m at the HNLC station. The South
Pacific Gyre exported about 2 mg m−2 d−1. While off Chilean coast
95% of the surface mixed layer matter was disaggregated, remineralized or
advected in the upper kilometer, 20% of the surface zone flux was
observed below 900 m near the Chilean coast. These results suggest that the
export to deep waters is spatially heterogeneous and related to the
different biotic and abiotic factors. |
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