nerc.ac.uk

Slow sinking particulate organic carbon in the Atlantic Ocean: magnitude, flux and potential controls

Baker, Chelsey A.; Henson, Stephanie A.; Cavan, Emma L.; Giering, Sarah L.C.; Yool, Andrew; Gehlen, Marion; Belcher, Anna; Riley, Jennifer S.; Smith, Helen E.K.; Sanders, Richard. 2017 Slow sinking particulate organic carbon in the Atlantic Ocean: magnitude, flux and potential controls. Global Biogeochemical Cycles. 10.1002/2017GB005638 (In Press)

Before downloading, please read NORA policies.
[img] Text
CBaker_SlowSinkingPOCManuscript_GBC_v3 (1).docx - Accepted Version
Restricted to NORA staff only

Download (1MB)

Abstract/Summary

The remineralization depth of particulate organic carbon (POC) fluxes exported from the surface ocean exert a major control over atmospheric CO₂ levels. According to a long held paradigm most of the POC exported to depth is associated with large particles. However, recent lines of evidence suggest that slow sinking POC (SSPOC) may be an important contributor to this flux. Here we assess the circumstances under which this occurs. Our study uses samples collected using the Marine Snow Catcher throughout the Atlantic Ocean, from high latitudes to mid latitudes. We find median SSPOC concentrations of 5.5 μg L-1, 13 times smaller than suspended POC concentrations and 75 times higher than median fast sinking POC (FSPOC) concentrations (0.07 μg L-1). Export fluxes of SSPOC generally exceed FSPOC flux, with the exception being during a spring bloom sampled in the Southern Ocean. In the Southern Ocean SSPOC fluxes often increase with depth relative to FSPOC flux, likely due to midwater fragmentation of FSPOC, a process which may contribute to shallow mineralization of POC and hence to reduced carbon storage. Biogeochemical models do not generally reproduce this behaviour, meaning that they likely overestimate long term ocean carbon storage.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1002/2017GB005638
ISSN: 08866236
Date made live: 04 Jul 2017 14:50 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/517271

Actions (login required)

View Item View Item

Document Downloads

Downloads for past 30 days

Downloads per month over past year

More statistics for this item...