n the spring of 2008, our expedition team returned to Exley’s Atlantida on a scientific quest to collect new cave animals while exploring an underground wonder that formed in a hot geologic instant.

Just 60 miles from the North African coastline, the beautifully peaceful island of Lanzarote hides its volatile past. Along this island arc are dynamic features that have revealed the earth’s innermost geologic secrets for perhaps millions of years. Sudden, violent eruptions have formed virgin islands overnight. To modern cave divers, Lanzarote has more than just a fiery history. Over a quarter century ago, this, the longest submerged lava tube in the world, almost claimed the life of cave diving pioneer Sheck Exley.
Our expedition leader, Dr. Tom Iliffe, vividly recalls the day in 1983 when Exley’s dive partner Ken Fulghum aborted decompression to call for emergency air supplies. Fulghum and Exley had run out of gas twice on exit and were now down to desperate levels. With the nearest chamber in Madrid, Spain, it was no place to get bent.

In his biography, Caverns Measureless to Man, Exley recounts this calamitous dive when Fulghum experienced a complete air loss at over 4500 feet of penetration. While buddy breathing, they sprinted towards stage bottles more than one thousand feet away. “One last, labored breath, then my air was completely gone,” he wrote. Still short of the stage drop, the divers hurried for the tanks ahead, lungs in a hungry spasm, pumping for air. With the second depot at 1550 feet, they would run out of air again. Dizzy from carbon dioxide build-up, the duo somehow managed another suffocating sprint to the final tanks. Despite snagging the guideline, they kept their composure and arrived at decompression within sight of the surface.

Not wishing to bring up ghosts of the past, Dr. Iliffe planned a completely different approach to exploring Atlantida in 2008. Using closed-circuit rebreathers, our team would be able to penetrate the cave with greater margins of safety while minimizing our affect on the environment that unique stygobitic cave animals depend on.
“The first time I came to this cave, some twenty-five years ago, we used conventional open circuit scuba, where every time a diver exhales, all their exhaled gas is lost as bubbles. Now we are using a more modern technology. We are using computer controlled close-circuit rebreathers. This greatly lessens our impact on the cave ... there are no bubbles and no polluting oxygen. We are not adding additional oxygen to an oxygen poor environment and we are preserving the character of the ecosystem in which the animals depend,” Iliffe explains.

The cave system associated with Atlantida Tunnel formed a mere three to four thousand years ago during the great eruptions of the Corona Volcano. A massive explosion carpeted lava down the slopes of the mountain. As the surface of the lava cooled and solidified, a thundering torrent of mol
ten magma continued to pour through the core of the flow - a virtual subterranean fire hose of lava. Meeting the ocean, a massive explosion vaporized seawater in its path as the hot tributary plunged below the surface. The final result was a tunnel almost four miles long that extends from the base of the volcano, down the side of the island to the coastline, before continuing an additional mile under the sea floor. From its vast size, unparalleled grandeur and enduring mysteries, it is easy to see why this final submarine section of the lava tube became known as the tunnel to Atlantis.

Several collapses on the lower slopes of the Monte Corona volcano provide entrances to the cave system - including a mile of passage opened as two separate tourist destinations. We accessed many other wild portions of the cave with basic dry caving and sump diving techniques.

Diving in Atlantida Tunnel is only possible through rare scientific permits, but it is not because of the challenges of entry. In fact, after walking through a show cave complete with a swimming pool, restaurants and concert hall, we arrive at our dive site. Carrying our gear, we parade past tourists standing at the bar, weave between diners and sightseers and climb over a railing in the restaurant to get to the water.
At this stunningly beautiful location, the Lanzarote-born artist Cesar Manrique has magically blended the stark volcanic landscape and blue water of the cave with artistic features including an extensive museum on vulcanology. A natural auditorium space can seat 600 and is renowned for its excellent acoustics. The overall beauty of the surroundings is filled with gentle, new age music inspiring visitors to whisper as they walk reverently through the cathedral-like spaces beside the Jameo Chico Lagoon. Dotting the black volcanic rock like twinkling stars, blind albino crabs (Munidopsis polymorpha) are found in this lagoon and nowhere else on earth.

The walls of the entry pool to Atlantida are covered with exotic and colorful algae that are fed by the mix of artificial lights and the fluctuating tidal flows in the cave. Festive bands of gold, green and cyan algae are brightly contrasted with stark maroon and black lava rock beneath. Once submerged, one is struck by the sheer size of the cave passage often soaring to over 50 feet in height. The gin clear water offers visibility far in excess of 200 feet.

