ANIMALS GLOW IN DIFFERENT WAYS
In fluorescence, molecules absorb light of one colour and emit light of a different colour. This emitted light, with its modified colour, is visible only while the stimulating light is turned on, so you cannot see fluorescence in complete darkness. In phosphorescence, the chemical reactions take longer to emit light, so a glow remains after the light has been removed. In bioluminescence, plants and animals create their own light.
GLOWING PLANTS, ANIMALS MADE BY SCIENTISTS
Scientists can produce their own glowing plants and animals too, such as these made-in-Singapore fluorescent zebrafish. They normally sport silver and black stripes, but can be made to glow red, green, orange and yellow with the help of jellyfish and anemone genes.
This fluorescent frog was discovered recently in Argentina. Under normal light, the amphibian's translucent skin is a muted yellowish-brown with red dots, but when scientists shone an ultraviolet light on it, the frog turned a celestial green.
DEEP SEA JELLYFISH
An image of an abundant deep sea jellyfish, photographed by its own bioluminescence.
The Singapore jumping spider uses ultraviolet reflectance and UV-induced fluorescence to communicate during courtship rituals.
Fireflies use light flashes to communicate. Scientists found that fireflies control oxygen distribution to light up their cells. This microimage shows larger cell channels branching into smaller ones, supplying oxygen for a firefly's light emission. The smallest channels are 10 thousand times smaller than a millimetre.
Corals glowing in rainbow hues have been found in the Red Sea's deep-water reefs, surprising researchers because their shallow-water counterparts in the same reef contain only green fluorescent pigments. Many corals at depths of over 50m have been found to glow in colours ranging from yellow to red.
BIOLUMINESCENCE IN THE OCEAN
Most bioluminescence in the ocean is blue, but there are exceptions such as the yellow bioluminescence of some pelagic worms. Also shown (clockwise from worm in yellow) are the squid, the Northern krill, the scaleless black dragon fish and the deep sea jellyfish.
This photo is of a biofluorescent chain catshark. Researchers found that catsharks are not only able to see the bright green biofluorescence they produce, but that they increase the contrast of their glowing pattern when deep underwater. Fluorescence makes catsharks more visible to neighbours of the same species at the depths that they live and may aid in their communication.
Using ultraviolet light that causes scorpions to fluoresce a ghostly glow helped researchers discover an intriguing new scorpion in Death Valley National Park in the United States.