SCIENTISTS have discovered why two shark species glow in the dark.
The researchers have uncovered a group of molecules that can give the creatures an eerie green glow and their study could teach us more about why some creatures have fluorescent bodies.
Catsharks glow in the darkCredit: PA:Press Association
Chain catsharks and swell sharks live deep down in the northwest Atlantic Ocean and the eastern Pacific Ocean respectively.
When taken from the water they appear brown but recent studies have shown that the blue light that penetrates the depths of the ocean makes them glow green due to a process called biofluorescence.
Biofluorescence involves blue light in the ocean being absorbed by a creature and re-emitted as light.
During a new study, scientists were able to pinpoint never before seen molecules which they think absorb the light and make the sharks fluorescent.
A special “shark eye” camera was used to take footage of the sharks glowingCredit: PA:Press Association
The molecule that makes the sharks glow is only present in some parts of the skinCredit: PA:Press Association
They also found that glowing skin might even help the fish protect themselves from harmful microbes and lure prey towards them.
Professor David Gruber, of City University of New York, and his team have published an article in the journal iScience, which states that the molecules they have discovered may never have been seen before.
These molecules were limited to certain parts of the sharks’ bodies and were typically found where the skin was paler or in white spots.
Tissue analysis revealed eight types of molecules that glow when blue light is shined on them, with one in particular giving off a bright green glow.
The researchers think that glowing might help sharks to communicate with each other and observed that male and female sharks have different light patterns.
When the fluorescent substances were tested against a number of different bacteria, including MRSA and a common marine bacteria, the molecules were able to stop the growth of some of the bacteria on the sharks skin.
This is something that could one day be applied to the medical industry if more research regarding isolating the molecules is conducted.
Swell sharks look like this when seen in anything other than just blue lightCredit: PA:Press Association
The creatures can turn an eerie green colourCredit: PA:Press Association
