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Atmospheric CO 2 elevation has little effect on nitrifying and denitrifying enzyme activity in four European grasslands
Author(s) -
Barnard Romain,
Barthes Laure,
Roux Xavier Le,
Harmens Harry,
Raschi Antonio,
Soussana JeanFranÇois,
Winkler Barbro,
Leadley Paul W.
Publication year - 2004
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1529-8817.2003.00746.x
Subject(s) - denitrifying bacteria , grassland , environmental chemistry , ecosystem , environmental science , biomass (ecology) , agronomy , ecology , chemistry , nitrogen , denitrification , biology , organic chemistry
The objective of this study was to determine what patterns, if any, existed in the response of nitrifying enzyme activity (NEA), denitrifying enzyme activity (DEA), soil microbial N and soil inorganic N to elevated CO 2 across a broad range of grassland environments. We studied the response of these N pools and microbial activities in four CO 2 ‐enrichment sites of the MEGARICH project (Managing European Grasslands as a Sustainable Resource in a Changing Climate). CO 2 treatment was studied in factorial combination with a cutting frequency treatment at two sites and with a temperature treatment at one site. Our study showed that microbial biomass N, NEA, DEA and extractable soil [NH 4 + ] and [NO 3 − ] were generally not affected by elevated CO 2 in these grassland ecosystems after several years of treatment, nor by cutting frequency or temperature at the sites that included these treatments. Exceptions to this were that DEA and soil [NO 3 − ] decreased by 22% and 45%, respectively, at the French site at elevated CO 2 . We discuss the possible explanations for this lack of response.