Diving in a nuclear bomb crater is surreal. A truly catastrophic event took place here, and yet here you are, swimming among corals, reef fish, and sharks. Everyone is just going about their business- swimming, eating, searching for a mate- as if there’s nothing unusual about their surroundings. It’s hard not to wonder how recovery managed happen here at all, much less in just a few decades.
From 1946 to 1958 the U.S. Navy detonated 63 nuclear bombs in the Marshall Islands, a collection of atolls, rings of coral islands, in the middle of the Pacific. This summer, as part of my dissertation research, I traveled with an interdisciplinary team spanning the fields of physics, biology, environmental science, law, journalism, and technical diving to conduct research in this understudied but extremely important region of the world. The legacy of nuclear testing in the Marshall Islands is a devastating one. The people of Bikini, Enewetak, Rongelap, and Utirik were forced to abandon their homes, and in most cases the food and water sources are still poisoned, so their descendants cannot return. Despite this, at Bikini Atoll, where 23 bombs were detonated, the ecosystem appears to have healed enormously since testing ended 60 years ago. Our question is, has it really?
As the biologist on the team, I look for answers in the DNA of animals living at former nuclear test sites. Are these animals, which are continuously exposed to higher-than-normal levels of radiation, actually doing fine? Do the genes of the animals living there indicate that they really are in good health, or is there something more sinister lurking in the DNA, waiting to be discovered?
To answer this, I plan to sequence the genomes of some of the animals most likely to be affected and study their somatic mutations. Somatic mutations occur naturally, but they can happen at a higher rate due to certain carcinogens, including radiation. They can be beneficial, neutral, or deleterious. The most well-known are notorious for being the cause of cancers. My team and I took clippings of corals while on snorkel or SCUBA, and we bushwhacked through jungle to catch, measure, and take samples of coconut crabs, the largest terrestrial arthropod on the planet. We stored the samples in RNAlater, a preservative that keeps the genetic material in good condition until it gets back to the lab to be processed.
My DNA samples are safely stored in the lab freezer at the Hopkins Marine Station now. Thanks to an Inter-Campus Research Award from the Chan-Zuckerberg Biohub, later this month I will begin the next part of the scientific process: processing and analyzing my collected samples to discover the story of these irradiated coral genes. Who knows what stories the genomes of the corals and crabs living at Bikini for the last few decades will tell us?
Elora López is a 4th year Biology Ph.D. candidate and the president of the Hopkins Marine Station Graduate Student Organization. She uses genomics to address ecological, evolutionary, and conservation questions.
Funding for this fieldwork came from the Columbia K=1 Project, a National Geographic Early Career Explorer grant, and an Explorers Club Rolex Explorer Grant.