But our circadian rhythms, which are the rhythms that help us to wake and sleep and be alert and relaxed and so forth and so on, they are much more triggered by blue light.

And so what happens is every morning when the sun comes up the squid goes back to sleep, it buries itself in the sand, and it's got a pump that's attached to its circadian rhythm, and when the sun comes up it pumps out like 95 percent of the bacteria.

Prof Czeisler recommended that students should consider setting an alarm for when to go to bed, as well as for when to wake, and be aware of the harmful effects of 'blue light' emitted by electronic screens and LED lighting, which can throw your circadian rhythm out of kilter, leading to problems falling asleep.