Scientists have demonstrated the importance of hot temperatures in maximizing hydrogen peroxide generation from rocks during geological fault movement, and they believe it may have influenced the early evolution, and possibly even the origin, of life in hot environments on the early Earth prior to the evolution of photosynthesis.
Newcastle University scientists have discovered an oxygen source that may have influenced the evolution of life before photosynthesis. The groundbreaking study, led by Newcastle University’s School of Natural and Environmental Sciences and published today in Nature Communications, discovered a mechanism that can generate hydrogen peroxidefrom rocks during geological fault movement.
While hydrogen peroxide can be harmful to life at high concentrations, it can also be a useful source of oxygen for microbes. Prior to the evolution of photosynthesis, this additional source of oxygen may have influenced the early evolution, and possibly even the origin, of life in hot environments on the early Earth.
While previous research has suggested that small amounts of hydrogen peroxide and other oxidants can be formed by stressing or crushing of rocks in the absence of oxygen, this is the first study to show the vital importance of hot temperatures in maximizing hydrogen peroxide generation.
Jordan Stone
The movement of the Earth’s crust in tectonically active regions not only causes earthquakes, but also riddles the subsurface with cracks and fractures lined with highly reactive rock surfaces containing many imperfections, or defects. Water can then filter down and react with the newly fractured rock’s defects.
Jordan Stone, a Masters student, simulated these conditions in the laboratory by crushing granite, basalt, and peridotite – rock types that would have been present in the early Earth’s crust. These were then added to water at varying temperatures under tightly controlled oxygen-free conditions.
While hydrogen peroxide is toxic to living things at high concentrations, it may also provide a beneficial supply of oxygen to microbes. This additional oxygen supply may have influenced the early evolution, and possibly even the origin, of life in hot environments on the early Earth prior to the evolution of photosynthesis.
In tectonically energetic areas, the motion of the Earth’s crust not solely generates earthquakes however riddles the subsurface with cracks and fractures lined with extremely reactive rock surfaces containing many imperfections, or defects. Water can then filter down and react with these defects on the newly fractured rock.
The experiments demonstrated that substantial amounts of hydrogen peroxide — and as a result, potentially oxygen — was only generated at temperatures close to the boiling point of water. Importantly, the temperature of hydrogen peroxide formation overlaps the growth ranges of some of the most heat-loving microbes on Earth called hyperthermophiles, including evolutionary ancient oxygen-using microbes near the root of the Universal Tree of Life.
“While previous research has suggested that small amounts of hydrogen peroxide and other oxidants can be formed by stressing or crushing of rocks in the absence of oxygen, this is the first study to show the vital importance of hot temperatures in maximizing hydrogen peroxide generation,” said lead author Jordan Stone, who conducted this research as part of his MRes in Environmental Geoscience.
Dr Jon Telling, Senior Lecturer and Principal Investigator added: “This study shows that defects on crushed rock and minerals can behave very differently than more ‘perfect’ mineral surfaces. All of these mechanochemical reactions require water, crushed rocks, and high temperatures, which were all present on the early Earth before the evolution of photosynthesis and could have influenced the chemistry and microbiology in hot, seismically active regions where life may have first evolved.”
