Snow of Tomorrow | Life at the Limit

Despite temperatures far below freezing, high UV radiation and an almost complete lack of nutrients, a highly specialized habitat exists here. Snow algae, unicellular microorganisms, bacteria, lichens and even tiny animals such as tardigrades have developed strategies to survive in conditions that would be fatal for almost all other organisms.

The "eternal ice" is therefore not a lifeless place, but fascinating proof of the adaptability of life. At the same time, it is a fragile habitat that is coming under increasing pressure due to the progressive retreat of glaciers in the Alps. For this reason, the following article aims to draw attention to these special creatures in order to create an understanding of why the preservation of their habitat, the glaciers, is so worth protecting!

Alpine tardigrade

They survive extreme cold, dry periods and even outer space: tardigrades, also known as tardigrades, look almost like tiny fluffy animals with their chubby physique, but are among the most resilient organisms on earth.

With a size of only approx. 0.2 to 0.5 mm, they live almost everywhere: in forest mosses, in our rain gutters, in fresh and salt water - and even in alpine glaciers. They are true survival artists! The first evidence of this primeval animal strain in Austria comes from Ehrenberg (1853), who researched high alpine microorganisms. Since then, around 120 species of tardigrades have been described. In the Alps, specially adapted tardigrades colonize the high mountains and live there in small melt holes on the surface of the ice.

Bloody snow

If you are out and about in the mountains, you may come across red-colored snow fields in spring and summer, which often causes astonishment. The organism group of algae is responsible for this. Most of them are only visible under a microscope and thrive not only in lakes but also in snow. Of the approximately 350 known species of snow algae, the widespread green algae Chlamydomonas nivalis is particularly conspicuous.

During the winter months, it lies dormant under the snow in the form of red spores. When the snow begins to melt, the concentration of spores on the surface increases, resulting in the characteristic reddish coloration of the snow cover. The spores are finally released into the ground via the melting water, where they survive the cold season, ready to start their life cycle again the following spring. To reproduce, they only need light, water and carbon dioxide from the atmosphere, making them true survivors. In 2019, the algae was even voted Algae of the Year.

The phenomenon caused astonishment as early as 1818: when British sailors in search of a north-west passage sailed along the coasts of Baffins Bay on Greenland, they reported seeing snow fields of a "dark crimson color". Captain John Ross described the snow as being "penetrated to a depth of 10 to 12 feet by the colored substance". Under the microscope, the officers found dark red, seed-like formations and suspected a "vegetable product" behind them. Today we know: The red coloration comes from the snow algae Chlamydomonas nivalis.

Glacier flea

The glacier flea (Collembola), which is only about 2 mm in size, is a year-round inhabitant of the extremely inhospitable glacier habitat. These darkly pigmented, highly adapted organisms are often visible on the light-colored snow and ice and resemble grains of sand at first glance. The colloquial name "glacier flea" is derived from their characteristic, erratic flight behavior; systematically, however, they belong to the order of springtails and thus to the insects. In order to survive permanently in the cryogenic environment of ice and snow, the glacier flea has developed a series of specialized physiological and behavioural adaptations. For example, stored sugar and alcohol compounds - a natural "antifreeze" - prevent the body fluids from freezing, so that the animals can tolerate temperatures well below freezing.

Glacier weaver

The Glacier Weaver's Snake - a true Alpine endemic - does not live directly on the bare ice, but in the rubble and scree of the glacier retreat areas. Endemics are animal and plant species that occur exclusively in a very small, geographically limited area and cannot be found anywhere else in the world. In the case of the glacier weaver frog, this is the "Alps" habitat; the glacier weaver frog therefore only colonizes the Alps. It occurs exclusively above the tree line and has been recorded at altitudes of up to 3,600 meters.

As a representative of the arachnids, it is mainly active at dusk and at night and is exceptionally well adapted to the extreme conditions of the high mountains. Similar to the glacier flea, it has a kind of biological "antifreeze" in its body that prevents its cells from freezing. This enables it to survive temperatures of minus 20 degrees and below, and even its enzymes remain functional in the freezing cold.

Adult animals appear in the short Alpine summer and remain in a state of torpor during frosty nights. They can even freeze completely into the ice and resume their activity as soon as they thaw out again. A particularly astonishing fact: the glacier weaver frog probably uses the temperature gradient in the scree to find suitable hiding places - an ability that helps it to track down even the smallest, warmer niches in the ice environment.

But its survival is becoming increasingly difficult. With the progressive retreat of glaciers as a result of global warming, the cool habitats to which it is perfectly adapted are also disappearing. At high altitudes, there is hardly any room for it to move further up - its habitat is literally shrinking with every year.