Extremeophiles and Extreme Environments: July 2013

How Did Life On Earth Get Started?

Three papers co-authored by Mike Russell at NASA's Jet Propulsion Laboratory strengthen the case that Earth's first life began at alkaline hydrothermal vents at the bottom of oceans. Scientists are interested in understanding early life on Earth because if we ever hope to find life on other worlds - especially icy worlds with subsurface oceans such as Jupiter's moon Europa and Saturn's Enceladus - we need to know what chemical signatures to look for.

Purple bacteria contain pigments that allow them to use sunlight as their source of energy, hence their color. Small as they are, these microbes can teach us a lot about life on Earth, because they have been around longer than most other organisms on the planet.

Lake Vostok, the 7th largest (by volume) and 4th deepest lake on Earth, is covered by more than 3,700 m of ice, making it the largest subglacial lake known. The combination of cold, heat (from possible hydrothermal activity), pressure (from the overriding glacier), limited nutrients and complete darkness presents extreme challenges to life.