Research article - Peer-reviewed, 2021
Chronic Atmospheric Reactive Nitrogen Deposition Suppresses Biological Nitrogen Fixation in Peatlands
Saiz, Ernesto; Sgouridis, Fotis; Drijfhout, Falko P.; Peichl, Matthias; Nilsson, Mats B.; Ullah, SamiAbstract
Biological nitrogen fixation (BNF) represents the natural pathway by which mosses meet their demands for bioavailable/reactive nitrogen (Nr) in peatlands. However, following intensification of nitrogen fertilizer and fossil fuel use, atmospheric Nr deposition has increased exposing peatlands to Nr loading often above the ecological threshold. As BNF is energy intensive, therefore, it is unclear whether BNF shuts down when Nr availability is no longer a rarity. We studied the response of BNF under a gradient of Nr deposition extending over decades in three peatlands in the U.K., and at a background deposition peatland in Sweden. Experimental nitrogen fertilization plots in the Swedish site were also evaluated for BNF activity. In situ BNF activity of peatlands receiving Nr deposition of 6, 17, and similar to 2 kg N ha(-1) yr(-1) was not shut down but rather suppressed by 54, 69, and 74%, respectively, compared to the rates under background Nr deposition of kg N ha(-1) yr(-1). These findings were corroborated by similar BNF suppression at the fertilization plots in Sweden. Therefore, contribution of BNF in peatlands exposed to chronic Nr deposition needs accounting when modeling peatland's nitrogen pools, given that nitrogen availability exerts a key control on the carbon capture of peatlands, globally.Keywords
N-15(2) assimilation method; biological nitrogen fixation; Sphagnum mosses; diazotrophs; Nr deposition; peatlands; nitrogen biogeochemistryPublished in
Environmental Science and Technology2021, volume: 55, number: 2, pages: 1310-1318
Publisher: AMER CHEMICAL SOC
Authors' information
Drijfhout, Falko P.
Keele University
Saiz, Ernesto
Keele University
Sgouridis, Fotis
University of Bristol
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Ullah, Sami
University of Birmingham
UKÄ Subject classification
Environmental Sciences
Publication Identifiers
DOI: https://doi.org/10.1021/acs.est.0c04882
URI (permanent link to this page)
https://res.slu.se/id/publ/111193