| Summary: | Something strange and old lurks under the ice in Antarctica, at a place called Blood Falls. It is an echo of the early Earth. Blood Falls is hard to reach and easy to find. Look through the seas of blue ice, white snow, and gray rocks for the bright-red frozen waterfall, spilling out of the ice around it in a gory cascade five stories tall. This is a red flag made from chemistry, telling that even the coldest environment on Earth is not completely dead. Liquid water can be found there, and in the water is life eking out an existence from the water around it and the dirt under it, just like it did a few billion years ago. The “blood” at Blood Falls spills out of life, but it’s not blood. Like blood, this substance is a form of iron bound to oxygen. In your blood, the protein hemoglobin hosts the iron, but Blood Falls is straight-up iron oxide, similar to rust. I saw some of this chemical last August near Mount Rainier. As we hiked up to Goat Lake, the frozen water looked dirty. The pure white ice was dusted with bright-red powder blown around from the iron-rich rocks surrounding it. The land was red as blood. That was geological, but Blood Falls is biological. It shows that life in an extreme environment eats some pretty strange food—like John the Baptist eating locusts and honey in the wilderness—and outputs blood- red iron as waste. A pocket of liquid water hides behind Blood Falls, sealed under the ice so tightly that air cannot penetrate. Even in solitude, away from the sun and oxygen, liquid water supports life. The microbes under the glacier get energy from adding oxygen to carbon to make stable CO2, just like us. The subglacial lake is sealed off from the air, so the oxygen must come from a solid or liquid source. These bacteria eat sulfate, pulling one of the four oxygens off it and producing the three-oxygen chemical sulfite.
|
|---|