Blood Falls: Scientists solve century-old mystery of Antarctica's red waterfall

Scientists have finally solved a century-old mystery involving a famous red waterfall in Antarctica by linking it to a large source of salty water.

Blood Falls, found in 1911 by geologist Griffith Taylor in East Antarctica, is famous for its sporadic releases of iron-rich salty water. The brine turns red when the iron contacts air.

Researchers, including those from University of Alaska Fairbanks (UAF) in the US, have now provided new evidence which links the Blood Falls to a large source of salty water that may have been trapped under Taylor Glacier for more than one million years.

They tracked the brine with radio-echo sounding, a radar method that uses two antenna - one to transmit electrical pulses and another to receive the signals.

"We moved the antennae around the glacier in grid-like patterns so that we could 'see' what was underneath us inside the ice, kind of like a bat uses echolocation to 'see' things around it," said Christina Carr, a doctoral student at UAF.

Researchers also made another significant discovery - that liquid water can persist inside an extremely cold glacier.

Scientists had previously thought this was nearly impossible, but researchers said the freezing process explains how water can flow in a cold glacier.

"While it sounds counterintuitive, water releases heat as it freezes, and that heat warms the surrounding colder ice," said Erin Pettit from UAF.

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," Pettit said.

The study was published in the Journal of Glaciology.