1 Differential sensitivity of ammonia oxidising archaea and bacteria to matric and 1 osmotic potential 2 3 Marcus O. Bello, Cécile Thion * , Cécile Gubry-Rangin, James I. Prosser 1 4 School of Biological Sciences, University of Aberdeen, Cruickshank 5 Building, St. Machar Drive, Aberdeen AB24 3UU, UK. 6 7 1 Correspondence address: JI Prosser, School of Biological Sciences, University of Aberdeen, 8 Cruickshank Building, Aberdeen AB24 3UU, United Kingdom 9 Email: j.prosser@abdn.ac.uk 10 Telephone: +44 (0) 1224 273254 11 Mob: +44 (0) 7802 959364 12 Fax: +44 (0) 1224 272703 13 14 * Present address: Environmental Microbial Genomics group, Laboratoire Ampère, UMR 5005 15 CNRS-École Centrale de Lyon-Université Claude Bernard, Université de Lyon, 69134, Ecully 16 CEDEX, France 17 18 Keywords: soil nitrification; drought; osmotic potential; matric potential; ammonia oxidising 19 archaea; ammonia oxidising bacteria. 20 21 22