Major role of particle fragmentation in regulating biological sequestration of CO2 by the oceans

Type Article
Date 2020-02
Language English
Author(s) Briggs NathanORCID1, 2, 3, Dall'Olmo Giorgio4, 5, Claustre Herve2, 3
Affiliation(s) 1 : Natl Oceanog Ctr, Southampton, Hants, England.
2 : Sorbonne Univ, LOV, Villefranche Sur Mer, France.
3 : CNRS, Villefranche Sur Mer, France.
4 : Plymouth Marine Lab, Plymouth, Devon, England.
5 : Natl Ctr Earth Observat, Plymouth, Devon, England.
Source Science (0036-8075) (Amer Assoc Advancement Science), 2020-02 , Vol. 367 , N. 6479 , P. 791-793
DOI 10.1126/science.aay1790
WOS© Times Cited 49
Abstract

A critical driver of the ocean carbon cycle is the downward flux of sinking organic particles, which acts to lower the atmospheric carbon dioxide concentration. This downward flux is reduced by more than 70% in the mesopelagic zone (100 to 1000 meters of depth), but this loss cannot be fully accounted for by current measurements. For decades, it has been hypothesized that the missing loss could be explained by the fragmentation of large aggregates into small particles, although data to test this hypothesis have been lacking. In this work, using robotic observations, we quantified total mesopelagic fragmentation during 34 high-flux events across multiple ocean regions and found that fragmentation accounted for 49 +/- 22% of the observed flux loss. Therefore, fragmentation may be the primary process controlling the sequestration of sinking organic carbon.

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