Iron concentration and fluxes in the water column during POLARSTERN cruises in the Southern Ocean


Autoria(s): de Jong, Jeroen; Schoemann, Véronique; Lannuzel, Delphine; Croot, Peter L; de Baar, Hein JW; Tison, Jean-Louis
Cobertura

MEDIAN LATITUDE: -58.638571 * MEDIAN LONGITUDE: -27.456868 * SOUTH-BOUND LATITUDE: -67.370700 * WEST-BOUND LONGITUDE: -55.413100 * NORTH-BOUND LATITUDE: -44.015500 * EAST-BOUND LONGITUDE: 20.011300 * DATE/TIME START: 1988-11-30T09:03:00 * DATE/TIME END: 2005-01-07T11:40:00

Data(s)

08/03/2012

Resumo

In large parts of the Southern Ocean, primary production is limited due to shortage of iron (Fe). We measured vertical Fe profiles in the western Weddell Sea, Weddell-Scotia Confluence, and Antarctic Circumpolar Current (ACC), showing that Fe is derived from benthic Fe diffusion and sediment resuspension in areas characterized by high turbulence due to rugged bottom topography. Our data together with literature data reveal an exponential decrease of dissolved Fe (DFe) concentrations with increasing distance from the continental shelves of the Antarctic Peninsula and the western Weddell Sea. This decrease can be observed 3500 km eastward of the Antarctic Peninsula area, downstream the ACC. We estimated DFe summer fluxes into the upper mixed layer of the Atlantic sector of the Southern Ocean and found that horizontal advection dominates DFe supply, representing 54 ± 15% of the total flux, with significant vertical advection second most important at 29 ± 13%. Horizontal and vertical diffusion are weak with 1 ± 2% and 1 ± 1%, respectively. The atmospheric contribution is insignificant close to the Antarctic continent but increases to 15 ± 10% in the remotest waters (>1500 km offshore) of the ACC. Translating Southern Ocean carbon fixation by primary producers into biogenic Fe fixation shows a twofold excess of new DFe input close to the Antarctic continent and a one-third shortage in the open ocean. Fe recycling, with an estimated 'fe' ratio of 0.59, is the likely pathway to balance new DFe supply and Fe fixation.

Formato

application/zip, 4 datasets

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.808656

doi:10.1594/PANGAEA.808656

Idioma(s)

en

Publicador

PANGAEA

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: de Jong, Jeroen; Schoemann, Véronique; Lannuzel, Delphine; Croot, Peter L; de Baar, Hein JW; Tison, Jean-Louis (2012): Natural iron fertilization of the Atlantic sector of the Southern Ocean by continental shelf sources of the Antarctic Peninsula. Journal of Geophysical Research-Biogeosciences, 117, G01029, doi:10.1029/2011JG001679

Palavras-Chave #at 300 m; average, <200 m; average, upper mixed layer; base, upper mixed layer; Depth; DEPTH, sediment/rock; DEPTH, water; Depth water; diffusive, dissolved Fe; Diffusivity, apparent; Diffusivity app; Distance; Elevation; ELEVATION; Event; Fe; Fe diss; Fe flux; Fe flux std dev; Fe part; Fe sol; horizontal advection; horizontal diffusion; horizontal eddy diffusivity in m**2/s; International Polar Year (2007-2008); IPY; Iron; Iron, dissolved; Iron, particulate; Iron, soluble; Iron flux; Iron flux, standard deviation; labile; Length; MDL; Mixed layer depth; potential; PP C area; PP C std dev; Primary production of carbon, standard deviation; Primary production of carbon per area, daily; Profile/sampling length; refractory; scale length; Station; to coastline; total; total dissolvable; upper; vertical advection; vertical diffusion
Tipo

Dataset