Scientists To Probe Seabed Treasures

22 September 2004

Scientists To Probe Seabed Treasures

New Zealand and American scientists set off this week on a three-week voyage on the deepwater research vessel Tangaroa to investigate submarine volcanoes in the Kermadec Arc, northeast of New Zealand.

They will map and probe a 550km stretch of seafloor between Giggenbach volcano and just south of Tonga. The first 450km of the survey area lies within New Zealand's Exclusive Economic Zone. The balance is in international waters.

The project is the third in a series of voyages, which started in 1999, aimed at mapping and investigating submarine volcanoes and seafloor hotsprings along the 2500km of volcanic arc between New Zealand and Tonga.

Along this Kermadec section of the Pacific Ring of Fire, scientists believe there are about 90 submarine volcanoes, many of which are active. This geologically complex stretch of seabed is only partly mapped and not well understood.

It features a high frequency of seafloor venting of hot fluids. Living next to these vents are communities of unusual marine species, some of which are new to science. They range from super-tough microscopic organisms to primitive tubeworms and shellfish.

Scientists believe that life on earth may have begun next to seafloor hotsprings such as those in New Zealand's offshore territory. They hope to collect some of these organisms and find out more about their biology and physiology.

Another reason for exploring this stretch of New Zealand's underwater territory, is the large seafloor deposits of metallic minerals next to the vents. Within New Zealand's EEZ, they represent a strategic resource needing prudent management for future generations of New Zealanders.

This project, like the previous two in this series, is a collaboration involving Geological and Nuclear Sciences Ltd (GNS), the National Institute of Water & Atmospheric Research (NIWA), and American research organisation National Oceanic and Atmospheric Administration (NOAA).

It is called NZAPLUME III, short for New Zealand and American Plume Mapping Expedition. Led by GNS, it also involves scientists from Australia and Tonga, plus four senior university students assigned to special tasks.

At each volcano site, Tangaroa's multibeam sonar mapping system will produce high-resolution maps of the seafloor to guide the discovery of hydrothermal plumes rising from volcanoes and their associated vents.

The plumes are typically very rich in dissolved iron, manganese and copper, along with lesser concentrations of zinc, lead, and gold. Metallic compounds in the plumes precipitate out and settle on the seabed forming large mineral deposits.

As in the previous voyages, the scientists will endeavor to recover rocks, minerals, and rare marine species at places of particular interest. They will be brought back to New Zealand for analysis. On the northward journey to the survey area, scientists will deploy special monitoring equipment at the large and active Brothers volcano which sits in 1800m of water. The equipment will be recovered during another voyage in March 2005.

Three current meters will be positioned around the perimeter of the volcano to enable estimates of volumes of gas and hot fluid being emitted from the vents at Brothers. Three hydrophones will be placed inside Brother's crater to listen for volcanic and seismic activity inside the volcano.

Data captured by this equipment will give scientists rare insights into submarine volcanic activity and its significance in terms of ocean chemistry and emissions of greenhouse gases.

A freelance journalist will accompany the scientists on Tangaroa to file regular reports on the many projects that make up the voyage. He also intends writing background stories about life on a busy research ship where everyone works 12-hour shifts non-stop for three weeks. Voyage updates can be seen at: www.gns.cri.nz/kermadec

The voyage leaves Miramar Wharf, Wellington, on 23 September and is scheduled to return to Tauranga on 17 October.

ENDS

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