The deep ocean remains Earth's final frontier. Below 1,000 meters, in perpetual darkness and crushing pressure, life takes on alien forms that challenge our understanding of biology.
Bioluminescence is nearly universal in the deep sea—an estimated 90% of deep-sea creatures produce their own light. This ability serves multiple purposes: attracting prey, communicating with potential mates, and confusing predators.
The lack of sunlight means no photosynthesis, so deep-sea ecosystems depend on alternative energy sources. "Marine snow"—a constant rain of organic particles from above—feeds many creatures. Others cluster around hydrothermal vents, where chemosynthetic bacteria form the base of the food chain.