Cs enrichment controlled by microbial community: Evidence from sinters along a temperature gradient of the Daggyai Major Geyser, Tibet

The Daggyai sinters in Tibet are known for their Cs-bearing deposits. To understand the relationship between Cs concentrations and sinter fabrics, variations in fabrics and Cs contents along a temperature gradient from 81 to 43 degrees C associated with the Daggyai Major Geyser are examined herein. The fabrics of sinters vary from stromatolite-like in the pool margin to palisade with numerous large-diameter filaments along the overflow apron to diatoms and small-diameter filaments at the distal end of discharge channel. The large-diameter filaments are tentatively assigned to Chloroflexi, whereas the filamentous mats found at the pool margin and distal end of discharge channel may have been formed by cyanobacteria. The Cs concentrations are highest in the sinters associated with the cyanobacteria. These results indicate that Cs enrichment may be controlled by the composition and abundance of microbial community.