Sr-rich microbial mats at Zhemchug hot springs, southwest Lake Baikal, Russia

Kazue Tazaki, Koushirou Miyata, Natalia Belkova, Ryuji Asada
At Zhemchug hot springs, southwest Lake Baikal, Russia, the biomats contain high concentration of Ca and Sr, which microbiological, chemical and mineralogical analyses were carried. Optical and scanning electron microscopic observation revealed that carbonate minerals were associated with cyanobacteria. The biomats have colorful layered structure, such as green, white, brown and black. Chemical analysis of the biomats revealed high concentration of CaO (85-96 wt%) and SrO (1.1-2.2 wt%) in the
more » ... ur layers. The mineralogical composition of the layered structure is mainly aragonite associated with calcite. Elemental layered patterns of the biomats are shown in EPMA elemental content maps indicating the coincidence of Ca and Sr. By increasing pH and the oxygen concentration on the surface of biomats, the cyanobacteria could potentially increase the rate of metal accumulation. The cyanobacteria in hot spring biomats may carry important role to accumulate Ca with Sr.