Plate tectonics, which is vital for life on Earth, may have been initiated by simple microorganisms, according to a research team led by Shengxing Zhang from the Chinese University of Science and Technology. Their hypothesis suggests that iron-oxidizing microorganisms left thick deposits on the seafloor that pushed down the lithosphere. When the lithosphere gave way under the weight, it led to the formation of continental plates. These plates are essential for the habitability of Earth and potentially habitable exoplanets.
Iron-oxidizing bacteria and archaebacteria obtain energy by oxidizing ferrous iron to ferric iron. The team’s calculations, published in Geophysical Research Letters, indicate that these deposits reached their peak during the Neoarchean period, between 2.4 billion and 2.75 billion years ago. The weight of these deposits may have been enough to push the lithosphere down, causing the crust to tear open. This biogeochemical process was unique to Earth during this specific period, highlighting the role of life in shaping the conditions for subsequent life to develop.
Plate tectonics, described around a century ago, is now recognized as a fundamental requirement for life. It releases heat from the Earth’s interior and enables the development of continents and other geological conditions necessary for familiar fauna and flora. However, there have been doubts about whether plate tectonics existed before the emergence of life, as previously assumed. A recent study published in Nature supports this notion, and the new research from China further affirms it.
The connection between the origin of life and plate tectonics has implications not only in understanding Earth’s history but also in the search for extraterrestrial life. John Tarduno from the University of Rochester, who led the research suggesting that plate tectonics may not have existed during the time of the first life, highlights that the findings imply we should not exclusively seek exoplanets with plate tectonics when looking for potential life. Instead, the study suggests that it could have been the other way around, with life influencing the development of plate tectonics.
