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Tsuname Source Area Now A Dead Zone
By John von Radowitz in London
A "DEAD zone" devoid of life has been discovered at the epicentre of last year's tsunami four kilometres beneath the surface of the Indian Ocean.
Scientists taking part in a worldwide marine survey made an 11-hour dive at the site five months after the disaster.
They were shocked to find no sign of life around the epicentre, which opened up a 1000-metre chasm on the ocean floor.
Instead, there was nothing but eerie emptiness. The powerful lights of the scientists' submersible vehicle, piercing through the darkness, showed no trace of anything living.
A scientist working on the Census of Marine Life project, Ron O'Dor, of Dalhousie University in Canada, said: "You'd expect a site like this to be quickly recolonised, but that hasn't happened. It's unprecedented."
The scientists teamed with television crews from the BBC and Discovery Channel to investigate the heart of the deadliest tsunami on record. On Boxing Day last year an earthquake with a magnitude of 9.3 tore the earth apart off the west coast of Sumatra. Part of the ocean floor was thrust up to create a 40-metre-high undersea cliff that then collapsed.
Huge volumes of water were displaced in the process, creating the giant waves that killed more than 270,000 people.
"Normally, when you go to the bottom of the sea anywhere and take a sample or look around, there's always something alive," Professor O'Dor said. "But five months after the earthquake, this entire plain, created by the collapse of the cliff, was essentially devoid of life."
The group had expected to find several species of fish, plus cephalopods, sea cucumbers, brittle stars, corals and sponges, crustaceans and worms.
Professor O'Dor thought the collapsing cliff had buried the food sources of bottom feeders, which in turn had an effect on larger predators. "No one has ever got to a site like this so quickly before," he said. "It may just be that it takes a while for things to get back to normal. The sea is very cold at this depth, and typically the speed of life is proportional to temperature. Nothing happens very fast at 4C."
The tsunami epicentre findings were included in a report marking the halfway point in an ambitious project to catalogue all life in the oceans by 2010.
About 1700 scientists from 73 countries are taking part in the project. So far they have electronically tagged almost 2000 animals from 21 species, including sharks, fish, birds, turtles, seals and sea lions.
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