The water up here at the glacier snout is ice-cold. Nevertheless, we have no other option than to take off our shoes and wade through the young brook. After all, we did not come up here to admire the Damma glacier, but to visit the eight researchers who are busy collecting soil samples on the other side of the brook. These scientists from ETH Zurich are up here investigating how micro-organisms colonise a recently exposed glacial forefield.

Conquering new country

"Where glaciers recede new areas appear forming a habitat that is then gradually conquered by pioneer organisms," says my companion, Professor Josef Zeyer, head of the Soil Biology group at the ETH Institute of Terrestrial Ecology (1). The rule is that the nearer to the glacier, the younger the population one meets with. "Thanks to numerous studies we have a fairly good idea of how plants and animals spread out over these areas", continues Zeyer, "but very little is known about the process by which micro-organisms take up occupation of the new habitat and the biogeochemical processes involved."

The reason for this dearth of information on the processes is mainly methodic. It is only now that routine DNA and RNA analyses can show how many species occur in the soil and with what frequency. "We surmise that in the proximity of the glacier, on the newest exposed areas, a few specialised species dominate the unfolding process," explains Zeyer. "The further away from the glacier one gets, the more balanced the composition of species should be."

Advance disturbs chronology

There are very good reasons why the team is carrying out their investigations at this spot. To begin with, the Damma glacier lies within easy reach from Zurich. Moreover, it lies in a geologically fairly homogeneous and well-known region that has been subjected to exact survey for decades. The Damma glacier has receded around 400 metres in the past eighty years and during that time has made only one significant readvance. This is a very important point, as Zeyer explains. "When a glacier suddenly starts to grow again over a couple of years, it rapidly disturbs the chronology on the glacial forefield."

On principle it makes sense that the researchers gather samples from areas of soil that lie at different distances to the glacier in order to document both the microbiological and geochemical processes. But once one is standing in front of the glacier it quickly becomes clear just where the methodic problems of the approach lie. A glacial forefield is by no means a uniform terrain, but an area composed of many different kinds of micro-habitats. "Last year we tried to get around this problem of inhomogeneities by taking samples from habitats that were as similar as possible," Zeyer goes on to say. "This year we are focussing our attention precisely on this small scale variability."

Josef Zeyer and Ciro Miniaci taking samples at the foot of the Damma glacier large

Researchers collecting earth samples surrounding a plant (picture: C. Miniaci). large

Plants as forerunners

In the meantime we have reached Ciro Miniaci's "workplace". The PhD student, has pegged out a kind of grid, knotted from ropes,on the ground and he is taking soil samples from each square of the netting with a small shovel. "One of our hypotheses is that plants influence and encourage microbial diversity and activity over very small areas and thus accelerate colonisation of the soil by new micro-organisms," explains Miniaci.

As we arrive, he has just placed the sample grid around an alpine marguerite (Chrysanthemum alpinum). He has already put the plant, with roots, in a plastic sample bag and now he is collecting the soil in which it had grown. He then proceeds by collecting more soil samples at a number of defined distances to the plant. Nearby, colleagues are carrying out the same procedure on comparable control areas without plants.

Strenuous drudgery

In principle, only two of the eight scientists are actually working on the research project. But in order to expedite the time-consuming stage of collecting samples, others from the institute lend a helping hand whenever fieldwork is called for. "I never have any trouble finding volunteers," says Zeyer, with a wide smile. And this, even though a weekend on the Göscheneralp really takes it out of the participants.

On Saturday, for example, after having worked all day collecting samples over a considerable area, the team had to accomplish the steep climb up to the SAC Damma hut in the late afternoon. And on Sunday, after everything has been classified and packed the soil samples have to be carried back to the car. An individual sample might weigh very little, but a considerable weight accumulates during the course of a whole day in the field.

Studying the entire process chain

Some of the samples have to be transported in special boxes with dry ice. Zeyer wants to examine the nitrogen content of the soil of these pioneer habitats more closely. "There are two methodically fairly simple approaches to carry out this analysis. Either one can directly measure the quantity of nitrogen in the soil with biochemical methods or, using molecular-biological analyses, we can determine which organisms are involved in nitrogen production according to their genetic layout ," explains Zeyer.

"What we hope to achieve now is a bridge to better understand the whole process chain leading from DNA to activity." This is why the researchers are now analysing the so-called messenger RNA in certain samples, which shows whether the corresponding genes are activated or not. This messenger RNA, however, decomposes very quickly and the respective material must therefore be cooled in dry ice immediately.

Before the cases with the valuable samples are brought to the laboratory in Schlieren, the team pauses for a moment. It's time to toast the successful field work and to thank all helpers for theircooperation. And as Miniaci miraculously conjures up a buffet, spread with Italian specialities, in front of the imposing backdrop of the glacier this agrees very well with the prevailing good humour.