Blood-Snow! Is Earth Bleeding?!

Reviewed by: BD Editors

Some new observations from a research outpost in Antarctica are freaking some people out. “The Earth is Bleeding,” the internet says.

While this is simply the byproduct effect of a species of algae, the fact that the phenomenon is related to climate change, and looks like blood, is really the perfect symbol. See for yourself:

"Blood" or "Watermelon" Snow, caused by a species of algae.
“Blood” or “Watermelon” Snow, caused by a species of algae.

But, to explain why blood snow is the perfect symbol of climate change, we have to understand a couple of biological concepts: Algal Blooms and Extremophiles.

Algal Blooms

Algae is a single-celled organism that is essentially constantly reproducing in the right conditions. Most of the time, in both freshwater and marine environments, nutrients are relatively sparse, sunlight is somewhat blocked, and other conditions keep algae at relatively low levels.

However, there are many human activities that can inadvertently remove one or more of these barriers, causing a massive increase in algae reproduction. For instance, many deadly algal blooms occur as rivers empty into the ocean. The rivers, loaded with washed-off nutrients from farms spanning the river’s length, spill these concentrated nutrients right into the ocean.

The effects can harmful and damaging to wildlife, humans, and entire marine ecosystems. Some of the largest algal blooms actually cause “dead-zones” below their surface. As the algae grow thick, the lower layer begins to die. Bacteria, eager to feed on the massive bounty of dying algae, quickly consume all the oxygen in the water and killing many organisms. Other algal blooms actually release toxic chemicals as they die off, poisoning the water for any that enter. The effects are so drastic that even adult whales can be killed.

A whale that has died due to toxins in an algal bloom.
A whale that has died due to toxins in an algal bloom.

But, to understand this recent blood-colored algal bloom on the snow, we can look at one more biological concept: Extremophiles.


Extremophiles are any organisms that live in what most other creatures would consider a “hostile” environment. In other words, extremophiles can survive in places that destroy other forms of life. In fact, there are many different types of extremophile:

  • Acidophile – acid lovers
  • Alkaliphile – “All About that Base”
  • Halophiles – live in extremely salty places
  • Radiophile – organisms that just LOVE toxic radiation
  • Anaerobe – oxygen is for wimps
  • Osmophile – too much sugar? Never a problem.

While the list goes on and on, the blood algae are actually just a form of green algae that is also an extremophile. A “cryophile”, to be more precise. These algae can live in much colder temperatures than a typically algal cell, thanks to mutations that give it an extra cell wall and allow it to melt surrounding ice into fresh, clean water!

This brings us back to blood algae as a symbol of climate change.

Is Earth bleeding? Maybe…

While this is not actual blood and has been observed several times, these giant red algal blooms seem to be happening more often. The barrier holding these algae back is simply the lack of water. So, once a little melting starts to happen these algae can really start to take off and melt much more ice.

Since ice reflects sunlight, and water does not, the water begins to heat up and melt even more ice. Therefore, the more frequent these algal blooms become, the faster the effects of climate change will be seen. While these blooms are not known to be harmful, other algal blooms also caused by global warming and pollution could easily poison our water supply and contribute to the destruction of entire ecosystems.

So, in a way, the Earth is bleeding and we should pay attention.

Cite This Article

MLAAPAChicago Editors. "Blood-Snow! Is Earth Bleeding?!." Biology Dictionary,, 02 Mar. 2020, Editors. (2020, March 02). Blood-Snow! Is Earth Bleeding?!. Retrieved from Editors. "Blood-Snow! Is Earth Bleeding?!." Biology Dictionary., March 02, 2020.

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