Five stories high and emerging from the Taylor Glacier in the Dry Valleys of Antarctica, Blood Falls seeps into an ice-covered body of water called Lake Bonney. It’s one of the continent’s most enigmatic natural features and has fascinated scientists for decades. What makes it red? Does it always flow? And can anything actually survive near it? To find out—and see just how bizarre Blood Falls is with their own eyes—Caitlin and Arlo travel to the Dry Valleys, about 60 miles from McMurdo Station. There, they meet with microbiologist Jill Mikucki and hydrogeologist Peter Doran to investigate why this glacier looks the way it does, what lives there (spoiler: CHARISMATIC MICROBES!), and what clues it holds for finding and understanding life on other planets and moons in our solar system, like Mars, Jupiter’s Europa, and Saturn’s Enceladus. Answering these questions, it turns out, requires lots of probes, cameras, and even a massive sensor hanging from a helicopter.
CORRECTION: A previous version of this video incorrectly stated that Enceladus is a moon of Jupiter. It is a moon of Saturn.
Why is this Antarctic Glacier “Bleeding?”
Published: February 12, 2020
Caitlin Saks: This might be the most shocking feature in all of Antarctica...
Jill Mikucki: What do you think of when you see it?
Caitlin: Honestly? I think of the glacier having its period.
Jill Mikucki: OK. Yeah…
Caitlin: Blood Falls. What is this place? Why is there so little ice on this part of antarctica? And why is this glacier bleeding?
Arlo Pérez: We are in the Dry Valleys—one of the most unusual spots in Antarctica—because it is part of the 1% of the continent that isn’t covered by ice.
Caitlin: Instead, here we find craggy mountains. Rock is carved by wind and grit to form impossible looking sculptures.
Arlo: It looks more like Mars than Earth.
Caitlin: This makes the Dry Valleys one of the most scientifically interesting regions to study on the planet.
Jill Mikucki: I think it's a great analog for both Mars and a place like and Enceladus.
Arlo: And, here in the Dry Valleys, Blood Falls is one of the most intriguing features.
Peter Doran: Blood Falls is a bit of an obsession for a lot of people. There's nothing
else like this on Earth.
Jill Mikucki: It's like this really visceral feature just jumps out at you... you know, Blood Falls.
Peter Doran: It’s an outlier and so we learn from those extremes. It’s different than anything else we know.
Arlo: To find out more about this exotic landscape, we’ve come to Lake Bonnie, to meet with scientists Jill Mikucki and Peter Doran.
Caitlin: You heard that right—this is a lake.
Peter Doran: It’s really like any other lake on earth but there’s just a really thick ice cover that stays here all the time.
Caitlin: Peter studies the lakes and streams—he’s a hydrogeologist.
Arlo: Jill’s a microbiologist. She studies what’s living here.
Caitlin: So there's actually stuff living in the dirt?
Jill Mikucki: Oh yeah, in the dirt and in the lakes, in the lake ice, in the rocks.
Peter Doran: There's actually worms in the dirt. There are microscopic worms,
Caitlin: What?! I can’t believe anything lives here, where it can get down to -75 in winter.
Jill Mikucki: What got me interested at first was this notion of how life survives below ice because of other worlds in our solar system—places like Mars, Europa, or Enceladus. These are going to be really cold places.
Caitlin: So this is running water? That is actually the Blood Falls? Actually flowing?
Jill Mikucki: I don’t know, we’ll see, let’s go find out.
Caitlin: I’ve joined jill to investigate what exactly Blood Falls is, and why she’s so fascinated by it. It’s well below freezing, so I am surprised to see running water on a day like today. To figure out what's going on, we measure the temperature of the water.
Jill Mikucki: Look at that's minus 5.2! I need to put my glove back on my hand.
Caitlin: Wow. -5 Celsius is how much Fahrenheit?
Jill Mikucki: You can do that in your voice over.
Caitlin: Negative 5.2 degrees celsius is about 23 degrees Fahrenheit. Why is this water flowing almost 10 degrees below the freezing point of water?
Jill Mikucki: Right now the salinity is reading, I don't know if you can't see that, 75 parts per thousand, 80, there it is, 83 parts per thousand.
Caitlin: What's like ocean water?
Jill Mikucki: 35.
Caitlin: Oh wow. So this is super salty.
Jill Mikucki: This is super salty.
Caitlin: This water isn’t frozen because it is so salty—more than twice as salty as ocean water. But that also means something extraordinary about where this water comes from.
Jill Mikucki: The fact that it's so salty tells you it's not glacier melt, right? It has to be coming from somewhere else.
Caitlin: Glacier ice is made of hundreds to thousands of years worth of snowfall—and snow is made of fresh—not salty—water. So where is this briny water coming from? Looking around there’s another clue. The red color that makes this feature look bloody.
Jill Mikucki: All the red here is iron oxides. But as you can see this water here is pretty clear. If the water is clear and there's iron in it, that means it hasn't been oxidized yet. And as it spends time at the surface, that's when it becomes oxidized and leaves this beautiful red color around.
