Source: [astrobio.net]

Astrobiologists have outlined how geochemistry and metabolism are connected in subsurface microbial ecosystems beneath Spain’s Rio Tinto region. The Iberian Pyrite Belt (IPB) in the Río Tinto area is the largest known deposit of sulfide on Earth, and for decades it has been a field-site for scientists studying chemolithotrophic microbes.

In the early 2000’s, NASA joined with the Centro de Astrobiología (CAB) in Spain to explore habitats for life beneath the Earth at the Rio Tinto. Since then, the Mars Analog Research and Technology Experiment (MARTE) has been using this analog site to develop instruments for future Mars missions, including remote drilling techniques. Previous studies focused on testing equipment, but now a team of scientists has performed a thorough investigation of the microorganisms collected in drill cores.

Drilling depths ranged from 5 meters to over 166 meters. Samples were collected at one meter intervals and multiple tests were performed, including: DNA extraction, cultivation, ATP activity, Microscopic analysis, and Geochemistry analysis. In total, more than 200 samples were collected.

The results allowed the team to construct a preliminary model of how biogeochemical processes operate in the subsurface of the Iberian Pyrite Belt. This includes microbial metabolisms like sulfate reduction, methanogenesis and anaerobic methane oxidation.

The MARTE project is a joint project between NASA and CAB with partial funding from the Astrobiology Science and Technology for Exploring Planets (ASTEP) element of the NASA Astrobiology Program. The study was published in the journal Geobiology