Bioluminescence

Substrates

4 kinds, all termed luciferins.

Occurrence rate in organisms of the pelagic zone/ water column

80-90%

Communication

A few species possibly use bioluminescence to communicate

Fluorescence

A fraction of light is absorbed and re-emitted as a different color. Ultraviolet light. In pelagic organisms, concentrated on certain body parts and used for identification and prey attraction. Benthic creatures are byproduct of tissue chemistry and play no obvious role.

Vomit

Bioluminescence can be vomited

Siphonophores

Colonial organisms, highly specialized zooids, extremely precise pattern of distribution. Cnidarians, longest animals in world, gelatinous, mostly water, fragile. Active predators, tentacles, small fish and crustaceans. Portuguese Man O' War.

Most common bioluminescent creatures

Fish, squid, gelatinous organisms made mostly of water(jellies, siphonophores)

Benefits

Hunting for food Evading predators

Bioluminescent bacteria

Glow continuously, live in black poches which the organism can open and close

Searchlights

Lights organs near eyes serve as searchlights

Evolution

Luciferins are great antioxidants and light emission may have been a way to remove harmful oxygen from cells.

Counterillumination

Many small light sources on the underside of an organism hides silhouette when viewed from above

Touch induced light

Most bioluminescence occurs only when an organism is touched; could be to startle predators, attract animals which eat the predator, or distract predator by detaching glowing body part.

Blue

Most common color of bioluminescence

On land

Mostly limited to a few insects and mushrooms

Chemiluminescence

Production of visible light by a chemical reaction; bioluminescence is a form of this. Causes fireflies to glow. More common in marine environment.

Geographic distribution

Rare on land and in freshwater, less common on coral reefs and near shore, most common in water column

Phosphorescence

Similar to fluorescence but light is emitted for a much longer time after the external light is removed

Chemistry

Small, organic substrate is oxidized; requires energy and enzyme.

Photocytes

Specialized light emitting cells; sometimes grouped into complex, lens like photophores (light comes out instead of going in like eyes)

Bioluminescent bait

Stalks of light can be lured for prey or mates

Bioluminescence

The production of light by living organisms; a form of chemiluminescence

Lack in lakes

While the oceans are older than freshwater, scientists guess that biolum has evolved at least 40 times. They do not know why it has not appeared in lakes.