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Fungal oxygen exchange between denitrification intermediates and water
Author(s) -
Rohe Lena,
Anderson TrauteHeidi,
Braker Gesche,
Flessa Heinz,
Giesemann Anette,
WrageMönnig Nicole,
Well Reinhard
Publication year - 2013
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.6790
Subject(s) - denitrification , chemistry , nitrate , nitrite , electron acceptor , oxygen , environmental chemistry , isotopologue , electron donor , nitrogen , catalysis , photochemistry , organic chemistry , molecule
RATIONALE Fungi can contribute greatly to N 2 O production from denitrification. Therefore, it is important to quantify the isotopic signature of fungal N 2 O. The isotopic composition of N 2 O can be used to identify and analyze the processes of N 2 O production and N 2 O reduction. In contrast to bacteria, information about the oxygen exchange between denitrification intermediates and water during fungal denitrification is lacking, impeding the explanatory power of stable isotope methods. METHODS Six fungal species were anaerobically incubated with the electron acceptors nitrate or nitrite and 18 O‐labeled water to determine the oxygen exchange between denitrification intermediates and water. After seven days of incubation, gas samples were analyzed for N 2 O isotopologues by isotope ratio mass spectrometry. RESULTS All the fungal species produced N 2 O. N 2 O production was greater when nitrite was the sole electron acceptor (129 to 6558 nmol N 2 O g dw –1 h –1 ) than when nitrate was the electron acceptor (6 to 47 nmol N 2 O g dw –1 h –1 ). Oxygen exchange was complete with nitrate as electron acceptor in one of five fungi and with nitrite in two of six fungi. Oxygen exchange of the other fungi varied (41 to 89 % with nitrite and 11 to 61 % with nitrate). CONCLUSIONS This is the first report on oxygen exchange with water during fungal denitrification. The exchange appears to be within the range previously reported for bacterial denitrification. This adds to the difficulty of differentiating N 2 O producing processes based on the origin of N 2 O‐O. However, the large oxygen exchange repeatedly observed for bacteria and now also fungi could lead to less variability in the δ 18 O values of N 2 O from soils, which could facilitate the assessment of the extent of N 2 O reduction. Copyright © 2013 John Wiley & Sons, Ltd.