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| Titel |
Export fluxes in a naturally iron-fertilized area of the Southern Ocean – Part 1: Seasonal dynamics of particulate organic carbon export from a moored sediment trap |
| VerfasserIn |
M. Rembauville, I. Salter, N. Leblond, A. Guéneugues, S. Blain |
| 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. 11 ; Nr. 12, no. 11 (2015-06-02), S.3153-3170 |
| Datensatznummer |
250117955
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| Publikation (Nr.) |
 copernicus.org/bg-12-3153-2015.pdf |
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| Zusammenfassung |
| A sediment trap moored in the naturally iron-fertilized Kerguelen Plateau in
the Southern Ocean provided an annual record of particulate organic carbon
and nitrogen fluxes at 289 m. At the trap deployment depth, current speeds
were typically low (~ 10 cm s−1) and primarily
tidal-driven (M2 tidal component). Although advection was weak, the sediment
trap may have been subject to hydrodynamical and biological (swimmer feeding
on trap funnel) biases. Particulate organic carbon (POC) flux was generally
low (< 0.5 mmol m−2 d−1), although two episodic export
events (< 14 days) of 1.5 mmol m−2 d−1 were recorded.
These increases in flux occurred with a 1-month time lag from peaks in
surface chlorophyll and together accounted for approximately 40% of the
annual flux budget. The annual POC flux of 98.2 ± 4.4 mmol m−2 yr−1 was low considering the shallow deployment depth but comparable
to independent estimates made at similar depths (~ 300 m) over
the plateau, and to deep-ocean (> 2 km) fluxes measured from
similarly productive iron-fertilized blooms. Although undertrapping cannot
be excluded in shallow moored sediment trap deployment, we hypothesize that
grazing pressure, including mesozooplankton and mesopelagic fishes, may be
responsible for the low POC flux beneath the base of the winter mixed layer.
The importance of plankton community structure in controlling the temporal
variability of export fluxes is addressed in a companion paper. |
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