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Climate change is causing Antarctica’s snow to turn green, the study said

In the coastal Antarctica, a little snow is not white – it is green. And while small amounts of green snow have been seen for years, it is beginning to spread across the continent because of it climate change,,

According to a study published Wednesday in the journal Nature Communications, vibrant color is caused by microscopic algae that bloom on the surface of snow. Using satellite data and field observations, a team of researchers from the University of Cambridge and the British Antarctic Survey created the first large-scale map of green algae and predicted the future spread of the bizarre snow.

Green snow appears along the coast of Antarctica, growing in “warmer”

; areas, where average temperatures reach slightly above freezing in summer. Although individual algae are microscopic when growing in scale, green snow can even be seen from space.

For the study, the team combined a two-summer ground study in the Antarctic Peninsula with images from the European Space Agency’s Sentinel 2 satellite taken between 2017 and 2019. In total, the team identified more than 1,600 individual flowering algae on the snow surface.

Lead author Matt Davey samples snow algae on Laguna Island, Antarctica.

Sarah Vincent

The team found that the distribution of green algae in the snow was strongly influenced by seabirds and mammals, as their excrement works extremely well as a fertilizer. Over 60% of the blooms were found near penguin colonies, while others were found near bird nesting sites.

“This is a significant advance in our understanding of terrestrial life in Antarctica and how it may change in the coming years as the climate warms,” ​​lead author Dr Matt Davey of the University of Cambridge said in a press release.

If bird populations are severely affected by climate change, as they are likely to be, algae may lose key sources of nutrients. But the results of the study show that green snow will spread widely as global temperatures are rising,,

This is because in order to thrive, organisms need water available. Temperatures on the peninsula, where the green snow is located, have risen dramatically in recent decades, increasing the amount of water available.

Because the planet is warming more than Antarctica the snow is melting, the algae will spread, the scientists said. And while some algae will be lost to areas that completely lose snow, much more will be gained.

Photo showing the island of Anchorage, dominated by green algae, which begins to melt under the surface snow on January 26, 2018.

Natural communications

“As Antarctica warms, we predict that the total mass of snow algae will increase, as the spread to higher ground will significantly exceed the loss of small island spots of algae,” said co-authored author Dr. Andrew Gray of the University. at Cambridge and the University of Edinburgh.

It is not clear how the spread of algae will affect the planet. It plays a key role in cyclic nutrients and the extraction of carbon dioxide from the atmosphere through photosynthesis, Davy said, but it also darkens snow and absorbs more heat from the sun.

The amount of algae discovered by the team creates a carbon sink that absorbs about 500 tons of carbon each year, the equivalent of about 875,000 average car trips in the United States, the researchers said.

The amount of algae found is actually a conservative estimate, as the satellite was only able to pick up green algae, lacking their red and orange counterparts. “The snow is multicolored in places, with a palette of reds, oranges and greens – it’s a pretty amazing sight,” Davy said.

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