Fabien Cousteau, grandson of famed oceanographer and filmmaker (and wearer of red caps) Jacques Costeau has embarked on a 31-day mission aboard the Aquarius Reef Base, a small laboratory located 60 feet below the ocean's surface in the Florida Keys. 

Jacques Costeau. AP

Fabien and a crew of five others will spend their time in the underwater lab focusing on climate change and ocean acidification, ocean pollution, and shrinking biodiversity as a result of resource overconsumption, among other things. Mission 31 overlaps with the 50th anniversary of Jacques's own unprecedented underwater living experiment aboard Conshelf Two, and will also expand on that expedition in a number of ways. According to the Mission 31 website:  

Mission 31 will broaden the original Cousteau experiment by one full day, 30 more feet of saturation and will broadcast each moment on multiple channels exposing the world to the adventure, risk and mystique of what lies beneath.

It will also break some ground of its own: 

This will be the first time a mission of this length has taken place in the Aquarius lab, the only underwater marine habitat and lab in the world, located 9 miles off the coast of Key Largo, Fla., and operated by Florida International University.

Cousteau, who took the plunge on Sunday, said that he and his crew expect to miss the sun but are otherwise looking forward to the mission. "I imagine we'll want to stay down once we get comfy down there," he said, adding, "we won't want to come back up to the surface because it's such a magical place."

Cousteau also said he's looking forward to being in touch with us landlubbers while living in the sea. You can watch the mission live via a web cam, posted on the mission website, and he's already started tweeting from on board the lab: 

Fabien is also planning to film a documentary while on board the lab. Until then, we'll be checking in on the live stream to see what life is like under the sea.