HR: 0800h
AN: OS11B-0508    [Abstracts]
TI: Vertical Distributions of Iron Complexing Ligands in the Southern Ocean
AU: * Ibisanmi, E
EM: eibisanmi@chemistry.otago.ac.nz
AF: Department of Chemistry, University of Otago, Dunedin, 9054, New Zealand
AU: Hunter, K A
EM: khunter@chemistry.otago.ac.nz
AF: Department of Chemistry, University of Otago, Dunedin, 9054, New Zealand
AU: Sander, S G
EM: sylvias@chemistry.otago.ac.nz
AF: Department of Chemistry, University of Otago, Dunedin, 9054, New Zealand
AU: Boyd, P W
EM: pboyd@chemistry.otago.ac.nz
AF: NIWA Centre for Chemical Oceanography, Chemistry Department, University of Otago, Dunedin, 9054, New Zealand
AU: Bowie, A R
EM: Andrew.Bowie@utas.edu.au
AF: Antarctic Climate & Ecosystems CRC, University of Tasmania, Hobart, 7001, Australia
AU: Hugh, D
EM: hdoyle@chemistry.otago.ac.nz
AF: Department of Chemistry, University of Otago, Dunedin, 9054, New Zealand
AB: In order to better understand the origins of iron-(III) complexing ligands in the open ocean it is essential to first investigate their vertical distributions over the water column. This paper presents profiles of iron-(III) complexing ligands through the upper 1000 m of a high nitrate low chlorophyll (HNLC)region of the Southern Ocean, south of Australia in austral summer (January – February, 2007). Ligand concentrations were high (0.86 nM) in the upper 25 m, but decreased with depth towards the deep chlorophyll maximum (DCM), which was centered at 40 m. Ligand concentrations again peaked immediately below the DCM but remained relatively constant at about 0.6 nM below 200 m. The high ligand concentrations in the upper 25 m surface mixed layer is indicative that ligands are produced by the biota in iron-depleted surface waters. Additional high ligand concentrations measured just below the DCM may suggest that the remineralization of phytoplankton and detritus pool also contribute to the total ligand pool.
DE: 4807 Chemical speciation and complexation
DE: 4875 Trace elements (0489)
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting