Phys. Rev. Lett. (in the press); preprint at https://arxiv.org/abs/1710.02098

Various organisms that live in environments subjected to a diurnal rhythm have developed timekeeping capabilities. In many cases such biological clocks are based on limit-cycle oscillators, which can run autonomously. Some chronometric mechanisms, however, seem to rely on sustained oscillatory input and relax to a stable fixed point once driving stops. Among cyanobacteria both types of timepiece are found, and the question is why. Michele Monti and colleagues argue that it could have to do with noise resilience.

Monti et al. studied several network designs for timekeeping and looked at how noise in the external input — such as variations in light intensity during daytime — affects the precision with which different types of oscillators estimate time. For low input noise, they found no significant differences between limit-cycle oscillators and their damped counterparts. But when they cranked up the noise, the former emerged as the victor.