Diazotrophic cyanobacteria under elevated CO2

Ondřej Prášil

We have been studying the response of diazotrophic cyanobacteria to expected increases in pCO₂ (900 ppm expected in 2100). The first study [1] indicated that Trichodesmium might double its growth rate and nitrogen fixation under elevated CO₂. The follow-up studies [2,3] analysed in detail the underlying molecular mechanisms. We have shown that it is the re-allocation of cellular resources from CO₂ concentrating mechanisms to nitrogen fixation that allows Trichodesmium to increase its overall productivity. In addition, we have also studied the differences in CO₂ response among cyanobacteria with different strategies of regulation of photosynthesis and nitrogen fixation - namely Anabaena and Cyanothece.

The project is supported by grant GACR 206/08/1683

1. Kranz, S.A., Levitan, O., Richter, K-U., Prášil, O., Berman-Frank, I., Rost, B.: Combined effect of CO₂ and light on the N₂ –fixing cyanobacterium Trichodesmium IMS101: Physiological Responses. – Plant Physiology 154, 334-345, 2010.
2. Levitan, O., Kranz, S.A., Spungin, D., Prášil, O., Rost, B., Berman-Frank, I.: Combined effect of CO₂ and light on the N₂ –fixing cyanobacterium Trichodesmium IMS101: A mechanistic view. – Plant Physiology 154, 346-356, 2010.
3. Levitan, O., Rosenberg, G., Šetlík, I., Šetlíková, E., Grígel, J-. Klepetář, J., Prášil, O., Berman-Frank, I. (2007) Elevated CO2 enhances nitrogen fixation and growth in the marine cyanobacterium Trichodesmium. - Global Change Biology 13, 1-8.