The kingdom of Tonga has been in the news recently for political instability; but for much longer Tonga has been the subject of another kind of instability—geological. Tonga is a prime cruising destination, and recent geological events there have provided some interesting experiences for sailors.
A piece of state of the art technology originally developed for the military is exploring one of earth's last frontiers—under the ice of Antarctica. It is a remote operated vehicle (ROV), known as the Phantom, a mobile underwater camera capable of recording high quality pictures at depths inaccessible to divers. The ROV has been jointly bought at a cost of $250,000 by the University of Otago and Television New Zealand's natural history unit. The portable vehicle, which needs a small crew for cabling, piloting, camera operation and technical maintenance, is powered by high voltage thruster motors and includes a control console, high resolution camera and fibre optic cable. Each motor is one horsepower. The camera stored on board is similar to one used by Television New Zealand for outside broadcasts, except that it is sealed in an underwater housing. A separate 35mm camera is used for still photography. It is controlled from the surface and has its own flash unit. The ROV can dive to depths of 700 metres—ten times the depth a diver can reach. The ROV'S first job in New Zealand involves filming for a documentary called "Under The Ice" for the Wild South series. The 50 minute film will be the first documentary to concentrate on life under the ice, says natural history unit producer Neil Harraway, who left for Antarctica in December. As this issue of New Zealand Geographic went to press, the team had completed its first dive with the ROV. In a short message from the icy continent, Harraway simply said the experience was "superb, fantastic, amazing." The predominant life form under the ice is the sponge, with colonies of different species and colours covering the entire seabed. Below 30 metres, where ice never forms, the sponges live for centuries and grow up to two metres wide and two metres high. Living among the sponges are orange seaspiders, white sealice, huge lavender-coloured nemertean worms, red and white urchins, orange starfish and red anemones. In the cold, undisturbed water, the animals have grown huge. Scientists say that the constantly low water temperature of two degrees below zero acts as a growth stimulus. The ROV was developed by Deep Ocean Engineering in California. It can be deployed from a helicopter, inflatable boat or conventional ship. The vehicle is hollow, with most of the engines and control machinery housed inside the hulls. Aside from the cameras and lights, little is outwardly visible. Otago University intends to use the ROV to further its research around Otago Harbour and the peninsula, while TVNZ has plans to explore the depths of Fiordland where it will investigate an unexplained sonar reading at 120 metres outside Milford Sound.
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