Dissolved organic matter uptake by Trichodesmium in the Southwest Pacific

Mar Benavides, Hugo Berthelot, Solange Duhamel, Patrick Raimbault, Sophie Bonnet

Research output: Contribution to journalArticlepeer-review

36 Scopus citations


The globally distributed diazotroph Trichodesmium contributes importantly to nitrogen inputs in the oligotrophic oceans. Sites of dissolved organic matter (DOM) accumulation could promote the mixotrophic nutrition of Trichodesmium when inorganic nutrients are scarce. Nano-scale secondary ion mass spectrometry (nanoSIMS) analyses of individual trichomes sampled in the South Pacific Ocean, showed significant 13 C-enrichments after incubation with either 13 C-labeled carbohydrates or amino acids. These results suggest that DOM could be directly taken up by Trichodesmium or primarily consumed by heterotrophic epibiont bacteria that ultimately transfer reduced DOM compounds to their host trichomes. Although the addition of carbohydrates or amino acids did not significantly affect bulk N 2 fixation rates, N 2 fixation was enhanced by amino acids in individual colonies of Trichodesmium. We discuss the ecological advantages of DOM use by Trichodesmium as an alternative to autotrophic nutrition in oligotrophic open ocean waters.

Original languageEnglish (US)
Article number41315
JournalScientific reports
StatePublished - Jan 24 2017
Externally publishedYes

ASJC Scopus subject areas

  • General


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