Researchers discover that the ice cap is teeming with microorganisms

Researchers discover that the ice cap is teeming with microorganisms

Researchers discover that the ice cap is teeming with microorganisms

Danish researchers have found more than 4,000 different species of microorganisms in such melting holes in the ice. Photo credit: Laura Halbach

There are no plants and very few animals: people rarely come here. The large glaciers in Greenland have long been perceived as ice deserts. Gigantic ice sheets where living conditions are extremely harsh.

But now, it seems, we were wrong. There is much more life on the glaciers than we thought.

A group of researchers from Aarhus University’s Faculty of Environmental Sciences, led by Professor Alexandre Anesio, have discovered that the glaciers are teeming with life. Microbes that have adapted to life on the ice. And not just one or two species. Several thousand different species.

“In a small meltwater puddle on a glacier, 4,000 different species can easily live. They live on bacteria, algae, viruses and microscopic fungi. It’s a whole ecosystem that we didn’t even know existed until recently,” says Alexandre Anesio.

What do the microbes live on?

Over the past 50 years, researchers have been repeatedly surprised by the robustness of life. Life has been found several kilometers underground – where there is neither sun nor oxygen. Billions of microorganisms “eat” minerals in the bedrock and are able to survive.

Researchers have shown that life can survive even in space. In 2007, European researchers placed a colony of more than 3,000 microscopic tardigrades (tardigrades) outside of a satellite and sent them into orbit around the Earth. The orbit lasted 10 days, after which the satellite returned to Earth. As many as 68% of microbes survived the vacuum of space and deadly radiation.

Researchers discover that the ice cap is teeming with microorganisms

The researchers took this aerial photo with a drone. You are standing on the white ice on the left, while the black, slippery ice on the right is overgrown with algae. Photo credit: Laura Halbach

It is therefore not surprising that life also thrives on the glaciers. After all, there is sun, oxygen and water. Despite this, until recently, researchers believed that the ice had insufficient food for life. But they were wrong.

There is food. Only in incredibly small amounts, explains Alexandre Anesio.

Black Algae

One of the microorganisms on the ice that the researchers spent most of their time studying is a small black alga. The algae grow on the ice and turn it black. There’s a reason black algae are so interesting to researchers.

“As the ice darkens, it becomes more difficult to reflect sunlight. Instead, the heat from the sun’s rays is absorbed by the ice, which begins to melt. The more the ice melts, the warmer it gets on earth. So the algae play an important role in global warming,” says Alexandre Anesio.

In recent years, larger and larger areas of the ice have been tainted by the algae, causing the ice to melt even faster. Alexandre Anesio calculated that the algae increase ice melt by about 20%.

The algae on the ice also existed before humans started global warming through industrialization. However, climate change means that spring is arriving earlier and earlier in the Arctic, giving algae a longer season to grow and spread.

“The algae spread a little more every year. Now, when I travel to Greenland, I see vast areas where the ice is completely dark because of the algae,” he says.

Researchers discover that the ice cap is teeming with microorganisms

The algae that color the ice looks like this under a microscope. Long microorganisms that protect themselves from solar radiation with dark pigment. Photo credit: Alexandre Anesio

Looking for an algaecide

Alexandre Anesio and his colleagues spend a lot of time with the black algae trying to find out if there is any way to slow down the growth of the algae.

That’s a balance in most ecosystems—a kind of balance—because the different organisms keep each other in check. That’s why Alexandre Anesio wants to learn more about the relationship between the different microbes.

“The different microorganisms on the ice influence each other. Some leave food on which others live. Small virus particles attack and consume bacteria. We think some of the fungal spores may be eating the black algae. ” he says.

However, he stresses that even if they find a way to curb algae growth, it will not solve climate change. Although it might slow him down.

Algae growth is a result of us releasing too many greenhouse gases into the atmosphere. And here the problem needs to be solved. We need to focus on slowing down our emissions.

Researchers discover that the ice cap is teeming with microorganisms

If the ice is heavily infested with algae, it will be black rather than white. Researchers used to think the color was due to dust deposited on the ice. Today we know that the black color is caused by tiny algae. Photo credit: Laura Halbach

The same pigment as in black tea

Algae are found practically everywhere. In the sea, in lakes, on trees and rocks and even as small spores in the air. Most algae are greenish. Like plants and trees, they are green because of chlorophyll. A molecule that allows them to photosynthesize.

This is different with black algae.

“Because the algae live on the ice, they are bombarded with sunlight and radiation. To protect themselves, they produce a lot of black pigment. It’s actually the same pigment as in black tea. The pigment forms a protective layer outside the algae and protects the chlorophyll molecules from the dangerous radiation,” says Alexandre Anesio. When the pigment absorbs the sun’s rays, it generates heat. This heat melts the ice around the algae. And that comes to the algae actually benefit, they need both water and micronutrients from the ice to live.

And they can only use the water when it is liquid.

NASA also keeps an eye on his research

Alexandre Anesio’s research on life on ice is important for a better understanding of climate change. But NASA is also following his research results closely. The results could be crucial in the hunt for life in space.

Researchers discover that the ice cap is teeming with microorganisms

Alexandre Anesio collects samples on the ice in Greenland. Later he will examine the samples under the microscope to see what microorganisms they contain. Photo credit: Laura Halbach

“NASA has approached us on a number of occasions because we work with life living in one of the most inhospitable places on earth. If life thrives on and below the ice, there’s a good chance we’ll find life in the ice of Mars, or the icy moons of Jupiter and Saturn, for example,” he says.

Before NASA sent their rover Perseverance to Mars, they even invited Alexandre Anesio to a meeting.

“They were afraid that the rover would take microbes from Earth with it. Microbes that would potentially survive on Mars and contaminate the samples they would take from Mars. So they wanted to know under what conditions life can survive. What are the limits of life?”

NASA is so interested in studying life in ice because we haven’t found liquid water on any other planet in the solar system. At least not yet. But we found a lot of ice.

However, there is evidence that there are liquid oceans beneath the frozen surface of Saturn’s moon Enceladus and Jupiter’s moon Europa – and one of the necessities of life as we know it is liquid water.

As such, NASA and other space agencies are keen to learn more about the types of life that can live on and beneath the ice. Because organisms similar to those in Greenland, they will likely look for them on the icy moons.

“Like us, they are very interested in how the microorganisms on the ice work. How much food do they need? What kind of food? And how does the ecosystem they are part of work? These are questions that we can hope to answer in the future,” says Alexandre Anesio.

Corresponding research results are published in the journal geobiology.

More information:
James A. Bradley et al, Active and dormant microorganisms on glacier surfaces, geobiology (2022). DOI: 10.1111/gbi.12535

Provided by Aarhus University

Citation: Researchers Discover Ice Cap Teeming with Microorganisms (2023 May 2) Retrieved May 3, 2023 from

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