The timing of nearly all behavioural and physiological functions in terrestrial organisms is controlled by an internal daily, or circadian, molecular clock. As in humans, this runs with a periodicity of approximately 24 hours. For marine organisms such as ragworms, there is an additional rhythm: the tidal cycle, which averages 12.4 hours.

A recent discovery has shown that common shore-dwelling ragworms Nereis virens and Nereis diversicolor, normally associated more with angling than with high-profile science, have a biological clock which is able to track not just the passage of the days and tides but can also probably tell the time of one without the presence of the other.

Dr Kim Last, the SAMS research scientist leading the investigation together with scientists from the Universities of Newcastle and Leicester explains why the humble ragworm is such an interesting animal.

Read more...