When Earth was young and wild, processes on our planet transformed a mix of ingredients into what was needed to power life. For this, nitrogen is crucial, an essential nutrient for forming proteins, amino acids and nucleic acids. Scientists have discovered geological evidence indicating that lightning discharges associated with volcanic events may have played a key role in fixing nitrogen in the early Earth, making it available for biological processes as well.
An international team of scientists suggests in a new study, recently published in the journal Proceedings of the National Academy of Sciences, that volcanic rays They may have fixed enormous amounts of atmospheric nitrogen early on in our planet, allowing life to begin on Earth.
ancient eruptions
According to a article Published in Phys.org, the analysis of volcanic deposits gave researchers clues about how the ancient eruptions they may have produced nitrates, potentially used to create amino acids. Different theories postulate that the development of life required the fixation of nitrogen, a primary component of amino acids, during the early years of Earth.
Today, about 78 percent of the atmosphere is made up of nitrogen. But living organisms cannot use it in its atmospheric form: they need to fix it and create compounds such as nitrates or ammonia. Biological processes developed by microbes living in plant roots can accelerate this process.
However, before life emerged, a non-biological process was required to initiate nitrogen fixation. Considering that electrical discharges can fix nitrogen and that lightning is so ubiquitous during volcanic eruptions, scientists thought that these phenomena could have played an important role in triggering the nitrogen cycle, even more so considering the intense volcanism that characterized the early Earth.
A large explosion occurred in 2016 at the Sakurajima volcano in southern Japan: the volcanic eruption produced columns of ash that rose several kilometers high. The rising ash produced impressive static discharge lightning bolts. Credits: JMA/dutchsinse/YouTube.
Electricity and life
How are volcanic lightning produced? According to a article Published in 2021 in The Conversation by scientist Alfonso Blázquez Castro, from the Autonomous University of Madrid, during the expulsion of gases and ash through the volcanic cone, strong currents are produced, which cause turbulence and very intense friction of the grains of ash and lava expelled. This friction gives rise to the electric charge which, upon reaching a certain value, causes the discharges that we observe as lightning.
Now, specialists have found evidence that nitrogen in the atmosphere could have been set by good heavens volcanic, which interact with the ashes. The team led by geoscientist Adeline Aroskay of Sorbonne University in Paris, France, found nitrates embedded in ancient volcanic deposits.
According to a article published in Science Alert, they collected samples from several volcanic deposits from explosive eruptions in Turkey and Peru, which took place between 1.6 and 20 million years ago: they specifically looked for nitrates, which are the end product of the nitrogen oxidation. They discovered significant concentrations of nitrates in all the deposits, with characteristics indicating that most of it was formed during volcanic eruptions.
These conclusions are in line with different previous research, which marked the importance of volcanic lightning in the beginnings of life on Earth. It is also known that rays that interact with volcanic gases could produce molecules used by living beings, such as amino acids. All of these findings suggest that life on our planet could have emerged near volcanoes, later evolving in hydrothermal vents.
Reference
Geological evidence of extensive N-fixation by volcanic lightning during very large explosive eruptions. Adeline Aroskay et al. PNAS (2024). DOI:https://doi.org/10.1073/pnas.2309131121