Tiny Salt Crevices Could Act As Miniature "Greenhouses" For Martian Microbes

A new study suggests that on Mars, salt crystals may act as mini-greenhouses for microbial life. The research, led by Anna Bognar, indicates that during the Martian day, when temperatures rise to 0℃, salt crystals absorb moisture and expand, while during the night, when temperatures drop to -80℃, they absorb water and contract, creating microscopic crevices filled with brine. This process allows for temporary liquid water to exist in these crevices, which could support microbial life. The study highlights that the salt crystals can trap water for up to a few hours each day during the summer, providing a temporary environment where life could potentially survive.

The research notes that the salt crystals, specifically halite, can contract by up to 1.6% between 150 K and 300 K, creating microfractures that trap water. The brine inside these crevices remains liquid during the day, but the cracks seal when the sun heats the salt, preventing water from escaping. The study also mentions that the salt can be sealed by a few millimeters of material, offering protection from UV radiation, but leaving the microbes exposed to higher energy cosmic rays. The findings suggest that while the environment may be inhospitable for most Earth-based life, it could still provide a temporary habitat for microbial life.

The study notes that while the conditions are not ideal, the salt crevices could be a promising place to search for life. The research highlights that similar processes occur on Earth, with cyanobacteria living in halite rocks in the Atacama desert. However, there are still challenges, including the possibility of water leakage, perchlorate contamination, and exposure to cosmic rays. The study concludes that while it is theoretically possible for life to survive in such an environment, it is unlikely. Nevertheless, the findings support the idea that Mars might still harbor life, and the search continues.

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