Antarctica has become more unusual green snow

US, WASHINGTON (ORDO NEWS) — British scientists have compiled the first map of the distribution of green algae in the snow cover of Antarctica. Climate change is causing snow on the shores of the southern continent to become greener. The results are published in the journal Nature Communications.

Scientists from the University of Cambridge and the British Antarctic Service, combining satellite data with ground-based observations, created the first ever large-scale map of microalgae that live on the surface of snow along the coast of the Antarctic Peninsula.

The authors used satellite imagery taken by the Sentinel 2 satellite of the European Space Agency in 2017–2019, as well as ground-based data from two field seasons in Ryder Bay, Fildes Peninsula, and Adelaide and King George Islands.

The results show that the areas of snow algae distribution on the coast of the Antarctic Peninsula are expanding every year with increasing global temperature. Although each individual algae has microscopic dimensions, in bulk they give the snow a bright green color, which is visible even from space.

Snow algae are more common along the west coast of the Antarctic Peninsula, especially on the islands. They grow in warmer areas where average temperatures during the summer season exceed zero degrees Celsius.

The researchers also found that the fields of green snow algae are often confined to the habitats of seabirds and mammals, whose excrement acts as a natural fertilizer. More than 60 percent of the green snow was found at distances up to five kilometers from penguin colonies, nesting sites for other birds, including skuas, and coastal areas where seals go.

“We have identified 1,679 individual spots of blooming green algae on a snowy surface that together occupy an area of ​​1.9 square kilometers, which is equivalent to an absorption of carbon of about 479 tons per year,” the words of the research leader, Dr. Matt Davey, are quoted in a Cambridge University press release. Davey) – This is significant progress in our understanding of land life in Antarctica and how it can change in the coming years when the climate gets warmer. Snow algae are a key component of the continent’s ability to capture remove carbon dioxide from the atmosphere through photosynthesis.”

Almost two-thirds of the areas of green algae are in small low-lying islands. As the Antarctic Peninsula heats up due to rising global temperatures, these islands, according to scientists, may lose their summer snow cover, and with it the snow algae will disappear.

But, at the same time, they can spread more widely on the hills – in the north of the Antarctic Peninsula and the South Shetland Islands, scientists say.

“As Antarctica warms up, we predict that the total mass of snow algae will increase, as distribution on a hill will significantly outweigh the loss of small island spots of algae in the lowlands,” says the first author of the article, Dr. Andrew Gray.

In this regard, the researchers note, the total amount of carbon held in the snowy green algae of the Antarctic will become much larger over time. In addition, carbon dioxide is also absorbed by red and orange algae, which were not studied in this study.

At the next stage of work, scientists plan to include these groups of plants in their work, as well as to disseminate an estimate of the distribution of snow algae throughout the entire territory of Antarctica.

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