They seem to have nothing in common. However, these reptiles have an unthinkable record on their shells. What do nuclear tests and turtles have to do with each other?
Turtle shells store information about nuclear testing and nuclear fuel work. A U.S. team, led by Cyler Conrad, looked for evidence. It found records of past nuclear tests in the turtle bodies. The turtles could be in the zone of radioactive contamination and accumulate radioactive isotopes in the tissues.
Those that lived near nuclear weapons test sites had increased uranium isotope ratios. They managed to find five turtle scutes in museum collections. These were extracted from different nuclear test areas, as well as from uranium mining sites and nuclear fuel works.
A green turtle from Eniwetok Atoll had been radioactively contaminated a year before its death. Probably, during nearby nuclear tests, uranium-235 and uranium-236 ended up in the water and sand. And from there into the reptile’s body, for example, with the algae it ate. Another Utah tortoise lived far from the test site, however, probably fell under the fallout.
Turtles are capable of accumulating anthropogenic radioactive isotopes from the environment in their shells. At the same time, it is possible to estimate the proportion of different uranium isotopes from even a very modest amount of keratin. What does this allow us to do? To reconstruct more precisely the history of the contamination of ecosystems by radioactive waste.
In 1940-1990, nuclear weapons tests were conducted in many regions of the world. Now only North Korea continues this practice. As a rule, they were organized in a remote and sparsely populated area. For example, the Soviet military used to use polygons in the steppes and Arctic tundra for nuclear tests. The Americans and French preferred deserts or Pacific atolls. But even so, nuclear weapons tests have had serious and negative consequences for people and the environment. Their extent is still under investigation. Nuclear testing and turtles are related, sadly.