The mountains of northeastern Oman are rugged, dry, and as much as 2,500 meters above sea level. Millions of years ago, parts of these mountains were beneath the sea. The landscape is known to geologists as the Semail (or Samail) ophiolite, and it holds evidence of the creative and destructive forces that shape our planet.NASA Earth Observatory/Jesse Allen, Robert Simmon (Advanced Land Imager data from NASA EO-1 team)/Michon Scott.
NASA-supported researchers have provided new insights into microorganisms that survive on products from serpentinization reactions. The findings could shed light on some of the earliest organisms on Earth and help scientists understand the types of biosignatures such organisms could leave behind.
Serpentinization is a natural process that happens when water interacts with a type of igneous rock. This process produces byproducts that can serve as an energy source for microbes. Geological formations known as serpentinite formations are thought to be one of the most likely places for early life on Earth to have gained a foothold. Scientists studied life in the Samail Ophiolite in the Sultanate of Oman as an analog for serpentinite formations on the early Earth. In particular, they were looking for acetogens (microorganisms that produce acetate) that call this serpentinite formation home. They collected genetic information on organisms living in fluids from the environment and found acetogens that are specialized to grow on products of water-rock interactions. In addition, when examining drill core samples from the Samail Ophiolite, researchers identified potential biosignatures left behind by once-living microorganisms.
The first study, “Deep-branching acetogens in serpentinized subsurface fluids of Oman,” was published in the Proceedings of the National Academy of Sciences (PNAS). The second study, “Microbial biosignature preservation in carbonated serpentine from the Samail Ophiolite, Oman,” was published in the journal Nature Communications, Earth and Environment.