By Katelin Mei
How can life exist with little to no sunlight? How do organisms live? How do they navigate, find food, and escape predators under the crushing weight of the ocean, and the absolute darkness?
Sunlight can enter the ocean to provide light for up to 200 metres. After that, the ocean remains in partial darkness, for up to 1,000 metres. Past here, the ocean is bathed in darkness. This “lightless” area is called the aphotic zone, also referred to as the “midnight zone.” It exists below 1,000 metres. There is no sunlight that can reach this area. The only light in the midnight zone is provided by the fish themselves.
Life thrives in the midnight zone. Here are some of the creatures that live in these depths.
- Viperfish – If you are going to be a predator in the darkness, you need to be ferocious so that your prey cannot escape; otherwise, you might not have food for a long time. The viperfish is one of the fiercest predators in the deep sea. They are characterized by long needle-length teeth and a hinged jaw, allowing them to eat almost any kind of prey they come across.
- Pacific barreleye fish – Every fish in the deep sea has unique adaptations to the darkness. The Pacific barreleye fish has tube-shaped eyes that look through a clear dome. While their eyesight is very narrow, the tubular eyes are very efficient for picking up any kind of light. Their eyes are surrounded by a fluid-filled shield, allowing them to swivel their eyes and look around them.
- Hatchetfish – Predators are fierce in the darkness, so as a result, many of the deep-sea fish have found unique ways to camouflage themselves. One such fish is the hatchetfish. These fish have light-producing organs on their bellies. Many predators hunt by looking upwards for silhouettes. The hatchetfish counters that by making its belly match the daylight filtering through. Now, it is nearly invisible.
- Anglerfish – This is one of the most famous deep-sea fish species, for the way it uses its bioluminescence for hunting. Other fish will see the light from the lure, and swim close. Then, the Anglerfish eats her prey. Only the female anglerfish have a glowing lure. They have large mouths and pliable bodies, granting them the ability to swallow prey twice their size.
These are only some of the organisms that live in this area. Humans haven’t explored much of the deep sea; we’ve actually explored space more than our own oceans, so there are more mysteries to discover. But we know for sure that life lurks in even the darkest parts of our oceans.
Sources:
Light Editor: Renée Vazquez
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