Organic metabolite uptake by diazotrophs in the North Pacific Ocean
Filella, Alba; Cébron, Aurélie; Paix, Benoît; Vallet, Marine; Martinot, Pauline; Guyomarch, Léa; Guigue, Catherine; Tedetti, Marc; Grosso, Olivier; Turk-Kubo, Kendra A; Riemann, Lasse; Benavides, Mar. 2025 Organic metabolite uptake by diazotrophs in the North Pacific Ocean. ISME Communications, 5 (1). 10.1093/ismeco/ycaf061
Before downloading, please read NORA policies.Preview |
Text
© The Author(s) 2025. Published by Oxford University Press on behalf of the International Society for Microbial Ecology. ycaf061.pdf - Published Version Available under License Creative Commons Attribution 4.0. Download (1MB) | Preview |
Abstract/Summary
Dinitrogen (N₂) fixation by diazotrophs supports ocean productivity. Diazotrophs include photoautotrophic cyanobacteria, non-cyanobacterial diazotrophs (NCDs), and the recently discovered N2-fixing haptophyte. While NCDs are ubiquitous in the ocean, their ecology and metabolism remain largely unknown. Unlike cyanobacterial diazotrophs and the haptophyte, NCDs are primarily heterotrophic and depend on dissolved organic matter (DOM) for carbon and energy. However, conventional DOM amendment incubations do not allow discerning how different diazotrophs use DOM molecules, limiting our knowledge on DOM–diazotroph interactions. To identify diazotrophs using DOM, we amended North Pacific microbial communities with 13C-labeled DOM from phytoplankton cultures that was molecularly characterized, revealing the dominance of nitrogen-rich compounds. After DOM additions, we observed a community shift from cyanobacterial diazotrophs like Crocosphaera and Trichodesmium to NCDs at stations where the N2-fixing haptophyte abundance was relatively low. Through DNA stable isotope probing and gene sequencing, we identified diverse diazotrophs capable of taking up DOM. Our findings highlight unexpected DOM uptake by the haptophyte’s nitroplast, changes in community structure, and previously unrecognized osmotrophic behavior in NCDs, shaped by local biogeochemical conditions.
Item Type: | Publication - Article |
---|---|
Digital Object Identifier (DOI): | 10.1093/ismeco/ycaf061 |
ISSN: | 2730-6151 |
Additional Keywords: | DNA-SIP, nifH, osmotrophy, N2 fixation, DOM, DOM composition, mixotrophy, NCDs |
Date made live: | 30 Jun 2025 14:56 +0 (UTC) |
URI: | https://nora.nerc.ac.uk/id/eprint/539722 |
Actions (login required)
![]() |
View Item |
Document Downloads
Downloads for past 30 days
Downloads per month over past year