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ORIGINAL RESEARCH article

Front. Mar. Sci.
Sec. Marine Biogeochemistry
Volume 12 - 2025 | doi: 10.3389/fmars.2025.1461723

Carbon injection potential of the mesopelagic-migrant pump in the Southern Ocean during summer Authors

Provisionally accepted
Katherine Baker Katherine Baker 1,2*Svenja Halfter Svenja Halfter 1,3Ben Scoulding Ben Scoulding 4Kerrie M. Swadling Kerrie M. Swadling 1,2Shane A Richards Shane A Richards 5Matthieu Bressac Matthieu Bressac 6Caroline Sutton Caroline Sutton 4Philip W Boyd Philip W Boyd 1,2
  • 1 Institute for Marine and Antarctic Studies, College of Sciences and Engineering, University of Tasmania, Hobart, Tasmania, Australia
  • 2 Australian Antarctic Program Partnership (AAPP), Hobart, Australia
  • 3 National Institute of Water and Atmospheric Research (NIWA), Wellington, New Zealand
  • 4 Environment, Commonwealth Scientific Industrial Research Organisation (CSIRO), Hobart, Australia
  • 5 Department of Mathematics, School of Natural Sciences, College of Sciences and Engineering, University of Tasmania, Hobart, Australia
  • 6 Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, Villefranche-sur-Mer, France

The final, formatted version of the article will be published soon.

    The passive sinking flux of particles, termed the biological gravitational pump (BGP), is an important component of the ocean’s biological carbon pump. In addition, carbon-rich particles are actively injected to depth through the diel vertical migration (DVM) of micronekton and mesozooplankton from the surface to the oceans’ twilight zone (200 m – 1000 m depth). This is known as the mesopelagic-migrant pump (MMP). We investigated the magnitude of the MMP at one subantarctic and two polar sites in summer by assessing particulate and dissolved carbon export below 200 m depth based on DVM and the composition of the mesopelagic community. Carbon injection potential (CIP) for the dominant taxa at each site was estimated through four pathways, i.e., excretion, respiration, fecal pellets, and carcass production. Blooms of two migratory tunicate species, the pyrosome Pyrosoma atlanticum (subantarctic) and the salp Salpa thompsoni (polar) dominated the micronekton biomass and MMP export ranged from 5.0 to 9.4 mg C m-2 d-1 across the three Southern Ocean sites. Mesozooplankton abundance was dominated by copepods, which contributed an additional 0.7 to 32.2 mg C m-2 d-1 to the MMP. Results from this summertime study suggest an increase in the relative importance of the MMP compared to the BGP south of the Polar Front, however, future work should target the seasonality of the MMP, which necessitates linking environmental drivers to micronekton and mesozooplankton community composition, life history, and DVM.

    Keywords: Micronekton, Mesozooplankton, Southern Ocean, diel vertical migration, active carbon export

    Received: 09 Jul 2024; Accepted: 03 Jan 2025.

    Copyright: © 2025 Baker, Halfter, Scoulding, Swadling, Richards, Bressac, Sutton and Boyd. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Katherine Baker, Institute for Marine and Antarctic Studies, College of Sciences and Engineering, University of Tasmania, Hobart, 7004, Tasmania, Australia

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