Bioluminescence—the natural ability of organisms to produce and emit light—is one of the ocean’s most captivating phenomena. From the sunlit surface to the deep sea, bioluminescent organisms are far more abundant in marine environments than on land. While the glow emitted by these organisms is generally perceived as blue-green, their color variation is often assumed to be minimal. However, even small wavelength shifts can profoundly impact how effectively light travels through seawater, influencing visibility, signaling, and ecological interactions in the marine realm.

Our research highlights an often-overlooked aspect of bioluminescence: the color of light emitted by luminous bacteria. We explore how subtle differences in bioluminescent hue relate to bacterial ecology and investigate the evolutionary mechanisms shaping luciferase gene sequences and genome architectures. By integrating molecular, ecological, and evolutionary perspectives, we aim to uncover how these microorganisms fine-tune their light for survival, revealing new insights into the adaptive significance of bioluminescent color in the ocean’s living light show.