1. The
Center for NanoBioEarth, Department of Geosciences, Virginia Tech, Blacksburg, Virginia 24061, United States
2. Department
of Geosciences, East China Normal University, 3663 North Zhongshan Road, Shanghai, 200062, China
3. Center
for the Environmental Implications of NanoTechnology (CEINT), Duke University, Durham, North Carolina 27517, United States
4. Biology
Department, Duke University, Durham, North Carolina 27708, United States