A piece of ice or, now, with melting ice, a small pool of water on the surface of a glacier in Greenland can contain up to 4,000 different species of microorganisms, living or dormant (which can be activated depending on environmental conditions). An example of this biological diversity is black algae, which under normal conditions are really scarce, but with rising temperatures they are spreading through the ice.
Black algae are an example of a vicious circle of damage and the effects of climate change: warming facilitates the growth of black algae and these, in turn (by proliferating and having a dark color and not reflecting sunlight), cause an increase of ice and water temperature.
A team led by experts from the University of Aarhus (Denmark) has specialized in the study of the biological diversity of permanent ice in Iceland and Greenland and now warns, once again, of the risk that climate change poses to the stability of these masses of frozen water and the multiple forms of life that are maintained in them. The work of these experts has now been disclosed by the communication department of their university, in a detailed specialized report that includes the results recently published in the scientific journal Gebiology.
“There are no plants, and only very few animals: people rarely come here. Greenland’s great glaciers have long been perceived as ice deserts. Gigantic sheets of ice where conditions for life are extremely harsh. But now , apparently, we have been wrong. There is much more life in the glaciers than we thought”, recalls the University of Aarhus.
Led by Professor Alexandre Anesio, a group of researchers from the Department of Environmental Sciences at Aarhus University have discovered that glaciers teem with life. Microbes that have adapted to life on ice. And not just one or two species. Several thousand different species.
“A small pool of meltwater on a glacier can easily have 4,000 different species living in it. They live on bacteria, algae, viruses and microscopic fungi. It’s a whole ecosystem that we didn’t know existed until recently,” says Alexandre Anesio.
One of the microorganisms in the ice that the researchers spent the most time investigating is a small black algae. The algae grow on the ice and turn it black. There’s a reason black algae is so interesting to researchers.
“When 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 the temperature on Earth. Therefore, algae play an important role in global warming,” says Alexandre Anesio.
In recent years, algae have stained larger and larger areas of the ice, causing the ice to melt even faster. Alexandre Anesio has calculated that algae increase ice melt by 20 percent.
The algae in the ice also existed before people caused global warming through industrialization. However, climate change means that spring comes earlier and earlier in the Arctic, and as a result, algae have a longer season to grow and spread.
“The algae spread a little more each year. When I travel to Greenland, I now see vast areas where the ice is completely dark due to algae,†she says.
Alexandre Anesio and his colleagues are spending a lot of time on black algae because they are trying to figure out if the growth of the algae can be slowed down one way or another.
There is a balance in most ecosystems, a kind of balance, because the various organisms control each other. So Alexandre Anesio wants to learn more about the relationship between the different microbes.
“The various microorganisms in the ice affect each other. Some leave the nutrition on which others live. Small viral particles attack and consume bacteria. We think that some of the fungal spores could eat the black algae. This is what we’re looking for.†However, even if they find a way to curb algae growth, it won’t solve climate change. Although it could slow it down, indicates this expert.
Algae growth is a consequence of the release of too many greenhouse gases into the atmosphere. And this is where the problem must be solved. “We have to focus on slowing down our emissions,” stresses Aarhus University.
Algae are found practically everywhere. In the sea, in lakes, on trees and rocks, and even as tiny 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. But it is different for black algae.
“Because the algae live in ice, they are bombarded with sunlight and radiation. To protect themselves, they produce a large amount of black pigment. It is actually the same pigment as that in black tea. The pigment forms a protective layer outside algae and protects the chlorophyll molecules against dangerous radiation,” says Alexandre Anesio.
When the pigment absorbs the sun’s rays, it generates heat. This heat causes the ice around the algae to melt. And this really benefits the algae. They need water and micronutrients from the ice to live. And they can only use water when it’s liquid.
NASA is also closely following the results of these and other similar investigations, not only because of their effects on climate change on Earth, but also because they may help the search for life in space.
“NASA has approached us several times because we are working with life that lives in one of the most inhospitable places on Earth. If life thrives on and below the ice, there is a chance that we will also find life in the ice of Mars”. or the icy moons of Jupiter and Saturn, for example,†she says.
NASA is so interested in investigating life in ice because we have not found liquid water on any other planet in the solar system but there is a lot of ice and there are indications that liquid water and some forms of life may exist under the ice.
Therefore, NASA and other space agencies are very interested in learning more about the kind of life that can live on and under the ice. Because the organisms that look like the ones in Greenland are probably the ones they’ll be looking for on the ice moons.
“Like us, they are very interested in how the microorganisms in the ice function. How much nutrition do they need? What kind of nutrition? And how does the ecosystem of which they are a part function? These are questions that we hope to be able to answer in the future”, says Alexandre Anesio.
