Elemental and isotopic fractionation of Sr and Ba by cyanobacteria forming intracellular CaCO3

Among cyanobacteria forming intracellular CaCO3, G. lithophora has shown the capability to incorporate preferentially Ba over Sr over Ca (Cam et al., 2016). G. lithophora incorporates Ba and Sr even when they are at very low concentrations compared to Ca, which leads to significant Sr and Ba accumulations within cells when these elements are constantly provided by an external source such as microbialites in Mexican lakes (Blondeau et al., subm). Recently, in collaboration with Julien Bouchez and Frederic Moynier at IPGP, we moreover measured the isotopic fractionation of Sr and Ba by G. lithophora to look for additional signatures of this process (Coutaud et al. in prep). Overall, this bio-process may inspire remediation strategies to efficiently remove Ba and/or Sr from polluted environments.


Elemental map obtained by transmissin electron microscopy of carbonate inclusions with distinct Ba, Sr and Ca cores and shells.

© Nithavong Cam

Cécile Duflot - 06/11/17