A team of Dutch and German researchers has discovered the operation of one of the oldest biological clocks in the world, which is crucial for life on earth as we know it. The researchers applied a new combination of cutting-edge research techniques. They discovered how the biological clock in cyanobacteria works in detail. Important to understand life, because cyanobacteria were the first organisms on earth producing oxygen via photosynthesis. The results of their research will be published in Science.