Hydrothermal vents are among the strangest ecosystems on Earth: eerie places where the planet’s deep heat and chemicals mingle with ocean water to support thriving networks of bizarre life-forms that don’t need sunlight to survive.
Stranger still, sometimes short-lived versions of these ecosystems form when Earth is struck by asteroids—including the space rock that killed off nonavian dinosaurs 66 million years ago. New evidence published in Communications Earth & Environment suggests that this impact created a hydrothermal vent system that lasted far longer than scientists thought was possible—perhaps as long as eight million years.
Previous research based on modeling had indicated that the impact site, called Chicxulub Crater, likely did host hydrothermal vents after the asteroid hit but for just two million years. Now researchers have analyzed samples taken from within the structure itself—specifically, the crater’s peak ring, an inner ring that formed when the Chicxulub impact produced enough debris to form a mound in the center of its crater that later collapses.
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In 2016 a team of scientists drilled into the crater left behind by the Chicxulub impact, along the coast of Mexico’s Yucatan Peninsula, according to a statement. The researchers snagged four samples from within the crater’s peak ring from depths ranging from 2,316 to 2,480 feet (706 to 756 meters) below the seafloor. Then the researchers compared the ratios of two different isotopes of argon—which provides a chemical fingerprint that scientists can use to estimate the age of minerals in the rocks and thus of the hydrothermal system.
The analyses revealed a long span of hydrothermal activity at the site—with the oldest samples dating to around 66 million years ago and the freshest to about 58 million years ago. It’s not clear whether that long-lived activity was localized to where the researchers got their samples or if it was true across the structure more generally. Still, they posit the peak ring may have been particularly suited to supporting hydrothermal vents.
That’s intriguing for scientists, given how vibrant hydrothermal vent ecosystems can be. “The porous, fractured rocks created by impacts create microenvironments where micro-organisms can be protected from radiation and extreme temperatures,” said Annemarie Pickersgill, a member of the team and a scientist at SUERC: Center for the Isotope Sciences, a collaboration of the University of Glasgow and the University of Edinburgh, in the statement. “Those conditions give life the chance to take hold and flourish.”
As intriguing as the results are for understanding the surprising potential for life in the aftermath of Earth’s most infamous cataclysm, Pickersgill and her team are considering whether the findings have extraterrestrial applications, too. It’s possible that similar phenomena may have unfolded on Mars, which could have offered an opportunity for any life on that planet to blossom at exotic hydrothermal vents.
“As we look to the future of space exploration, these findings could help future missions to other planets determine which impact craters might have been most likely to sustain life,” Pickersgill said.
