Flowing water when the air is below freezing is a rare sight, but at Blood Falls, it's something else entirely: liquid water the color of fresh blood pours out of a crack in an Antarctic glacier. It's taken scientists years to understand why it happens, but what they've discovered could mean good things for finding life on other planets.
Put Some Ice On That Wound
Why is Blood Falls blood red? For years, scientists believed it was due to red algae, the same thing that causes bizarre "watermelon snow." But in 2015, an international team of researchers discovered what it really is: saltwater chock-full of iron. When it comes in contact with oxygen, that iron turns a deep red color, the same way your bike chain accumulates reddish rust in the rain.
In 2017, some of those same researchers confirmed their findings and pinpointed the exact source of the Dracula-inspired waterfall. Even though Taylor Glacier, where Blood Falls calls home, is located within the McMurdo Dry Valleys — an area named for its extreme desert conditions — the team discovered that the blood-red water comes from a liquid reservoir of brine below the glacier. But what's really exciting is that it's not the only one: there's an entire waterway flowing beneath the ice.
"We found that these brines were more widespread than previously thought," Jill Mickucki, a microbiologist and lead author of the 2015 study, told Rachel Feltman of The Washington Post. " They appear to connect these surface lakes that appear separated on the ground. That means there's the potential for a much more extensive subsurface ecosystem, which I'm pretty jazzed about."
Go with the Flow
Water doesn't normally flow through ice, as you know. But the scarlet brine of Blood Falls actually heats up as it freezes. That's because a phase change, like when liquid water turns to ice, produces heat energy. When it comes to this brine, the heat produced by it freezing is enough to keep the rest of it flowing. That's exciting because brine is a perfect place to find microbial life — Blood Falls is no exception — and if brine can stay liquid under layers of ice, that means microbial life might live deep within icy worlds of our solar system and beyond.
To learn more about the alien world of Antarctica, check out "Endurance: Shackleton's Incredible Voyage" by Alfred Lansing. The audiobook is free with a trial of Audible. We handpick reading recommendations we think you may like. If you choose to make a purchase through that link, Curiosity will get a share of the sale.