This is an I-Heart podcast.

This is Solvable. I'm Jacob Weisberg.

So it kind of looks like a pepperoni pizza.

It's about that size.

And you imagine the pepperonies are the little corals there?

Around the world, coral reefs are rapidly being destroyed by a combination of overfishing,

local pollutants, and rising sea temperatures due to climate change.

When you consider that nearly 25% of all fish spend at least part of their lifetime in the reefs

and that the reefs support coastal tourism in various ways, you can start to understand the scale

of this loss. And there's more.

Hurricane Irma, which was in 2017, had 25-foot waves hitting the Florida reef track.

We had a storm surge at our building of only five-foot.

So if we didn't have a reef system there or a healthy reef system there,

you can imagine that that storm surge

and those waves would really decimate the land.

Sarah Hamlin is a biologist at the Moat Marine Laboratory.

She's devoted to coral reef restoration.

She helps maintain 21 species of stony and branching coral and splits her time between the Lou

Key Reef and her land base on Summerland Key in South Florida.

It's amazing. You're like an underwater gardener.

That's exactly what we are. We are underwater gardeners.

Her lab uses a process called micro-fragmentation and fusion, and its impact on underwater wildlife

...