Earth microbe made methane in simulated Enceladus ocean
Wednesday 30th September 2026 on 10:15 in
Estonia
An ancient microorganism from Earth produced methane in a laboratory simulation of the ocean beneath Saturn’s moon Enceladus, even under extremely alkaline conditions, ERR reported. The findings by German and US researchers could broaden understanding of where life might exist on distant planets and moons.
Enceladus has a vast ocean beneath its icy surface. Geysers at the moon’s south pole send water vapour, hydrogen and methane into space, prompting questions about whether the methane could have a biological origin.
The ocean’s chemistry is a challenge for potential life: its water is highly alkaline, with a pH of 8 to 12. In those conditions, free carbon dioxide, which organisms need, is largely converted into carbonates and bicarbonates.
To mimic the ocean and Enceladus’s rocky core, researchers prepared a mineral mixture containing silica, magnesium, iron and calcium. They heated it in water for two days at 65 degrees Celsius in an oxygen-free environment. The reaction produced a greenish-blue mineral deposit and a substantial amount of hydrogen without biological activity. The researchers said the formation and dissolution of iron-rich brucite resembled processes that may occur in Enceladus’s hydrothermal fractures.
They then introduced Methanothermococcus okinawensis, a heat-loving archaeon from Earth that naturally lives in deep-sea hot springs and uses hydrogen and carbon. The species had previously been thought unable to tolerate a pH above 8.5, but it survived and reproduced in the simulation at pH 11.
The microbes used hydrogen released from the rocks and produced methane as a byproduct of their metabolism, even though the water contained very little free carbon dioxide. Researchers said genes that are usually inactive helped the organisms adapt to the scarcity of carbon, allowing them to use the reductive acetyl-CoA pathway to capture the remaining carbon dioxide.
The microbes’ activity shifted the system’s chemical balance. As they consumed carbon, reactions between the ocean water and minerals released new carbon dioxide from bicarbonates, restoring the balance.