Corals are always quite photogenic, but pretty as these examples are, what's most fascinating is where these things are growing: in one of the craters left by the US nuclear testing on Bikini Atoll in the 1940s and 1950s.

Castle Bravo Crater was excavated by a 15 megatonne nuclear bomb in 1954, and it was recently visited by a team of divers from the Australian Research Council Centre of Excellence for Coral Reef Studies as part of a study of how the atoll is recovering from the effects this and the other Bikini nuclear tests. From the Centre's press release:
After diving into the crater, Zoe Richards of the ARC Centre of Excellence for Coral Reef Studies and James Cook University says, "I didn't know what to expect - some kind of moonscape perhaps. But it was incredible, huge matrices of branching Porites coral (up to 8 meters high) had established, creating thriving coral reef habitat. Throughout other parts of the lagoon it was awesome to see coral cover as high as 80 per cent and large tree-like branching coral formations with trunks 30cm thick. It was fascinating - I've never seen corals growing like trees outside of the Marshall Islands.
"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."
However the research has also revealed a disturbingly high level of loss of coral species from the atoll. 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 missing corals are fragile lagoonal specialists - slender branching or leafy forms that you only find in the sheltered waters of a lagoon," Zoe explains. While corals in general have shown resilience, Zoe adds that the coral biodiversity at Bikini Atoll has proven only partially resilient to the disturbances that have occurred there.
We all know that what should have happened is that the diving team vanished without a trace, leaving behind only grainy footage of an attack by mutated giant cnidarians, but I suppose that this is the next best thing. More pictures can be found here.
Geotagging (View all geotagged posts)

Chris Rowan is a geologist specialising in the dark arts of paleomagnetism, and getting people to pay him to travel to exotic destinations for fieldwork. Having drilled up New Zealand during his PhD, and South Africa in his first post-doc, he now works at the University of Edinburgh.
Anne Jefferson has a love of all things water-related and blends hydrology, geomorphology, geology, and climate change in her work. She has a Ph.D. from Oregon State University and is now an assistant professor at the University of North Carolina at Charlotte.

Comments
What they don't tell you is that those photos were take at midnight, without a flash.
Posted by: Bob O'H | April 15, 2008 12:44 PM
"However the research has also revealed a disturbingly high level of loss of coral species from the atoll. 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 missing corals are fragile lagoonal specialists - slender branching or leafy forms that you only find in the sheltered waters of a lagoon," Zoe explains. While corals in general have shown resilience, Zoe adds that the coral biodiversity at Bikini Atoll has proven only partially resilient to the disturbances that have occurred there."
It sure seems to me that as time increases, the diversity of coral species will increase, too. These are just the "pioneer" species of coral. Zoe even mentions that they are "local extinctions." I'm not worried...yet. Give it time - more coral will show up.
Posted by: socalmike | April 15, 2008 7:01 PM
Can we draw the inference that more atolls would have luxuriant corals if people left them alone?
Posted by: Monado, FCD | April 15, 2008 10:21 PM
But that would be such a surprising inference!
Posted by: Silver Fox | April 15, 2008 11:31 PM
Kind of in line with the Chernobyl exclusion zone: it's a very healthy bit of forest, effectively a very well-protected park. The environmental impact of heavy radioactive contamination is much less than the environmental impact of human habitation...
Posted by: Anne | April 16, 2008 2:50 AM
Gads! What's that eerie blue glow in the background? Get outta there! No, wait a minute, it's just the ocean....
Posted by: Ian | April 16, 2008 11:11 AM
>
Umm, if they had "vanished w/out a trace", where would we be getting the grainy footage??
Posted by: Scott M. | April 16, 2008 11:21 AM
Oh, I'm sure the corals have superpowers. They just haven't figured out how to use them to fight eco-crime yet.
Posted by: Maria | April 16, 2008 1:42 PM
Last I heard about the Chernobyl site is that the wildlife did have increased numbers of deformities and reduced lifespan. Like you pointed out, Anne, the zone was still generally healthier than other forest in Russia. It's kinda sad that humans are harder on an ecosystem than an atomic explosion.
Posted by: Adam | April 16, 2008 2:43 PM
They just haven't figured out how to use them to fight eco-crime yet.
That would be awesome. Maybe in the Aleutians they have nascent superhero rockfishes that are going to come up out of the deep and kick our asses, but good.
Posted by: Tlazolteotl | April 16, 2008 5:59 PM
Ian,
I'm wondering whether anyone has investigated that giant yellow pushpin in the center of the crater. It appears to be about 500 feet long.
Posted by: Daryl McCullough | April 22, 2008 1:15 PM
Adam, Chernobyl was not an atomic explosion. It was a steam explosion caused by a very poorly designed reactor. The fire that ensued burned nuclear fuel and the smoke that was expelled had a TON of dirty radioactive fallout. None of the nuclear power plants in France or the US would ever do the same thing that Chernobyl did. It was a bad design, and the reactor was not even housed in a containment chamber.
Posted by: Brian | February 10, 2009 8:19 PM
Daryl,
The pushpin is obviously a primary example of a radiologically induced mutation resulting in gigantism.
Posted by: gor | September 8, 2009 2:29 AM
Brian,
The Chernobyl disaster resulted from a graphite pile that ignited after the cooling system failed. When the flow of water was restored the fire was aggravated because burning graphite produces enough energy to disassociate water molecules to their component atoms. The hydrogen thus produced re-ignited which produced still more energy. Firefighters compounded the difficulty of battling the flames by initially relying on water to combat it. The fire continued until the graphite pile was destroyed. The remaining slag stayed hot enough to melt through the Earth's crust and recombine chemically with it, thus leaving a rock-hard and radioactive legacy for succeeding generations.
Posted by: gor | September 8, 2009 3:09 AM