The Trail of Discovery:

Plate tectonics and seafloor spreading revolutionized the big picture of how our planet works. Scientists were eager to zoom in to see details of what was happening at the seafloor—close-up and first-hand. They wanted to confirm, for example, that hydrothermal vents actually existed. A flurry of research cruises in the 1970s gave scientists the prize they sought—and something else that they never expected. Each cruise provided a piece of the puzzle.


Divers prepare Alvin between the pontoons of its mother ship, Woods Hole’s R/V Lulu.

(Courtesy of WHOI Archives)

ANGUS, Woods Hole’s deep-towed camera system, is deployed during the Galápagos Rift Expedition.

(Courtesy of WHOI Archives)

Aboard R/V Knorr, scientists and technicians stand vigil, tracking ANGUS as it is towed near the seafloor in 1977.

(Photo by Emory Kristof © National Geographic Society)

A series of seafloor photos taken by ANGUS shows the sudden appearance of a dense accumulation of live white clams. Within hours, the clams led scientists to find hydrothermal vents for the first time.

(Courtesy of WHOI Archives)

Alvin’s manipulator arm picks up a large clam from the Clambake 1 vent site.

(Photo by Robert D. Ballard, WHOI)

ANGUS captured this photo of a skate swimming above lava near the Galápagos Rift vent site.

(Photo courtesy of WHOI Archives)


A purple octopus scavenges in a clam-filled vent site

(Photo by Robert D. Ballard, WHOI)

ANGUS took this photo of dead clams at Clambake 2. The clams died because the vent was no longer active.

Courtesy of WHOI Archives)

Tubeworms, white crabs, and a pink fish gather at a Galápagos Rift vent site

(Photo by John M. Edmond, MIT)


John B. Corliss cradles a specimen of a giant clam retrieved on 1977 Galápagos Rift expedition.

(Photo by Emory Kristof © National Geographic Society.)

Scientists of the 1977 Galápagos Rift Expedition (left to right), Bob Ballard, Jack Corliss, and John Edmond, convene on the deck ofR/V Knorr.

(Photo by Ken Peal, WHOI)




The Discovery Cruise Begins

The Galápagos Hydrothermal Expedition, funded by the National Science Foundation, began in Februry 1977, with Woods Hole’s R/V Knorr cruising out of the Panama Canal.

The expedition included a team of top-notch geologists, geochemists, and geophysicists hunting for hydrothermal vents. No one imagined any need for a biologist on board.

Sleepy, Dopey, Bashful and ANGUS

On Feb. 15, ANGUS (Acoustically Navigated Geophysical Underwater System) was lowered to the depths to scout the area. Watching and waiting all through the evening of Feb. 15, scientists aboard R/V Knorr tracked ANGUS in the depths below. At just about midnight, ANGUS registered a spike in water temperature. The signal lasted three minutes, then water temperatures returned to a near-freezing 2°C (35.6°F). The scientists carefully noted the time and ANGUS’s position when the spike (called a “temperature anomaly” by scientists) occurred. ANGUS continued its mission through the night.

Thirteen fateful photos
ANGUS also had still camera mounted on the chassis that shot 3,000 color photos over 16 kilometers (7.25 miles) of seafloor. When the film was developed, the scientists studied the photos, starting from the first one. They looked at hundreds of photos, frame by frame, until they reached the photos that corresponded with the time when the temperature spike, or “anomaly,” occurred.

In a 1977 article in Oceanus magazine called “Notes on a Major Oceanographic Find,” Bob Ballard recalled the surprising findings:

“The photograph taken just seconds before the temperature anomaly showed only barren, fresh-looking lava terrain. But for thirteen frames (the length of the anomaly) the lava flow was covered with hundreds of white clams and brown mussel shells. This dense accumulation, never seen before in the deep sea, quickly appeared through a cloud of misty blue water and then disappeared from view. For the remaining 1,500 pictures, the bottom was once again barren of life."

