Dataset Information

Phosphate availability affects fixed nitrogen transfer from diazotrophs to their epibionts.

ABSTRACT: Dinitrogen (N₂) fixation is a major source of external nitrogen (N) to aquatic ecosystems and therefore exerts control over productivity. Studies have shown that N₂ -fixers release freshly fixed N into the environment, but the causes for this N release are largely unclear. Here, we show that the availability of phosphate can directly affect the transfer of freshly fixed N to epibionts in filamentous, diazotrophic cyanobacteria. Stable-isotope incubations coupled to single-cell analyses showed that <1% and ~15% of freshly fixed N was transferred to epibionts of Aphanizomenon and Nodularia, respectively, at phosphate scarcity during a summer bloom in the Baltic Sea. When phosphate was added, the transfer of freshly fixed N to epibionts dropped to about half for Nodularia, whereas the release from Aphanizomenon increased slightly. At the same time, the growth rate of Nodularia roughly doubled, indicating that less freshly fixed N was released and was used for biomass production instead. Phosphate scarcity and the resulting release of freshly fixed N could explain the heavy colonization of Nodularia filaments by microorganisms during summer blooms. As such, the availability of phosphate may directly affect the partitioning of fixed N₂ in colonies of diazotrophic cyanobacteria and may impact the interactions with their microbiome.

SUBMITTER: Schoffelen NJ

PROVIDER: S-EPMC6794295 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Phosphate availability affects fixed nitrogen transfer from diazotrophs to their epibionts.

Schoffelen Niels J NJ Mohr Wiebke W Ferdelman Timothy G TG Duerschlag Julia J Littmann Sten S Ploug Helle H Kuypers Marcel M M MMM

The ISME journal 20190627 11

Dinitrogen (N<sub>2</sub>) fixation is a major source of external nitrogen (N) to aquatic ecosystems and therefore exerts control over productivity. Studies have shown that N<sub>2</sub> -fixers release freshly fixed N into the environment, but the causes for this N release are largely unclear. Here, we show that the availability of phosphate can directly affect the transfer of freshly fixed N to epibionts in filamentous, diazotrophic cyanobacteria. Stable-isotope incubations coupled to single-c ...[more]

PMID: 31249392

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Dataset Information

Phosphate availability affects fixed nitrogen transfer from diazotrophs to their epibionts.

Publications

Phosphate availability affects fixed nitrogen transfer from diazotrophs to their epibionts.

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