Reconciliation of the carbon budget in the ocean’s twilight zone

Sarah L. C. Giering, Richard Sanders, Richard S Lampitt, Thomas R Anderson, Christian Tamburini, Mehdi Boutrif, Mikhail V Zubkov, Chris M Marsay, Stephanie A Henson, Kevin Saw, Kathryn Cook, Daniel J. Mayor

Research output: Contribution to journalLetterpeer-review

240 Citations (Scopus)
15 Downloads (Pure)


Photosynthesis in the surface ocean produces approximately 100 gigatonnes of organic carbon per year, of which 5 to 15 per cent is exported to the deep ocean1, 2. The rate at which the sinking carbon is converted into carbon dioxide by heterotrophic organisms at depth is important in controlling oceanic carbon storage3. It remains uncertain, however, to what extent surface ocean carbon supply meets the demand of water-column biota; the discrepancy between known carbon sources and sinks is as much as two orders of magnitude4, 5, 6, 7, 8. Here we present field measurements, respiration rate estimates and a steady-state model that allow us to balance carbon sources and sinks to within observational uncertainties at the Porcupine Abyssal Plain site in the eastern North Atlantic Ocean. We find that prokaryotes are responsible for 70 to 92 per cent of the estimated remineralization in the twilight zone (depths of 50 to 1,000 metres) despite the fact that much of the organic carbon is exported in the form of large, fast-sinking particles accessible to larger zooplankton. We suggest that this occurs because zooplankton fragment and ingest half of the fast-sinking particles, of which more than 30 per cent may be released as suspended and slowly sinking matter, stimulating the deep-ocean microbial loop. The synergy between microbes and zooplankton in the twilight zone is important to our understanding of the processes controlling the oceanic carbon sink.
Original languageEnglish
Pages (from-to)480-483
Number of pages4
Issue number7493
Early online date19 Mar 2014
Publication statusPublished - 27 Mar 2014


  • Animals
  • Aquatic Organisms
  • Atlantic Ocean
  • Biota
  • Carbon
  • Carbon Cycle
  • Carbon Dioxide
  • Carbon Sequestration
  • Cell Respiration
  • Food Chain
  • Observation
  • Seawater
  • Uncertainty
  • Zooplankton
  • Ocean sciences
  • Ecosystem
  • Ecology
  • Biogeochemistry
  • Microbial ecology


Dive into the research topics of 'Reconciliation of the carbon budget in the ocean’s twilight zone'. Together they form a unique fingerprint.

Cite this