1. Center for Biofilm Engineering and Department of Civil Engineering, Montana State University, Bozeman, Montana 59717-3980, Department of Chemical Engineering, Center for Multiphase Environmental Research, Washington State University, Dana Hall Room 118, Pullman, Washington 99164-2710, and Fundamental Science Directorate, Pacific Northwest National Laboratory, P.O. Box 999, K8-96, 3335 Q Avenue, Richland, Washington 99352