Global warming is turning parts of Antarctica green, scientists say

Pablo Tucker
May 22, 2020

PARTS of the Antarctic Peninsula will change colour as "green snow" caused by blooming algae is expected to spread with increases in global temperatures, research showed today.

Although often considered devoid of plant life, Antarctica is home to several types of algae, which grow on slushy snow and suck carbon dioxide from the air. The polar regions are warming faster than anywhere else on the planet, so some of these islands may lose their summer snow cover, while the coastal regions of the continent will experience a significant increase in algae blooms over the coming decades. The Peninsula is the part of Antarctica that experienced the most rapid warming in the latter part of the last century. They found 60 percent of the detected blooms are within 5 kilometers (3.1 miles) of a penguin colony, as well near other birds' nesting sites, and where seals come to rest ashore.

The team used images from the European Space Agency's Sentinel 2 satellite taken between 2017 and 2019, and combined these with measurements they made on the ground in Antarctica at Ryder Bay, Adelaide Island, and the Fildes Peninsula, King George Island. Nearly two thirds of the green snow the scientists found was on smaller, low-lying islands. The study says this equals the emissions of around 875,000 vehicle journeys in the United Kingdom.

The blooms form on the top of snow in warmer areas along the coast, where temperatures tend to stay above 0 C. It normally appears between November and February, with growth accelerated by the presence of nitrogen and phosphorus.

Almost two-thirds of the blooms were on the small, low-lying islands, the researchers noted, but they expect it to spread greatly as temperatures rise.

"As Antarctica continues to warm on small low-lying islands, at some point you will stop getting snow coverings on those in the summer", said Andrew Gray, lead author and researcher at the University of Cambridge and NERC Field Spectroscopy Facility, Edinburgh.

Photosynthesis is the process in which plants and algae generate their own energy, using sunlight to capture carbon dioxide from the atmosphere and release oxygen.

Gray told AFP that the green snow blooms on higher ground would "more than offset" the effect of sea-level algae losses.

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

"A lot of people think Antarctica is just snow and penguins".

Scientists have beforehand noticed a rise in inexperienced lichen and moss, however these develop extraordinarily slowly in contrast with algae. This new study has found that microscopic algae also play an important role in Antarctica's ecosystem and its carbon cycling.

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