ZeglinLH, University of New Mexico, Albuquerque, USA, lzeglin@unm.edu
Takacs-Vesbach, C, D, University of New Mexico, Albuquerque, USA, cvesbach@unm.edu
Dahm, C, N, University of New Mexico, Albuquerque, USA, cdahm@sevilleta.unm.edu
Barrett, J, E, Virginia Polytechnic Institute and State University, Blacksburg, USA, John.E.Barrett@Dartmouth.EDU
Gooseff, M, N, Colorado School of Mines, Golden, USA, mgooseff@mines.edu
 
BIOLOGICAL, PHYSICAL AND NUTRIENT GRADIENTS IN NEAR-STREAM HYDROLOGIC MARGINS OF HOT AND COLD DESERTS (Abstract ID: 922)
Near-stream nutrient transfer is of great importance to stream and terrestrial biota. The desert stream hydrologic margin (HM) is a gradient of water content and solute distribution between aquatic and terrestrial zones. A ribbon of soil where the primary water limitation is relieved, the HM is a hotspot of biological activity and nutrient transformation. We describe the distribution of nitrogen and bacterial communities across this wet-dry gradient at two sites: the Rio Salado (Sevilleta National Wildlife Reserve, New Mexico, USA) and Onyx River (McMurdo Dry Valleys, Victoria Land, Antarctica). Denaturing gradient gel electrophoresis (DGGE) and 16S rRNA clone libraries reveal more biological heterogeneity across this gradient in the the cold desert versus the hot desert, though the controls on inorganic nitrogen distribution appear similar. Also, cold desert sediment communities show more diversity than the hot desert. 16S rRNA sequence data suggest that community composition in the hot desert is constrained not by water but by salinity. We will next quantify nitrogen cycling genes to elucidate biological versus physical control of nitrogen distribution across this land-water interface.
 
Presentation is (Oral, Poster or No Preference): Poster
Presentation is given by student: Yes
   
 
           
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