Amino acid production exceeds plant nitrogen demand in Siberian tundra

verfasst von

Birgit Wild, Ricardo J.Eloy Alves, Jiři Bárta, Petr Čapek, Norman Gentsch, Georg Guggenberger, Gustaf Hugelius, Anna Knoltsch, Peter Kuhry, Nikolay Lashchinskiy, Robert Mikutta, Juri Palmtag, Judith Prommer, Jörg Schnecker, Olga Shibistova, Mounir Takriti, Tim Urich, Andreas Richter

Abstract

Arctic plant productivity is often limited by low soil N availability. This has been attributed to slow breakdown of N-containing polymers in litter and soil organic matter (SOM) into smaller, available units, and to shallow plant rooting constrained by permafrost and high soil moisture. Using ¹⁵N pool dilution assays, we here quantified gross amino acid and ammonium production rates in 97 active layer samples from four sites across the Siberian Arctic. We found that amino acid production in organic layers alone exceeded literature-based estimates of maximum plant N uptake 17-fold and therefore reject the hypothesis that arctic plant N limitation results from slow SOM breakdown. High microbial N use efficiency in organic layers rather suggests strong competition of microorganisms and plants in the dominant rooting zone. Deeper horizons showed lower amino acid production rates per volume, but also lower microbial N use efficiency. Permafrost thaw together with soil drainage might facilitate deeper plant rooting and uptake of previously inaccessible subsoil N, and thereby promote plant productivity in arctic ecosystems. We conclude that changes in microbial decomposer activity, microbial N utilization and plant root density with soil depth interactively control N availability for plants in the Arctic.

Organisationseinheit(en)

Institut für Bodenkunde

Externe Organisation(en)

Universität Wien
Austrian Polar Research Institute
Göteborgs Universitet
Stockholm University
University of South Bohemia
Russian Academy of Sciences (RAS)
Stanford University
Martin-Luther-Universität Halle-Wittenberg
University of New Hampshire
Universität Greifswald
Lancaster University

Typ

Artikel

Journal

Environmental research letters

Band

13

ISSN

1748-9318

Publikationsdatum

03.2018

Publikationsstatus

Veröffentlicht

Peer-reviewed

Ja

ASJC Scopus Sachgebiete

Erneuerbare Energien, Nachhaltigkeit und Umwelt, Allgemeine Umweltwissenschaft, Öffentliche Gesundheit, Umwelt- und Arbeitsmedizin

Ziele für nachhaltige Entwicklung

SDG 3 – Gute Gesundheit und Wohlergehen, SDG 7 – Erschwingliche und saubere Energie

Elektronische Version(en)

https://doi.org/10.1088/1748-9326/aaa4fa (Zugang: Offen)
https://doi.org/10.15488/4924 (Zugang: Offen)