doi:10.1038/nindia.2017.11 Published online 30 January 2017
Researchers have identified a rare group of microbes in red clays of deep-sea oceanic basins. Photosynthesizing using carbon dioxide, heat and light generated by geochemical processes in deep-sea hydrothermal vents, the microbes are potentially useful as model organisms to find life in the extreme conditions that prevail on Venus and Mars.
Deep-sea red clays are iron-oxide and show microbial activity. Fluids circulating through the hydrothermal vents on the sea floor help microbes proliferate. Despite being home to diverse microbial species, red clays are largely unexplored.
To identity microbes in red clays, scientists from Agharkar Research Institute-Maharashtra Associations for the Cultivation of Science, Pune, CSIR-National Institute of Oceanography, Goa, and Ahmedabad-based Indian Space Research Organisation and Physical Research Laboratory sequenced the genes of diverse microbes isolated from deep-sea red clay samples.
They showed an active microbial community with abundance of specific rod-shaped bacteria, particularly green-sulphur and purple bacteria. Sophisticated imaging techniques revealed an active sulphur cycle in the red clays.
Besides sea-floor fluids, a glow from methane-producing microbes provided light for the photosynthesis of red-clay-inhabiting microbes.
Analysis of iron-rich red clays might be useful to understand how the metal shaped the evolution of ancient life forms on Earth and Mars. Understanding the red clay deposits on the Martian surface could also help determine landing sites for future mission to Mars, the researchers say.
1. Das, A. et al. Astrobiological implications of dim light phototrophy in deep-sea red clays. Life. Sci. Space. Res. (2017) doi: 10.1016/j.lssr.2017.01.002