Microbial Bubble Mats

Between the Emerald and Rainbow Terraces, to the left of the boardwalk on the Emerald Terrace, living orange and green microbial bubble mats and partially silicified bubble mats occur side by side.

The white periphery around the bubble mats is silica sinter. here the rate of silica deposition is greater than the rate of microbial growth.

Eventually so much silica will deposit that the microbes will die and become totally silicified, leaving their fossilised signature in the sinter. Then the sinter becomes a source of information about the environment at the time of silicification, indicating conditions such as water temperature and flow rate.