The Chemistry of Luminescence

The Chemistry of Luminescence

By Josh Bogen

An Alternate Route to Light

• There is one other way that organisms can produce light.
• In this system, the luciferin and the luciferase combine with another element usually oxygen. This combination is called a photoprotein.
• When combined with a cation, usually calcium, the photoprotein emits light.

See?

Bioluminescence

Luciferase

• When luminescence is used by living organisms for their own purposes, this is known as bioluminescence.
• This is because the prefix bio means living, so bioluminescence means living light.
• However, bioluminescence is a very broad word with a very broad definition. There are many different kinds of bioluminescence, and has greatly varied uses.

The Reaction cont.

• Luciferase is the second chemical needed in the reaction to create light.
• The job of the luciferase is to cause the oxidation of the luciferin.
• Once the luciferase has done its job, it creates a third chemical known simply as oxyluciferin.
• Oxyluciferin is a light emitting chemical.

What is Luminescence?

Human Uses for Bioluminescence

• Bioluminescence can be found in thousands of organisms, and the same chemical reactions are being used in other aspects of life, such as making fireworks change color, a possible cure for cancer, and lasers.
• Bioluminescence doesn't just beautify and illuminate our world, it is being used to change it.

• Following the initial emission of light, the organism has to sustain the light. This is because if the organism doesn't show a constant light, there would really be no point to their possession of bioluminescence now would there?
• In order to provide this constant emission of light, they must continue to replenish their supply of the chemicals.
• All organisms that possess bioluminescence take in these chemicals through their day to day diet, or by absorbing them from their environment.
• Some have learned to harness the energy emitted by their own light to create the chemicals within their bodies.

• Luminescence is the system that creates light using sources other than heat.
• Luminescence is used by many animals and other living things to lure pray, light their way, and for many other reasons.
• Instead of heat, luminescence uses things such as chemicals and the air itself to create light.

Dinoflagellates

• The name Dinoflagellates make these organisms seem like very foreign creatures, or some ET alien.
• But, they are actually just small, ocean-surface-dwelling organisms that employ bioluminescence in order to attract food.
• These creatures are actually the most commonly spotted bioluminescent organism in the world.
• These creatures are most often seen from boats, however, they are known to come in with the tide in the hundreds of thousands and provide quite the light show.

Luciferin

• Luciferin is the chemical in the reaction that will create light.
• However, luciferin cannot create light without the help of luciferase.
• Again, luciferin is not a specific chemical, just the name of all of the chemicals that can create light within organisms in the process of bioluminescence.

Colors of Bioluminescence

Luciferin Groups

• Most bioluminescent organisms give out light at a wavelength between 440 nanometers and 479 nm.
• For the purposes of bioluminescence, all you have to know about that, is that a wavelength of that size emits a bluish green light. About 90% of all bioluminescent organisms give out this bluish green color.
• In the case of the Angler Fish's red light, it has adapted to emit a wavelength of 505 nm.
• For the record, the light emitted from a single single celled organism is bright enough to be visible to the naked eye, easier so at night.

The Differences in Luciferin

The Chemistry

• Here are the different types of luciferin matched with the group of organisms that use it.
• Bacterial-obviously bacteria.
• Dinoflagellate-simply dinoflagellates (explained later)
• Vargula-most fish
• Coelenterazine-most shellfish, and some fish.
• Firefly-hmmmmm. fireflies, and other insects.
• Some organisms don't use any system of luciferin that scientists understand, and aren't included in this list. These organisms include earthworms, and freshwater organisms.

• The chemical process that creates bioluminescence requires just two chemicals. These two chemicals differ from species to species, but they all fall under two umbrella names: luciferin and luciferase.
• It is crucial to understand that each organism's chemistry is different, and luciferin and luciferase are not the names of the specific chemicals, only the umbrella term for these kinds of chemicals.

• The different types of luciferin chemicals are known as:

Bacterial, Dinoflagellate, Vargulin, Coelenterazine, and Firefly.

• All of these different luciferins use the elements Hydrogen, Oxygen, Nitrogen, and Carbon.
• The only differences exist in the structures of the elements, meaning how they are put together, as well as which species employ them.

Length of Light

• As discussed earlier, most organisms produce continuous light, however, some produce intermittent light, these appear as flashes.
• These flashes are caused by the fact that these organism's luciferin is reproduced with energy from their nervous system, and so only produces light when they are excited or when they want to.
• Flashes are generally used to attract mates, or find others in their family.

This shoreline in Virginia kind of proves that.