The world’s top freedivers — athletes who compete to see how deep and how long they can go on a single breath of air — will gather in Nice, France, next month for the 2012 AIDA Freediving Team World Championships.

Team USA captain Ted Harty, 38, a Fort Lauderdale freediving instructor, will lead his delegation of six primary athletes and two alternates to try for the top combined score in three disciplines of men’s and women’s competition. Team members have two world and 15 national records among them.

In the constant weight category, both men and women will swim as deep as possible then return to the surface while holding their breath. In static apnea, they float facedown on the surface of a pool for the maximum amount of time. In dynamic apnea, they swim as many laps as they can underwater. AIDA judges will monitor each athlete carefully to make sure no rules are violated. If an athlete passes out, that performance will be disqualified.

“It’s not the team that has the best freedivers that wins. It’s the team that has the best discipline and doesn’t make mistakes,” Harty said.

The United States will compete against more than 35 countries, with some of the stiffest competition coming from Russia. Although Harty can hold his breath in the pool for more than six minutes and dive 278 feet deep on a single breath, Alexey Molchanov of Russia and his mother Natalia have handily beaten both marks.

Alexey holds the AIDA world record for constant weight at 410 feet; Natalia, with seven world freediving records, has dived 331 feet deep on a single breath and remained static in the pool for 8 minutes 23 seconds.

To train for the worlds, Harty and his teammates have been practicing breath-hold exercises in the pool and on the couch and cross-training in the gym and on the track.

But to prepare for the constant weight competition, they plan to go to Long Island in the Bahamas this month to do deep dives in Dean’s Blue Hole. The landlocked marine cave, which plunges 663 feet deep, has been the scene of multiple freediving world record attempts over the past few years. Because it is not in open water, the divers can train safely even in unfavorable weather.

Also on the team: Nick Mevoli of Brooklyn, N.Y., one of Harty’s former students; Ashley Chapman of Wilmington, N.C.; Erin Magee of Cloverdale, Calif.; Ron Smith of Sahuarita, Ariz.; and Jenna McGrath of Santa Barbara, Calif. Ben Weiss of Santa Barbara and Kyle Gion of Honolulu are alternates.

Team USA is looking for sponsors to help with the costs of transportation and training, and it created a website — www.supportteamusa.org — to generate money and publicity.

Harty wishes more people understood the athleticism and discipline of freediving. Very popular in Europe, breath-hold competition has gained a foothold in the United States only in the past 20 years.

“People associate freediving with crazy people,” Harty said.

Harty said the majority of students he has taught how to dive deep while holding their breath don’t care about competition, but really want to learn how to be better spearfishers.