TY - JOUR

T1 - Association of novel and highly diverse acid-tolerant denitrifiers with N2O fluxes of an acidic fen

AU - Palmer, Katharina

AU - Drake, Harold L.

AU - Horn, Marcus A.

N1 - Copyright: Copyright 2010 Elsevier B.V., All rights reserved.

PY - 2010/2

Y1 - 2010/2

N2 - Wetlands are sources of denitriflcation-derived nitrous oxide (N 2O). Thus, the denitrifler community of an N2O-emitting fen (pH 4.7 to 5.2) was investigated. N2O was produced and consumed to subatmospheric concentrations in unsupplemented anoxic soil microcosms. Total cell counts and most probable numbers of denitriflers approximated 10 11 cells · gDW-1 (where DW is dry weight) and 108 cells • gDW-1, respectively, in both 0- to 10-cm and 30- to 40-cm depths. Despite this uniformity, depth-related maximum reaction rate (vma-) values for denitriflcation in anoxic microcosms ranged from 1 to 24 and - 19 to - 105 nmol N2O h-1 • gDW-1, with maximal values occurring in the upper soil layers. Denitriflcation was enhanced by substrates that might be formed via fermentation in anoxic microzones of soil. N2O approximated 40% of total nitrogenous gases produced at in situ pH, which was likewise the optimal pH for denitriflcation. Gene libraries of narG and nosZ (encoding nitrate reductase and nitrous oxide reductase, respectively) from fen soil DNA yielded 15 and 18 species-level operational taxonomie units, respectively, many of which displayed phylogenetic novelty and were not closely related to cultured organisms. Although statistical analyses of narG and nosZ sequences indicated that the upper 20 cm of soil contained the highest denitrifler diversity and species richness, terminal restriction fragment length polymorphism analyses of narG and nosZ revealed only minor differences in denitrifler community composition from a soil depth of 0 to 40 cm. The collective data indicate that the regional fen harbors novel, highly diverse, acid-tolerant denitrifler communities capable of complete denitriflcation and consumption of atmospheric N2O at in situ pH.

AB - Wetlands are sources of denitriflcation-derived nitrous oxide (N 2O). Thus, the denitrifler community of an N2O-emitting fen (pH 4.7 to 5.2) was investigated. N2O was produced and consumed to subatmospheric concentrations in unsupplemented anoxic soil microcosms. Total cell counts and most probable numbers of denitriflers approximated 10 11 cells · gDW-1 (where DW is dry weight) and 108 cells • gDW-1, respectively, in both 0- to 10-cm and 30- to 40-cm depths. Despite this uniformity, depth-related maximum reaction rate (vma-) values for denitriflcation in anoxic microcosms ranged from 1 to 24 and - 19 to - 105 nmol N2O h-1 • gDW-1, with maximal values occurring in the upper soil layers. Denitriflcation was enhanced by substrates that might be formed via fermentation in anoxic microzones of soil. N2O approximated 40% of total nitrogenous gases produced at in situ pH, which was likewise the optimal pH for denitriflcation. Gene libraries of narG and nosZ (encoding nitrate reductase and nitrous oxide reductase, respectively) from fen soil DNA yielded 15 and 18 species-level operational taxonomie units, respectively, many of which displayed phylogenetic novelty and were not closely related to cultured organisms. Although statistical analyses of narG and nosZ sequences indicated that the upper 20 cm of soil contained the highest denitrifler diversity and species richness, terminal restriction fragment length polymorphism analyses of narG and nosZ revealed only minor differences in denitrifler community composition from a soil depth of 0 to 40 cm. The collective data indicate that the regional fen harbors novel, highly diverse, acid-tolerant denitrifler communities capable of complete denitriflcation and consumption of atmospheric N2O at in situ pH.

UR - http://www.scopus.com/inward/record.url?scp=76649101774&partnerID=8YFLogxK

U2 - 10.1128/AEM.02256-09

DO - 10.1128/AEM.02256-09

M3 - Article

C2 - 20023077

AN - SCOPUS:76649101774

VL - 76

SP - 1125

EP - 1134

JO - Applied and Environmental Microbiology

JF - Applied and Environmental Microbiology

SN - 0099-2240

IS - 4

ER -