What are Microbial Mats and Where are Microbial Why is NASA Studying Stromatolites? Mats Found? Microbial Mats? Microbial mats are complex Simple mats can be found in Mats help us to understand the communities of microbes, streams, lakes, soils, even interaction of Earth's past life and usually organized into layers drinking fountains and rain its environment, and are centrally that can be seen with the gutters. These are relatives important to NASA's search for naked eye. They were one of the oldest forms of life evidence of life both within and of the earliest ecosystems on Earth! The more outside our solar system. Image: TPF Web Site on Earth. Photosynthetic complex microbial mats Gases produced by mats may mats were responsible for that NASA studies have Evidence for accumulate in the atmospheres of often evolved to live in hypersaline (salty) extrasolar planets, to be detected creating the oxygen-rich environments, by missions such as Terrestrial atmosphere that we breathe. Photo: Mary Hogan & Tracy Cote "extreme environments" (hot, perfect places to Planet Finder. Close-up View of find mats on Stromatolites, our oldest fossils, are a Microbial Mat cold, salty, or dry habitats, even Earth, has been inside rocks) where they are safe from Hot Springs in reported by the microbial mats with a mineral (rock) Yellowstone National Mars Exploration component. grazing animals. Park Rovers! Image: MER Web Site Side view of a mat from a hypersaline (salty) environment. The small In addition to gases, microbial divisions on the ruler are mats may produce structures, millimeters. minerals, or chemical compounds (collectively called "biosignatures") that may be discovered with robotic explorers. A Thin Microbial Mat from a Tidal Flat in Baja California, Mexico Photo: Gerard Heyenga Microbial mats are complete Mats are complete, Macro photography by Bruce J. Russell ecosystems in miniature, and functioning ecosystems in conduct complex biogeochemical microscale. They may be transformations (e.g., extremely useful for studying photosynthesis, nutrient cycling) the effects of space flight on over extremely small spatial scales. biological processes. NASA-funded scientists are engaged in both laboratory and field-based research on microbial mats in order to better understand how the ecology of these mats determines the kinds of biomarkers Salt Marsh Microbial that mats have left on Earth, and Mats, Sippewisset, MA may be creating on other worlds. Photomicrograph: Lee Prufert-Bebout Because microorganisms in mats are so closely associated, mats are a great place to Microbial Mat Inside study interactions that occur. This microscopic view of the inside of a microbial mat Gypsum Crystals from shows many types of microbes, including cyanobacteria and purple sulfur bacteria. Baja California, Mexico Photo Courtesy NASA Photo: Steven Carpenter.