HARI SREENIVASAN:

On a muggy summer day, almost a dozen workers and volunteers form a bucket brigade. They pass 20 to 30 pound bags of trucked in oyster shells onto waiting rowboats.

Then they transport them down the shore, piling the bags strategically in the shallow water next to the marsh.

About 200 bags of oyster shells are used to build each 20 foot artificial reef, a form of green infrastructure known as a living shoreline.

Rachel Gwin is the restoration coordinator for the Choctawhatchee Basin Alliance, or CBA, a nonprofit environmental organization building this living shoreline at a waterfront home on Florida's panhandle.

So without these reefs, what's happening to this shore?