Caitlin: The red crust on this glacier is actually rust! But this means… not only is Blood Falls strangely salty, but the Blood Falls brine has also not been exposed to the atmosphere for a very long time. It's from deep below the glacier!
Jill Mikucki: The liquid source below the glacier has potentially been isolated for millions of years. So, the next thing to do would be to collect some samples and take this back to the lab and see if there's any microbes in here.
Caitlin: These microbes Jill hopes to find could offer insight into what kind of extreme life we might find elsewhere in the solar system … like on mars, where we know there’s salty liquid below the polar ice.
Caitlin: It's so cool that it's actually flowing while we're here.
Jill Mikucki: Yeah. This is amazing. This is actually quite fortunate. This is a tricky little feature it doesn't always flow when you'd like it to, I guess. So it's one of those challenging mysteries to study and it always keeps me guessing.
Arlo: But what makes Blood Falls actually flow? Why is it only here that we see this bizzare feature? To find out, Peter Doran's team is watching it’s activity with a camera.
Krista Myers: This camera has been taking photos for the past two years. Twice a day.
Arlo: But what is the point of taking a picture of it?
Krista Myers: No one really has a super complete record of actual flow events. The timing, how often, and when it’s flowing is not really known.
Arlo: Looking at the time lapse over a few days, you can sometimes spot distinct discharge events—it isn’t always flowing.
Caitlin: You could say that Blood Falls… isn’t regular.
Peter Doran: We don't think there's a yearly cycle. So we're trying to figure out what the Cycle is and whether it's connected to seasonality, whether it's connected to maybe even windstorms. My view is Blood Falls is a pressure relief valve. Whenever there is a pressure change by a movement of the glacier something happens and sometimes Blood Falls squirts out. Sometimes it doesn't.
Caitlin: Peter thinks that Blood Falls flows when there is pressure from the glacier on the underground liquid. Which begs the question: how big is this aquifer that feeds Blood Falls? Is this an isolated system? Or is Blood Falls tapping something… bigger?
To find out, we have to peer deep below the ice… by taking to the skies. A project called Skytem flies a massive electromagnetic sensor over the area, allowing scientists to peel back the surface, and see what lies beneath.
Peter Doran: Skytem can see hundreds of meters into the ground and tell us the difference between frozen ground and unfrozen ground and where there's water. Where there's groundwater.
Caitlin: Skytem has revealed that there’s much more to the Dry Valleys than meets the eye. Here, the green shows underground liquid. Lots and lots of it. This part of the Dry Valleys has an expansive ground water system.
Peter Doran: For the longest time, we didn't think there was groundwater underneath the Dry Valleys. We've always viewed these lakes as being isolated… they weren’t connected by any ground water system. And then we flew this sensor over. We spent two weeks flying the sensor around the Dry Valleys and it completely changed our perception of water and connectivity in the Dry Valleys.
Jill Mikucki: So perhaps it's like a deep groundwater system that might exist on Mars. They've recently found a sub glacial lake below the southern-southern ice cap on Mars.
Caitlin: And Blood Falls, is like a window into this alien environment.
Peter Doran: It's a portal into the water beneath the surface of the valley. And it's the first one we've had.
Caitlin: By studying it, scientists may discover clues about how life could evolve and survive in the extreme environments of other planets.
Jill Mikucki: How do you live in the absence of sunlight for extended periods of time?
What does that look like? What unique adaptations do these organisms have to be able to survive in cold darkness under extremely saline conditions?
If we can understand how life operates below ice here we have a much better chance of knowing where to look or how to look for the life on other worlds.
Life Under the Ice photography Courtesy of Ariel Waldman. Produced with support of the National Science Foundation and the National Geographic Society.
Hosted by Caitlin Saks and Arlo Pérez
Digital Producer/Editor: Emily Zendt
Producer: Caitlin Saks
Digital Associate Producer: Arlo Pérez
Field Director/Cinematographer: Zachary Fink
Executive Producer: Julia Cort
Coordinating Producer: Elizabeth Benjes
Project Director: Pamela Rosenstein
Production Assistance: Matthew Buckley, Emily Pattison, Sean Cuddihy
Director of Audience Development: Dante Graves
Senior Digital Producer: Ari Daniel
Audience Engagement Editor: Sukee Bennett
Outreach Manager: Gina Varamo
Special thanks to Michael Amundson
Special thanks to the United States Antarctic Program
Additional Footage: Ariel Waldman, Bill Dunford, Brad Herried, Brian Wilcox, Byron Adams, Brigham Young University, G. Neukum (Freie Universitaet, Berlin), Denys Grombacher, ESA, JPL-Caltech, Lars Jensen, NASA, Peter Doran, Polar Geospatial Center, Ricardo Garza-Giron, Robert Simmons, Space Science Institute, University of Arizona, USGS
© WGBH Educational Foundation 2020