Does man still live in harmony with nature? The climate says "no"! Since the industrial revolution, man has gradually placed himself above nature and thus triggered the current change. This project throws out a utopian idea of how a symbiosis can function in order to benefit from each other again. The cycle begins with the exhalation of carbon dioxide by humans, which helps the microalgae to reproduce. Through its photosynthesis oxygen is produced, which in turn provides the basis for life. At the same time, the algae biomass produced in the cycle provides a healthy food supplement, especially in view of the growing population and the resulting lack of food.