A2 Review article, Literature review, Systematic review
A review of the importance of mineral nitrogen cycling in the plant-soil-microbe system of permafrost-affected soils : changing the paradigm (2022)

Ramm, E., Liu, C., Ambus, P., Butterbach-Bahl, K., Hu, B., Martikainen, P. J., Marushchak, M. E., Mueller, C. W., Rennenberg, H., Schloter, M., Siljanen, H. M. P., Voigt, C., Werner, C., Biasi, C., & Dannenmann, M. (2022). A review of the importance of mineral nitrogen cycling in the plant-soil-microbe system of permafrost-affected soils : changing the paradigm. Environmental Research Letters, 17(1), Article 013004. https://doi.org/10.1088/1748-9326/ac417e

JYU authors or editors

Publication details

All authors or editors: Ramm, Elisabeth; Liu, Chunyan; Ambus, Per; Butterbach-Bahl, Klaus; Hu, Bin; Martikainen, Pertti J.; Marushchak, Maija E.; Mueller, Carsten W; Rennenberg, Heinz; Schloter, Michael; et al.

Journal or series: Environmental Research Letters

eISSN: 1748-9326

Publication year: 2022

Publication date: 01/01/2022

Volume: 17

Issue number: 1

Article number: 013004

Publisher: IOP Publishing

Publication country: United Kingdom

Publication language: English

DOI: https://doi.org/10.1088/1748-9326/ac417e

Publication open access: Openly available

Publication channel open access: Open Access channel

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/79730

Abstract

The paradigm that permafrost-affected soils show restricted mineral nitrogen (N) cycling in favor of organic N compounds is based on the observation that net N mineralization rates in these cold climates are negligible. However, we find here that this perception is wrong. By synthesizing published data on N cycling in the plant-soil-microbe system of permafrost ecosystems we show that gross ammonification and nitrification rates in active layers were of similar magnitude and showed a similar dependence on soil organic carbon (C) and total N concentrations as observed in temperate and tropical systems. Moreover, high protein depolymerization rates and only marginal effects of C:N stoichiometry on gross N turnover provided little evidence for N limitation. Instead, the rather short period when soils are not frozen is the single main factor limiting N turnover. High gross rates of mineral N cycling are thus facilitated by released protection of organic matter in active layers with nitrification gaining particular importance in N-rich soils, such as organic soils without vegetation. Our finding that permafrost-affected soils show vigorous N cycling activity is confirmed by the rich functional microbial community which can be found both in active and permafrost layers. The high rates of N cycling and soil N availability are supported by biological N fixation, while atmospheric N deposition in the Arctic still is marginal except for fire-affected areas. In line with high soil mineral N production, recent plant physiological research indicates a higher importance of mineral plant N nutrition than previously thought. Our synthesis shows that mineral N production and turnover rates in active layers of permafrost-affected soils do not generally differ from those observed in temperate or tropical soils. We therefore suggest to adjust the permafrost N cycle paradigm, assigning a generally important role to mineral N cycling. This new paradigm suggests larger permafrost N climate feedbacks than assumed previously.

Keywords: nitrogen cycle; nitrogen fixation; mineralisation; soil; vegetation; plants; microbiome; arctic region; permafrost; climate changes; meta-analysis

Free keywords: permafrost; nitrogen; gross N turnover; mineralization; meta-analysis; plant-soil-microbe system; global change

Contributing organizations

Ministry reporting: Yes

Reporting Year: 2022

JUFO rating: 3