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
|Author(s)||Rembauville M.1, 2, Salter I.1, 2, 3, Leblond N.4, 5, Gueneugues A.1, 2, Blain S.1, 2|
|Affiliation(s)||1 : Univ Paris 06, Univ Paris 04, Observ Oceanol, UMR7621,LOMIC, Banyuls Sur Mer, France.
2 : CNRS, Observ Oceanol, UMR7621, LOMIC, Banyuls Sur Mer, France.
3 : Alfred Wegener Inst Polar & Marine Res, Bremerhaven, Germany.
4 : Univ Paris 06, Univ Paris 04, Observ Oceanol, LOV,UMR7093, Villefranche Sur Mer, France.
5 : CNRS INSU, LOV, Observ Oceanol, UMR7093, Villefranche Sur Mer, France.
|Source||Biogeosciences (1726-4170) (Copernicus Gesellschaft Mbh), 2015-06-02 , Vol. 12 , N. 11 , P. 3153-3170|
|WOS© Times Cited||23|
|Note||Special issue KEOPS2: Kerguelen Ocean and Plateau Study 2|
|Abstract||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 (similar to 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 mmolm 2 yr(-1) was low considering the shallow deployment depth but comparable to independent estimates made at similar depths (similar to 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 meso-zooplankton 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.|