
Only a sliver of Earth's deep ocean has ever been seen by humans, study finds
A May 2025 Science Advances study led by Katy Croff Bell finds humans have visually observed about 0.001% of the deep ocean floor—roughly 3,823 square kilometers—with most dives clustered in five countries’ EEZs and many from older, low‑resolution footage. Vast regions remain unseen, biased toward shallower depths and coastal areas, raising concerns about biodiversity, carbon cycling, and the ecological risks of future deep-sea mining. A 2026 follow‑up maps 10,000 priority targets to guide more representative, cost‑effective exploration using modern tech.











