Heterogeneous nitrogen fixation rates confer energetic advantage and expanded ecological niche of unicellular diazotroph populations

0524517 - ÚVGZ 2021 RIV GB eng J - Journal Article
Masuda, Takako - Inomura, K. - Takahata, N. - Shiozaki, T. - Sano, Y. - Deutsch, C. - Prášil, O. - Furuya, K.
Heterogeneous nitrogen fixation rates confer energetic advantage and expanded ecological niche of unicellular diazotroph populations.
Communications Biology. Roč. 3, č. 1 (2020), č. článku 172. E-ISSN 2399-3642
R&D Projects: GA MŠMT(CZ) LO1416; GA ČR GA16-15467S
Institutional support: RVO:86652079
Keywords : vahine mesocosm experiment * amazon river plume * n-2 fixation * crocosphaera-watsonii * dinitrogen fixation * individual cells * cyanobacteria * trichodesmium * carbon * light
OECD category: Microbiology
Impact factor: 6.268, year: 2020
Method of publishing: Open access
https://www.nature.com/articles/s42003-020-0894-4

Nitrogen fixing plankton provide nitrogen to fuel marine ecosystems and biogeochemical cycles but the factors that constrain their growth and habitat remain poorly understood. Here we investigate the importance of metabolic specialization in unicellular diazotroph populations, using laboratory experiments and model simulations. In clonal cultures of Crocosphaera watsonii and Cyanothece sp. spiked with N-15(2), cellular N-15 enrichment developed a bimodal distribution within colonies, indicating that N-2 fixation was confined to a subpopulation. In a model of population metabolism, heterogeneous nitrogen (N-2) fixation rates substantially reduce the respiration rate required to protect nitrogenase from O-2. The energy savings from metabolic specialization is highest at slow growth rates, allowing populations to survive in deeper waters where light is low but nutrients are high. Our results suggest that heterogeneous N-2 fixation in colonies of unicellular diazotrophs confers an energetic advantage that expands the ecological niche and may have facilitated the evolution of multicellular diazotrophs.
Permanent Link: http://hdl.handle.net/11104/0308866