Catherine Brahic
NewScientist.com
Tuesday, November 28, 2006

The weird and wonderful creatures living by methane vents in the southwest Pacific have been photographed for the first time (see images right and below).

The deep-sea communities live around methane seeps off New Zealand’s eastern coast, up to 1 kilometre beneath the sea surface. The team of 21 researchers from the US and New Zealand, who spent two weeks exploring the area, have just returned to shore. See video footage recorded by the researchers here, here and here.

“It's the first time cold seeps have been viewed and sampled in the southwest Pacific, and will greatly contribute to our knowledge of these intriguing ecosystems,” says Amy Baco-Taylor from the Woods Hole Oceanographic Institution in the US.

Cold seeps are areas of the seabed where methane or hydrogen sulphide gas escape from stores deep underneath. Like hydrothermal vents, the gases support unique life forms that can convert the energy-rich chemicals into living matter in the absence of any sunlight.

Sheer extent
Animals living around methane seeps off Chile and Japan have been observed before, but not near New Zealand. “The seeps here are remarkable in the sheer extent of their chemosynthetic communities,” says Baco-Taylor, whose team visited eight such sites between 750 and 1050 metres beneath the surface.

They used sonar to map the seafloor and to detect plumes of water rich in methane, then lowered a video and stills camera system over each site.

This allowed them to record images of tube worms between 30 cm and 40 cm in length as they emerged from beneath limestone boulders. They also recorded corals, sponges and shell beds covered with various types of clam and mussel.

The expedition was led by scientists from the Woods Hole Oceanographic Institution, the Scripps Institution of Oceanography and the University of Hawaii at Manoa in the US, and New Zealand’s National Institute of Water and Atmospheric Research.