This diptych depicts a fascinating phenomenon: in the ocean, at depths of more than 1,000 meters, no natural light penetrates. In this environment, most marine organisms have developed bioluminescence to meet their basic needs: feeding, defense, and reproduction. Fish, jellyfish, squid, and phytoplankton can create their own light to glow in the dark. In total, three-quarters of marine animals — as well as bacteria — are bioluminescent. This ability results from a chemical reaction between a molecule (luciferin), whose oxidation — catalyzed by an enzyme (luciferase) — releases light through the energy produced. A magnificent example of adaptation to life in an extreme environment.