A living organism depends upon some special conditions to survive and endure on this planet. Basic things such as sunlight, energy, food, freshwater and shelter are the foremost needs for every living organism’s survival. However, the deep sea creatures are refrained from these special needs and undergo a far more challenging life compared to those that live outside the ocean.
Read on more to understand the difficulties and how these tough creatures which are thousands of meters deep, cope with the challenges in everyday life like high pressure, small amounts of oxygen, very little food, no sunlight, currents, extreme cold, pitch darkness and much more.
Light only reaches the shallow water that is above the continental shelf. After 200m to 1km depth, the zone is known as the twilight zone which is completely dark since the sun’s rays cannot reach that far.
How do they see in the dark?
Some creatures in the deep sea have quite enormous eyes and reflective retinas that really work for them, while others identify their prey by sensing vibrations. Others produce their own light through an organ known as ‘photophores’ that is known as ‘bioluminescence’. This helps them to detect their potential food. The light produced by them is ghostly blue in color.
The pressure at the bottom of an ocean is many folds compared to the pressure on the surface. This pressure keeps on increasing as one move deeper. The pressure is greater in oceans because the water is pressed down heavily. At 10m below the water, the pressure doubles, At 20, the greatness is thrice than on the surface.
How do they survive the pressure?
Deep sea animals can survive these conditions because they are mostly made of liquid that are not easily compressed. Other fishes have gas-filled buoyancy bladders that are much more compressible. For example, a “blobfish” has the capacity to withstand pressure at 1000m as its body has a mass which is gelatinous that has a density lesser than water.
- Buoyancy -
Don’t deep sea creatures sink in such deep ocean water?
Many of the fishes are lucky that they have light bones and flesh; therefore it helps them to maintain their buoyancy in water. Some also comprise of gas bladders that stop them to sink. With the help of gas bladders, they can move around and swim deep down or move up whenever they feel the need to. While the heavier fishes don’t swim as much but spend most of the time they rest on the ocean floors and search for food.
How do they survive without food?
All deep sea animals including sea anemones, tube worms, sponges, barnacles simply wait for the food to come down to the sea floor from above. They wait for the death of some pretty large animals like sharks, squids, dolphins or whales. As soon as its carcass sinks down, it provides a big feast for the creatures below.
- Temperature –
How do they survive in this freezing temperature?
Most of the deep sea animal’s move very slowly as the cold slows down their metabolism. While some of the deep sea fishes consist of special enzymes to deal with the harsh environment. Some of the animals carry high unsaturated fats in their cell walls which help them to maintain the membrane fluidity in freezing cool depths of the ocean.
- Mating –
The probability of finding a mate in the deep sea is quite low. Finding the right mate in the right place is quite a challenge for all the deep sea fishes.
How do they adapt to deal with low density of mates?
Angler fish are ten times smaller to the female. After it gets matured, it loses its capability to feed itself as its digestive system stops working. Locating a female becomes their utmost priority and the only way to stay alive. A scent is released by the female and their mating story starts. It hooks itself to the female by its mouth and releases enzymes that enable the fusion of the two. The male totally becomes dependent on the female from that time.
Other female species help themselves get a mate by using their light organ ‘photophores’ which attracts males. Apart from these, there are other under water animals that are hermaphroditic (animals having both male and female sex organs and other sexual characteristics).
Watch this video to have an in-depth understanding of their environment and living conditions: