ICYMI: Turtles tell tales

    If you missed our September Periodic Table, catch up on this surprising research

    November 1, 2022

    @theBradbury November
    Turtle shells grow in layers like tree rings, but with a key difference.

    Researchers at Los Alamos have a new way to study the presence of radioactive materials in the environment. The key to their research may seem unusual, but the scientists believe they have found the ideal recorder of nuclear events. It’s a turtle.

    @theBradbury November
    Each unique layer of keratin (numbered) in an adult turtle’s shell corresponds with one year of the animal’s life. The layers can reveal which elements and isotopes were present in the turtle’s environment when that layer was made.

    “Turtles are useful in tracing nuclear activities because of the specific characteristics of how their shells grow,” says Los Alamos archaeologist Cyler Conrad, who is leading the study. “This work has the potential to provide insight into historical radiological operations or releases into the environment.”

    As a turtle or tortoise grows, each year its shell produces a thin layer of keratin that then becomes inert. Layers build up, like rings of a tree, and elements from the environment are trapped within the layers. In this way, the shell maintains a time-constrained record of all the environmental conditions in which the animal lived.

    Among various kinds of environmental signatures, turtle shells can pick up very small concentrations of radionuclides. These are radioactive forms of elements, some of which form naturally while others are formed anthropogenically. Conrad and his team are looking specifically at anthropogenic uranium, plutonium, strontium, and others.

    Jez Inglis, a Laboratory geochemist on the team, says at first the idea behind the study struck him as “a little bit out there.” He recalls, “When Cyler came to me and suggested that we could use turtle shells to do the same thing that people have attempted with tree rings, I thought, ‘that’s kind of interesting, we could give it a go’.”

    Read the full story from 1663 magazine.