NASA Astrobiology Program

Recently Published Research from the NAI

By Keith Cowing
August 2, 2009

Marine Methane Oxidation Without Sulfur

A new study in Science from NAI’s Penn State Team shows that the anaerobic oxidation of methane is not solely a sulfate-dependent process. Microbes cultured from marine methane seeps in California’s Eel River Basin have demonstrated capability of using manganese and iron to oxidize methane to carbon dioxide. These same compounds may have been key to methane oxidation in the early, oxygen-less days of Earth’s atmosphere.

Nickel: The New Biomarker

Members of NAI’s team at Penn State and their colleagues have a new paper in PNAS exploring the viability of using isotopes of the element nickel as biomarkers. Nickel is an important trace nutrient for methanogens, which preferentially use one isotope of nickel over another in their metabolic processes. Nickel, unlike iron, doesn’t seem to go through significant redox changes without a biological tie, therefore considering it as a biomarker is less complicated and potentially more reliable. Testing ancient sediments and observing nickel isotopic fractionation could pinpoint where and when methanogens arose.

Increasing the Lifespan of Life on Earth

According to a new study from NAI’s Virtual Planetary Laboratory Team and colleagues at Cal Tech, the lifespan of Earth’s biosphere could be prolonged, even as the Sun’s luminosity increases and threatens to wipe out all life on Earth. Published in PNAS, the study points to the substantial reduction of the total pressure of Earth’s atmosphere, achieved by removing massive amounts of nitrogen from it. This would regulate the surface temperatures, allow carbon dioxide to remain in the atmosphere to support life, and could tack an additional 1.3 billion years onto Earth’s expected lifespan.

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