Influence of Heterogeneous Ammonium Availability on Bacterial Community Structure and the Expression of Nitrogen Fixation and Ammonium Transporter Genes during in Situ Bioremediation of Uranium-Contaminated Groundwater

P A U L A J . M O U S E R , * , † , ⊥ A . L U C I E N ’ G U E S S A N , † H I L A E L I F A N T Z , † D A W N E . H O L M E S , † K E N N E T H H . W I L L I A M S , ‡ M I C H A E L J . W I L K I N S , § P H I L I P E . L O N G , | A N D D E R E K R . L O V L E Y † Department of Microbiology, University of Massachusetts, Amherst, Massachusetts 01003, Lawrence Berkeley National Laboratory, Berkeley, California 94720, Department of Environmental Science, Policy and Management, University of California, Berkeley, California 94720, and Pacific Northwest National Laboratory, Richland, Washington 99352