Diazotroph culture collection

Isolating new strains of diazotrophs for both academic and applied research purposes.


Principal investigators

Sophie Bonnet et Cécile Guieu

The goal of the TCCC is to isolate new strains of diazotrophs for both academic and applied research purposes. Most of our strains have been isolated from the Central and Western Subtropical and equatorial Pacific Ocean.
This region is known to present :
- high rates of N2 fixation (Bonnet et al., 2017),
- high rates of endemism, which can reach up to 88 % in terrestrial plants (Richer de Forges et al. 2008).
Yet, the biodiversity of marine plants (in particular microalgae and cyanobacteria) was poorly explored and motivated the initiation of a strain collection of diazotrophic cyanobacteria from this region.

Upper panel: Map from Bonnet et al., (2017) showing the areal rates of N2 fixation activity in the Western tropical SOuth Pacific as compared to the global database Luo et al., (2012). Lower panel: Map of the world showing areas of exceptional biodiversity 'hotspots' based on Myers et al. (2000).

Our strain collection currently includes ~150 isolates and 64 purified strains, and their genetic characterization (in progress) confirms that endemism is also found in marine micro-organisms since some of the isolates are original and have never been described before (Camps et al., In prep.; Bonnet at al., In prep.).  

These new strains are used
- to perform fundamental research and complement field studies,
- our consortium has also been looking for properties/molecules of interest in these strains, with a view to sustainable development for the food and nutraceutical sectors. The TCCC comples with the Nagoya Protocol.


accurately quantifying iron (and other biogeochemically relevant compounds) inputs from shallow submarine volcanoes and associated hydrothermal sources along the Tonga volcanic arc (20 and 25ºS) for the productive layer in comparison with atmospheric iron inputs,


study the fate of shallow hydrothermal plumes in the water column at local and regional scales,


investigate the bioavailability and potential impact of these hydrothermal inputs on planktonic communities and carbon export in the WTSP.


Accepted publications

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