Blood Falls gushes red water from Antarctica’s ice. It took scientists 106 years to figure out what causes its color.


JANUARY 10, 2023

Antarctica’s Blood Falls seeps from the end of the Taylor Glacier into Lake Bonney on November 26, 2006. – National Science Foundation/Peter Rejcek

  • Blood Falls is a waterfall of vibrant red water that oozes out of Antarctica’s Taylor Glacier.
  • Its unique color is due to iron salts seeping out of the ice that turn red when exposed to oxygen.
  • The falls are home to microbes that can survive extreme conditions, with no light or oxygen.

A large glacier in Antarctica produces a bright red river that oozes out of the ice, aptly named Blood Falls. Why the reddish water pours out of Antarctica’s Taylor Glacier and into Lake Bonney puzzled scientists for decades.

The red falls are named for their unusual color. Mark Ralston/AP
The phenomenon was first discovered by geologist Griffith Taylor in 1911. At the time, he thought that red algae living in the water was responsible for the water’s striking red hue. – Sources: National Science Foundation, University of Alaska Fairbanks

A closer image shows briny water pouring out of the glacier. – Peter West / NSF

More than a century later, scientists found what causes the bloody river: iron salts seeping out of the ice that turn red when they make contact with the air.


Blood Falls and the Taylor Glacier near McMurdo Station, Antarctica, on Friday, November 11, 2016. – Mark Ralston/AP

In a 2017 study, scientists found that Taylor Glacier formed roughly 2 million years ago, trapping a saltwater lake under it. Millions of years later, the ancient lake has reached the edge of the glacier, squeezing out salt water.

The bright orange of Blood Falls is visible where Taylor Glacier meets Lake Bonney.Hassan Basagic/Getty Images

In a 2015 study, researchers found a network of rivers flowing through cracks in the glacier using ice-penetrating radar. That means liquid water can exist inside an extremely cold glacier.

Image of Blood Falls taken by NASA’s Terra satellite.esse Allen/NASA/GSFC/METI/ERSDAC/JAROS/U.S./Japan ASTER Science Team

“While it sounds counterintuitive, water releases heat as it freezes, and that heat warms the surrounding colder ice,” Erin Pettit, a glaciologist at University of Alaska Fairbanks and co-author of the 2017 study, said in a press release. “The heat and the lower freezing temperature of salty water make liquid movement possible. Taylor Glacier is now the coldest known glacier to have persistently flowing water.”

Above, researchers are collecting radar data on Taylor Glacier in front of Blood Falls. – Erin Pettit

In a 2009 study, researchers discovered that the underwater lake is home to unique inhabitants — a community of microbes that can survive extreme conditions, with no light or oxygen. Instead, they use iron and sulfate to survive.

A cross-section of Blood Falls showing how microbial communities survive.Zina Deretsky / NSF

Researchers believe the lake trapped beneath the glacier millions of years ago was full of microbes.

Blood Fall is named for its fiery red hue. Erin Pettit

“Among the big questions here are ‘how does an ecosystem function below glaciers?’, ‘How are they able to persist below hundreds of meters of ice and live in permanently cold and dark conditions for extended periods of time, in the case of Blood Falls, over millions of years?,” Jill Mikucki, a microbiologist and the study’s lead author, said in a press release.

Blood Falls overlooking Lake Bonney.Peter West / NSF

Scientists believe studying these microbes will be a boon for astrobiology. They can shed light on how life might survive in other worlds with similar bodies of frozen water, like Earth’s neighbor — Mars.

Mars has two polar ice caps. Above is the one in the planet’s’ North Pole. – NASA/JPL-Caltech/Malin Space Science Systems

Courtesy/Source: Business Insider