Nitrification controls N2O production rates in a frozen boreal forest soil

• The winter season has been identified as a significant contributor to N2O emissions from boreal soils, but our understanding of the processes regulating these emissions is fragmentary. We investigated potential N-sources and pathways involved in N2O formation in a frozen boreal forest soil by labeling soil samples with N-15-containing substrates, and measured rates of (N2O)-N-15/N-15(2) formation under both oxic and anoxic conditions. Our results showed that all N2O produced in the frozen samples originate from denitrification, but the rate-limiting factor is NO3- availability, which is largely governed by nitrification. This suggests that N2O formation in frozen boreal soils may be sustained for a prolonged period of time, but is governed by a delicate balance of the O-2 regime. (c) 2007 Elsevier Ltd. All rights reserved.

Subject headings

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Keyword

denitrification

low-temperature

nitrification

nitrous oxide emission

MASS-SPECTROMETRY

NITROUS-OXIDE

DENITRIFICATION

DINITROGEN

CH4

CO2

Publication and Content Type

ref (subject category)

art (subject category)