Biologists aren't in full agreement about exactly where the first life on Earth appeared. It might have evolved at the bottom of the ocean, in shallow rock pools or from building blocks delivered by asteroid impacts — or maybe all of the above. We do know that all life on Earth needs water to survive, so life likely first evolved there. But water alone isn't enough to spark life; it also needs energy.
"UV [radiation] is great because it's so energetic that it will generate ionized molecules, making them more reactive" and more likely to combine into the larger, more complex molecules needed to generate the building blocks for life, Camprubi-Casas told Live Science. However,"UV radiation generates a problem of basically breaking down anything you have," as well, Camprubi-Casas said.
When water from the hydrothermal vents combined with carbon dioxide dissolved in water, the resulting molecules became"much more chemically active, and you can start adding nitrogen to make amino acids or adding nitrogen and oxygen to form the building blocks of DNA," Camprubi-Casas said.