Eel dominated hydrothermal vents: a new ecosystem discovered by underwater explorers

27 May 2005

Researchers from the University of Sydney have discovered a unique community of hundreds of eels living on the eruption site of an active underwater volcano, just off the coast of Samoa.

During a research cruise to study a Samoan 'hot spot', the scientists, members of a collaborative team of oceanographic investigators from the University of Sydney and institutes in the United States, undertook a voyage of discovery to explore for the first time the underwater volcano Vailulu'u. The researchers found a new biological community surrounding the eruption site, and were amazed to find an "Eel City," a community of hundreds of slithering eels. 

Eel City
Eel City

This new cone of the volcano, dubbed Nafanua after the ferocious Samoan goddess of war, did not exist just four years ago, with a growth rate of at least eight inches per day; the volcanic cone has rapidly emerged since their last expedition to this area in May 2001. Nafanua now stands at 300 meters, or nearly 1,000 feet of water.

The scientists were alerted to the volcano's existence when they profiled the seafloor of the Vailulu’u crater using multibeam mapping. Existing maps of the seafloor in the area gave little indication that this volcano existed. When sound beams were directed into the crater this time, they measured an unusually shallow depth. These interesting results prompted further investigation of the area using the manned NOAA submersible the Pisces V operated from the University of Hawaii - a seven-foot sphere that has the capability to dive to depths of more than 6,000 feet. 

'Much of Nafanua is covered with yellow "fluff," which are microbial aggregations that are produced by microscopic life feeding on chemical energy from the volcano's hydrothermal system,’ said Dr Adele Pile, Senior Lecturer in Marine Science at Sydney University's School or Biological Sciences. 

'As the team explored the area, they discovered a number of large communities of eels inhabiting the fragile cavernous rock pillars surrounding the hydrothermal vent area.  As the submarine landed near this area, scores of eels, approximately one foot in length, emerged from the rock caves and crevices. The team named this novel marine hydrothermal community "Eel City",' she said

At this point the team does not know why they found such extensive eel communities surrounding the volcano—it's a mystery that we hope to learn more about on future cruises which will take place in the beginning of July 2005.

To learn more about this research cruise and to see video and photos, visit the cruise website.

For further information and to arrange an interview please contact Jake O’Shaughnessy at the Media Office on ph: +61 2 9351 4312 or m: 0421 617861.

Notes to Editors:

  • This research was funded by the Australian Research Council, National Oceanic and Atmospheric Association (NOAA) and the National Science Foundation (NSF). The discovery of Nafanua included investigators from oceanographic institutions in the US and Australia, in addition to graduate, undergraduate and high school students.