Red Eyes is a blemish on the Pennsylvania landscape. In summer, a bird's eye view shows two red-orange scars glaring up out of the lush green Gallitzin State Forest. But we approached the higher of the two streams, aptly named Upper Red Eyes, in the dead of winter, after ice skating in thick rubber boots down the frozen footpath.
The entire forest was dead, bare brown trees sticking up out of the hard ground like toothpicks. But there was something different about the trees looming out of the iced-over water flow before me. They were more brittle, like they hadn't felt green in a long time. Logs that used to be attached to trunks were strewn around, white like stone, and splintered. Try to grow a tree in acid and this is what happens.
Red Eyes, upper and lower, are streams of acid water flowing up from underground and over this formerly verdant landscape. The ground is rusty orange with iron, and the only sign of life is a bear print at the edge of the pool. All signs point to "barren wasteland."
But Dan Jones, a short, stocky Penn State graduate student, hunched down over a crack in the ice. With his bare, soon-to-be chapped hand, he scraped a pipette along the iron-coated bottom of the stream bed, sucking up some liquid and sediment as he went. The water here has about the same acidity as orange juice ― not high enough to instantly melt skin off your bones, but pretty uncomfortable to take a long swim in. Definitely strong enough to destroy a few trees.
Jones squatted on the frozen flow, balancing on the balls of his feet, while he emptied the pipette into little sealed vials. These samples were going back to the Penn State lab. Jones was going to analyze and categorize their contents for inclusion in his thesis about communities of tiny organisms. Because thriving in just those few grams of soil and acid water are billions of microscopic life forms.
..."The day after our Red Eyes outing, Dan Jones stood behind a push cart surrounded by Dixie cups of lemon juice, crushed up bits of chalk, and five kids from a local fifth grade class. It was "Shake, Rattle and Rocks" day, an outreach program put on by the Penn State geology department and the kids were there to learn about microbes. "So what do you guys like to eat?" he asked.
A few of them shouted out their favorite eats: "Macaroni and cheese!"
"Right on. So, when you guys eat macaroni and cheese and sugar and things like that, when you breathe in…" He paused.
"Oxygen!" They yelled.
"Right! So your body is taking that oxygen and reacting it with the food that you eat and then you're producing carbon dioxide that you breathe out as a waste product." The kids fingered the lemon juice cups, studying Jones's faded black T-shirt advertising 2009's 15th International Congress of Speleology.
"So how many of you guys would like to eat…this rock?" He presented the kids with two chunks of butter yellow stone.
"Me!" One youngster raised his hand.
"Yeah. Well certain types of bacteria would like nothing more than to eat various types of rocks. Do you guys know what this kind of yellow-y rock is called?"
"Sulfur!"
"Exactly! Good job. How about this shiny golden one?"
"Fool's gold."
"Yeah, pyrite." He spun it in his hand so the shiny flecks twinkled in the light. "So these rocks, they have a lot of chemical energy in them. It's just that we can't use that energy, but different types of bacteria can."
He held up a beaker with a coating of crushed up sulfur rock and wiggled it, letting the pieces roll around the bottom. "So, you guys see this sort of yellow powder here? These guys can take this sulfur, react it with oxygen, and live off that, and then produce sulfuric acid as a byproduct instead of carbon dioxide. So what do you think about that? Does that sound like an environment you'd want to live in? A bunch of sulfuric acid?"
"Noooooo," they chorused.
A steaming hot plate of freshly exposed brimstone or fool's gold is not appetizing to us, but as Jones explained to the kids, for some acidophiles it's a gourmet meal.
Rocks, like all matter, are made up of molecules bound tightly together. Molecules are made of atoms, and atoms consist of three smaller bits - protons, neutrons and electrons. And the electrons are what cells care about. Human cells break down the food we consume and use electrons to produce the energy that keep us going. Some acidophiles also enjoy organics, like sugars or proteins found right in nature, to energize just like a human cell. Most acidophiles, though, would prefer to extract their electrons from the sulfur sprinkling offered up by Jones.
Cells put these electrons to good use through an elaborate game of Hot Potato. Crammed inside a cell resides an army of molecules ready and waiting to grab electrons and pass them down the line, one after another. The last molecule-at-arms in line hoists the electron out to something known as a receptor. For humans and many acidophiles, the receptor is oxygen. Some acidophiles, however, toss the last electron out to be received by iron or sulfur. We breathe oxygen; some acidophiles, in a sense, breathe rocks.
