- A glacier in the Italian Alps is turning pink as algae eats away at its snow.
- Algae that changes the colour of snow or ice causes it to melt faster, a process which drives glacier melt across the globe.
- Glacier-eating algae could be seen more frequently as global temperatures rise.
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In the heart of the Italian Alps, a mountainside is blanketed in fields of watermelon-pink snow.
Biagio Di Mauro, a researcher at the Institute of Polar Sciences at Italy’s National Research Council, thinks the colour change comes from a snow alga called Chlamydomonas nivalis. It’s eating away at the mountain’s Presena glacier.
The plant is common in the Alps, but this year’s bloom is “impressive,” Di Mauro told CNN on Monday.
He attributed the growth to low snowfall and high temperatures in the area this spring and summer – a sign that the warming climate may be giving rise to yet another threat to the world’s glaciers.
“This creates the perfect environment for the algae to grow,” Di Mauro said.
“It is for sure bad for the glacier,” he added.
That’s because darker snow absorbs more heat from the sun. As the alga turns the snow pink, the glacier melts faster. When the ice melts, it provides water and oxygen to feed more algae, and the cycle accelerates. If the algae feed for long enough, the glacier could disappear.
The Presena glacier has lost more than one-third of its volume since 1933, according to Agence France-Presse. Every summer, conservationists rush to cover the ice in reflective white tarps to protect it from the sun’s warmth.
Climate change is diminishing glaciers across the globe. In 2019, Greenland’s glaciers melted at a rate some scientists hadn’t expected until 2070. Some glaciers worldwide are even at risk of hitting critical tipping points that could set them on an irreversible course of melting that leads them to disappear entirely. If that happens, especially in Greenland, catastrophic sea-level rise would swallow coastal cities across the globe.
Algal blooms on glaciers are regular seasonal occurrences. One species frequently turns Antarctic snow green. But as global temperatures rise, these algae could flourish more than usual and further accelerate ice melt.
Di Mauro recently discovered another alga, called Ancylonema nordenskioeldii, in the Alps for the first time. The species usually grows on glaciers in Greenland, but its presence in the Alps shows that glaciers melting due to hungry algae is a “global process,” he wrote in a study published in March.
“Pink snow due to algae is not uncommon (we have it every year in June in the Pyrenees),” Simon Gascoin, a hydrologist at the French National Centre for Scientific Research, said of the Presena glacier on Twitter. “The question is whether it gets more frequent due to climate change or other factors.”