Atfirst glance, the snow that’s changed from white to bright pink in the Italian-组卷网

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At first glance, the snow that’s changed from white to bright pink in the Italian Alps seems like a stunning feat of nature. But scientists say it may actually be a warning sign of environmental trouble.

Algae (藻类) are to thank or blame for the pink layer that coats the Presena Glacier in northern Italy. Scientists say it’s not an uncommon phenomenon in the spring and summer, but they warn that it could become a problem if it starts occurring more frequently.

Biagio Di Mauro, director of the Institute of Polar Sciences (ISP) at Italy’s National Research Council, traveled to the glacier to investigate the mysterious algae. While the phenomenon is well-documented, “there is relatively little scientific literature on this phenomenon, which has the direct effect of accelerating the melting of snow and ice,” the institute said.

Photos from the trek show a massive algae bloom, turning large swaths of the glacier from white to pink. Di Mauro said on Twitter that the algae was likely Chlamydomonas nivalis (极地雪藻). According to a study published in the journal Nature, snow algae has influence on carbon dioxide in the atmosphere. The algae is not dangerous; it is a natural phenomenon that occurs during the spring and summer periods in the middle latitudes but also at the Poles, Di Mauro said in a press release.

The algae could accelerate melting in the already fragile region. Climate change, contributing to 2020’s unseasonably warm temperatures and lack of snow, is exacerbating the issue. Typically ice reflects the majority of the sun’s radiation, but algae darken the ice, causing a decrease in reflectivity. This causes the snow to absorb more heat and melt more quickly. “Everything that darkens the snow causes it to melt because it accelerates the absorption of radiation,” said Di Mauro, In order to flourish, the organisms need an available supply of water. So, as the ice melt even more algae will appear.

In May, Antarctica saw green snow, also caused by microscopic algae. At the time, scientists said that as the planet warms and more of Antarctica’s snow melts, the algae will only continue to spread.

【小题1】What can we learn about snow’s changing from white to bright pink?

A．It is proved a masterpiece of nature.

B．It occurs mainly because of the algae.

C．It is a common phenomenon in the winter.

D．It has led to serious environmental problems.

【小题2】What does the underlined word “exacerbating” in Paragraph 5 mean?