Swimming with Tom down the passage on the first dive, I was stunned by the sheer scale and fascinated by what appeared to be a white deposit of silt on the rocks. Finally curious enough to touch the silt, I discovered that what I thought was sediment was in fact a sort of submarine cement, coating the horizontal surfaces of the rock. There was almost no silt to disturb in the cave.

Accustomed to diving in limestone caves formed over hundreds of thousands of years, I was now diving in a cave that was formed in an instant! The contrast is sobering. Dripping formations were born from molten rock. Scours from rapidly flowing lava etched the walls in distinct layers. In places, undulating lava waves peeled off the wall, frozen in time.

While Tom and I enjoyed our first look at the cave, team members Jim Rozzi and Terrence Tysall worked tirelessly arranging fill logistics. Oxygen was scarce and expensive at $400 for a k-bottle. Luckily, we had
a small KISS Baby Booster enabling us to use every bit of precious gas. But, as Jim and Terrence collected bail-out tanks and drive gas at local dive shops, we realized that lack of available equipment and short-fused deadlines would thwart our plans for deep helium dives. With only two weeks of diving activities, we could not safely set-up and de-rig the cave for mixed gas dives, as well as complete the mission’s scientific objectives of collecting animals and water chemistry data.

On the second day, our team reached a unique landscape approximately 2300 feet inside the cave. While swimming through vast dark tunnels, something white in the distance began to take shape. As we closed ranks, I realized we were approaching an edifice known as Sand Mountain. A small opening in the ceiling of the cave has allowed tiny grains of sand from the ocean floor to drop into the cave and form a monument over 50 feet high. This enormous slope was dotted with urchin spines, small shells and even tiny animals. Biological specimens from this location were closely examined and found to contain new species and a number of new records from this unusual habitat.
But the animals we most wanted to find were those associated with the greatest scientific mystery. Biologists Pedro Oromi and Stefan Konemann, hoped Tom would retrieve samples of an elusive crustacean that had been first collected here twenty-five years earlier. This rare and much sought-after remipede may be an example of the oldest living fossil on the planet. Having remained essentially stable in its form for some hundreds of millions of years, these creatures may reveal vital clues about evolution and survival of life on our planet.

I was fascinated by the fact that these exceptionally ancient creatures are living in a very young cave, one significantly younger than their ancestral past, indicating that they migrated from an adjacent, but much older location. Although we could not answer questions about where these animals came from, we knew that closely related remipedes from the same genus inhabit caves on the opposite side of the Atlantic suggesting an origin during the breakup of the continents in the ancient Tethys Sea. Remipedes have been collected in caves in the Bahamas, the Yucatan, Cuba, the Dominican Republic and even remote parts of Western Australia.
The highlight of our expedition came with the successful collection of several remipede specimens that appear to represent an entirely undocumented species.

Despite the success of the expedition’s efforts to collect keystone animals, many questions remain. Where do these stygobitic animals come from? Do they live in deep ocean habitats or in tiny spaces within the matrix of mid ocean ridges and seamounts? Did they simply ride around the globe on ancient drifting continental rafts? Is their rarity an indication of changing water conditions or a testament to perfection in evolutionary form?
Stygobitic cave animals have a unique survival strategy. Living in subaquatic darkness, these creatures developed improved senses of smell, taste and vibration detection. Eyes and pigment, and other unused anatomical features gradually disappeared. These animals are often endemic to a single, remote site, adapting to its particular environment and very scarce food sources.

Dr. Iliffe sums it up best. “Many of these animals are basically missing links in helping us to understand the origins of life in the oceans and generally the origins of life on Earth. They are totally new forms of life than is already known from anywhere else on the planet. The animals here provide us with a glimpse of what the Earth was like many, many millions of years ago.”
Unlike divers, these adaptable creatures somehow thrive in low levels of oxygen. And unlike most people encountering a potentially fatal reality, Sheck Exley and Ken Fulghum adapted to their situation, retaining composure during one of the most spectacular emergency exits in cave diving history.

The scientific results of our team’s extraordinary research will benefit biologists for decades.

I however, am not a scientist. Swimming through the depths of this lava tube, tracing the fin kicks of Exley and Fulgham, I am keenly aware and grateful for what I am. I am an explorer.

More of Jill Heinerth's photos can be found on her website at She also hosts an interactive multi-media online resource which carries video and audio content as well as articles about what's hot in the world of rebreather diving.