by Pat McShea
Most of the information stored in museum specimens has yet to be read. When museum curators make such claims, they often hint at labyrinths of undeciphered genetic code within the tissue of preserved plants and animals. As a recent study by two University of Chicago graduate students makes clear, “readable” information coats even the exterior of some carefully collected and prepared specimens.
Shane DuBay and Carl Fuldner charted a 135-year record of air pollution across America’s rust belt by examining soot on the breast feathers of more than 1,300 bird specimens in the collections of The Field Museum, the University of Michigan Museum of Zoology, and Carnegie Museum of Natural History. A summary of their work was recently published in the Proceedings of the Natural Academy of Sciences.
Because birds molt their feathers each year, and every study skin includes a reference to a collection date and location, the researchers treated the darkened specimens as recording instruments. Scanning electron microscope images were used to document black carbon as the soot component clinging to feather filaments, collection care and storage protocols were reviewed to discount the possibility that birds became soot-coated after becoming museum specimens, and an innovative technique was developed to measure carbon levels differences among the study skins based upon variations in reflected light.
The study’s findings, which cover the period between 1880 and 2015, fill information gaps about pollution levels before the establishment of air quality monitoring standards in the 1950’s. By improving the accuracy of past air pollution estimates, information gleaned from the preserved birds will help refine existing models for predicting future atmospheric change.
To learn more about this innovative study, please visit the Proceedings of the Natural Academy of Science.
Patrick McShea works in the Education and Visitor Experience department of Carnegie Museum of Natural History. Museum employees are encouraged to blog about their unique experiences and knowledge gained from working at the museum.