It was a laborious process spanning three months of round-the-clock drilling, Gohn said.
But the hard work paid off. Brine found in the impact structure contained roughly twice as much salt as regular seawater, the researchers say.
Communities around the bay largely rely on freshwater aquifers and could potentially draw brine into the wells if they're overpumped.
Water managers have now started to take the crater into account, Gohn added.
Death and Life
The research also represents the first microbial sampling within a crater structure, scientists say.
The results show that the crater had both destructive and beneficial effects on local marine life.
The heat of the impact probably exceeded 250 degrees Fahrenheit (120 degrees Celsius)—the temperature traditionally used to sterilize bacteria—explained team member Mary Voytek, a USGS microbiologist.
"Any organisms living there would not be able to survive," she said.
Some areas of the crater remain too salty be habitable, she added, but life likely returned in other crater locations about 10,000 years after the impact when temperatures started to cool.
Now in some portions of the impact structure, such as the upper edges and deep in the belly, ten to a hundred times as many organisms are present as there are at similar depths outside of the pit, she said.
The release of broken and porous rock material appeared to act much like churning a compost pile or tilling a field, freeing fresh organic nutrients from plants killed during the impact, she explained.
As the material filled in the crater, a habitable space was created for organisms in what had been nutrient-poor solid rock, she said.
"If you get habitable temperatures, space, and nutrients, you can get things to grow back and grow back well," Voytek said.
Mars Connection
The findings, which were released this week in the journal Science, could hold clues about the role craters played in the evolution of life on early Mars, Voytek said.
The red planet's surface is currently inhospitable to life because of high levels of ultraviolet radiation and frigid temperatures, but material and a suitable environment could have been introduced into the subsurface during impacts.
The new data suggest that "there's a higher probability we'll find life in the subsurface" on Mars, she said.
David Kring of NASA's Lunar and Planetary Institute was not involved in the research.
"The recent drilling project is an excellent probe of the crater's geology, and this study reveals important details of the crater's formation," he said. "The crater is possibly an analog for impacts that may have occurred long ago on Mars, when the planet may have had intermittent seas."
Elisabetta Pierazzo, a planetary physicist at the Planetary Science Institute in Tucson, Arizona, was also not part of the new study.
She said that the findings help unravel how underwater life reacts to external bombardments.
"This is very important for studying Mars, where a subsurface biosphere may have existed in the past."
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