A pair of scientists, sporting white clean-suits complete with helmets and face masks, approach a prefab agricultural greenhouse in a clearing at Duke University’s Research Forest. Inside are two long rows of wooden boxes the size of large horse troughs, which hold samples of the natural world that surrounds them-the pine groves and rhododendron thickets of North Carolina’s piedmont, which at this moment are alive with bird song.

Looking a lot like the government bad guys in E.T., the two men cautiously hover over a row of boxes containing native sedges, water grasses, and Zebra fish to spray a fine mist of silver nanoparticles over them. Their goal: to investigate how the world inside the boxes is altered by these essentially invisible and notoriously unpredictable particles.

The researchers are part of a multidisciplinary coalition of scientists from Duke, Stanford, Carnegie Mellon, Howard, Virginia Tech, and the University of Kentucky, headquartered at Duke’s Center for the Environmental Implications of NanoTechnology (CEINT), that represents one of the most comprehensive efforts yet to measure how nanoparticles affect ecosystems and biological systems.

So far the questions about whether nanoparticles are an environmental risk outnumber the answers, which is why the Duke scientists take the precaution of wearing […]