Manhattan's Central Park is surrounded by one of the densest cities on the planet. It's green enough, yet hardly the first place most people would think of as biologically rich.
But a team of scientists got a big surprise when they recently started digging there.
They were 10 soil ecologists — aka dirt doctors. Kelly Ramirez from Colorado State University was among them. "We met on the steps of the natural history museum at 7 a.m. with our collection gear, coolers and sunblock," she recalls.