Prof. Dr. Gabriele Berg’s keynote speech about the Microbiome
There may be 1030 million bacteria on Earth today. They were the planet’s earliest life form, appearing about 3.8 billion years ago. By comparison, plants arrived much later, around 475 million years ago, and the earliest humans only about 2 million years ago and Homo sapiens only about 300,000 years ago. In absolute numbers and in numbers of species, micro-organisms make up by far the largest part of the tree of life.
In many ways, we could say that the microbiome has been shaping evolution since the beginning. And in many ways, microbes have been shaping evolution from the very beginning. Early bacteria pioneered photosynthesis, and cyanobacteria eventually produced the oxygen that transformed Earth’s atmosphere, making it possible for complex life to evolve and diversify.
In short, radically-shared aliveness includes far more than the eye can see. This is why the World Ethic Forum invited Prof. Dr. Gabriele Berg, microbiome researcher at the Technical University of Graz, to give a keynote speech on our 2025 annual public event, and take us on a journey to encounter the microbiome.
This field of research can trace its origins to the 1600s, with van Leeuwenhoek’s observation of the first micro-organisms. Since about the turn of the millennium, it has gained enormous momentum. With this came a shift in perspective: since about the middle of the 19th century, with the work of Koch and Pasteur , micro-organisms had been associated with illness. Today, we recognise that they’re just as central to health.
No animal including humans can survive without its microbial partners. In humans, we encounter them mainly in the colon, but they’re also present in our respiratory track and on the skin. In total, each human carries 1–2 kilograms of microbiome. Around half of it is inherited from the mother, while the other half comes from the environment we grow up and live in. It impacts our overall well-being, affects many chronic diseases, and – through the gut-brain axis – plays a critical part also in our mental health.
Importantly, the global microbiome is changing, impacting humans and the more-than-human. Across many environments—including soils, plants, and even human bodies—researchers have observed a decline in slow-growing, highly specialised microbes and an increase in fast-growing, generalist species. These shifts can lead to microbial communities that respond quickly to disturbance but are less stable and less resilient over time.
Many of these changes are linked to land use and agricultural practices. Research conducted both in environmental disaster zones – such as the desiccated and highly polluted Aral Sea – and in best-case scenario settings like spaces devoted to biodynamic agriculture, confirm that the type of microbiome present in the soil, the water and the environment is directly tied to land use and agriculture, including levels of disturbance, irrigation, and the use of synthetic fertilisers and pesticides.
When the microbiome collapses, ecosystems and planetary processes break down as well. The loss of microbial diversity also affects human health. It has been linked with around 90% of chronic conditions, including autoimmune diseases and cancer.
As new research further reveals the depth of our connection with microbial life, it’s important to remember all the unseen beings and communities that make our own lives and the entire living world possible: there is no radically-shared aliveness without the microbiome.