By: Nour Hany

When we go looking for Earth's greatest mysteries, we will probably find most, if not all of them, underwater!

In a significant research, scientists discovered three shark species that actually glow in the dark; in a survey in January 2020, the kitefin shark, the blackbelly lanternshark, and the southern lanternshark, were discovered off the Chatham rise, which is an oceanic area off New Zealand's east coast. The largest among the three glowing sharks, is the kitefin shark, which is now known as the largest-known luminous underwater creature. The shark is usually found preying on crustaceans, ground fish and smaller sharks, 300 meters below sea level.

Worth mentioning that it is the first time for scientists to spot such proof of bioluminescence in sharks, as this feature was previously found in other underwater creatures, such as jellyfish and squids. The study published said that "Bioluminescence has often been seen as a spectacular, yet uncommon, event at sea, but considering the vastness of the deep sea and the occurrence of luminous organisms in this zone, it is now more and more obvious that producing light at depth must play an important role structuring the biggest ecosystem on our planet”.

The three sharks, however, live 200 to 1000 meters below sea level, in what is known as the ocean's "twilight zone", "beyond which solar light does not penetrate and is too weak to initiate photosynthesis”.

As there is no place to hide at the bottom of the ocean, researchers suggest that the sharks glow to survive, as this will help them fend off their potential predators and spot their prey.

It is still unclear, why the kitefin shark has this ability to glow while it has few or no predators, unlike the other the sharks. Researchers think that they may be using this ability to illuminate the ocean floor while hunting for food or approaching prey, as they are a slow-moving species.

References

https://www.nbcnews.com/news/world/sharks-glow-dark-scientists-discover-luminous-deep-sea-predators-new-n1259252.