worms are an integral part of the vent community food
feet down, along the Galapagos Rift, Bob
Ballard made a discovery that would forever change scientists'
understanding of life on earth. Using the submersible Alvin
to explore the Mid-Ocean Ridge, the 42,000-mile underwater
mountain range that is the planet's largest geological feature,
Ballard found deep vents in the seafloor. Around these vents,
he was shocked to see giant white clams, a sign of life in
the dark, seething-hot waters.
examination revealed an entire ecosystem unlike any found
before - fields of giant red worms living in strange tubes,
octopuses, crabs, and even fish. Rather than relying on the
sun as their energy source, these vent creatures used a system
of chemosynthesis, depending instead on the heat of the earth
for survival. Many scientists now speculate that life on this
planet may have originated in just such an environment.
has made more deep
ocean discoveries than any other sub.
For the twenty-five years since this breakthrough, researchers
have carefully brought vent specimens to the surface for study,
using elaborate pressurized systems to keep them alive. Today,
hundreds of hydrothermal vent communities are known to exist
around world. As Ballard tells Alan, this was his proudest
moment of discovery.
more on this topic, see the Web feature:
Earth on the Move