Abstract
Understanding the coevolution of life and the earth's environments is one of the important subjects of the Decoding the Earth Evolution Program, a grant-in-aid scientific research for the priority areas, Ministry of Education, Japan. A large amount of stromatolites and banded iron formations has been collected for this purpose. Although many of them have been regarded as remnants of microbial mats, quite few direct evidence for microbial communities, their biogeochemical roles, or ecological settings has been preserved. Here we argue that recent microbial mats and stromatolitic structures observed in many active hot springs may provide important clues for modeling stromatolite formation processes as well as Precambrian biosphere. We present some results of chemical mapping of microbial mat sampled from hot springs in central Japan. The scanning X-ray analytical microscope we introduced here provides new and important information on the morphological and chemical structures of microbial mats.
