title: Initial nitrogen enrichment conditions determines variations in nitrogen substrate utilization by heterotrophic bacterial isolates.
abstract: The nitrogen (N) cycle consists of complex microbe-mediated transformations driven by a variety of factors, including diversity and concentrations of N compounds. In this study, we examined taxonomic diversity and N substrate utilization by heterotrophic bacteria isolated from streams under complex and simple N-enrichment conditions.
  
  
  
  Diversity estimates differed among isolates from the enrichments, but no significant composition were detected. Substrate utilization and substrate range of bacterial assemblages differed within and among enrichments types, and not simply between simple and complex N-enrichments.
  
  
  
  N substrate use patterns differed between isolates from some complex and simple N-enrichments while others were unexpectedly similar. Taxonomic composition of isolates did not differ among enrichments and was unrelated to N use suggesting strong functional redundancy. Ultimately, our results imply that the available N pool influences physiology and selects for bacteria with various abilities that are unrelated to their taxonomic affiliation.
authors.affiliation: Department of Biological Sciences, Kent State University, Kent, OH, 44242, USA.
authors.forename: Suchismita
authors.initials: S
authors.lastname: Ghosh
authors.affiliation: Department of Biological Sciences, Kent State University, Kent, OH, 44242, USA. akwettey@gmail.com.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Ayayee
authors.affiliation: International Center for Tropical Botany (ICTB), Florida International University, Miami, FL, 33199, USA.
authors.forename: Oscar J
authors.initials: OJ
authors.lastname: Valverde-Barrantes
authors.affiliation: Department of Biological Sciences, Kent State University, Kent, OH, 44242, USA.
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Blackwood
authors.affiliation: School of Public and Environmental Affairs, Indiana University, Bloomington, Bloomington, IN, 47405, USA.
authors.forename: Todd V
authors.initials: TV
authors.lastname: Royer
authors.affiliation: Department of Biological Sciences, Kent State University, Kent, OH, 44242, USA.
authors.forename: Laura G
authors.initials: LG
authors.lastname: Leff
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D044822:Biodiversity; D004269:DNA, Bacterial; D019015:Geologic Sediments / Q000382:microbiology; D052836:Heterotrophic Processes / Q000502:physiology*; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism*; D058458:Nitrogen Cycle; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D045483:Rivers / Q000382:microbiology; D017421:Sequence Analysis
chemical_list: D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S; D009584:Nitrogen
keywords: Bacterial isolates; Dissolved organic nitrogen; Nitrogen cycle