Climate change leads to an increase in green snow in Antarctica

Satellite data collected between 2017 and 2019, combined with measurements on the ground over two summers in Antarctica, allowed scientists to map the microscopic algae as they bloomed through the snow of the Antarctic Peninsula.

Green snow algae are microscopic when measured individually, but when organisms grow simultaneously, they make snow green bright and can even be spotted from space, the researchers said in a study published in the Nature Communications Wednesday diary.

Snowy green algae spots are found along the Antarctic coast, usually in “warmer” areas, where average temperatures are slightly above zero degrees Celsius during the southern hemisphere summer months from November to February.

The Antarctic Peninsula is the part of the region that has undergone the fastest warming in the last part of the last century, researchers say.

Scientists identified 1,679 distinct green algae blooms on the snow surface, covering an area of ​​1.9 km2 – which equates to a carbon sink of approximately 479 tons per year. A carbon sink is a tank that absorbs more carbon than it releases.

Researchers believe organisms will expand as global temperatures rise.

“As Antarctica heats up, we predict the overall mass of snowy algae will increase, as spreading over higher terrains will significantly outweigh the loss of small island areas of algae,” said Dr. Andrew Gray, lead author of the article and researcher at Cambridge University, said in a statement.

He told CNN that rising temperatures would create more “habitable” environments for algae.

However, while an increase in melting snow could lead to greater algae growth, Gray told CNN that the distribution of organisms is strongly linked to bird populations, whose droppings act as fertilizer to accelerate growth.

Because bird populations, especially penguins, are affected by warming temperatures, “snow algae could lose nutrient sources to grow,” he said.

An increase in blooms could also lead to further melting of the snow, he said.

“It is very dark – a bloom of green snow algae will reflect about 45% of the light hitting it while fresh snow will reflect about 80% of the light that hits it, thus increasing the melting rate of snow in a localized area” he explained.

The researchers found that almost two thirds of the blooms were on small low islands and claimed that as the Antarctic Peninsula warms up due to rising global temperatures, these islands could lose their summer snow cover and algae, although in terms of mass most of the snow-covered algae are found in areas where they can spread over higher ground when the snow melts.