Sediment Trap and 234Th Methods for Carbon Export Flux Determination

Chair: Ken Buesseler (USA)

Other Full Members: Avan N. Antia (Germany), Scott Fowler (Monaco), Orjan Gustafsson (Sweden), Koh Harada (Japan), Chen Min (China-Beijing), M.M. Sarin (India), Deborah K. Steinberg (USA), Tom Trull (Australia), and Michiel Rutgers van der Loeff (Germany)

Associate Members: Anthony F. Michaels (USA)

Terms of Reference

  • To explain the terms "export production" and "new production" and their inter-relation. How does the carbon flux determined using traps and 234Th relate to export production?
  • To review the current status of carbon export flux determination using moored and floating sediment traps, their advantages and problems, associated uncertainties and their magnitudes.
  • To suggest suitable trap designs and necessary protocols to get reliable flux data.
  • To review the basis of 234Th based carbon export flux measurements, models, assumptions and parameters used in the calculations.
  • To assess the reliability of these assumptions/parameters, the sources and magnitudes of associated uncertainties. (For example: How do the time scales of sampling, temporal variability in 234Th fluxes, POC/234Th ratio in different particulate pools affect the flux data?).
  • To intercompare the carbon export fluxes determined by trap and 234Th methods. If they differ, what are the main causes of discrepancy and how can they be resolved?
  • To suggest experimental design and protocols to be followed to obtain quantitative and reliable carbon export fluxes based on the above methods. Can 234Th serve as a global survey tool to determine carbon export fluxes?
  • To prepare an interim report within 2 years and a final report in 2 years.

Approved: 1999

Financial Sponsors: U.S. National Science Foundation, SCOR


#1: 8-9 July 2001 in Amsterdam, The Netherlands

#2: 3-7 November 2003 on Catalina Island, California, USA

#3: 19-21 August 2004 in Woods Hole, Massachusetts, USA

#4: 18-21 April 2005 in Xiamen, China

Product: Buesseler et al. 2007. An assessment of the use of sediment traps for estimating upper ocean particle fluxes. Journal of Marine Research, 65, 345–416 - Used with permission from the Journal of Marine Research (

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