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Research article - Peer-reviewed, 2020

Denitrification rates in lake sediments of mountains affected by high atmospheric nitrogen deposition

Palacin-Lizarbe, Carlos; Camarero, Lluis; Hallin, Sara; Jones, Christopher M.; Catalan, Jordi


During the last decades, atmospheric nitrogen loading in mountain ranges of the Northern Hemisphere has increased substantially, resulting in high nitrate concentrations in many lakes. Yet, how increased nitrogen has affected denitrification, a key process for nitrogen removal, is poorly understood. We measured actual and potential (nitrate and carbon amended) denitrification rates in sediments of several lake types and habitats in the Pyrenees during the ice-free season. Actual denitrification rates ranged from 0 to 9 mu mol N2O m(-2) h(-1) (mean, 1.5 +/- 1.6 SD), whereas potential rates were about 10times higher. The highest actual rates occurred in warmer sediments with more nitrate available in the overlying water. Consequently, littoral habitats showed, on average, 3-fold higher rates than the deep zone. The highest denitrification potentials were found in more productive lakes located at relatively low altitude and small catchments, with warmer sediments, high relative abundance of denitrification nitrite reductase genes, and sulphate-rich waters. We conclude that increased nitrogen deposition has resulted in elevated denitrification rates, but not sufficiently to compensate for the atmospheric nitrogen loading in most of the highly oligotrophic lakes. However, there is potential for high rates, especially in the more productive lakes and landscape features largely govern this.


Reactive nitrogen; Earth-system processes; freshwater ecosystems; mountain lakes

Published in

Scientific Reports
2020, volume: 10, number: 1, article number: 3003

Authors' information

Palacin-Lizarbe, Carlos
Camarero, Lluis
Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology
Swedish University of Agricultural Sciences, Department of Forest Mycology and Plant Pathology
Catalan, Jordi

UKÄ Subject classification

Environmental Sciences

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