Articles

Dissolved organic matter uptake by Trichodesmium in the Southwest Pacific

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

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 13C-enrichments after incubation with either 13C-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 N2 fixation rates, N2 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.

Geographic Areas

Files

  • thumnail for Benavides-2017-ScReports.pdf Benavides-2017-ScReports.pdf application/pdf 293 KB Download File

Also Published In

Title
Scientific Reports
DOI
https://doi.org/10.1038/srep41315

More About This Work

Academic Units
Lamont-Doherty Earth Observatory
Biology and Paleo Environment
Published Here
August 8, 2018