Think the Earth

Pacific atoll of Bikini in the Marshall Islands experienced 23 US nuclear bomb tests from 1946 to 1958. About 50 years after the last nuclear bomb, an international team of scientists from 7 countries, such as Australia and Germany, found that the corals are flourishing again.

The largest hydrogen bomb on the atoll - a thousand times more powerful than the Hiroshima bomb - exploded in 1954. This explosion left a crater 2km wide and 73 deep in the atoll, and caused radioactivity, and increased water temperature and nutrient levels. The marine environment was considered to be completely devastated.

However, the scientists dived in the area and were greatly impressed to see healthy coral cover as high as 80 per cent, which included 8m high or 30cm thick branch corals. Their analysis showed that two factors might have contributed to this coral recovery, 1) No human disturbance in the atoll due to the fear of radioactivity, 2) Neighboring Rongelap Atoll, the second largest in the world, served as the coral breeding area for Bikini Atoll. Though Rongelap Atoll was contaminated by radioactive ash, no nuclear tests were carried out directly on it.

The corals in Bikini Atoll demonstrated a high resistance and ability to recover from large scale destruction. However, the number of coral species decreased. Compared to the early 1950s, 42 species are still missing, and 28 species are considered extinct in this area.