Amazing underwater pictures taken by cave diver

It also helps that Jill, 44, is acknowledged as the world's premier female cave diver.

Holding the world record for distance travelled in underwater caves as well as being the first person to cave dive in an Antarctic iceberg, Jill has been at the top of her game for 20 years.

Expert at traversing pitch-black freezing tunnels, full-time cave photographer Jill carries up to 300 pounds of equipment with her on each expedition.

Using technology more advanced than average scuba diving gear, the Florida based adventure cave diver makes use of electric heated wetsuits and unique carbon dioxide recycling aqua-lungs.

"The images of me with my team from Antarctica still bring back the excitement of that unique expedition," says Jill, who lives in the much warmer climate of High Springs in Florida.

"That was a National Geographic jaunt to the B-15 iceberg, which at the time was larger than Jamaica.

"The aim was to become the first people to cave dive in an active iceberg.

"To say that it was fraught with danger is an understatement."

The 2001 trip was denied endorsement by the United States National Science Foundation because they deemed it too dangerous.

As a result they had to travel under the flag of New Zealand whose government accepted the risk of the party

Travelling the 12 days by boat from New Zealand to the Ross Sea area, Jill and her team including National Geographic photographer Wes Skiles entered the dramatic caves.

"The thing with the iceberg was that it was constantly moving," explains Jill who works as a professional photographer and filmmaker in Florida.

"Entrances and creases were opening and closing as the iceberg went through the motions.

"What didn't help as well was the -1.2 degree sea temperature, that was something else."

Usually carrying up to £30,000 of torches, cutting tools, rope, special 're-breather' aqualungs in triplicate on her cave journeys, Jill's motto is to never be unprepared.

Due to the delicate nature of cave diving even a series of bubbles released from her aqua-lung could cause rocks or ice to dislodge and trap her.

"The most obvious thing that could go wrong is to get stuck, in the dark and without any idea which way you are facing," says Jill.

"It sounds glib, but do not panic. If you do you increase your chances of dying dramatically.

"It is a real test of mind over matter."

Stunned by her experiences in the pristine, unexplored Antarctic, Jill's fame in the cave diving world has grown since the mid 1990's.

"I have been scuba diving for twenty years, but when I broke the world women's record for distance travelled underground, underwater, then my career really took off," says Jill.

"I pushed 10,000 feet in a lateral movement 300ft down in the Wakulla Springs cave complex in north Florida in 1998.

"I was experimenting with a 3-D mapping device that cost the best part of £470 million.

"It is the technology that one day Nasa hope to send to the underwater caves of Europa, one of the moons of Jupiter."

Living with her husband of three years Robert McCellen, Jill admits that he gets worried when she goes off on another adventure.

"We have an agreement," explains Jill.

"I call him the minute I surface. That keeps his worry under wraps."

http://www.telegraph.co.uk/earth/wildlife/6258997/Amazing-underwater-pictures-taken-by-cave-diver.html