Why is NASA exploring Hawaiian Caves to search for life on Mars?

In 2019, scientists from NASA and other institutions descended into a lava tube - the dark and isolated subterranean environment - on Hawaii's Mauna Loa to study the microbes and minerals that could survive underneath and could reveal insights about similar environments on Mars.

For the unversed, Mauna Loa is the largest active volcano on Earth. Chloe Fishman, a researcher at the Gladstone Institutes at the University of California, San Francisco, and her colleagues found that microbes were thriving in the lava tube of Mauna Loa, even in areas without sunlight and were likely using chemicals in the rocks for nourishment.

During the time when this study was conducted, Fishman was an undergraduate researcher in the lab of Sarah Stewart Johnson, an associate professor at Georgetown University in Washington, D.C.

The researchers reported their findings in the Journal of Geophysical Research: Planets last month.

Wondering how exploring Hawaiian caves will help NASA search for life on Mars?

Mars in its early years is believed to have been similar to Earth in many ways, with active volcanoes, a warmer climate, a thicker atmosphere, and flowing water on its surface. Lava tubes are also believed to have formed on the Martian surface during this time, suggesting that the Red Planet may have been capable of supporting life in its early history.

Fishman and her colleagues studied a lava tube located on the northern flank of Mauna Loa volcano, which formed approximately 200 years ago. This makes it a relatively "young" tube in comparison to others that have formed over billions of years. Because it has been less affected by weathering conditions such as water, this young Hawaiian tube is thought to closely resemble the lava tubes that existed on Mars billions of years ago.

Fishman had come to the Hawaiian cave to scrape flakes to bring back to the lab to look for microbial life while most of her colleagues focused on mineral analysis. Insight from this research could help Martian rovers pinpoint promising sites to sample for signs of past or present life on the Red Planet.

"We have identified minerals similar to those found at Mauna Loa on the Martian surface and right below it," said Amy McAdam, a geochemist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. 

Fishman collected approximately 20 half-teaspoon-size samples from the lava tube and brought them back to Johnson's lab. She then extracted DNA from the cells and its sequencing revealed the genetic codes for the organisms. She has sequenced the genomes of 72 new organisms and has analysed the genomes of two microbes so far. This allowed her to classify them based on their characteristics and add them to global databases.

Is this Earth or mars? 🤔@nasa scientists discovered dozens of new microbe species while studying lava caves in Hawaii to better understand how to search for past or present life on Mars. https://t.co/TRikIkTjX2 pic.twitter.com/G7WaLjqgsr

— NASA Earth (@NASAEarth) April 10, 2023