A reduced estimate of the strength of the ocean's biological carbon pump

Stephanie A. Henson*, Richard Sanders, Esben Madsen, Paul J. Morris, Frederic Le Moigne, Graham D. Quartly

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

178 Citations (Scopus)

Abstract

A major term in the global carbon cycle is the ocean's biological carbon pump which is dominated by sinking of small organic particles from the surface ocean to its interior. Several different approaches to estimating the magnitude of the pump have been used, yielding a large range of estimates. Here, we use an alternative methodology, a thorium isotope tracer, that provides direct estimates of particulate organic carbon export. A large database of thorium-derived export measurements was compiled and extrapolated to the global scale by correlation with satellite sea surface temperature fields. Our estimates of export efficiency are significantly lower than those derived from the f-ratio, and we estimate global integrated carbon export as similar to 5 GtC yr(-1), lower than most current estimates. The lack of consensus amongst different methodologies on the strength of the biological carbon pump emphasises that our knowledge of a major planetary carbon flux remains incomplete. Citation: Henson, S. A., R. Sanders, E. Madsen, P. J. Morris, F. Le Moigne, and G. D. Quartly (2011), A reduced estimate of the strength of the ocean's biological carbon pump, Geophys. Res. Lett., 38, L04606, doi: 10.1029/2011GL046735.

Original languageEnglish
Article numberARTN L04606
Number of pages5
JournalGeophysical Research Letters
Volume38
DOIs
Publication statusPublished - 18 Feb 2011

Keywords

  • TH-234
  • EXPORT PRODUCTION
  • PRODUCTIVITY
  • ATLANTIC-OCEAN
  • NITRIFICATION
  • PARTICULATE ORGANIC-MATTER
  • FLUX
  • NITROGEN REGENERATION
  • NORTH PACIFIC
  • SOUTHERN-OCEAN

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