The origin of Antarctica's Blood Falls

Blood Falls — that's how the place is officially called — was discovered back in 1911. So far nothing else similar has been found. The 'waterfall' looks as if the glacier is bleeding red-brown liquid, which flows in jets to the surface of an ice lake and freezes immediately.

Meanwhile, there are tiny streams of unfrozen water at the bottom of the glacier, though the local average temperature is -17 degrees Celsius! And the water in them is 2.5 times saltier than in the ocean.

For a long time, it was believed algae are responsible, which somehow survived in the depths of the glacier and now go out.

But the story was brought to a close only in the late 2010s.

Millions of years without oxygen

Antarctica used to be a green continent. But 45 and a half million years ago ice started to cover the continent as a result of climate change.

Incoming glaciers locked the water of local reservoirs. For millions of years, this water did not see sunlight and even had no access to the atmosphere, but accumulated underground salts.

But something happened (the glacier probably started to press too hard) and some of the water broke its way to the surface, taking the iron particles with it.

Iron, which itself had no contact with the atmosphere for millions of years, suddenly found itself in an oxygen-saturated environment and an oxidation reaction occurred - in other words, it started to rust.

That's right - samples of the orange mass from the waterfall showed that ordinary rust is responsible for the shade. Iron atoms in the presence of water (even if it is just very humid air) and oxygen always begin to pass their electrons to oxygen, which 'lacks' them.

As a result of a chain of reactions, metal then turns into iron oxide layer by layer, a brittle red mass that we call rust.

The presence of salts only accelerates this process, since salts have many atoms that, like oxygen, need electrons. Salty water freezes at lower temperatures than freshwater; very salty water - rust forms faster. Here comes Blood Falls!

What does Mars have to do with it?

Rust is certainly not the most interesting thing about this phenomenon. Since Blood Falls brings ancient water to the surface, which for millions of years was in a closed ecosystem, scientists immediately began to look for microorganisms in it - and found some.

Moreover, after studying the underground world of the glacier with an electromagnetic scanner, which was transported by helicopter, the scientists found a multi-kilometer system of groundwater around the waterfall, something never known before.

It is assumed that it was the groundwater, together with the lake, that became the source of water for the waterfall.

The most interesting thing is that similar subglacial systems can exist on other celestial bodies of the Solar System, and we are not only talking about the distant satellites of Jupiter and Saturn.

In recent years, for example, there is increasing evidence that there may be a system of several ancient salt lakes under the southern ice sheet of Mars.

If microorganisms have survived all this time under Blood Falls, maybe they are also there, under the Martian 'Antarctica'?

It is impossible to say for sure - it must be confirmed by the rovers.

Text: Windy.app team

Cover photo: pbs.org