The blooming of algae in the Arctic spring and summer gives a red tint to snow. Image: David Wicks via Flickr
Microscopic forms of coloured algae are suspected of helping to speed up the melting rate of snow by reducing its crucial ability to reflect the sun’s rays.
LONDON, 2 July, 2016 – German scientists have fingered a new suspect in the great glacial melting mystery. The secret agent that may be darkening the summer snows and speeding up the absorption of solar rays is a family of microscopic, cold-loving organisms that tint the snow red.
The identification is not a simple matter, and no arrest is likely to be made soon. But researchers say that the cryophilic micro-eukaryotes can make the snow 13% − and sometimes up to 20% − less likely to reflect radiation back into space.
They then subjected their samples to genetic and microbiological analysis to identify what they describe as a “cosmopolitan” culprit. Despite the variation in geography, only about six kinds of algae – the biologist’s choice of word is taxa – colonised and coloured the snow in all the sites.
“Our results point out that the ‘bio-albedo’ effect
is important and has to be considered
in future climate models”
Snow isn’t just a product of the climate machine, it is also part of the machinery – and part of life’s cycle. Permanent and seasonal snow together can cover up to 35% of the planet’s surface.
The reflectivity of this gleaming surface helps keep the planet cool at the poles, and it is this difference between polar regions and tropics that drives the atmospheric circulation.
But microscopic creatures that flourish on snow are vital too, flourishing in the spring and summer with the first melting of the snow surface. They are the first form of primary productivity in the Arctic landscape, and they are the basis of the food web that leads all the way up to the walrus and the polar bear.
The Potsdam team reports that among the microbes are algae that can darken the surface of the snows and play a role in the melting of Arctic glaciers.
So the “red snow” effect simply speeds up the process, because the more the algae bloom, the more the surface darkens, and the more the snows melt and feed more algal growth.
The result of the latest research is that climate scientists now have a new factor to consider when they calculate the mix of circumstances that, increasingly, will warm the Arctic, raise global sea levels and accelerate climate change.
“Our results point out that the ‘bio-albedo’ effect is important and has to be considered in future climate models,” Dr Lutz says. – Climate News Network