Its presence has spread to coastal areas and increasingly south. Due to its color, it absorbs sunlight and increases temperatures.
Richard Garcia, El Mercurio. A new sign of global warming is emerging in Antarctica.
It is becoming more frequent to see red snow. These microalgal blooms, also known as snow algae, typically occur in summer.
But these blooms have a disturbing side. Wherever they occur, the snow is more liquid in nature.
“It greatly accelerates the melting of the snow; we still do not know how much more,” says Iván Gómez, a researcher at the Research Center Dynamics of High Latitude Marine Ecosystems (IDEAL) of the Universidad Austral de Chile.
This summer, Gomez and his colleague, Pirjo Huovinen, took samples at Yelcho Base and analyzed the algae’s reaction to increased temperatures and UV rays.
They found that the greater temperatures that are occurring on the frozen continent favor snowmelt and the accelerated melting, in turn, increases snow algae blooms.
The key is in the albedo, which ranges from 0 to 1 and indicates how much sunlight reflects off the Earth. Freshly fallen snow results in the highest albedo. “That white that is so white it hurts your eyes to see it,” says Gómez. Any substance that is not white lowers the albedo, so as the snow gets “dirty”, it absorbs more solar radiation in the form of heat. The alga buds darken the snow and, therefore, it reflects less sunlight. Indeed, it absorbs the light, which adds to the melting,” explains the specialist from the Universidad Austral de Chile.
Food for the birds
Unlike blooms of other microalgae, such as Alexandrium catenella, which produces red tide, this alga is not known to be toxic.
These algae live naturally in the ocean, but are carried by waterfowl feces to the coasts. “The penguins feed on them because they contain nutrients, especially carotenes, which give the blooms their red color.”
The monitoring carried out so far has shown that snow algae are steadily expanding their presence in Antarctica. They are now found not only on the coasts but also several kilometers inland and spreading towards the south of the continent.
“If these algae continue to spread, there will be more melting and more liquid water, but this proliferation will not continue forever and a time will come when they lose habitat.”
They may also have physical limitations. That’s why researchers are studying how much light they can withstand or the maximum temperature at which they photosynthesize.
The researchers acknowledge that it is likely that the entire continent will turn red, since these algae also have minimum temperature limits for survival. “In the central plateau, where the temperature for any organism is -70 C, that is a completely inhospitable situation”.