TODAY | August 10, 2013
>>> a group of wounded veterans have a new job in front of them. fighting to save the greatest natural wonders. mark potter recently went to the front line of that.
>> reporter: in the water off the florida keys , a floatilla arrives to save the reefs. some are america's finest who have already given so much. they are all u.s. military veterans who lost limbs or suffered traumatic brain injuries and are part of a support group called combat wounded veterans challenge. the biggest challenge to come back whole after suffering the wounds of war. a retired chief who lost a leg says it camaraderie of fellow vets he owes his soul.
>> it allows me to be the master chief, again. the loss of identity is back. it's everything.
>> reporter: on this day, the vets joined scientists at a laboratory who grow coral in an underwater nursery. when it's big enough, it's replanted on reefs decimated.
>> the great thing is our military mission is they want a purpose. in transplanting coral, they have a purpose.
>> reporter: another reason is to do research on how they can better use the prosthetic devices in water. there's little study so far. helping with that is billy kos costel costello. he lost a leg in afghanistan. just a year later, he climbed mt. kilimanjaro. a group of florida teens who dove with the vets at the coral farm.
>> i just want to say, gosh, look what this guy can do. he can climb mountains.
>> reporter: wounded vets healing themselves helping and inspiring others. mark potter , nbc news in the florida keys .