Ancient source of oxygen for life hidden in the Earth’s crust

Aug. 8 () –

Scientists at Newcastle University have discovered a source of oxygen that may have influenced the evolution of life. before the advent of photosynthesis.

The pioneering research project, directed by the Faculty of Natural and Environmental Sciences and published in Nature Communicationsdiscovered a mechanism that can generate hydrogen peroxide from rocks during the movement of geological faults.

While hydrogen peroxide in high concentrations can be harmful to life, it can also provide a useful source of oxygen for microbes. This additional source of oxygen may have influenced early evolution, and possibly even in the origin of life in warm environments on the early Earth before the evolution of photosynthesis.

In tectonically active regions, the movement of the Earth’s crust not only generates earthquakes, but riddles the subsurface with cracks and fractures lined with highly reactive rock surfaces that contain many imperfections or defects. Water can then seep in and react with these defects in the newly fractured rock.

In the lab, graduate student Jordan Stone simulated these conditions by crushing granite, basalt, and peridotite, rock types that would have been present in the early Earth’s crust. They were then added to water under well-controlled oxygen-free conditions at varying temperatures.

Experiments showed that substantial amounts of hydrogen peroxide, and as a result, potentially oxygen, were only generated at temperatures close to the boiling point of water. Importantly, the formation temperature of hydrogen peroxide overlaps the growth ranges of some of the most heat-loving microbes on Earth called hyperthermophiles, including ancient evolutionary oxygen-using microbes near the root of the Universal Tree of Life.

Lead author Jordan Stone, who conducted the research as part of his Master’s in Environmental Geoscience, said it’s a statement: “While previous research has suggested that small amounts of hydrogen peroxide and other oxidants can be formed by stressing or crushing rocks in the absence of oxygen, This is the first study to show the vital importance of high temperatures in maximizing hydrogen peroxide generation.”

Lead researcher Dr Jon Telling, Senior Lecturer, added: “This research shows that defects in crushed rock and minerals can behave very differently from how more ‘perfect’ mineral surfaces would be expected to react. All of these reactions mechanochemical processes need to generate hydrogen peroxide, and therefore oxygen, is water, crushed rocks, and high temperatures, which were present on the early Earth before the evolution of photosynthesis and which could have influenced the chemistry and microbiology in regions warm and seismically active where life may have first evolved“.