Paulina Martinez-Koury collects samples at the Great Salt Lake in June of 2021. Credit: Bonnie Baxter | Westminster University
Scientist say it may hold clues for life on other planets, too, especially Mars, which was once replete with salty lakes. Specifically, researchers recently found protected crystalline micro-environments at the Great Salt Lake supporting an array of microscopic organisms. The mineral formations could potentially help living things thrive over millennia, even under intense solar radiation, extreme cold and low oxygen.
“If there ever was life on Mars,” said Paulina Martinez-Koury, a [graduate student at the University of Utah and] former biology student with Westminster University’s Great Salt Lake Institute, “it would have been in these bodies of water.”
In 2021, NASA’s Perseverance Mars rover landed in the Jezero Crater, the site of an ancient lakebed. The rover has collected soil and rock samples across the formation, with the long-term goal of rocketing them to our home planet so scientists can look for evidence of alien life.
The year after the rover began roaming the Martian surface, the Great Salt Lake reached a historic low elevation back on Earth. Scientists with Westminster University scoured the receding shoreline of the lake’s hypersaline north arm. They found dime to palm-sized gypsum crystals entombing microorganisms like bacteria, archaea and fungi.
“We weren’t really prepared for how much diversity there was within,” Martinez-Koury, [who is situated in the Caron Lab in the U's School of Biological Sciences] said.
Gypsum and clay may provide nutrients for the organisms to support themselves, while the outer shell shields them from outside extremes. Similar microbiomes may even exist in the samples collected by Perseverance, the researchers said, since the Red Planet’s drying salty lakes would have left behind the same materials.
“If we know that gypsum can entomb microbial ecosystems on Earth,” Baxter said, “Then it begs the question, could that have also happened on Mars?”
The scientists published their findings last week in the journal Astrobiology.
Around 4 billion years ago, Mars looked a lot like Earth with flowing surface water and conditions suitable for life. That changed when the planet lost its magnetic field and atmosphere. Some of its water froze into polar ice caps. Large lakes on the surface became exposed to increased solar radiation and began to shrink, getting saltier and saltier as they evaporated away.
“So at one time, there would have been a lot of salt lakes on Mars,” Baxter said. “And now what we have instead are salt flats.”
That makes the Great Salt Lake, and its super-salty northern half in particular, a useful analog for studying Martian life.
“Anything that can live in the north arm of the Great Salt Lake has to have some pretty special adaptations,” said Martinez-Koury, who is currently working on a Ph.D. at the University of Utah.
The north arm is mostly sealed off from any rivers flowing to the Great Salt Lake by a rock-filled railroad causeway. Its salt content ranges between 25% to 30%. No plant life, brine shrimp or bugs survive under those conditions. Solar radiation is high. But its soupy water has turned a lavender hue due to abundant halophilic microorganisms, proof life can thrive in inhospitable places.
NASA's Mars Perseverance rover captured this image using its onboard Right Navigation Camera (Navcam) on Aug. 12, 2025. Credit: NASA/JPL-Caltech
As the lake’s water receded in its northern stretches, Baxter and Martinez-Koury collected gypsum crystals that emerged on the shoreline, then took them back to the lab.
They found the minerals encased microbes, pollens, more than 200 bacteria species and other organic material.
They crystals also included clays, which may hold water to support life over time. And Baxter said they found evidence some of the organisms can photosynthesize and generate energy.
“So they can actually make oxygen inside the crystal,” Baxter said. “It’s like this little self-sustaining microcosm.”
The crystal samples from the Great Salt Lake are only a few hundred years old or less, Baxter said. But past research shows minerals can encase and preserve biological material over geologic time, and microbes from saline environments can survive millions of years.
“To be flowing at those cold temperatures,” Baxter said, “it would have to be salty water, which makes me kind of excited.”
Astronomers have detected gypsum crystals in Mars’s Jezero Crater, Baxter added. She said she’s eagerly awaiting Perseverance’s samples to get launched back to Earth.
“Many times when I take people up to that north arm of the lake,” Baxter said, “they say ‘This looks like a Martian landscape.’ ... To have science to back up that feeling is kind of cool.”
But the “Mars Sample Return” portion of the interplanetary mission, a cooperative effort between NASA and the European Space Agency, recently hit a snag. This spring, the Trump Administration called for NASA to cut its budget by almost 50% and eliminate the Mars Sample Return project.
Congress stepped in and continued funding for NASA projects through the One Big Beautiful Bill Act in July, including $700 million that will support the Mars Sample Return. But the bill does not block other budgetary cuts the White House proposed for the agency.
Baxter said she hopes to see the samples in Earth-based labs sometime in the next decade.
New York’s Colgate University, the Utah Geological Survey and Brigham Young University also contributed to the Great Salt Lake gypsum crystal research.
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