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Drawdown of Atmospheric pCO2 via Variable Particle Flux Stoichiometry in the Ocean Twilight Zone
  • Tatsuro Tanioka,
  • Katsumi Matsumoto,
  • Michael William Lomas
Tatsuro Tanioka
University of Minnesota, University of Minnesota

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Katsumi Matsumoto
University of Minnesota, University of Minnesota
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Michael William Lomas
Bigelow Laboratory For Ocean Sciences, Bigelow Laboratory For Ocean Sciences
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The strength of the biological soft tissue pump in the ocean critically depends on how much organic carbon is produced via photosynthesis and how efficiently the carbon is transferred to the ocean interior. For a given amount of limiting nutrient, phosphate, soft tissue pump would be strengthened if the carbon (C) to phosphorus (P) ratio of sinking organic matter increases as the remineralization length scale of C increases. Here, we present a new data compilation of particle flux stoichiometry and show that C:P of sinking particulate organic matter (POM) in the ocean twilight zone on average is likely to be higher than the C:P ratio of surface suspended POM. We further demonstrate using a physics-biology coupled global ocean model combined with a theory from first principles that an increase in C:P export flux ratio in the ocean’s twilight zone can lead to a considerable drawdown of atmospheric pCO2.
28 Nov 2021Published in Geophysical Research Letters volume 48 issue 22. 10.1029/2021GL094924