Chronic atmospheric reactive nitrogen deposition suppresses biological nitrogen fixation in peatlands

Ernesto Saiz, Fotis Sgouridis, Falko Drifjhout, Matthias Peichl, Mats Nilsson, Sami Ullah

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
93 Downloads (Pure)


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 27 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 μ2 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.

Original languageEnglish
Pages (from-to)1310-1318
Number of pages9
JournalEnvironmental Science and Technology
Issue number2
Early online date4 Jan 2021
Publication statusPublished - 19 Jan 2021


  • N assimilation method
  • Nr deposition
  • Sphagnum mosses
  • biological nitrogen fixation
  • diazotrophs
  • nitrogen biogeochemistry
  • peatlands

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry


Dive into the research topics of 'Chronic atmospheric reactive nitrogen deposition suppresses biological nitrogen fixation in peatlands'. Together they form a unique fingerprint.

Cite this