Mixing accounts for more than half of biogeochemical changes along mode water ventilation pathways

Jutras, M. ORCID: https://orcid.org/0000-0001-5154-5009; Bushinsky, S. M. ORCID: https://orcid.org/0000-0001-5106-4678; Cerovečki, I. ORCID: https://orcid.org/0000-0001-8979-9952; Briggs, N. ORCID: https://orcid.org/0000-0003-1549-1386. 2025 Mixing accounts for more than half of biogeochemical changes along mode water ventilation pathways. Geophysical Research Letters, 52 (7). 10.1029/2024GL113789

Before downloading, please read NORA policies.

Preview

Text © 2025. The Author(s).This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Geophysical Research Letters - 2025 - Jutras - Mixing Accounts for More Than Half of Biogeochemical Changes Along Mode.pdf - Published Version Available under License Creative Commons Attribution 4.0. Download (1MB) | Preview

Abstract/Summary

Mode waters are critical for ocean ventilation and carbon sequestration. Using observations, we trace their subduction pathways and biogeochemical evolution. Solving modified mixing equations that account for respiration reveals that less than 50% of the oxygen changes along mode water ventilation pathways are due to respiration within the water mass, the rest being due to mixing with oxygen-poorer surrounding waters. Consequently, measured changes in oxygen or Apparent Oxygen Utilization overestimate respiration by a factor of up to two, as do derived biogeochemical quantities such as remineralized carbon. Measured nitrate changes either overestimate or underestimate remineralization depending on surrounding concentrations. Mean true respiration rates in mode waters range from −0.1 to −0.4 μ mol. Applying a fixed stoichiometric ratio to this respiration, we find that the total carbon export is highest in Southern Ocean mode waters, while carbon remineralization rates are highest in subtropical mode waters.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.1029/2024GL113789
ISSN:	0094-8276
Additional Keywords:	marine biogeochemistry, apparent oxygen utilization, mixing, respiration, argo
Date made live:	28 Apr 2025 15:01 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/539346

Actions (login required)

View Item

Document Downloads

More statistics for this item...