BRAIN: Professor Mosbrugger, why should we as humans devote more thought to the important but largely unspectacular bacteria?

Dr Volker Mosbrugger: Man’s behaviour on Earth is more or less like that of any bacterium, ant or bird. We use naturally available resources to survive as best we can in the largest possible number, just like all of Earth’s living creatures. The only thing that distinguishes us from them is our ability to reflect on our actions, and to change our behaviour if necessary. And what’s more, we couldn’t live at all without bacteria.

BRAIN: As we said before, we should also take microbial life forms into account in our efforts to mitigate climate change and protect the environment. Why have you decided to champion the cause of those invisible organisms?

Dr Volker Mosbrugger: Bacteria are key organisms that are vital for survival. All multicellular animals live in close symbiosis and interaction with microorganisms and could simply not exist without their “microbiome”. They also play a key role in ecosystems. If they were absent from the soil, for instance, harvests might be poorer or fail completely. Mostly, we only recognise these microbiological and ecologi- cal connections when we feel their direct negative impact – and then it’s often too late. So we should invest more in preventive research that is geared to findings instead of mainly looking for solutions to existing problems.

BRAIN: Microorganisms have adapted to the most extreme living conditions on Earth ...

Dr Volker Mosbrugger: ... You are referring to habitats in which microorganisms survive without oxygen in rocks a hundred metres below the sea, in permafrost conditions, sulphurous springs or at high pressure in the deep sea.

BRAIN: Yes, important sources that BRAIN also draws from. Could these sources dry up one day, independently of how the climate develops?

Dr Volker Mosbrugger: To wipe out these masters in the art of survival, or all life on Earth, liquid water would have to completely disappear from our planet, and that will not happen in the fore- seeable future.

BRAIN: Man has also adapted to his environment and is fond of calling himself the pinnacle of creation. This attitude has led to a parting of the ways, from natural evolution to so-called “cultural evolution”: clothing and houses protect us against fluctuations in temperature, medicines protect us from diseases, and the knowledge and products of the food industry protect us from malnutrition.

Dr Volker Mosbrugger: Yes, man is the only animal that is no longer directly influenced by natural environmental factors as a result of “cultural evolution”. This is reflected, for example, in the fact that people who have been vaccinated against an aggressive strain of influenza are more likely to survive an epidemic that those who have not. Today, the survival prospects of our children usually depend more on the available medicine and the culture in which they live than on their genes. So we as a species are not directly threatened, but we do have a direct influence on the quality of our future.

BRAIN: Do our knowledge of the history of evolution and the adaptability of bacteria to extreme living conditions, and our possibilities of reflection, equip us to preserve the future of our planet?

Dr Volker Mosbrugger: I think they do, even though many things are changing. We just have to gear ourselves up. Changes are a firm component of Earth’s history, and as always, there will be winners and losers. Take anthropogenic global warming, for example. Statements such as “Man is destroying the natural balance” are simply incorrect in scientific terms. There is no such balance. We know that various extreme conditions have already existed on Earth. About 600 million years ago, Earth was a huge snowball on which probably only simple organisms like bacteria were able to survive in the ice-free regions of the deep sea. There were also periods when there was no ice on the Earth’s poles. Crocodiles lived where there is now Arctic ice. Then there were phases when the carbon dioxide content of the at- mosphere was three to four times as high as it is today. Earth and life on Earth can tolerate many different conditions, including the expected anthropogenic climate change. But the transition to these warmer global conditions will be extremely painful, which is why it is imperative for us to rapidly reduce the emission of greenhouse gases. We should do our best not to count among the losers when this self-inflicted climate change hits us.

BRAIN: BRAIN’s work focuses on sustainability, including the development of more resource-saving technologies. In view of the larger picture, this is certainly only a small attempt to conserve a future that is worth living. Nevertheless, there are many plans that involve searching for a habitable planet beyond Earth. Do you think such plans stand any chance of success?

Dr Volker Mosbrugger: Well, I’m an evolutionary biologist by training, so I’m convinced that evolutionary “trial and error” processes are ideal for developing a viable and highly complex systems. The ecological viability of Earth as a system is changing in the wake of technological developments. With the technologies that existed 50,000 years ago, Earth’s ecological viability would never have sufficed to feed seven billion people. Today, seven billion people could live quite decent lives on Earth if w