Everyone has seen snow, and snowflakes are white, which is common sense. However, in February this year, "red snow" appeared near the Ukrainian Antarctic station in the Antarctic region. A large blood-red snow spread out on the ice, as if broken watermelons were spilled on the snow, and even smelled a little watermelon pulp. Just a few days ago, researchers from Cambridge University and British Antarctic Survey discovered "green snow" in Antarctica. It seems that the Antarctic snowfield has become a grassland, which can be seen in space. What's going on here? Why do white snow flowers turn red and green?

After investigation, Antarctic expedition members found that "red snow" was originally a red seaweed named "Chlamydomonas", which appeared in a large area on the snowfield. Chlamydomonas, also known as "watermelon snow", mostly appears on polar and alpine glaciers, and is also found on some icebergs on the Qinghai-Tibet Plateau in China. Climbers often see things as red as watermelon pulp in the snow.

So why is Chlamydomonas red? In fact, the mantle can also carry out photosynthesis, so it contains chlorophyll, so it was originally green, but when Chlamydomonas walked from the water to the ice and displayed in the sun (dry Chlamydomonas can fly in the air with the wind), it was irradiated by ultraviolet rays in the sun, which would produce a variety of red pigments such as carotene, so it turned red.

So why is there Chlamydomonas in Antarctica? In fact, this native plant is widely distributed. In recent years, the Antarctic climate has become warmer, which is very suitable for the growth of Chlamydomonas. At the edge of the Antarctic, these algae appear in large numbers in some places, dyeing the snow red, so there will be "red snow".

The appearance of "red snow" will further aggravate the climate warming in the Antarctic region, because it can absorb more sunlight and make the ice and snow melt further. The increase of temperature will give birth to a large number of Chlamydomonas and accelerate the melting of ice and snow. Therefore, this kind of algae is increasing in Antarctica, which is regarded by climatologists as a typical sign of Antarctic and even global warming.

What about Green Snow? In fact, it is also some algae, mainly green algae! They all contain chlorophyll, and there are a lot of green algae on the surface of the snowfield, which will make the original white snow look green, so some places look like grasslands.

The emergence and survival mechanism of green algae is similar to that of Chlamydomonas. The reason for its abundant existence is that the temperature in Antarctica is rising and the climate is warming, while green algae like to live in eutrophic water, so its abundant existence also shows that the organic matter in some parts of Antarctica is increasing.

Both "red snow" and "green snow" absorb sunlight more easily than white snow, so their appearance is also considered to aggravate polar climate warming, but one advantage is that they have strong ability to absorb carbon dioxide, which makes a slight contribution to maintaining the balance of oxygen and carbon dioxide content in the atmosphere.