Snow Algae in Antarctica | Why Does the Snow Turn Red, Green, and Pink?

By Coty Perry

a gentoo penguin wandering on rocks and red snow algae on petermann island antarctic peninsula shutterstock secret atlas

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Snow Algae in Antarctica | Why Does the Snow Turn Red, Green, and Pink?

In case you are familiar with environmental news, the growth of algae in Antarctica turning the snow red might have attracted your attention. But this odd phenomenon is nothing new and not limited to Antarctica. In fact, this was observed by Aristotle back in 300 BC.

But it is only recently that the important role that snow algae play in impacting climate change has come into focus. With algal blooms increasing in Antarctica, their role in influencing Antarctica’s climate and ecosystems is turning out to be significant.

What is snow algae?

Snow algae is found growing in the polar and alpine regions across the globe, and they prefer temperatures close to 0°C. These single-cell algae can survive in freezing conditions and grow in soil having low nutrient content.

One common snow algae species is Chlamydomonas nivalis. However, there are other species that researchers have found - more than 450 species are known to exist. These green algae are a part of the complex snow microbiome that consists of other bacteria and fungi.

What makes these algae special is their ability to adapt to the environment by altering their pigmentation. In spring and summer, they form red spores under the snow by generating carotenoid pigments - think of it as algae sunscreen that helps them to survive harsh UV rays.

Red coloured snow is not something that is commonly known about Antarctica. No wonder the algae has been given poetic names like ‘watermelon snow’ and ‘blood snow’.

clamydomonas nivalis unicellular alga on snow shutterstock secret atlas

Origins and adaptations

While visiting Antarctica, you may find green snow algae is found along the coastline, and on the islands where the average temperatures do not drop below zero degrees. These photosynthetic algae live on the water layer covering the snow and ice. Their origin can be traced back to other species of social and aquatic algae.

Their distribution depends on multiple factors like snow pH, salinity, sunlight and nutrient availability. In Antarctica, areas that are nesting sites of marine birds and mammals have a high distribution of snow algae. The reason is simple - animal excrements are an excellent source of nutrients for them.

snow algae blooming in antarctica shutterstock secret atlas

Life cycle of snow algae

The life cycle of the snow algae is complex and closely related to the snow properties. They can survive harsh conditions in a resting phase as spores and zygotes, and bloom when conditions are favourable.

The spores have thick walls and energy reserves to withstand long and dry winters. Some species produce a chemical that helps them to adhere to the snow and prevents them from getting washed away by meltwater.

What causes the snow to turn red, green, and pink?

While the algae are primarily green in colour, their cysts can be yellow-green, red, or orange. These are the same pigments found in oranges and carrots. The colour of the snow depends on the pigments formed in the algal cells.

The effect of the pigments is not so good for the ice though - especially with global warming threatening Antarctic ecosystems. The pigments absorb heat and melt the surrounding ice, which in turn produces more algae, creating a natural feedback loop that contributes to climate change.

snow algae or also known as watermelon snow shutterstock secret atlas

Other reasons for colorful snow in Antarctica

Apart from the green and red shades resulting from algae, you will find blue-coloured ice in Antarctica. These are large and dense ice crystals, that are mainly deep glacial ice. This ice appears blue as it reflects the short-wavelength blue light. Generally, a leading edge of a glacier that is breaking away, can appear blue.

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Planning your trip to Antarctica

The climatic influence of the snow algae is not something commonly mentioned in Antarctica travel guides. However, this is one more pointer towards the fragility of Antarctica’s ecosystem which makes responsible travel a necessity.

So, choosing a reliable option for exploring Antarctica is not enough. You need to pick an Antarctic cruise that takes the right steps to make the journeys sustainable.

Visit Antarctica with Secret Atlas

A journey to Antarctica with Secret Atlas is an exploration that goes beyond the conventional definitions of an Antarctic cruise. Our small ship expeditions are about immersing yourself fully in the experiences that the land has to offer by staying away from crowds and fixed schedules.

From observing the incredible wildlife to fascinating landscapes, our journeys are curated to help you witness the best of Antarctica. Connect with us to learn more about our upcoming trips.