[Answered] What is red snow? What causes red snow? Discuss various concerns over red snow in Antarctica.


Demand of the question

Introduction. What is red snow?

Body. Discuss what causes red snow and various concerns over red snow in Antarctica.

Conclusion. Way forward.


Red snow is a natural phenomenon, which is also known as ‘watermelon snow’ in which snow turns red in colour naturally. It can be observed in the Arctic, the Alps and other high mountain ecosystems. Recently, snow around Ukraine’s Vernadsky Research Base, located off the coast of Antarctica’s northernmost peninsula has started to take on a red tinge.


Mechanism of red snow formation:

  1. Microscopic algae: It is a phenomenon caused by Chlamydomonas nivalis, a species of green algae containing a secondary red carotenoid pigment in addition to chlorophyll which give red tint to the snow.
  2. Natural phenomenon: The microscopic Chlamydomonas nivalis algae produce the tinted sunscreen to keep themselves warm.
  3. Cryophilic: Unlike most species of fresh-water algae, it is cryophilic (cold-loving) and thrives in freezing water.
  4. Protective mechanism: This bright red carotenoid pigment, protects the chloroplast from intense visible and also ultraviolet radiation, as well as absorbing heat, which provides the algae with liquid water as the snow melts around it.


Various concerns over red snow in Antarctica:

  1. Faster melting: The intensity of the redness increases with the dense presence of the algae. The darker tinge leads to more absorption of heat by the snow. Subsequently, the ice melts faster.
  2. Albedo: Further, these algae change the snow’s albedo (the amount of light or radiation the snow surface is able to reflect back). Changes in albedo lead to more melting. In the melting of snow in the Arctic, the key drivers have been snow and ice albedo.
  3. Floods: Due to rise in melting there is associated risk of flooding of the plains and adjacent region of polar areas.
  4. Accelerate melting rate: It has been calculated that a teaspoon of melted snow contains a million or more cells. The algae sometimes accumulate in “sun cups”, which are shallow depressions in the snow. The carotenoid pigment absorbs heat and as a result it deepens the sun cups, and accelerates the melting rate of glaciers and snowbanks.
  5. Global warming: As the snow melts more, it releases stored carbon in the glaciers and leads to further warming of the atmosphere.


A study of German Research Center for Geosciences, examines summer snow microbes (like C. nivalis) and found that the algae are so global, that the algae’s effect on melting snow and ice needs to be included in climate models. Many suggest that future climate simulations should account for the effects of algae when making predictions about the rate of melting ice and contributions to climate change.

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