The Antarctic snow suddenly turned red, and strange "blood snow" appeared. What happened?

In mystery novels, there is a classic "Snowstorm Manor" model: a group of people are trapped in an isolated environment, and then some strange things happen to them. Although this is just a technique in mystery novels, for scientists stationed at the Vanadsky Station in Antarctica, they have personally experienced such a strange "Snowstorm Manor Incident":

On February 6, 2020, when the scientists woke up, they found that the view outside the window seemed different. Not far from the research station, the originally bright snow was dyed into a large area of ​​bloody red , as if a "massacre" had occurred here after they fell asleep, and blood was flowing all over the ground.

The sudden appearance of red snow at the Wonardsky Station｜yourweather

In this isolated island in Antarctica, it is impossible for outsiders to enter. Scientists began to suspect that seals had hunted penguins here, but they quickly ruled out this possibility: they did not hear any noise, and it was impossible to ignore the figures of penguins or seals in the polar day. They also suspected that some careless team members had spilled raspberry jam outside, but everyone said that they had never done such a thing.

Curious scientists took samples of the "blood" and found that the red snow smelled like watermelon. Under a microscope, the truth was revealed: the red color came from a cold-resistant organism, Chlamydomonas nivalis .

Polar snow algae under the microscope | wiki

As early as the third century BC, Aristotle had recorded the phenomenon of red snow , and since then, similar phenomena have occurred in many cold regions around the world. But for a long time, people always regarded the sudden appearance of red in the snow as mineral deposits or pollen. In 1819, when the British polar expedition returned from the Arctic and brought back samples of red snow, people realized that red snow was actually a living thing. It was not until the early 20th century that the scientific community figured out that this was the spores of an algae .

Polar snow algae may appear on snowfields or mountaintops all over the world. Most of the time, it stays dormant in the ice and snow all year round. Only in the warm season, as the ice and snow melt, polar snow algae begin to become active, grow rapidly in low-temperature water, and produce red spores , just like red pigment squeezed out of a white palette.

Polar snow algae appeared not only on the snow, but also on the glaciers｜weather

The same story happened at the Wernadsky Station. It was the Antarctic summer at the time, and the station recorded a record high temperature of 18.3°C. The polar snow algae, which had been dormant for who knows how long, were awakened by the warmth, forming the rare "watermelon snow" phenomenon.

Scientists who study the environment and climate are very concerned about the presence of polar snow algae because it is very much like a "domino effect": after the algae begin to appear, due to its own red color, it will absorb more heat in the snow, causing the surrounding snow to melt faster, thereby further accelerating the reproduction of the surrounding algae .

In Antarctica, not only red snow has appeared, but also green snow｜aeif.asia

However, for biologists, they are more concerned about the unique cold-resistant property of polar snow algae. Polar snow algae will hardly be frozen to death, and it can reproduce normally as long as the temperature is above 5℃. When the environment begins to freeze, it begins to hibernate, and the cold outside has almost no effect on it. This is why it appears in the Arctic and Antarctic.

By sequencing the genes of polar snow algae, scientists have found that it is closely related to another green algae, Chlamydomonas reinhardtii, and the two have many similarities. But the biggest difference between them is that Chlamydomonas reinhardtii, like most algae, prefers warm environments, while polar snow algae only prefer low temperatures. It is precisely the difference in environmental selection that ultimately led to the differentiation of the two. So, why is polar snow algae not afraid of the cold?

Red snow in the Alps | mikrobalpina

You should know that in Antarctica, where polar snow algae are "rampant", it is not just about the low temperatures . Although it is a world of ice and snow, the annual precipitation is only 30 to 50 mm, and the air is as dry as the Sahara Desert.

Moreover, during the polar night, there is no sunlight for nearly half a year, but during the polar day, due to the thin ozone layer over Antarctica, the intensity of solar radiation is very high, and strong ultraviolet rays can damage the cells of organisms. However, polar snow algae can perfectly adapt to life in Antarctica and are widely distributed in many areas of the Antarctic continent.

In order to adapt to polar life, polar snow algae have indeed undergone many changes compared to other algae: its cell wall has become thicker and has more protrusions on it to increase the surface area, which can protect the vacuole inside the cell from drought or radiation. However, the most important change is that polar snow algae can secrete carotene and astaxanthin, which is the key to its fearlessness of cold and the origin of the red snow phenomenon.

The spores of polar snow algae can remain dormant for long periods of time in the dark and cold, but quickly come back to life when resuspended in water | mikrobalpina

These carotenoids can transfer the energy used by polar snow algae for photosynthesis and absorb excess free radicals, which not only improves the efficiency of photosynthesis but also plays a protective role. These dark pigments can also melt the ice and snow crystals around the snow algae cells to obtain limited nutrients and water that are not available under other circumstances. Other secondary metabolites synthesized by it, such as biopolymers (gallerten), antifreeze glycoproteins (AFGPs), stress regulators, and permeable amino acids and sugars, also help snow algae better adapt to low temperature environments.

In-depth research on polar snow algae can reveal how organisms can survive in low-end environments. It is also likely to become one of the first organisms sent to the moon or Mars base in the future. As a highly adaptable plant, it can continuously produce the oxygen necessary for interstellar immigrants. However, today, it has become a hot research subject in another field, that is, skin care and health .

Cosmetics made from polar snow algae extract｜мыло-опт

Nowadays, many cosmetics manufacturers have conducted more in-depth research on polar snow algae, especially its antioxidant and anti-aging effects. At the cellular level, polar snow algae produces a calorie restriction mechanism, which controls the conversion of energy. Calorie restriction has also been proven to be a method that can prolong individual lifespan and delay the occurrence of aging-related diseases.

In the current experiment, the polar snow algae extract optimized skin metabolism by simulating calorie restriction, thereby extending the lifespan of skin cells, strengthening the defense of skin cells, improving the ability to resist oxidative stress, and stimulating the production of more collagen.

In fact, many facial masks and essential oils now use polar snow algae extract as raw materials. This is also an unexpected surprise for scientists in the process of solving the "mystery of red snow"!

References

[1] Meteored. »Blood snow invades an Antarctic island«. https://www.yourweather.co.uk/news/science/blood-snow-invades-an-antarctic-island-world-weather-news-global-latest-science-environment-antarctica.html

[2] Gorton HL, Vogelmann TC. Ultraviolet radiation and the snow alga Chlamydomonas nivalis (Bauer) Wille. Photochem Photobiol. 2003 Jun;77(6):608-15. doi: 10.1562/0031-8655(2003)077<0608:uratsa>2.0.co;2. PMID: 12870846.

[3] Cvetkovska, M., Hüner, NPA & Smith, DR Chilling out: the evolution and diversification of psychrophilic algae with a focus on Chlamydomonadales. Polar Biol 40, 1169–1184 (2017). https://doi.org/10.1007/s00300-016-2045-4

[4] Zhongguo Fei Ai Za Zhi. 2023 Jun 20;26(6):473–478. [Article in Chinese] doi: 10.3779/j.issn.1009-3419.2023.101.19

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Source: Bring Science Home (ID: steamforkids)

Author: Quasimodo by the River

Editor: Wang Mengru

Proofread by Xu Lailinlin