It's not blood. It's run-off from a hidden lake of microbes.
United States Antarctic Program Photo Library
It’s not blood. It’s just ketchup. No, it’s run-off from a hidden lake of microbes.

We knew we’d been doing some damage to the planet, but we didn’t realize we’d been making it bleed.

OK, fine, blood isn’t really seeping out of that glacier in the photo above. What is seeping out from this red waterfall, discovered in the Taylor Glacier in Antarctica’s McMurdo Dry Valley, in 1911, is in fact the run-off from a microbe-filled lake deep beneath the surface of the glacier. The run-off seeps out through a fissure in the glacier, and it is red not because the poor microbes are bleeding, but because it comes from a very iron-rich environment.

The very existence of the lake is proof that life can exist in very crazy conditions (inside a glacier, with no access to oxygen, light, or warmth) and also provides an interesting look at life that’s more than 2 million years old, as that is when this ecosystem was sealed away. It is also proof that this planet is host to some crazy looking stuff. More photos here.