Fabien Cousteau Mission 31

Fabien Cousteau, standing by a hatch, clasps his hands as he returns to the dock after 31 days undersea in the Aquarius Reef Base, Wednesday, July 2, 2014, in Islamorada, in the Florida Keys.

Researcher visits Cousteau underwater

Russell Callender, right, Deputy Assistant Administrator for Ocean Services and Coastal Zone Management for the National Oceanic and Atmospheric Administration, checks his gear before leaving Islamorada, Fla., as he prepares to visit Aquarius Reef Base.

Undersea Lab Cousteau

Thomas Potts, director of Florida International University's Aquarius Reef Base, dives down to Aquarius, Tuesday, June 24, 2014.

Undersea Lab Cousteau

Fabien Cousteau waves from inside Aquarius Reef Base, on June 24, 2014.

Mission crew, Tuesday, June 24, 2014

Mission scientist Grace Young, left an MIT graduate in Mechanical & Ocean Engineering, Ryan Stancil, center, Mission doctor, and Fabien Cousteau chat inside Aquarius Reef Base.

Scientists doing experiments outside the deep sea lab

Mission scientists Grace Young, left, and Liz Bentley Magee, right, conduct experiments on sponges outside Aquarius Reef Base,  63 feet below the ocean surface, Tuesday, June 24, 2014.

Fabien Coustea on Sunday, June 1, 2014

Fabien Cousteau waves, on Sunday, June 1, 2014, from the boat ferrying him  to the waters above Aquarius Reef Base in the Florida Keys National Marine Sanctuary.

Fabien Cousteau after 31 days under wate

Fabien Cousteau reacts as he returns to the dock after 31 days undersea in the Aquarius Reef Base, Wednesday, July 2, 2014, in Islamorada, in the Florida Keys.