Austria 2024: Red Snow

[Photography week arranged by Wildlife Worldwide, led by Alex Hyde and Nick Garbutt, and staying in Hotel Wiesenheim.]

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Midsummer, at 2400 metres, on a ridge high above the resort of Fiss the snow still lingers on the slopes.  Look closely, and the snow is tinged with red.

 

The phenomenon was recorded by the Greeks (Aristotle and Pliny) and seen by Charles Darwin in Peru.

 

In May 1818, four ships sailed from England to search, unsuccessfully, for the Northwest Passage. The captain, John Ross, noticed crimson snow that streaked the white cliffs like streams of blood as they were rounding Cape York on the northwest coast of Greenland. A landing party stopped and brought back samples to England.

 

Explanations based on meteorites and metal contamination were proposed, but a botanist tentatively suggested that the red snow might be caused by algae.

 

So, for 200 years the red snow has been attributed to algae called Chlamydomonas nivalis, but more recently botanists at Charles University, Prague, in the Czech Republic, identified an entirely new genus of microalgae that is responsible for causing red and orange snow in different parts of the world, which they named “Sanguina“. I can’t yet work out if Sanguina nivalis is a separate species, or a renaming of Chlamydomonas nivalis

 

Whichever name, they are actually green alga that owe their red color to a bright red carotenoid pigment, a sort of natural sun screen. Algal blooms may extend to a depth of 25 cm, with each cell measuring about 20 to 30 micrometers in diameter, about four times the diameter of a human red blood cell.

 

It has been calculated that a teaspoon of melted snow contains a million or more cells. Another source suggest half a million in a millilitre of snow.

 

In some places, such as the USA, the red snow is called watermelon snow, because it is meant to smell like watermelons.

 

Red snow drift

 

Naturally, Alex wanted to photograph the alga

 

He came equipped with a special lens and a massive set of extension tubes.

 

He showed me how to stick the lens into the snow and move slowly up and down, taking lots of shots in the hope that one or two might be sharp. [Photo credit: Alex]

 

This was taken by Alex with my camera and his lens. A 5 layer stack, no cropping.

 

And this with my modest macro lens, greatly cropped, but still able to see the individual algae. Amazing!!

 

Later we found a patch of snow melt, with dirt, maybe some Saharan dust, and definitely some Sanguina nivalis

 

On the right is the snow drift with the red melt

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Sources, and find out more:

• Watermelon snow
• Chlamydomonas nivalis
• The Amazing, and Alarming, Science Behind Red Snow
• The secrets of the Alps’ strange red snow

And if you are worried about travelling on ski lifts, read this

• How safe are ski lifts?

 

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Curious, I asked Google Gemini (AI) to tell me about red snow; the natural phenomenon found in mountains.  The result is somewhat impressive:

 

Red snow, also known as watermelon snow, pink snow, or blood snow, is a fascinating natural phenomenon caused by tiny organisms thriving in the harsh mountain environment. Here’s the breakdown:

 

Culprit: The culprit behind the red hue is a type of algae called Chlamydomonas nivalis (although recent studies suggest it might belong to a new genus called Sanguina). These microscopic green algae have a special trick up their sleeve.

 

Red Armor: While most algae use chlorophyll for photosynthesis, Chlamydomonas nivalis also produces a red pigment called astaxanthin. This red pigment acts like a natural sunscreen, protecting the algae from the intense ultraviolet radiation at high altitudes.

 

Blooming Beauty: During warmer summer months, these algae multiply rapidly, and the red pigment starts dominating, turning the snow a beautiful pink or red. Imagine millions of tiny red life jackets coloring the snow!

 

Melting Impact: Unfortunately, the red color has a downside. It absorbs more sunlight than white snow, causing the snow to melt faster. This faster melting can affect water runoff patterns and even accelerate glacial retreat.

 

Global Phenomenon: Red snow isn’t unique to a specific mountain range. It can be found in alpine and polar regions worldwide, from the Sierra Nevada in California to the icy plains of Antarctica.

 

So next time you see pictures of mountains with a reddish tinge to the snow, you’ll know it’s not some alien invasion, but a clever adaptation of life finding a way to thrive in the extreme conditions!

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