Saiz, E, Sgouridis, F, Drijfhout, FP, Peichl, M, Nilsson, MB and Ullah, S (2021) Chronic Atmospheric Reactive Nitrogen Deposition Suppresses Biological Nitrogen Fixation in Peatlands. Environmental Science and Technology, 55 (2). pp. 1310-1318. ISSN 0013-936X

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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 ∼2 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.

Item Type: Article
Additional Information: The final version of this article and all relevant information related to it can be found online at;
Uncontrolled Keywords: 15N2 assimilation method, biological nitrogen fixation, Sphagnum mosses, diazotrophs, Nr deposition, peatlands, nitrogen biogeochemistry
Subjects: Q Science > Q Science (General)
Q Science > QD Chemistry
Q Science > QD Chemistry > QD415 Biochemistry
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Related URLs:
Depositing User: Symplectic
Date Deposited: 05 Feb 2021 11:40
Last Modified: 04 Jan 2022 01:30

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