Clouds determine the amount of sunlight that reaches the surface of the Earth, and therefore they are of great importance to the Earth's heat balance. There is growing evidence that aerosols, in particular bioaerosols like bacteria, affect the physical properties of clouds. Nevertheless, we lack detailed knowledge of their fundamental role in clouds. For instance, several studies showed that bioaerosols affect cloud longevity and increase ice formation when the temperature is between 0 ° C and -15 ° C. Ice formation is crucial to the emergence of rain. Mineral dust, the main type of aerosols, only increases ice formation when the temperature is between -15 and -40 ° C. To estimate the role of aerosols and the quantitative significance of ice formation, we need direct measurements of their activity. The research project "DRAMA" will fill the gaps in our knowledge by determining the metabolic activity of microorganisms and their capacity to form ice under atmospheric conditions. Ultimately, DRAMA will contribute to improving the weather and climate models of the future.