Rhythms are a pervasive phenomenon at all levels of life on Earth. Neurons fire in synchrony to keep the heart beating, internal cell cycles determine how fast cells divide, populations and whole ecosystems wax and wane over time. Physiologists and ecologists traditionally study these phenomena within their disciplines but there is evidence that synchronization of oscillatory dynamics can occur across biological levels of organization. The Centre will be a vector of collaborations between pioneers of biological synchronization at the sub-individual level (Mackey, Glass, Guevara) and ecologists adapting this work to whole populations at regional to continental scales (Fussmann, Guichard, de Mazancourt). The synergistic effect is two-fold. First, the tools of mathematical analysis in both fields can be combined. Second, oscillatory phenomena that propagate from the cellular to the population level can be studied in novel ways with the combined expertise. For example, progression of the cell cycle of unicellular organisms (such as algae) often depends on extracellular conditions (e.g. nutrient concentration). This can lead to population-level oscillations because individual cells synchronize their cycles by communicating through the common medium. The mechanisms that lead to the emergence of such synchronized behaviour are scarcely studied.