Terra Nova, 24, 248–254, 2012
The study of microbe-mineral interactions and the identification of biominerals in sedimentary rocks provide crucial information on the coevolution of life and Earth surface environments. Desulfovibrio brasiliensis, a sulfate-reducing bacterium isolated from Lagoa Vermelha (Brazil), is known for its ability to precipitate dolomite, a mineral that is common in the geological record, but difficult to obtain in laboratory experiments simulating Earth's surface conditions. Here, we report on a new bacterial strain capable of precipitating Mg-calcite and Ca-dolomite, isolated from a microbial mat in the sabkha of Abu Dhabi (UAE). The 16S rRNA gene sequence of the isolate revealed a 99.6% identity (i.e. same species) with Desulfovibrio brasiliensis. The presence of the same microbial species at two geographically distant dolomite-forming locations is difficult to explain in terms of pure coincidence. Rather, it suggests that the ability of precipitating dolomite may be a unique characteristic associated with specific strains.