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Denitrification Temperature Dependence in Remote, Cold, and N‐Poor Lake Sediments
Author(s) -
PalacinLizarbe Carlos,
Camarero Lluís,
Catalan Jordi
Publication year - 2018
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2017wr021680
Subject(s) - denitrification , nitrate , environmental science , nitrogen cycle , reactive nitrogen , nitrogen , environmental chemistry , ecosystem , climate change , arctic , nitrogen fixation , atmospheric sciences , global warming , hydrology (agriculture) , ecology , chemistry , geology , biology , geotechnical engineering , organic chemistry
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 (N r ) 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 N r load. The estimated activation energy (E a ) for denitrification at nitrate saturation was 46 ± 7 kJ mol −1 (Q 10 1.7 ± 0.4). The apparent E a increased with nitrate (μ M ) limitation as E a = 46 + 419 [ NO 3 – ] −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.