Entering another world
Within hours of the startling clam discovery, R/V Lulu with Alvin on board arrived on the scene. The Alvin technical team prepared the submersible, and scientists eagerly awaited the dive at sunrise the next morning—Feb. 17. It was Alvin dive No. 713. Jack Donnelly was the pilot. Jack Corliss and Jerry van Andel were the scientific observers.

Alvin used acoustic beacons deployed on the seafloor to zero in on the area where ANGUS had photographed the clams. “But when they reached their target coordinates,” Ballard wrote in Oceanus, “Alvin and its three-man crew entered another world. Coming out of small cracks cutting across the lava terrain was warm, shimmering water that quickly turned cloudy blue as manganese and other chemicals in solution began to precipitate out of the warm water and were deposited on the lava surface, where they formed a brown stain.”

Alvin’s temperature sensors measured water temperatures of 8°C (46°F) at the bottom of the sea. The first hydrothermal vent had been discovered.

“ But even more interesting was the presence of a dense biological community living in and around the hydrothermal vents,” Ballard wrote in Oceanus. White clams—up 30 centimeters (1 foot) long—clustered in an area about 50 meters (165 feet) across.

Observing the scene from Alvin’s viewports, Corliss talked by acoustic telephone to his graduate student Debra Stakes, who was aboard R/V Lulu.

“ Isn’t the deep ocean supposed to be like a desert?” Corliss asked. When Stakes answered, “Yes,” Corliss replied: “Well, there’s all these animals down here.”

The ‘Garden of Eden’
The scientists called the area that Corliss, van Andel, and Donnelly found “Clambake 1.” But later dives in Alvin discovered four other vent sites with other thriving communities of life. The scientists gave playful names to each one.

Aside from the big white clams, “Clambake 1” had brown mussels, many white crabs, and a purple octopus, which probably preyed on other animals at the vent.

Soon the scientists found “Clambake 2,” where all the clams were dead. This was thought to be the site found the year before by the Pleiades expedition.

The “Dandelion Patch” had small, never-seen-before, orange animals that resembled—you guessed it—dandelions. The “Oyster Bed” vent site had no oysters (but, remember, geologists—not biologists—were doing the naming!).

Finally, the scientists came upon a vent site filled with tall, 1 1/2-foot-high, white-stalked tubeworms with bright red tops. Swaying in the water, they looked like a field of flowers swaying in the wind. Water temperatures here reached a balmy 17°C (63°F). The scientists called this site “The Garden of Eden.”

A foul-smelling clue
The scientists on board R/V Knorr were astonished by the discovery of life thriving without sunlight on the seafloor. They were eager to figure out what the organisms were eating.

“ But we were not biologists. We were supposed to be finding warm water,” Ballard wrote in his book The Eternal Darkness.

The scientists never imagined finding so much life on the seafloor, so they had no reason to stock the ship with lots of chemicals to preserve biological specimens. They stored specimens of clams and other seafloor animals retrieved by Alvin in a small amount of formaldehyde that one student had brought. Then they used the closest thing to formaldehyde that they had on board—some strong Russian vodka bought in Panama. But there was not nearly enough to preserve all the specimens.

What were these newly discovered organisms feeding on? Water samples from the vents obtained by Alvin soon provided a powerful clue. As chemists drew the first water sample, the smell of rotten eggs filled the lab. Crew members and scientists rushed to open portholes. The water was full of hydrogen sulfide.

‘ It was like Columbus’
“ A whole lot of things sort of fell into place,” said John Edmond, a geochemist from MIT, in Victoria Kaharl’s book Water Baby. “About halfway into the cruise, we realized that regular seawater was mixing with something. It was a unique solution I had never seen before.

“ We all started jumping up and down. We were dancing off the walls. It was chaos. It was so completely new and unexpected that everyone was fighting to dive (in Alvin). There was so much to learn. It was a discovery cruise. It was like Columbus.”

No one at the time was able to determine the source of energy or processes that could support these communities since most life on Earth depended on sunlight and photosynthesis, clearly these were not available at such great water depths.