Forest streams are important sources for nitrous oxide emissions - Nitrous oxide emissions from Swedish streams

Abstract

Streams and river networks are increasingly recognized as significant sources for the greenhouse gas nitrous oxide (N2O). N2O is a transformation product of nitrogenous compounds in soil, sediment and water. Agricultural areas are considered a particular hotspot for emissions because of the large input of nitrogen (N) fertilizers applied on arable land. However, there is little information on N2O emissions from forest streams although they constitute a major part of the total stream network globally. Here, we compiled N2O concentration data from low-order streams (~1,000 observations from 172 stream sites) covering a large geographical gradient in Sweden from the temperate to the boreal zone and representing catchments with various degrees of agriculture and forest coverage. Our results showed that agricultural and forest streams had comparable N2O concentrations of 1.6 +/- 2.1 and 1.3 +/- 1.8 mu g N/L, respectively (mean +/- SD) despite higher total N (TN) concentrations in agricultural streams (1,520 +/- 1,640 vs. 780 +/- 600 mu g N/L). Although clear patterns linking N2O concentrations and environmental variables were difficult to discern, the percent saturation of N2O in the streams was positively correlated with stream concentration of TN and negatively correlated with pH. We speculate that the apparent contradiction between lower TN concentration but similar N2O concentrations in forest streams than in agricultural streams is due to the low pH (

Keywords

agriculture; forest; greenhouse gas; nitrogen; nitrous oxide; river; stream

Published in

Global Change Biology
2020, volume: 26, number: 2, pages: 629-641

SLU Authors

• Audet, Joachim

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    
  • Aarhus University

• Bundschuh, Mirco

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    
  • University of Koblenz-Landau

• Buffam, Ishi

  • University of Cincinnati

• Feckler, Alexander

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Laudon, Hjalmar

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

• Löfgren, Stefan

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Öquist, Mats

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

• Peacock, Michael

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

• Wallin, Marcus

  • Uppsala University

Associated SLU-program

Forest
Eutrophication
Climate
Use of FOMA data

UKÄ Subject classification

Geochemistry
Environmental Sciences
Climate Science

Publication identifier

• DOI: https://doi.org/10.1111/gcb.14812

Permanent link to this page (URI)

https://res.slu.se/id/publ/103074