Investigating deep waters off Bahamas, US-based researchers recorded the glow of tiny bioluminescent species using a submersible vehicle.

Descending to sites between 600 and 1000m down, the scientists observed flashes of bioluminescence where plankton collided with boulders and corals.

The team also studied how crustaceans react to this light, and found previously unknown sensitivities to blue and ultra violet wavelengths.

The PhD study bt Dr. Susan Theiss showed that the wobbegong visual system contains only a single class of cone photoreceptor. Cone photoreceptors are the retinal cells that are used for vision under bright light conditions, whereas as rod photoreceptors are used in dim light.

These previous studies looked at opsins, which are light-sensitive proteins found in the photoreceptor cells of the retina. Rod opsins are used in low light and produce a black and white image, while cone opsins are used in bright light, and often to see colours.