World's Deepest-Diving Submersible To Come To NZ

World's Deepest-Diving Submersible To Come To NZ

Scientists from New Zealand and Japan will later this year explore submarine volcanoes and seafloor hot springs off the New Zealand coast in the world's deepest-diving research submersible.

The joint Japanese-New Zealand study in the Kermadec Arc, northeast of New Zealand, will be led by the Institute of Geological and Nuclear Sciences Limited (GNS).

It will be the first seafloor investigation in New Zealand waters by a submersible capable of diving to the bottom of the world's deepest oceans.

Government-owned Japan Marine Science and Technology Centre (JAMSTEC) is bringing its Shinkai 6500 submersible to the South Pacific to study seafloor hot springs and the organisms that live next to them. It will spend three weeks diving on volcanic rift features in the Lau Basin, southeast of Fiji, before coming to New Zealand.

The cost of the 17-day New Zealand leg of the project is being met by the Japanese government as part of an ongoing relationship between Japanese and New Zealand science organisations. The New Zealand leg starts in Auckland on 23 October 2004.

Three GNS scientists will be part of the scientific crew. They will characterise the physical and chemical environments in which the hot-spring organisms live. A NIWA marine biologist is to be part of the team studying the deep-sea creatures.

Capable of carrying three people to the ocean depths for nine hours at a time, the Shinkai 6500 is scheduled to make six dives to explore two hydrothermally active submarine volcanoes in the Kermadec Arc.

Cameras towed from surface ships in recent years have revealed a startling assortment of life flourishing in the hostile conditions next to seafloor hydrothermal vents. Many of these organisms are likely to be unknown to science.

The main focus of the New Zealand leg will be Brothers volcano, which is about three times the size of White Island and sits in 1850m of water. Brothers, about 400km northeast of White Island, is the most active of New Zealand's many offshore volcanoes. A 700m-thick volcanic plume rises from its large dish-like crater.

Project leader, Cornel de Ronde of GNS, said studies from a surface ship in 1999 and 2001 showed Brothers had two distinct vent sites - one near the centre of its crater and the other on the crater wall.

" The chemistry of the hot fluids discharging from the two vents differs markedly. The advantage of Brothers volcano is that we can study two very different vent habitats inside the one volcano," Dr de Ronde said.

The other dive target is likely to be Healy volcano, similar in size and activity to the nearby Brothers volcano.

" The Shinkai 6500 will allow us to be very precise in our sampling of rocks, minerals, hydrothermal vent fluids, and vent-related organisms."

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