Resurrection: Moss resurrects 400 years in the ice grave

Mosses buried for centuries under an arctic glacier strike back again

Fresh from the ice: a cushion of Aulacomnium turgidum moss in the run-up to the Teardrop Glacier in the Canadian Arctic © Catherine La Farge
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Moose are not that easy to kill, you've known that for a long time. However, these plants, which have been successful for around 400 million years, have astonished even botanists: For in the Canadian Arctic, mosses survived for 400 years under the meter-thick ice of a glacier - only to knock out when it melted down as if nothing had happened. This demonstrates impressively how resilient this group of plants is, according to Canadian researchers in the journal "Proceedings of the National Academy of Sciences". But it also shows that the soil exposed by the shrinking glaciers is neither dead nor uninhabited.

Increasing global warming is causing global glaciers to disappear. For example, on the Ellesmere Island in the Canadian Arctic, the Teardrop Glacier has retreated more than 200 meters since 1850. "In the glacier foreland, this is clearly visible on a sharp border, " report Catherine La Farge from the University of Alberta in Edmonton and her colleagues. While the normal Arctic vegetation grows outside of this border, there are numerous Istrümmer on the previously covered by ice, lighter ground and only a few isolated plants. Most of them are typical pioneer plants - the plants that grow particularly well on bare soil and therefore are usually among the first colonizers.

Buried in the Little Ice Age

In between, however, the researchers also discovered small moss cushions, which looked anything but healthy at first glance: they were blackish-brown instead of lush green. Obviously, La Farge and her colleagues concluded, these mosses had once migrated from the glacier, been preserved in the ice, and only now had they been uncovered. "Such subglacial plants have been found on other glaciers since the 1960s - but so far, all researchers considered them dead, " the scientists explain. Whether this is actually the case, they have now systematically tested.

In a first step, La Farge and her colleagues used the radiocarbon method to test how old the supposedly dead moss cushions were. It turned out: The plants were real Methusalems, they had already stately 400 to 600 years behind them. They come from the era of the so-called little ice age, a particularly cool climate period between 1550 and 1850. However, they were exceptionally well preserved: "Their stems, bristles and even the fine tips of the leaf hairs are still completely intact, " the researchers report. Apparently they have been preserved under the ice under ideal conditions.

New life comes to life: new shoots of 400 years of moss buried under ice Catherine La Farge

Clone artist of nature

But were the glacier moso really just conserved, or were they still alive? To test this, La Farge and her colleagues put the sample to the test. They collected samples from seven different subglacial mosses and placed shredded plant parts of the samples in the laboratory in pots containing potting soil or nutrient medium. display

"This works because mosses are predominantly clonal organisms: they have the ability to make a complete, new plant out of individual mature cells, " the researchers explain. This more than 470 million year old group of land plants has developed a unique evolutionary strategy. The success of this strategy was demonstrated by the laboratory tests: after all, around a third of the moss samples collected on the edge of the glacier did not prove to be dead, but rather lively and vigorous. They formed new green stems and leaves.

Among the mosses resurrected in this way were both drought-adapted species and moisturizing ones, as the scientists report. This demonstrates that mosses with very different ecological requirements have the ability to survive for centuries - and then turn them up again.

The eastern edge of the Teardrop Glacier on Ellesmere Island in the Canadian Arctic Catherine La Farge

Glacier bottom as a reservoir of life

As the researchers emphasize, there is nothing more to it than a little earth. In contrast, the glacial midge saved in 2012 by researchers from the Siberian permafrost could only be regenerated by a complex process. The researchers took tissue from a seed of the 30, 000-year-old flower plant, cloned the embryonic cells contained therein and then grew it using special nutrient solutions.

The mosses once buried by the glacier, on the other hand, manage to resurrect themselves, as La Farge and her colleagues at the Teardrop Glacier observed. For on closer inspection, they also found moss cushions released from the ice, which had developed the first new shoots.

"Soils and landscapes that are exposed by the receding ice of the glaciers can no longer be considered barren and free of land plants, " say the scientists. In addition to bacteria, microscopic algae and soil organisms, conserved mosses also form a first basis for the resettlement of such habitats. (Proceedings of the National Academy of Sciences (PNAS), 2013; doi: 10.1073 / pnas.1304199110)

(Proceedings of the National Academy of Sciences, 28.05.2013 - NPO)