Jellyfish with bioluminescence. Credit: TED/Edith Widder. Article featured image Credit: Edith Widder/NOA/TED

Some 80 to 90 percent of undersea creatures make light — and we know very little about how or why.


TED presents Bioluminescence expert Edith Widder who explores this glowing, sparkling, luminous world, sharing glorious images and insight into the unseen depths (and brights) of the ocean.

Bioluminescence is a form of chemiluminescence where light energy is released by a chemical reaction.

Some deep sea fish produce the chemicals luciferin and luciferase. Luciferin reacts with oxygen to create light and The luciferase acts as a catalyst to speed up the reaction. Also cofactors such as calcium ions or ATP sometimes mediate the reaction.

It occurs widely among some specific groups of animals, in deep-sea animals (jellyfish, fish), fungi, bacteria and in various invertebrates such as insects. Sea animals often produce light in the blue and green light spectrum, these are wavelengths that pass the furthest through seawater.