The deep sea covers about two-thirds of the Earth's surface, but only a tiny fraction of it

has ever been seen by human eyes.

That's the conclusion of a new study published this week, estimating humans have observed

less than one thousandth of a percent of the deep sea floor, an area roughly the size

of Rhode Island.

The study's author, Katie Croft Bell, is working to change that.

She's a National Geographic Explorer and the founder and president of the Ocean Discovery League.

Stephanie Sy has the story.

Katie Croft Bell, thank you so much for joining the program.

It's so fascinating to think that out of our vast ocean, we've seen basically a drop

in the bucket. I guess I would start by asking you why it matters that so much of the deep

ocean has gone unexplored. Well, the deep sea is the planet's life support system. It supports

plankton in the upper ocean, which produce

oxygen that we breathe. Those plankton also feed fish, which in turn feeds over a billion

people worldwide. The deep sea absorbs heat and carbon dioxide, which moderates our atmosphere

so we can live here on Earth. And increasingly, we're seeing pharmaceuticals that are based on

chemical compounds

from marine animals. But despite the numerous benefits from the ocean and the deep ocean, we're

impacting the deep sea at an unprecedented rate. And we really need to understand those habitats

and the processes that are happening down there before we do irreparable harm.

So 0.001% of it has been mapped.

How did you determine how much of it, how little of it, had been explored?

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