• 25.05.2018
  • News
  • Swiss Academy of Sciences

Prix Schläfli 2018 in Geosciences: Alexandre Bagnoud

Alexandre Bagnoud
Image: Alexandre Bagnoud
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Alexandre Bagnoud
Alexandre Bagnoud (Image: Alexandre Bagnoud)

Not far from St. Ursanne, the idyllic medieval village on the Doubs, there is another, quite different visitor attraction: swisstopo's Mont Terri rock laboratory. The microbiologist Alexandre Bagnoud often visited this laboratory between 2012 and 2016, not as a layman curious about optimum conditions for storing radioactive waste, but as an active researcher.

"Yes, I spent a lot of time in the tunnels there," recalls Bagnoud. It felt a little like babysitting, because his experiment needed a lot of attention. But he enjoyed the unique atmosphere deep inside the Jura rocks, the absence of day and night and the even temperatures, whether in summer or in winter. "When you're inside, you sort of lose your awareness of time."

But what is the link between an expert in bacteria and the issue of the permanent storage of radioactive waste? Experts think on a geological time scale when it comes to reducing the radioactivity of used fuel rods, and so research on nuclear waste also focuses on correspondingly slow processes. Researchers mainly analyse the physical properties of suitable rock formations and geodynamic processes that could threaten the hermeticity of deep geological repositories. But biological processes also play an important role, because there are micro-organisms almost everywhere, even thousands of metres below the earth's surface.

He has always been interested in the diversity of these simple life forms that look so similar under a microscope. "But when you look at their metabolism, these organisms have a much wider spectrum of variation than animals or plants." At the beginning of his research career, Bagnoud quickly realised that he wanted to investigate the role of these smallest - but far from unimportant - players in ecological systems.

In the course of his research for his doctoral thesis, he did in fact discover a microbial community consisting of seven kinds of bacteria with surprising properties. These bacteria do not pose a threat to a deep geological repository — quite the opposite in fact: if the design of the repository is adapted slightly, they can be used to bind the hydrogen that inevitably builds up when the steel containers start rusting. This development of gas is a factor of uncertainty in the storage of radioactive waste. The gas pressure could become so great that even a perfectly suited rock formation can become permeable.

After he solved the countless technical problems – in many respects, he entered new territory with his experimental design and his main challenge in the initial years lay in overcoming opposition – for two years Bagnoud followed the development of "his" family of microbes, which he exposed to large quantities of hydrogen, deep inside the Opalinus Clay rock formation at Mont Terri.

Once the bacteria had used up all the available oxygen and iron, there was a noticeable change in the composition of the community and the metabolism of the various bacteria species. They began to use hydrogen as their source of energy and in this way controlled the amount of gas. As a result of his doctoral thesis, the researchers involved in the project recommended constructing a niche for the bacteria in the repositories, a fourth "biological" barrier consisting of porous material. This would allow Bagnoud's darlings to set themselves up in an environment that would be downright hostile to us, but to them is actually very hospitable.

Alexandre Bagnoud was awarded the Prix Schläfli 2018 in Geosciences by the Swiss Academy of Sciences for his article "Reconstructing a hydrogen-driven microbial metabolic network in Opalinus Clay rock", which he published during his doctoral studies at the EPF Lausanne. He is now researching at the University of Vienna.

Those who wish to learn more about the research into the permanent storage of radioactive materials can also visit the Mont Terri rock laboratory. More information is provided at: www.mont-terri.ch

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Preisträgerin und Preisträger Prix Schläfli 2018
  • 25.05.2018
  • Swiss Academy of Sciences
  • Press release

SCNAT honours the four best dissertations in sciences

The storage of radioactive waste, the pollination of plants, the use of solar energy, and the mathematical parsing of knots and surfaces – the Swiss Academy of Sciences (SCNAT) will honour the four most important discoveries and solutions by young researchers at Swiss universities with the Prix Schläfli 2018 in Bern on 25 May. Alexandre Bagnoud (Geosciences), Livio Liechti (Mathematics), Hester Sheehan (Biology) and Xiaojiang Xie (Chemistry) win the prize for discoveries made while working on their dissertations. The Prix Schläfli has been awarded since 1866.
Prix Schläfli 2018 Biologie: Hester Sheehan
  • 25.05.2018
  • Swiss Academy of Sciences
  • News

Prix Schläfli 2018 in Biology: Hester Sheehan

Those who frequent nightclubs know that when they wear white, their clothes take on a special glow in UV light. But researchers took a long time to realise that plants have a very similar "nightlife": the ways in which the colours of flowers determine which pollinating insects and birds they will attract have long been an important field of research, but the researchers – who mostly worked during normal working hours – only focused on the situation during daylight, on bright and vibrant flowers and eyes that specialise in seeing colour. In her research work, Hester Sheehan also looked at the way this phenomenon works during the night: boring white petunias that appear midnight black in the UV spectrum. An eye-catcher for nectar-hunting moths that are active during the night.
Xiaojiang Xie
  • 25.05.2018
  • Swiss Academy of Sciences
  • News

Prix Schläfli 2018 in Chemistry: Xiaojiang Xie

He is described as a "volcano of scientific ideas" by Eric Bakker, his PhD supervisor at the University of Geneva. Xiaojiang Xie laughs a little when he hears this on the phone in his hometown of Shenzen, to which he returned two years ago. Prior to that, he had been a researcher for five years in Geneva and Paris, where he launched a career that would make the world sit up and take notice.
Livio Liechti
  • 25.05.2018
  • Swiss Academy of Sciences
  • News

Prix Schläfli 2018 in Mathematics: Livio Liechti

We could start with flamenco. Or with doughnuts. But neither of these would really help us to understand Livio Liechti's research. "On the spectra of mapping classes and the 4-genera of positive knots" is the title of the thesis which he submitted a year ago – and anybody who can visualise this has to be a member of a select circle of specialists. Whereby "visualise" is a fairly apt term. "I like the fact that the objects of my field of research are quite visual," says Liechti. He thinks of them three-dimensionally – and his mathematical thought processes also often work on this visual level, and not only in formulas, figures and logical sentences.

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