Modeling Photosynthesis and Exudation in Subtropical Oceans

Zhen Wu, Stephanie Dutkiewicz, Oliver Jahn, Daniel Sher, Angelicque White, Michael J. Follows

Research output: Contribution to journalArticlepeer-review

Abstract

Marine phytoplankton contributes nearly half of the total primary production on Earth through photosynthesis. Parameterizations of algal photosynthesis commonly employed in global biogeochemical simulations generally fail to capture the observed vertical structure of primary production. Here we examined the consequences of decoupling photosynthesis (carbon fixation) and biosynthesis (biomass building) with accumulation or exudation of excess photosynthate under energy rich conditions in both regional and global models. The results show that the decoupling of these two processes improved the simulated vertical profile of primary production, increased modeled primary production over 30% globally and over 40% in subtropical oceans, improved simulated meridional patterns of particulate C:N:P and increased modeled surface pool of labile/semi-labile dissolved organic carbon. More generally, these results highlight the importance of exudation, which results from the decoupling of photosynthesis and biosynthesis, as a major physiological process affecting ocean biogeochemistry.

Original languageEnglish
Article numbere2021GB006941
JournalGlobal Biogeochemical Cycles
Volume35
Issue number9
DOIs
StatePublished - Sep 2021

Bibliographical note

Funding Information:
The authors are grateful for the support by the Simons Collaboration on Ocean Processes and Ecology (SCOPE, 329108 to M. J. Follows and A. White) and Simons Collaboration on Computational Biogeochemical Modeling of Marine Ecosystems (CBIOMES, 549931 to M. J. Follows). Additional support is provided by the NSF to the HOT program (OCE‐1756517 to A. White), the Human Frontiers Science Program (RGP0020/2016 to D. Sher). The authors thank the two anonymous reviewers whose comments and suggestions helped improve and clarify this manuscript. The authors also thank the dedicated efforts of the HOT and BATS teams who facilitated in situ sample collection.

Publisher Copyright:
© 2021. The Authors.

Keywords

  • biogeochemical model
  • exudation
  • photosynthesis
  • phytoplankton
  • primary production
  • subtropical gyres

ASJC Scopus subject areas

  • Global and Planetary Change
  • Environmental Chemistry
  • Environmental Science (all)
  • Atmospheric Science

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