title: Effect of natural iron fertilization on carbon sequestration in the Southern Ocean.
abstract: The availability of iron limits primary productivity and the associated uptake of carbon over large areas of the ocean. Iron thus plays an important role in the carbon cycle, and changes in its supply to the surface ocean may have had a significant effect on atmospheric carbon dioxide concentrations over glacial-interglacial cycles. To date, the role of iron in carbon cycling has largely been assessed using short-term iron-addition experiments. It is difficult, however, to reliably assess the magnitude of carbon export to the ocean interior using such methods, and the short observational periods preclude extrapolation of the results to longer timescales. Here we report observations of a phytoplankton bloom induced by natural iron fertilization--an approach that offers the opportunity to overcome some of the limitations of short-term experiments. We found that a large phytoplankton bloom over the Kerguelen plateau in the Southern Ocean was sustained by the supply of iron and major nutrients to surface waters from iron-rich deep water below. The efficiency of fertilization, defined as the ratio of the carbon export to the amount of iron supplied, was at least ten times higher than previous estimates from short-term blooms induced by iron-addition experiments. This result sheds new light on the effect of long-term fertilization by iron and macronutrients on carbon sequestration, suggesting that changes in iron supply from below--as invoked in some palaeoclimatic and future climate change scenarios--may have a more significant effect on atmospheric carbon dioxide concentrations than previously thought.
authors: Laboratoire d'Océanographie et de Biogéochimie, Centre Océanologique de Marseille, CNRS, Université de la Méditerranée, campus de Luminy, case 901, 13288 Marseille Cedex 09, France. stephane.blain@univmed.fr
authors: Stéphane
authors: S
authors: Blain
authors: Bernard
authors: B
authors: Quéguiner
authors: Leanne
authors: L
authors: Armand
authors: Sauveur
authors: S
authors: Belviso
authors: Bruno
authors: B
authors: Bombled
authors: Laurent
authors: L
authors: Bopp
authors: Andrew
authors: A
authors: Bowie
authors: Christian
authors: C
authors: Brunet
authors: Corina
authors: C
authors: Brussaard
authors: François
authors: F
authors: Carlotti
authors: Urania
authors: U
authors: Christaki
authors: Antoine
authors: A
authors: Corbière
authors: Isabelle
authors: I
authors: Durand
authors: Frederike
authors: F
authors: Ebersbach
authors: Jean-Luc
authors: JL
authors: Fuda
authors: Nicole
authors: N
authors: Garcia
authors: Loes
authors: L
authors: Gerringa
authors: Brian
authors: B
authors: Griffiths
authors: Catherine
authors: C
authors: Guigue
authors: Christophe
authors: C
authors: Guillerm
authors: Stéphanie
authors: S
authors: Jacquet
authors: Catherine
authors: C
authors: Jeandel
authors: Patrick
authors: P
authors: Laan
authors: Dominique
authors: D
authors: Lefèvre
authors: Claire
authors: C
authors: Lo Monaco
authors: Andrea
authors: A
authors: Malits
authors: Julie
authors: J
authors: Mosseri
authors: Ingrid
authors: I
authors: Obernosterer
authors: Young-Hyang
authors: YH
authors: Park
authors: Marc
authors: M
authors: Picheral
authors: Philippe
authors: P
authors: Pondaven
authors: Thomas
authors: T
authors: Remenyi
authors: Valérie
authors: V
authors: Sandroni
authors: Géraldine
authors: G
authors: Sarthou
authors: Nicolas
authors: N
authors: Savoye
authors: Lionel
authors: L
authors: Scouarnec
authors: Marc
authors: M
authors: Souhaut
authors: Doris
authors: D
authors: Thuiller
authors: Klaas
authors: K
authors: Timmermans
authors: Thomas
authors: T
authors: Trull
authors: Julia
authors: J
authors: Uitz
authors: Pieter
authors: P
authors: van Beek
authors: Marcel
authors: M
authors: Veldhuis
authors: Dorothée
authors: D
authors: Vincent
authors: Eric
authors: E
authors: Viollier
authors: Lilita
authors: L
authors: Vong
authors: Thibaut
authors: T
authors: Wagener
mesh_terms: D001272:Atmosphere / Q000737:chemistry; D002244:Carbon / Q000378:metabolism*; D002245:Carbon Dioxide / Q000378:metabolism; D002734:Chlorophyll / Q000032:analysis; D000077194:Chlorophyll A; D004058:Diffusion; D005843:Geography; D007501:Iron / Q000378:metabolism*; D009792:Oceans and Seas; D010313:Partial Pressure; D010839:Phytoplankton / Q000378:metabolism*; D012623:Seawater / Q000737:chemistry*; D013997:Time Factors
chemical_list: D002734:Chlorophyll; D002245:Carbon Dioxide; D002244:Carbon; D007501:Iron; D000077194:Chlorophyll A