Coral Reefs Can Recover From Disasters. How Can We Save Them From Us?

In 1946, the US military tested nuclear bombs on a coral reef in the Pacific, initiating an incidental 50-year experiment on how coral reefs recover. Credit: United States Department of Defense
Bikini Atoll, formed over millions of years around an island in the Pacific Ocean about halfway between Papua New Guinea and Hawaii, has been subjected to horrific human-caused disturbances. Between 1946 and 1958, the United States set off 23 separate nuclear explosions on or near the atoll to test the impacts of nuclear weapons on naval ships.

By Michael WebsterOcean Portal

The largest one, codenamed “Castle Bravo,” blasted a crater two kilometers wide and 73 meters deep into the reef on March 1, 1954, instantaneously raising the sea surface temperature to a staggering 55,000 degrees Celsius. (For comparison, the surface of the sun is a chilly 5,500 degrees Celsius.) While nobody took a comprehensive survey of reef life following these detonations (although Smithsonian researchers returned later), it‘s safe to say that nearby marine life would have died instantly as the blasts sterilized the seafloor.

In recent decades, radiation on Bikini Atoll has declined enough that it is safe for scientists to visit the reef and measure whether and how the corals have recovered. Despite the previous devastation, the reefs are thriving, have high coral cover, teem with fish, and most of the coral species have returned. This ability of an ecosystem to return to a similar ecological state following a disturbance is called resilience—and scientists are trying to figure out why some ecosystems can rebound, while others don’t recover.

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