Scientists Have Finally Solved One of the Last Mysteries About Antarctica’s Blood Falls

In 1911, a geologist is ultimately doomed Newfoundland Expedition To the South Pole Discover a red waterfall five stories high in the middle of the frozen desert lands of Antarctica. The area known as McMurdo Dry ValleysIt is the largest ice-free area on the continent, and one of the coldest and driest regions. Most similar to Mars Places on Earth.

The so-called blood falls oozing from the crack At Taylor Glacier on ice-covered Lake Bonney. The red brine is twice as salty as seawater, and never freezes. But why is it so red? This is due to the presence of extremely rich iron in the water, which oxidizes and turns crimson when exposed to air, explained a research team led by microbiologist Jill Mikuki. Discovered in 2009. As the team identified 17 Microorganisms In the surfactant solution. Before that, scientists thought that a type of algae might be responsible for the red color.

Further research discovered microscopic, amorphous iron nanospheres in iron-rich brine, filled with silicon, calcium, sodium and aluminum. These small molecules, which lack a crystalline structure, are actually what oxidize upon contact with air and create the red color of the waterfalls, according to a 2023 study published in the journal Frontiers in astronomy and space science.

Additional research By Mikuki, published on Nature CommunicationsHe discovered that the source of the Blood Falls is a subglacial lake. They have conducted the first-ever landscape-scale survey of subsurface resistivity in Antarctica. They mapped the area using a large airborne electromagnetic (AEM) system called SkyTEM, which was flown in by helicopter. like Smithsonian Notes– When water freezes, its electrical resistance is higher. On the other hand, salt-rich brine has low resistivity.

You can watch a short video of the AEM system here:

according to New worldThe sensor detected a lake 185 meters below the surface near Blood Falls. Virtually devoid of oxygen and trapped at a depth of a quarter mile for two million years, the lake nonetheless harbors life, which appears to… Using sulfates instead of oxygen for breathing. Because the researchers discovered large areas of low electrical resistivity below the surface, they believe the lake is one of two extensive subsurface saltwater systems.

As Mikuki L said The Washington Post“We found, as expected, that there was something emerging from the blood falls… and we found that these brines were more widespread than we previously thought. They seemed to connect these seemingly separate surface lakes on Earth. This means that there is the potential for a much more extensive subsurface ecosystem, which excites me very much.”

Further research has confirmed that the reason some of the water never freezes in Blood Falls is that some of the water is a very salty brine created when the Antarctic Ocean subsided millions of years ago, and is salty enough to keep it from freezing and allow it to flow over the ice.

Recently, a 2026 study was published in Antarctica Science It has solved one of the last great mysteries remaining about this strange phenomenon – what actually causes the blood-red water to flow. The study found that this crimson stream is caused by pressure changes in the brine below Taylor Glacier, as it slowly flows downstream. As the glacier moves, it puts enormous pressure on the salt water beneath it, sometimes creating deposits of iron-rich salt water, to the horror of the world.

This story was originally published in 2015 and was updated in 2026.