(CN) — Volcanoes aren’t just awe-inspiring emblems of the power and fury of nature: They may also have played a key role in fostering life on Earth, according to a new study published in the Proceedings of the National Academy of Sciences on Monday,
How exactly? The importance of volcanoes lies with their ability to unlock nitrogen, an essential component for sustaining life. While earlier research has suggested volcanoes' possible role, the study's authors say their research marks the first field evidence of large-scale nitrogen fixing by volcanoes.
Nitrogen is Earth's most common element, and one of the most abundant in the universe. It is the core component of the building blocks of our RNA and DNA, and a vital part of modern fertilizers that have allowed farmers around the world to enhance their soils and provide an abundance of food and crops.
But most nitrogen is in our atmosphere as a gas. For it to be useful for plants and animals, it has to go through a process called nitrogen fixation, where gas from the air is turned into ammonia that plants then absorb.
Since the last century, industrial processes have been used for making nitrogen-enriched fertilizers, but most nitrogen is fixed naturally by bacteria in the soil and on plant roots converting atmospheric gas into ammonia. The element can also be fixed by lightning strikes, causing it to react with oxygen, which produces nitrogen oxide, which then seeps into the soil.
Because nitrogen is so important to life, and lightning can cause it to react, scientists have long thought that barrages of lightning storms billions of years ago when Earth was young and barren released nitrogen into the soil and sparked the evolution of life on Earth. But according to the study's authors, it wasn’t only lightning from thunderstorms that helped stimulate life on Earth, but lightning caused by erupting volcanoes.
Examining samples of rocks and other material spewed out by volcanoes that erupted tens of thousands to millions of years ago in central Turkey, southern Peru and a volcanic island off the coast of Naples, Italy, scientists found significant amounts of nitrate formed by the oxidation of nitrogen with sulfur and chlorine, which point toward a volcano as their source.
“Indeed, nitrate produced by storm lightning all around the world are spread out on the Earth's surface, while volcanic deposits are formed locally in a very short period of time and, according to our results, can contain large amounts of fixed N, a prerequisite for the development of life,” the scientists write in the study.
Unlike lightning caused by thunderstorms, volcanic lighting is caused by the electrification of particles of ash- and water-rich plumes from a volcano’s eruption.
In 2022, an underwater volcano called Hunga Tonga-Hunga Ha'apaii in the South Pacific country of Tonga caused the largest atmospheric explosion ever recorded. With that, scientists also recorded the most intense rates of lightning ever, with bolts rising as high as 19 miles above sea level.
The eruption also caused a 65-foot-high tsunami that killed four people and displaced 1,500 in Tonga. The waves reached all the way across the Pacific Ocean and damaged structures in Fiji, Hawaii, Chile, California, Japan, Russia and New Zealand and killed two people in Peru.
“Our findings hint at a unique role potentially played by subaerial explosive eruptions in supplying essential ingredients for the emergence of life on Earth,” the scientists write.
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