Olofsson, Malin
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
- University of Georgia
Abstract
A large annual carbon flux occurs through the surface ocean's labile dissolved organic carbon (DOC) pool, with influx dominated by phytoplankton-derived metabolites and outflux by heterotrophic bacterioplankton uptake. We addressed the dynamics of this carbon flow between microbial primary and secondary producers through analysis of the Thalassiosira pseudonana CCMP1335 endometabolome, a proxy for the labile DOC released upon phytoplankton lysis, as temperature and bacterial presence were altered. Diatom strains acclimated at one of three different temperatures (14 degrees C, 20 degrees C, or 28 degrees C) were cultured either axenically or with the bacterium Ruegeria pomeroyi DSS-3, and their endometabolites analyzed by NMR. Median concentration variation between conditions was similar to 1.5-fold across all identified endometabolites. Those with roles as osmolytes varied most, exhibiting concentration differences up to 170-fold across conditions with the largest variations triggered by the presence/absence of the heterotrophic bacterium. Differential expression observed for diatom metabolite synthesis pathways suggested changes in synthesis rates as a mechanism for endometabolome remodeling. Consistent with expectations of high turnover by heterotrophic bacteria, endometabolite mean lifetimes in a DOC pool were
Keywords
diatoms; endometabolites; temperature acclimation; bacteria; co-culture
Published in
mSystems
2025
Publisher: AMER SOC MICROBIOLOGY
SLU Authors
UKÄ Subject classification
Microbiology
Oceanography, Hydrology, Water Resources
Publication identifier
- DOI: https://doi.org/10.1128/msystems.01036-25
Permanent link to this page (URI)
https://res.slu.se/id/publ/145622