The chemistry of ancient Martian lakes was similar to that of a group of salty, acidic lakes in Australia (Image: Kathy Benison)

Life not only survives but thrives in Australian lakes where conditions may be as harsh as those on ancient Mars, a new DNA analysis suggests.

Minerals on Mars studied by the NASA rovers suggest water once flowed on the planet’s surface, but was very salty and acidic, raising doubts about whether it could have supported life.

But in 2007, Melanie Mormile of Missouri University of Science and Technology in Rolla and colleagues cultured a bacterium from water sampled from one of several salty, acidic lakes in Western Australia.


The lakes are very shallow and periodically fill with rainwater before partially evaporating, which concentrates the salts within them. They may be the closest equivalents on Earth of the shallow pools thought to have once dotted Mars.

Minerals in the lakes also contain strange, microscopic structures dubbed “hairy blobs” that researchers have suggested are fossilised microbes.

A team led by Mormile has now turned up dozens more species by analysing DNA extracted from water and sediment in 11 of the lakes.

Vinegar pool

The most acidic lake has a pH like that of vinegar, yet it contains DNA evidence for 23 microbial species, most of which appear to be new to science. “There’s actually quite a diversity of life in these lakes,” Mormile told New Scientist.

The microbes probably did not simply fall into the lakes but lived and thrived there – some appear to be relatives of Salinibacter ruber, which is known to grow in other extremely salty environments (see The most extreme life-forms in the universe).

The results bolster the possibility that life could have lived in the salty, acidic lakes present on Mars in the ancient past, the researchers say.

But the researchers do not yet know what gives the Australian lake microbes their ability to survive the tough conditions. “It would be really interesting to look at the mechanisms that enable them to do that,” Mormile says.

Journal reference: Astrobiology (DOI: 10.1089/ast.2008.0293)