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Journal Articles Nature Year : 2012

Deep carbon export from a Southern Ocean iron-fertilized diatom bloom

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Victor Smetacek
  • Function : Author
Christine Klaas
  • Function : Author
Volker H. Strass
  • Function : Author
Philipp Assmy
  • Function : Author
Marina Montresor
Boris Cisewski
  • Function : Author
Nicolas Savoye
Adrian Webb
  • Function : Author
Jesús M. Arrieta
  • Function : Author
Ulrich Bathmann
  • Function : Author
Richard Bellerby
  • Function : Author
Gry Mine Berg
  • Function : Author
Peter Croot
  • Function : Author
Santiago Gonzalez
  • Function : Author
Joachim Henjes
  • Function : Author
Gerhard J. Herndl
  • Function : Author
Linn J. Hoffmann
  • Function : Author
Harry Leach
  • Function : Author
Martin Losch
  • Function : Author
Matthew M. Mills
  • Function : Author
Craig Neill
  • Function : Author
Ilka Peeken
  • Function : Author
Rüdiger Röttgers
  • Function : Author
Oliver Sachs
  • Function : Author
Eberhard Sauter
  • Function : Author
Maike M. Schmidt
  • Function : Author
Jill Schwarz
  • Function : Author
Anja Terbrüggen
  • Function : Author
Dieter Wolf-Gladrow
  • Function : Author

Abstract

Fertilization of the ocean by adding iron compounds has induced diatom-dominated phytoplankton blooms accompanied by considerable carbon dioxide drawdown in the ocean surface layer. However, because the fate of bloom biomass could not be adequately resolved in these experiments, the timescales of carbon sequestration from the atmosphere are uncertain. Here we report the results of a five-week experiment carried out in the closed core of a vertically coherent, mesoscale eddy of the Antarctic Circumpolar Current, during which we tracked sinking particles from the surface to the deep-sea floor. A large diatom bloom peaked in the fourth week after fertilization. This was followed by mass mortality of several diatom species that formed rapidly sinking, mucilaginous aggregates of entangled cells and chains. Taken together, multiple lines of evidence--although each with important uncertainties--lead us to conclude that at least half the bloom biomass sank far below a depth of 1,000 metres and that a substantial portion is likely to have reached the sea floor. Thus, iron-fertilized diatom blooms may sequester carbon for timescales of centuries in ocean bottom water and for longer in the sediments.

Dates and versions

hal-00757250 , version 1 (26-11-2012)

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Victor Smetacek, Christine Klaas, Volker H. Strass, Philipp Assmy, Marina Montresor, et al.. Deep carbon export from a Southern Ocean iron-fertilized diatom bloom. Nature, 2012, 487, pp.313-319. ⟨10.1038/NATURE11229⟩. ⟨hal-00757250⟩
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