Want to explore the deep sea? There's lots left to see

Researchers collected records of dives to determine how much of the bottom has been seen by humans

- REBECCA DZOMBAK

Humans have visually documented about 1,470 square miles, or a mere 0.001%, of the deep seafloor, according to a new study. That's a little larger than the size of Rhode Island.

The report, published Wednesday in the journal Science Advances, arrives as nations debate whether to pursue industrial mining of the seabed for critical minerals.

Some scientists argue that so little is known about the undersea world that more research on the deep seafloor is needed to responsibly move forward with extractive activities.

"More information is always beneficial, so we can make more informed and better decisions," said Katy Croff Bell, a deep ocean explorer who led the study and is the founder of the Ocean Discovery League, a nonprofit group that promotes seafloor exploration.

Learning more about the deep sea is essential for understanding how climate change and human activities are affecting oceans, she said. But the study also highlights the fundamental excitement of exploration that drives many marine scientists.

"You can just imagine what's in the rest of the 99.999%, " Bell said.

The era of visual documentation included in the study began in 1958, with the deep-sea submersible Trieste. The images collected since then let biologists discover new organisms and observe how they interact with each other and their environments, providing insights into ocean ecosystems.