Scientists have uncovered the origin of Antarctica’s mysterious Blood Falls

The Blood Falls are situated at the edge of the Taylor Glacier in the Antarctic McMurdo Dry Valleys. Bright red, salty water flows from beneath the glacier and is coloured by iron compounds upon contact with the air.

Scientists have long known why the water is red, but the origin of the subglacial brine itself has remained a subject of debate.

Details

The researchers collected 167 samples of water, sediment, ice and air in the vicinity of the glacier.

Using genetic analysis, they studied the composition of the microorganisms and discovered that the microbial communities in the area around the Bloody Waterfall consist almost entirely of organisms characteristic of a marine environment.

In other areas of the Dry Valleys, freshwater and terrestrial microorganisms predominated.

These findings support the hypothesis that the subglacial brine formed from seawater.

According to the scientists, during one of the warmer periods in the past, the sea flooded Taylor Valley. Later, sea levels fell, a glacier advanced and cut this body of water off from the sea.

The isolated ecosystem was able to survive beneath the ice for a very long time.

The authors also consider it unlikely that marine microorganisms were carried here by modern winds, which further confirms the brine’s ancient origin.

Why this is important

The research helps us better understand how microorganisms are able to survive in extreme conditions over long periods of time.

Furthermore, such subglacial ecosystems are regarded as a possible analogue for the conditions that may exist beneath the icy crusts of some of Jupiter’s and Saturn’s moons, where liquid water is also thought to be present.

Source

Study: Angela Zoumplis et al. Molecular evidence for a relict marine community in an Antarctic Dry Valleys subglacial brine-fed system.

Journal: Nature Geoscience (2026).