Export of Dissolved Organic Carbon (DOC) compared to the particulate and active fluxes near South Georgia, Southern Ocean

Lovecchio, Elisa ORCID: https://orcid.org/0000-0002-7183-4761; Clement, Louis ORCID: https://orcid.org/0000-0002-6935-9455; Evans, Claire ORCID: https://orcid.org/0000-0003-0569-7057; Rayne, Rachel; Dumousseaud, Cynthia; Roshan, Saeed; Giering, Sarah L.C. ORCID: https://orcid.org/0000-0002-3090-1876; Martin, Adrian ORCID: https://orcid.org/0000-0002-1202-8612. 2023 Export of Dissolved Organic Carbon (DOC) compared to the particulate and active fluxes near South Georgia, Southern Ocean. Deep Sea Research Part II: Topical Studies in Oceanography, 212, 105338. https://doi.org/10.1016/j.dsr2.2023.105338

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Official URL: http://dx.doi.org/10.1016/j.dsr2.2023.105338

Abstract/Summary

Quantifying the relative contributions of the export of particulate organic carbon (POC), dissolved organic carbon (DOC) and active fluxes by migrating organisms is essential to understand the functioning and vulnerability of the ocean's biological pump. However, these fluxes are rarely measured at the same time. Here we provide a first simultaneous comparison of these biological pump components in the region of South Georgia. We use a combination of in-situ data and an inverse model to calculate the DOC export and the suspended POC export and compare them to the sinking POC and active export. We find that, in this region, the DOC total export contributes about 6.6% (23.0–37.5 mg C m−2 day−1) to the total export flux, the active flux has no discernible contribution, and the sinking POC flux is dominant with a mean value of 409 mg C m−2 day−1. Diapycnal fluxes of DOC obtained from the cruise data constitute only a minor fraction (0.05–1.28 mg C m−2 day−1) of the total DOC export estimated by the inverse model and are exceeded on average by the diapycnal flux of suspended POC. Our results also indicate that the total export of DOC is driven by isopycnal transport. Future fieldwork in the region of South Georgia should focus on quantifying the isopycnal flux of DOC. Future measurement campaigns should also aim to simultaneously measure the particulate, dissolved and active components of the biological pump at contrasting locations and at different times to resolve the variability of their relative contribution.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1016/j.dsr2.2023.105338
ISSN:	09670645
Additional Keywords:	Biological pump, Dissolved organic carbon, Water mixing, Southern ocean, South Georgia
Date made live:	16 Oct 2023 16:15 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/536101

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1016/j.dsr2.2023.105338

ISSN:

09670645

Additional Keywords:

Biological pump, Dissolved organic carbon, Water mixing, Southern ocean, South Georgia

Date made live:

16 Oct 2023 16:15 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/536101