Until the last few decades very little was known about the diversity of deep sea animals, with most people believing the depths of the sea were devoid of life. Today, new technological developments, including remotely operated submarines have permitted exploration of the sea bed and oceanic trenches allowing scientists to discover an array of previously unknown lifeforms.
Despite living in a completely dark, cold, and often barren environment, the deepest places of the world are home to some of the most unusual and unique animals.
Just last month researchers in the Scripps Institution of Oceanography in the USA identified a ‘purple sock’ like creature. The creature was first photographed in 1943, but until last month researchers were baffled as how to classify this weird and primitive organism. Using DNA analysis, scientists revealed the creature to be a new species of Xenoturbella, a newly discovered primitive group of molluscs. Although it still remains a mystery how this strange organism feeds.
In 2014, the even more unusual mushroom-like Dendrogramma enigmatica was finally classified by scientists. These tiny 2cm creatures are believed to represent an early branch of animal kingdom, living in the Ediacaran period, around 600 million years ago. Dendrogramma may appear similar to jellyfish, but they lack certain key characteristics causing scientists to believe they represent a very primitive life form, previously thought to be long extinct. Although the creatures were first found South Eastern Australia in 1968, they were preserved in formaldehyde making genetic analysis was impossible, only in in September 2014 were these creatures were assigned a species after extensive analysis using electron microscopes.
While it is easy to see how a small and slow moving creatures like Xenoturbella and Dendrogramma enigmatica can go unnoticed, some recent deep sea discoveries have revealed much larger creatures.
Despite being up to 5m long, with a 1.3m mouth span the rare and elusive megamouth shark (Megachasma pelagios) was only discover in 1976 after one became tangled with the anchor rope of a US Navy ship off the coast of Hawaii. Whilst it may look fearsome with its oversized mouth, this species feeds on plankton and jellyfish, similar to the basking sharks which often visit the British coast.
Meanwhile, off the coast of the African Comoro Islands the giant prehistoric Coelacanth remained unknown until 1937. The coelacanth is a rare, and ancient fish, and the only extant member of the order Sarcopterygii or lobe-finned fish, which are more closely related to reptiles and mammals than other fish groups. The coelacanth is often described as a ‘living fossil’ with no closely related living relatives and a body form though to have evolved over 400 million years ago.
The deep sea represents the final frontier of exploration of earth, but with current threats from deep sea mining and climate change, these ancient ecosystems may not remain untouched for much longer.