Life after nuclear testing

Bikini Atoll, Marshall Islands

A scientist collects coral samples in the Bravo crater

Despite being the stage for enormous displays of destructive power, the Pacific Islands of Bikini Atoll have a remarkable sense of beauty and peace. A ring of tiny, low-lying islands bordered by sweeping white-gold beaches and covered in lush green vegetation and swaying palm trees surround a lagoon of invitingly warm turquoise waters. It is one of the picture-postcard images treasured by modern culture—the untouched, wild, desert island.

Upon closer inspection, however, this island paradise bears deep and dramatic scars from 23 nuclear weapons tests carried out here by the United States between 1946 and 1958. These tests, most particularly Operation Crossroads in 1946 and Castle Bravo in 1954, changed the course of human history.

In 1946, the people of Bikini reluctantly agreed to leave their treasured homeland “for the good of mankind and to end all world wars” and commenced their many years of unhappy displacement within the Marshall Islands.

Today, the remains of crumbling grey concrete bunkers and monitoring stations emerge incongruously from the vegetation reclaiming the islands. A gaping hole a mile wide on the north-western side of the atoll reminds us where the world’s first deliverable hydrogen bomb, code-named Castle Bravo, destroyed three islands before its fallout covered eighteen thousand square kilometres of the Pacific Ocean. The site, as it stands today, eloquently illustrates the fate of a nuclear test site. The entire property of Bikini Atoll—the technological ensemble of sunken ships, along with the bunkers, the craters and disappeared islands, and the conspicuous absence of people—stands as testimony to a significant stage in human history that encompasses nuclear colonialism, the start of the Cold War and the age of nuclear weapons.

The lagoon is home to spectacular corals, arrays of multicoloured fish, sponges and giant clams. A reef of remarkable health and richness of species, hovering and gliding seabirds and significant populations of rare and endangered animals, including sharks and turtles, exist here largely free from human disturbance.

Bikini was inscribed on the World Heritage List as a cultural site in 2010, and there is potential for inscription based on natural values in the future.

View images of Bikini atoll 

Size and Location:
Bikini Atoll is the northern-most atoll in the western, Ralik, chain of atolls of the Marshall Islands; 29 atolls known to the Marshallese as Aelōn̄ Kein. The atolls consist of biotic limestone on a deep basalt core, built over millions of years by living coral organisms that grew as the basalt core slowly subsided, creating a marine environment extremely rich in productivity, diversity and complexity. Bikini’s 23 islands, a total land area of only 720 hectares, encircle an elongated and irregular lagoon which extends 40 kilometres east to west and 22 kilometres north to south, and is around 60 meters at its deepest.

Flora and Fauna:
The marine environment of Bikini is home to many globally threatened species, including corals, giant clams, turtles and sharks. Around 50 of Bikini’s 183 coral species fall within an IUCN threatened category. Because its reef ecosystems are more pristine than those in more populated regions, Bikini Atoll provides some of the most significant reef habitat in the northern Pacific. The rare and threatened species of giant clam Tridacna gigas is disappearing from the Pacific region but is found growing in remarkable abundance at Bikini.

One special characteristic of Bikini is the particularly high concentration of several threatened shark species, including grey reef shark (Charcharhinus amblyrhyncos), reef whitetip shark (Trienodon obesus), reef blacktip shark (C. melanopterus) and silvertip shark (C. albimarginatus). The highest concentration is found at the so-called Shark Pass where hundreds of C. amblyrhyncos swim inoffensively and undisturbed along the inner wall and at the pass itself. Silvertips (C. albimarginatus) are in deeper water and more difficult to spot, but they are attracted by the visit of the casual diver and come often to shallower depths. Tiger sharks (Galeocerdo cuvier) are known to approach the shore at night, and the spotted eagle ray (Aetobatus narinari) is a frequent sight.

The special abundance of sharks at Bikini Atoll is indicative of a healthy and diverse ecosystem. The high variability of habitats offered by lagoon, pass and ocean environments at Bikini supports a very high diversity of fish—around 360 species. The southern and eastern walls of Bikini sustain a high biomass of carnivores (Lutjaunidae, Lethrinidae, Sphyraenidae, Carangidae), while the lagoon is rich in invertebrate feeders and herbivores (Mullidae, Ephinephelidae, Caesionidae).

The birds of Bikini are an impressive feature. Twenty-six species of birds are documented for Bikini Atoll, including 3 IUCN Red-listed species: Buller’s Shearwater (Puffinus bulleri), Sooty Shearwater (Puffinus griseus) and the Bristle-thighed curlew (Numenius tahitiensis). It is thought that the birds of Bikini have benefited from the absence of humans, as they were traditionally eaten by Bikinians. The Red-tailed Tropicbird (Phaeton rubricauda) now nests on Bikini, but was unknown prior to the testing.

Challenges (and threats):

Climate change is a major threat to the low‐lying Marshall Islands. The islands are at risk from more frequent storm surge in the short to medium term, and complete inundation in the future. Rises in sea temperature will likely cause coral bleaching – the extent and impact of which is unpredictable. Ocean acidification is predicted to seriously impact the ability of corals to grow and form skeletons. Bikini Atolll will best retain some resilience to climate change through maintaining the health and protection of its coral ecosystems.

Illegal, unreported and unregulated fishing is also a threat. Several fishing vessels have been caught in recent years fishing illegally in the Marshall Islands. In 2002 a vessel was found fishing for sharks at Bikini Atoll and was successfully prosecuted. The current extent of illegal fishing is not known due to difficulties in surveillance and monitoring.

Many land and marine invasive species, both plants and animals, are threatening the biodiversity of the Marshall Islands. Once an invasive species becomes established it can be extremely difficult and expensive to control or eradicate. Invasive species can cause the extinction of native and endemic species by taking over their positions in the ecosystem, or through predation. Bikini Atoll has many invasive exotic plant and animal species, particularly apparent in the terrestrial environment, due to the huge military and clean-up operations carried out here over many years.

Work area: 
Protected Areas
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