Oceanographers exploring some of the most remote deep-sea hot springs ever found have discovered what they say is a “riot of life” in a distinct biological zone that no one knew existed. They said the exploration, which occurred more than a mile down in the ocean just north of Antarctica, uncovered the most strikingly unique assemblage of life-forms found in decades, including thousands upon thousands of a species of crab never seen before, as well as new barnacle, anemone, snail and starfish species.
“It’s remarkable that we can be in the 21st century and still not know fundamental things about what lives on our planet,” said Cindy Van Dover, director of Duke University’s marine laboratory, who has been studying life at deep sea vents for 30 years but was not involved in the new discoveries. “This is really exciting because it keeps open the door for even more discovery down the road.”
Deep-sea hydrothermal vents are springs that can spew out water at temperatures of more than 800 degrees. Loaded with chemicals and minerals from the rocks below, the hot water mixes with the much colder seawater in a chemical frenzy that often creates billowing black plumes. Some of the minerals form chimneys around vents that can grow several stories tall.
Geologists discovered the first hydrothermal vents in the Pacific in 1977, near the Galapagos Islands. So unprepared were they to find life in such a hostile place that their team included no biologists, and they packed few biological supplies. But there were huge worms living in tubes, some as tall as a person, dominating the vents, alongside plots of massive clams. The geologists pickled samples of the strange animals as best they could, in some cases using Russian vodka they happened to have on hand.
Later work revealed that the tube worms and other vent animals got their food from bacteria that feed on the chemicals in a vent’s outflow. It was the first ecological system found to use chemicals, rather than sunlight, as a foundation.
For years, most scientists believed they would find hydrothermal vents only in the Pacific, the most geologically active ocean. But in 1985, a team from the National Oceanic and Atmospheric Administration found vents along the submerged mountainous ridge that runs down the middle of the Atlantic. Instead of a field of tube worms, these vents were crawling with hundreds of thousands of shrimp.
Further vent discoveries have involved dozens of new species every year, but the sea-vent life was always dominated by the same general type of animals.
The Southern Ocean, which surrounds Antarctica, has only recently been a focus of deep-sea exploration. It’s particularly difficult to reach, and its waters are treacherous, with storm swells regularly hitting 50 feet. Chris German, a geochemist at the Woods Hole Oceanographic Institution in Massachusetts, was the first to discover deep-sea vents in that area in 1999, after detecting the telltale water plumes, but he was unable to explore them for more than a decade.