It’s a story about mystery, grime, and a phoenix rising from the ashes—so of course it started in Chicago.
The Field Museum, a Greco-Roman citadel of natural history on the shores of Lake Michigan, is famous for its Egyptology exhibit and for displaying Sue, the largest T. rex ever discovered. But among scientists and biologists, it carries a different distinction. In its basement and archives, the Field Museum holds more than 3 million specimens: drawers and drawers full of the stuffed corpses of long-dead creatures.
Among these dead are hundreds of Illinoisan birds, many of them captured and killed in the decades after the city’s founding. For years, curators and collection managers had noticed that something was off about some of them. Birds from the late 19th century were noticeably darker than other specimens of their own species from other time periods or other locations. They suspected the birds had been stained by the soot that once choked Chicago’s skies—but without looking at the birds more closely, they couldn’t be sure.
Two eastern towhees in the Field Museum’s collection: The bird at the top was collected in Chicago’s South Side in April 1906; the bottom in the heart of the city’s downtown 106 years later, in April 2012. (Carl Fuldner)
Their drabber colors remained a mystery until a few years ago, when two University of Chicago graduate students took an interest in the birds. In 2014, Carl Fuldner, a historian of photography, and Shane DuBay, an evolutionary biologist who studies alpine birds, secured a grant to photograph some specimens in the Field Museum’s collection.
Using a scanning electron microscope, they confirmed that the wings were covered in black carbon. Black carbon is a tiny waste product of coal combustion. It’s of great note to scientists: Black carbon contributes to global warming, but it’s also a …read more
Source:: The Atlantic – Science