Marine species have developed weird and wonderful adaptations to allow them to live at depths far below where sunlight can reach.
- Over 200m below the surface of the sea, photosynthesis no longer occurs and there is very little sunlight.
- 1000m below the surface of the sea it is completely dark and very few organisms can survive.
- Creatures that live in the bathypelagic zone (1000m-4000m below sea level) are specially adapted to the extreme conditions.
- Millions of animals living deep in the sea migrate each night to feed closer to the surface where they can find food.
These sperm whales are about to dive from clear blue waters to depths of 1000m in search of food.
Their journey takes them from the warm sunlight layer, through the twilight zone and into total darkness.
As they reach 200m, sunlight begins to fade.
They have entered the mesopelagic zone, or twilight ...
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