Have they paved paradise?
May 27, 2002
by Lonny Lippsett

As the sun began to set in the Pacific Ocean, scientists, students, technicians, and crew gathered on RV Atlantis’ stern. They were eager –just as you are—to hear whether Tim Shank and Dan Fornari, diving today in Alvin, had found the vent site known as “Rose Garden.”

Timemerged from Alvin’s sail, climbed down the ladder, strode across the stern, and approached the small crowd.

“As far as we can tell,” he said. “Rose Garden may be no more.”

Alvin landed today near what scientists call the “axial high.” It is a raised strip of seafloor that runs down the middle of the Galápagos Rift Valley. It is raised because that’s where lava erupts at the seafloor and piles up and flows outward. Hydrothermal vent sites are often found on axial highs. Rose Garden was located on the southern side of the axial high.

Tim, Dan and Alvin Pilot Phil Forte found a central fissure—a crack in the seafloor that lava has spewed out of. They followed that fissure, first to the east, where they found shells of clams that Tim estimated had died 50 to 150 years ago. Any venting there had faded long ago.

Then they tracked the fissure westward, all along the axial high, all the way to the vent site Tim and Steve found yesterday with very small, very young mussels, clams, and tubeworms. They found the site late in their dive and did not have enough battery power left to look around and sample. They had marked the spot with a plastic bucket lid tied to a weight and marked with the letter “A.”

Today, they looked all around the site. They found that the young vent site lay atop another lava flow—like one hand atop another. The upper flow had the young animals. The lower flow had clumps of mature mussels and fully grown tubeworms. They sampled the lava.

“The lava is quite fresh,” Dan said. “The lava flow is very young.”

“We think the young community of animals has started to develop on lava that may have paved over older communities underneath it,” Tim said. One of those paved-over communities might have been Rose Garden. “Rose Garden may be a parking lot,” he said.

For biologists, Rose Garden is a unique, underwater paradise. First found in 1979, it was lush with life, and scientists revisited the site in 1985, 1988, and 1990. They studied the site extensively to see how vent communities change and how different animals move in and interact with each other. When they visited, they left dozens of plastic markers at the site. During perhaps a dozen dives to Rose Garden over the years, Alvin had also left behind more than 40 steel plates on the seafloor near Rose Garden—the steel plates that it uses to descend and that it drops to surface again. Today, Tim, Dan, and Phil saw no plastic markers and no weights. Were these, too, paved over by a fresh lava flow that occurred sometime after the last visit in 1990?

Perhaps. But perhaps not. “I find it difficult to believe that all signs of human activity could have been obliterated,” said Susan Humphris, who will dive tomorrow for another look. Perhaps Rose Garden is tucked away in a spot that Alvin has not yet crossed in the past two days.

[Back to top]