Corals recover - over half a century after nuclear blasts

April 16th, 2008 - 2:11 pm ICT by admin  

Sydney, April 16 (IANS) It took over half a century for life to re-assert itself - but not entirely. Corals have sprouted again on Bikini Atoll, a good 50 years after it was ravaged by dozens of nuclear bombs detonated by the US over an eight-year period. But compared to the early 1950s, some 42 species of corals are missing, a new study has found.

The gaping Bravo crater, some two km wide and 73 metres deep, was gashed by the impact of nuclear weapon ‘Bravo’ - said to be a thousand times more powerful than the Hiroshima bomb.

Researchers who led an expedition to the crater have reported “incredible, huge matrices of branching Porites coral (eight metres high) . . . creating a thriving coral reef habitat”.

“Throughout other parts of the lagoon it was awesome to see coral cover as high as 80 percent and large tree-like branching coral formations with trunks 30 cm thick,” said Zoe Richards of James Cook University.

“It was fascinating - I’ve never seen corals growing like trees outside the Marshall Islands,” said Richards who was a member of the research expedition.

“The healthy condition of the coral at Bikini atoll today is proof of their resilience and ability to bounce back from massive disturbances, that is, if the reef is left undisturbed and there are healthy nearby reefs to source the recovery,” Richards added.

The research team comprised scientists from Australia, Germany, Italy, Hawaii and the Marshall Islands. The expedition examined the diversity and abundance of marine life in the atoll.

However, they also revealed a disturbingly high level of loss of coral species. Compared with a famous study made before the atomic tests were carried out, the team established that 42 species were missing compared to the early 1950s.

At least 28 of these species losses appear to be genuine local extinctions probably due to the 23 bombs that were exploded there from 1946-58, or the resulting radioactivity, increased nutrient levels and smothering from fine sediments.

“The ambient gamma radiation the residential island of Bikini Atoll was fairly low - pretty much like the background radiation in an Australian city,” said Maria Beger of University of Queensland, who took a Geiger counter with the expedition.

“However, when I put the Geiger counter near a coconut, which accumulates radioactive material from the soil, it went berserk.”

Extensive decontamination works have been carried out at Bikini Atoll making it safe to visit. However, local produce is still unsafe to eat.

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