Green Blink in Japanese Deep-Sea Cave Reveals New Bioluminescent Coral
A JAMSTEC-led ROV dive in a 385-meter-deep limestone cave near Minamidaito Island, Japan, documented a new bioluminescent coral, Corallizoanthus aureus, that flashes green only when stimulated by touch or chemical cues, with glow localized to polyp tentacles (~515 nm). Analyses suggest an intrinsic luciferin-based mechanism (likely coelenterazine) and no bacterial symbionts; the light may function as a defensive burglar alarm by attracting predators of would-be attackers. This discovery marks the first documented bioluminescence in a deep-sea cave and expands knowledge of cave biodiversity and coral taxonomy, highlighting the value of specialized exploration tech in cryptic habitats.