According to a study published in Nature Communications, the impact site nurtured a biologically rich environment for at least 700,000 years, fueled by an enduring hydrothermal system that circulated nutrients into the overlying ocean. Scientists believe this post-impact activity played a critical role in supporting marine ecosystems.

"After the asteroid impact, the Gulf of Mexico records an ecological recovery process that is quite different from that of the global ocean, as continuous hydrothermal activity has created a unique marine environment," said Honami Sato, lead author and assistant professor at Kyushu University in Japan.

Co-author Sean Gulick, a research professor at The University of Texas at Austin's Jackson School of Geosciences, helped lead the 2016 expedition that retrieved 829 meters of rock core from the Chicxulub site. That core has been central to a wave of discoveries about how life returned so swiftly to the devastated region.

While previous findings confirmed that life reappeared at the impact site within years, the new study uncovers evidence that the crater's hydrothermal system and its buried melt sheet may have continuously enriched the ocean above for hundreds of thousands of years.

"We are increasingly learning about the importance of impact-generated hydrothermal systems for life," Gulick noted. "This paper is a step forward in showing the potential of an impact event to affect the overlying ocean for hundreds of thousands of years."

The team tracked osmium, a chemical element tied to asteroid material, to trace this prolonged underwater activity. Isotopic analysis revealed that osmium from the buried impactor had been mobilized by hydrothermal fluids circulating beneath the seafloor and then deposited into ocean sediments.

As those hot waters cooled and released their load, researchers identified the osmium-rich layers in the core samples, allowing them to map the duration and reach of the hydrothermal system. They found that the timing of osmium release correlated with shifts in marine plankton types: nutrient-rich plankton thrived during active hydrothermal phases, while low-nutrient species dominated once osmium levels returned to pre-impact norms.

This ecological shift marks the end of the hydrothermal system's influence on ocean life, though researchers believe it continued operating beneath the seafloor for millions of years, gradually buried under sediment.

"This study reveals that impact cratering events, while primarily destructive, can in some cases also lead to significant hydrothermal activity," said co-author Steven Goderis of Vrije Universiteit Brussel. "In the case of Chicxulub, this process played a vital role in the rapid recovery of marine ecosystems."

Though the Chicxulub event is widely recognized for causing mass extinction, Gulick emphasized that it may also demonstrate how impacts could help foster life. At UT's Center for Planetary Systems Habitability, Gulick and colleagues are exploring whether similar hydrothermal systems might exist on other worlds, potentially supporting extraterrestrial ecosystems.

The study brought together experts from Kyushu University; UT Austin's Jackson School of Geosciences; the Japan Agency for Marine-Earth Science and Technology; Vrije Universiteit Brussel; the Institute of Science Tokyo; Universidad de Zaragoza and Universitat de Barcelona in Spain; and Imperial College London.

Research Report:Prolonged 187Os/188Os excursion implies hydrothermal influence after the Chicxulub impact in the Gulf of Mexico

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