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Nitrogen isotopic fractionation associated with growth on dinitrogen gas and nitrate by cyanobacteria
Author(s) -
Bauersachs Thorsten,
Schouten Stefan,
Compaoré Justine,
Wollenzien Ute,
Stal Lucas J.,
Sinninghe Damsteé Jaap S.
Publication year - 2009
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2009.54.4.1403
Subject(s) - cyanobacteria , fractionation , nitrate , nitrogen , environmental chemistry , nitrogen fixation , isotopes of nitrogen , chemistry , biology , bacteria , chromatography , genetics , organic chemistry
This study investigated the bulk nitrogen isotopic composition and fractionation of marine and freshwater cyanobacteria growing at the expense of atmospheric dinitrogen gas (N 2 ) or nitrate (NO 3 − ). In agreement with previous studies, cyanobacteria using N 2 had Δ 15 N values ranging from ‐2‰ to ‐1‰ and fractionated by 2‐3‰ against atmospheric N 2 . When grown on NO 3 − , the analyzed cyanobacteria had a remarkably large range in Δ 15 N, from ‐14‰ to 1‰, and fractionated by 4‐19‰ relative to the supplied NO 3 − . Interestingly, several of the NO 3 − ‐utilizing cyanobacteria expressed a nitrogen isotopic signal similar to the one expected for diazotrophic species. Extrapolation to the natural environment indicates that Δ 15 N signals considered to be associated with dinitrogen fixation could also be generated by NO 3 − utilization, depending on the isotopic composition of the nitrogen source, the degree of fractionation, and the type of cyanobacterium involved.