caa a22 4500 467885877 CHVBK 20180406152734.0 cr unu---uuuuu 170328e20061201xx s 000 0 eng 10.1007/s10021-005-0039-0 doi (NATIONALLICENCE)springer-10.1007/s10021-005-0039-0 Inhibition of Nitrification Alters Carbon Turnover in the Patagonian Steppe [Elektronische Daten] [Amy Austin, Osvaldo Sala, Robert Jackson] Human activities are altering biodiversity and the nitrogen (N) cycle, affecting terrestrial carbon (C) cycling globally. Only a few specialized bacteria carry out nitrification—the transformation of ammonium (NH 4 + ) to nitrate (NO 3 − ), in terrestrial ecosystems, which determines the form and mobility of inorganic N in soils. However, the control of nitrification on C cycling in natural ecosystems is poorly understood. In an ecosystem experiment in the Patagonian steppe, we inhibited autotrophic nitrification and measured its effects on C and N cycling. Decreased net nitrification increased total mineral N and NH 4 + and reduced NO 3 − in the soil. Plant cover (P<0.05) and decomposition (P<0.0001) decreased with inhibition of nitrification, in spite of increases in NH 4 + availability. There were significant changes in the natural abundance of δ15N in the dominant vegetation when nitrification was inhibited suggesting that a switch occurred in the form of N (from NO 3 − to NH 4 + ) taken up by plants. Results from a controlled-condition experiment supported the field results by showing that the dominant plant species of the Patagonian steppe have a marked preference for nitrate. Our results indicate that nitrifying bacteria exert a major control on ecosystem functioning, and that the inhibition of nitrification results in significant alteration of the C cycle. The interactions between the C and N cycles suggest that rates of C cycling are affected not just by the amount of available N, but also by the relative availability for plant uptake of NH 4 + and NO 3 − . Springer Science+Business Media, Inc., 2007 carbon cycling nationallicence nitrification inhibition nationallicence nitrogen mineralization nationallicence semi-arid ecosystem nationallicence ammonium nationallicence nitrate nationallicence 15N stable isotope nationallicence Patagonian steppe nationallicence Argentina nationallicence nitrapyrin nationallicence Austin Amy Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA), Facultad de Agronomía, CONICET and Universidad de Buenos Aires, Avenida San Martín 4453, C1417DSE, Buenos Aires, Argentina aut Sala Osvaldo Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA), Facultad de Agronomía, CONICET and Universidad de Buenos Aires, Avenida San Martín 4453, C1417DSE, Buenos Aires, Argentina aut Jackson Robert Department of Biology and Nicholas School of the Environment, Duke University, 27708, Durham, North Carolina, USA aut Ecosystems Springer-Verlag; www.springer-ny.com 9/8(2006-12-01), 1257-1265 1432-9840 9:8<1257 2006 9 10021 https://doi.org/10.1007/s10021-005-0039-0 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-005-0039-0 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Austin Amy Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA), Facultad de Agronomía, CONICET and Universidad de Buenos Aires, Avenida San Martín 4453, C1417DSE, Buenos Aires, Argentina aut NATIONALLICENCE 700 1- Sala Osvaldo Instituto de Investigaciones Fisiológicas y Ecológicas Vinculadas a la Agricultura (IFEVA), Facultad de Agronomía, CONICET and Universidad de Buenos Aires, Avenida San Martín 4453, C1417DSE, Buenos Aires, Argentina aut NATIONALLICENCE 700 1- Jackson Robert Department of Biology and Nicholas School of the Environment, Duke University, 27708, Durham, North Carolina, USA aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag; www.springer-ny.com 9/8(2006-12-01), 1257-1265 1432-9840 9:8<1257 2006 9 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer