Dead Sea Shore microbial mat Raw sequence reads
Microbial mats and microbialites are like time machines helping us learn about ancient life and its environments. We collected a microbial mat from the unique Dead Sea's sinkholes, where life thrives in extreme conditions. In this mat, we found for the first time in this area a staggering 6.5 million-fold increase in arsenic, an element toxic to life. By closely studying the genes and chemistry of this microbial mat, we discovered that microbes were striving to clean up this excess arsenic, in a sort of natural detoxification process. It seems that a temporary spike in arsenic levels in the Dead Sea water triggered this clean-up work, which eventually stored the arsenic safely in the mat, away from the microbial cells. Our findings suggest that in the past, when microbial mats were one of the only ecosystems on Earth, changes in the water flowing over mats like this one could have caused similar accumulations of metals. So, when scientists study ancient fossilized microbial layers, these discoveries can help us look into the past and understand the chemical and biological conditions under which these ancient microbial mats formed.