Angel Scum

You can fit four million of them on a period.

...Scientists found the microbes living in a remarkably inhospitable environment, drainage water as caustic as battery acid from a mine in Northern California. The microbes, members of an ancient family of organisms known as archaea, formed a pink scum on green pools of hot mine water laden with toxic metals, including arsenic.

“It was amazing,” said Jillian F. Banfield of the University of California, Berkeley, a member of the discovery team. “These were totally new.” In their paper, the scientists call the microbes “smaller than any other known cellular life form.”

Scientists say the discovery could bear on estimates of the pervasiveness of exotic microbial life, which some experts suspect forms a hidden biosphere extending down miles whose total mass may exceed that of all surface life.