title: Impacts of labile organic carbon concentration on organic and inorganic nitrogen utilization by a stream biofilm bacterial community.
abstract: In aquatic ecosystems, carbon (C) availability strongly influences nitrogen (N) dynamics. One manifestation of this linkage is the importance in the dissolved organic matter (DOM) pool of dissolved organic nitrogen (DON), which can serve as both a C and an N source, yet our knowledge of how specific properties of DOM influence N dynamics are limited. To empirically examine the impact of labile DOM on the responses of bacteria to DON and dissolved inorganic nitrogen (DIN), bacterial abundance and community composition were examined in controlled laboratory microcosms subjected to various combinations of dissolved organic carbon (DOC), DON, and DIN treatments. Bacterial communities that had colonized glass beads incubated in a stream were treated with various glucose concentrations and combinations of inorganic and organic N (derived from algal exudate, bacterial protein, and humic matter). The results revealed a strong influence of C availability on bacterial utilization of DON and DIN, with preferential uptake of DON under low C concentrations. Bacterial DON uptake was affected by the concentration and by its chemical nature (labile versus recalcitrant). Labile organic N sources (algal exudate and bacterial protein) were utilized equally well as DIN as an N source, but this was not the case for the recalcitrant humic matter DON treatment. Clear differences in bacterial community composition among treatments were observed based on terminal restriction fragment length polymorphisms (T-RFLP) of 16S rRNA genes. C, DIN, and DON treatments likely drove changes in bacterial community composition that in turn affected the rates of DON and DIN utilization under various C concentrations.
authors.affiliation: Department of Biological Sciences, Kent State University, Kent, Ohio, USA.
authors.forename: Suchismita
authors.initials: S
authors.lastname: Ghosh
authors.forename: Laura G
authors.initials: LG
authors.lastname: Leff
mesh_terms: D001419:Bacteria / Q000145:classification / Q000302:isolation & purification / Q000378:metabolism*; D018407:Bacterial Physiological Phenomena; D018441:Biofilms; D058448:Biota; D002244:Carbon / Q000378:metabolism*; D007287:Inorganic Chemicals / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D009930:Organic Chemicals / Q000378:metabolism; D045483:Rivers / Q000382:microbiology*
chemical_list: D007287:Inorganic Chemicals; D009930:Organic Chemicals; D002244:Carbon; D009584:Nitrogen
references.citation: Appl Environ Microbiol. 2009 Aug;75(16):5428-33
references.pmid: 19561189
references.citation: Appl Environ Microbiol. 2003 Jul;69(7):3701-9
references.pmid: 12839735
references.citation: Appl Environ Microbiol. 2002 Mar;68(3):1015-24
references.pmid: 11872445
references.citation: J Environ Qual. 2004 Jan-Feb;33(1):201-9
references.pmid: 14964375
references.citation: Microb Ecol. 1984 Dec;10(4):335-44
references.pmid: 24221176
references.citation: Nat Rev Microbiol. 2010 Jan;8(1):15-25
references.pmid: 19946288
references.citation: Appl Environ Microbiol. 1997 Nov;63(11):4516-22
references.pmid: 9361437
references.citation: Microb Ecol. 2005 Feb;49(2):245-56
references.pmid: 15965720
references.citation: FEMS Microbiol Ecol. 2007 Nov;62(2):161-70
references.pmid: 17937673
references.citation: Ecology. 2010 May;91(5):1466-76
references.pmid: 20503878
references.citation: Appl Environ Microbiol. 2005 May;71(5):2278-87
references.pmid: 15870312
references.citation: Nature. 2011 Jul 20;475(7356):343-7
references.pmid: 21776080
references.citation: Nature. 2002 Jan 24;415(6870):416-9
references.pmid: 11807551
references.citation: Trends Ecol Evol. 1999 Aug;14(8):316-320
references.pmid: 10407429
references.citation: Proc Natl Acad Sci U S A. 2008 Aug 12;105 Suppl 1:11512-9
references.pmid: 18695234
references.citation: Appl Environ Microbiol. 2005 Oct;71(10):6193-8
references.pmid: 16204538
references.citation: Curr Issues Intest Microbiol. 2001 Mar;2(1):17-25
references.pmid: 11709853
references.citation: Microbiol Res. 2007;162(4):391-6
references.pmid: 17008079
references.citation: Nature. 2010 Apr 22;464(7292):1178-81
references.pmid: 20414306
references.citation: Appl Environ Microbiol. 2003 Feb;69(2):926-32
references.pmid: 12571013
references.citation: Nucleic Acids Res. 1997 Sep 1;25(17):3389-402
references.pmid: 9254694
references.citation: Microb Ecol. 2000 Aug;40(2):125-138
references.pmid: 11029081
references.citation: Appl Environ Microbiol. 2000 Jul;66(7):2732-42
references.pmid: 10877762