Weird and wonderful creatures of the deep sea
The deep sea is the earth’s largest and least explored ecosystem. With only 0.5% of the seafloor is mapped at 1–2 meter resolution, the deep sea is a mysterious world with many more discoveries to be made.
Rapid technological advancement enables new research to take place, leading to many fascinating discoveries of the deep, revealing many alien-like creatures.
Alongside this research, discoveries also reveal that human rubbish can be found in the most desolate locations on earth. Drink cans were found at 2300m in the Cayman Trough, food packaging 1000km from the nearest land and even a plastic bag at the bottom of the Mariana Trench- the deepest point in the ocean.
The deep ocean environment comes with many extreme conditions which life must adapt to in order to survive. These include high pressure, low temperature, lower oxygen levels and of course no light. In the clearest water light does not penetrate any deeper than 1000m, beyond this depth is classified as the midnight zone.
A widely used adaptation of deep sea creatures is bioluminescence; created by oxidation of a luciferin substance via a luciferase enzyme, some even host bioluminescent bacteria in photophore organs. This is used for a number of reasons including counter-illumination of the animals in the ‘twilight zone’ (where there is still some down-welling light) which prevents them casting a shadow, hiding them from predators below. Bioluminescence is also used for signalling and communication with the same species to attract mates, attract prey, and even to evade predators.
To overcome the difficulties of living under pressure, organisms have no air-filled spaces; making them incompressible as well as processing chaperone molecules which remove water molecules from protein molecules, allowing them to fold into the correct form. The deepest known fish is currently the snailfish Liparidae at 8178m in Mariana Trench.
The Antarctic ice dragon
This ghost-like fish occurs in the depths of the Southern Ocean and is a member of the white-blooded fish (Channichthyidae) family. With temperatures generally -1.8 to 2.0 °C they have a number of adaptations which enable them to thrive in icy conditions. Channichthyidae is the only known vertebrates to lack haemoglobin as adults, causing its ghost-like appearance. Having no blood cells and containing antifreeze in their blood allows the blood to flow much easier in the cold. Furthermore, the colder the water, the higher the oxygen content, allowing sufficient oxygen to diffuse into the blood without the need for blood cells.
The Dumbo octopus~ Grimpoteuthis
Named after the disney elephant, the Dumbo octopus gets its name from its enlarged ‘ears’ (actually modified flippers) which it uses to ‘fly’ though the water. This rare octopus is a member of the umbrella octopus family: with their eight arms fused into a web. Despite their huge eyes, they have poor vision in such darkness, instead the dumbo octopus feels its way around with the suckers on its tentacles or sensing the water current using the strand-like structures around its suckers called cirri. They live worldwide in the cold depths of the ocean floor from 400 to 7,000 meters below sea level, being the worlds deepest known octopus. Dumbo octopuses, like other deep-sea octopuses, have no ink sacs. This is because ink doesn’t serve any purpose in the dark.
Barbeled Dragonfish
The barbeled Dragonfish from the Stomiidae family has a combination of unique adaptations for survival in the deep. They are relatively small (2–50 cm), black and with no scales. Their large teeth prelude way out of their mouth with highly flexible jaws. Photophores run along the side of their teeth, beneath each eye acting as headlights and at the end of a barbell to lure in prey. A few species possess a very special adaptation: photophores that emit red light to hunt for prey. Red light is seen by very few deep sea creatures, acting as an advantage to the dragonfish. They poccess chlorophyll pigments in their eyes which boosts the colour range of their vision.
The colossal squid~ Mesonychoteuthis hamiltoni
The colossal squid is not only the earths largest invertebrate being 12–14 metres and weighing up to 750kg, but poccess the largest known eyes of the animal kingdom- up to 40cm in diameter! which it uses to maximise its vision in the deep water.
The Goblin shark~ Mitsukurina owstoni
This rare, deep-water shark is named after its elongated snout and needle-like teeth, giving it a menacing appearance. They poccess highly extendable jaws allowing them to eat larger prey and have semi translucent skin revealing the pink flesh of their insides.
