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Does export production measure transient changes of the biological carbon pump under global warming?
  • Wolfgang Koeve,
  • Paul Kähler,
  • Andreas Oschlies
Wolfgang Koeve
Helmholtz-Zentrum für Ozeanforschung Kiel, GEOMAR

Corresponding Author:[email protected]

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Paul Kähler
Helmholtz-Zentrum für Ozeanforschung Kiel, GEOMAR
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Andreas Oschlies
Helmholtz-Zentrum für Ozeanforschung Kiel, GEOMAR
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Abstract

In a widely-held conception, the biological carbon pump (BCP) is equal to the export of organic matter out of the euphotic zone. Using global ocean-atmosphere model experiments we show that the change in export production is a poor measure of the biological pump’s feedback to the atmosphere. The change in global true oxygen utilization (TOU), an integrative measure of the imprint of the biological carbon pump on marine oxygen, however, is in good agreement with the net change in the biogenic air-sea flux of oxygen. Since, TOU correlates very well with apparent oxygen utilization (AOU) in our experiments, we propos to measure the change of AOU from data of global float programs to monitor the feedback of the BCP to the atmosphere. For the current ocean we estimate that BCP changes lead to an uptake of CO by the ocean in the range of 0.07 to 0.14 GtC/yr.