Denitrification temperature dependence in remote, cold, and N-poor lake sediments
Palacín-Lizarbe, Carlos (Centre de Recerca Ecològica i d'Aplicacions Forestals)
Camarero, Lluís (Centre d'Estudis Avançats de Blanes)
Catalán, Jordi (Centre de Recerca Ecològica i d'Aplicacions Forestals)

Data:	2018
Resum:	The reservoir size and pathway rates of the nitrogen (N) cycle have been deeply modified by the human enhancement of N fixation, atmospheric emissions, and climate warming. Denitrification (DEN) transforms nitrate into nitrogenous gas and thus removes reactive nitrogen (Nr) back to the atmospheric reservoir. There is still a rather limited knowledge of the denitrification rates and their temperature dependence across ecosystems; particularly, for the abundant cold and N-poor freshwater systems (e. g. , Arctic and mountain lakes). We experimentally investigated the denitrification rates of mountain lake sediments by manipulating nitrate concentration and temperature on field collected cores. DEN rates were nitrate limited in field conditions and showed a large potential for an immediate DEN increase with both warming and higher Nr load. The estimated activation energy (Ea) for denitrification at nitrate saturation was 46 ± 7 kJ mol−1 (Q10 1. 7 ± 0. 4). The apparent Ea increased with nitrate (μM) limitation as Ea = 46 + 419 [ urn:x-wiley:00431397:media:wrcr23112:wrcr23112-math-0001]−1. Accordingly, we suggest that climate warming may have a synergistic effect with N emission reduction to readjusting the N cycle. Changes of nitrate availability might be more relevant than direct temperature effects on denitrification.
Ajuts:	Ministerio de Economía y Competitividad CGL2010-19737 Ministerio de Economía y Competitividad CGL2013-45348-P Ministerio de Economía y Competitividad CGL2016-80124-C2-1-P Ministerio de Educación y Ciencia FPU12-00644
Drets:	Tots els drets reservats.
Llengua:	Anglès
Document:	Article ; recerca ; Versió acceptada per publicar
Matèria:	Nitrogen cycle ; Activation energy
Publicat a:	Water Resources research, Vol. 54, Issue 2 (February 2018) , p. 1161-1173, ISSN 1944-7973

DOI: 10.1002/2017WR021680

Postprint 24 p, 11.4 MB

Appendix 11 p, 1.6 MB

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