From single-celled bacteria to multicellular organisms, cells are the building blocks of life. To comprehend the wide range of biological processes, we must first understand how cells behave, interact with one another, and respond to their surroundings. New approaches are revolutionizing single cell research, allowing us to study cells at unprecedented scales and in unparalleled depth. This project will use multi-colour flow cytometry as a robust and reliable method for analyzing the subpopulations within a microbial community, plant cell lines or even microplastics. In the rapidly changing field of applied microbiology, plant sciences, marine research, this approach can make the difference for both fundamental and applied research. The flow cytometer will have the capability to measure at least fourteen fluorescence parameters simultaneously on four lasers.