Lava Cave Minerals Actually Microbe Poop Richard A. Lovett National Geographic News November 20, 2009
Colorful cave deposits long thought to be ordinary minerals are actually mats of waste excreted by previously unknown types of microbes, scientists say.
Bright orange blotches coat the lava-rock walls of Gruta do Carvão in São Miguel, one of the Portuguese Azores islands, in an undated picture.
The discovery could offer clues in the search for life on Mars and beyond, researchers said in October at a meeting of the Geological Society of America.
"We're finding that you need to look at things you might write off as not being biological—they might be biological," said Penelope Boston, a cave scientist at the New Mexico Institute of Mining and Technology in Socorro.