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| Titel |
Downward particle flux and carbon export in the Beaufort Sea, Arctic Ocean; the role of zooplankton |
| VerfasserIn |
J.-C. Miquel, B. Gasser, J. Martin, C. Marec, M. Babin, L. Fortier, A. Forest |
| 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. 16 ; Nr. 12, no. 16 (2015-08-28), S.5103-5117 |
| Datensatznummer |
250118078
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| Publikation (Nr.) |
 copernicus.org/bg-12-5103-2015.pdf |
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| Zusammenfassung |
As part of the international, multidisciplinary project Malina, downward
particle fluxes were investigated by means of a drifting multi-sediment trap
mooring deployed at three sites in the Canadian Beaufort Sea in late summer
2009. Mooring deployments lasted between 28 and 50 h and targeted the
shelf-break and the slope along the Beaufort-Mackenzie continental
margin, as well as the edge between the Mackenzie Shelf and the Amundsen
Gulf. Besides analyses of C and N, the collected material was investigated
for pigments, phyto- and microzooplankton, faecal pellets and swimmers.
The measured fluxes were relatively low, in the range of
11–54 mg m−2 d−1 for the total mass, 1–15 mg
C m−2 d−1 for organic carbon and 0.2–2.5 mg
N m−2 d−1 for nitrogen. Comparison with a long-term trap data set
from the same sampling area showed that the short-term measurements were at
the lower end of the high variability characterizing a rather high flux
regime during the study period.
The sinking material consisted of aggregates and particles that were
characterized by the presence of hetero- and autotrophic microzooplankters
and diatoms and by the corresponding pigment signatures. Faecal pellets
contribution to sinking carbon flux was important, especially at depths below 100 m, where
they represented up to 25 % of the total carbon flux. The vertical
distribution of different morphotypes of pellets showed a marked pattern with
cylindrical faeces (produced by calanoid copepods) present mainly within the
euphotic zone, whereas elliptical pellets (produced mainly by smaller
copepods) were more abundant at mesopelagic depths. These features, together
with the density of matter within the pellets, highlighted the role of the
zooplankton community in the transformation of carbon issued from the primary
production and the transition of that carbon from the productive surface zone
to the Arctic Ocean's interior. Our data indicate that sinking carbon flux in
this late summer period is primarily the result of a heterotrophic-driven
ecosystem. |
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