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Microbial nitrogen dynamics in organic and mineral soil horizons along a latitudinal transect in western Siberia

Soil N availability is constrained by the breakdown of N-containing polymers such as proteins to oligopeptides and amino acids that can be taken up by plants and microorganisms. Excess N is released from microbial cells as ammonium (N mineralization), which in turn can serve as substrate for nitrifi...

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Autores principales: Wild, Birgit, Schnecker, Jörg, Knoltsch, Anna, Takriti, Mounir, Mooshammer, Maria, Gentsch, Norman, Mikutta, Robert, Alves, Ricardo J Eloy, Gittel, Antje, Lashchinskiy, Nikolay, Richter, Andreas
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley & Sons, Ltd 2015
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Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4676305/
https://www.ncbi.nlm.nih.gov/pubmed/26693204
http://dx.doi.org/10.1002/2015GB005084
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author Wild, Birgit
Schnecker, Jörg
Knoltsch, Anna
Takriti, Mounir
Mooshammer, Maria
Gentsch, Norman
Mikutta, Robert
Alves, Ricardo J Eloy
Gittel, Antje
Lashchinskiy, Nikolay
Richter, Andreas
author_facet Wild, Birgit
Schnecker, Jörg
Knoltsch, Anna
Takriti, Mounir
Mooshammer, Maria
Gentsch, Norman
Mikutta, Robert
Alves, Ricardo J Eloy
Gittel, Antje
Lashchinskiy, Nikolay
Richter, Andreas
author_sort Wild, Birgit
collection PubMed
description Soil N availability is constrained by the breakdown of N-containing polymers such as proteins to oligopeptides and amino acids that can be taken up by plants and microorganisms. Excess N is released from microbial cells as ammonium (N mineralization), which in turn can serve as substrate for nitrification. According to stoichiometric theory, N mineralization and nitrification are expected to increase in relation to protein depolymerization with decreasing N limitation, and thus from higher to lower latitudes and from topsoils to subsoils. To test these hypotheses, we compared gross rates of protein depolymerization, N mineralization and nitrification (determined using (15)N pool dilution assays) in organic topsoil, mineral topsoil, and mineral subsoil of seven ecosystems along a latitudinal transect in western Siberia, from tundra (67°N) to steppe (54°N). The investigated ecosystems differed strongly in N transformation rates, with highest protein depolymerization and N mineralization rates in middle and southern taiga. All N transformation rates decreased with soil depth following the decrease in organic matter content. Related to protein depolymerization, N mineralization and nitrification were significantly higher in mineral than in organic horizons, supporting a decrease in microbial N limitation with depth. In contrast, we did not find indications for a decrease in microbial N limitation from arctic to temperate ecosystems along the transect. Our findings thus challenge the perception of ubiquitous N limitation at high latitudes, but suggest a transition from N to C limitation of microorganisms with soil depth, even in high-latitude systems such as tundra and boreal forest. KEY POINTS: 1. We compared soil N dynamics of seven ecosystems along a latitudinal transect. 2. Shifts in N dynamics suggest a decrease in microbial N limitation with depth. 3. We found no decrease in microbial N limitation from arctic to temperate zones;
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spelling pubmed-46763052015-12-19 Microbial nitrogen dynamics in organic and mineral soil horizons along a latitudinal transect in western Siberia Wild, Birgit Schnecker, Jörg Knoltsch, Anna Takriti, Mounir Mooshammer, Maria Gentsch, Norman Mikutta, Robert Alves, Ricardo J Eloy Gittel, Antje Lashchinskiy, Nikolay Richter, Andreas Global Biogeochem Cycles Research Articles Soil N availability is constrained by the breakdown of N-containing polymers such as proteins to oligopeptides and amino acids that can be taken up by plants and microorganisms. Excess N is released from microbial cells as ammonium (N mineralization), which in turn can serve as substrate for nitrification. According to stoichiometric theory, N mineralization and nitrification are expected to increase in relation to protein depolymerization with decreasing N limitation, and thus from higher to lower latitudes and from topsoils to subsoils. To test these hypotheses, we compared gross rates of protein depolymerization, N mineralization and nitrification (determined using (15)N pool dilution assays) in organic topsoil, mineral topsoil, and mineral subsoil of seven ecosystems along a latitudinal transect in western Siberia, from tundra (67°N) to steppe (54°N). The investigated ecosystems differed strongly in N transformation rates, with highest protein depolymerization and N mineralization rates in middle and southern taiga. All N transformation rates decreased with soil depth following the decrease in organic matter content. Related to protein depolymerization, N mineralization and nitrification were significantly higher in mineral than in organic horizons, supporting a decrease in microbial N limitation with depth. In contrast, we did not find indications for a decrease in microbial N limitation from arctic to temperate ecosystems along the transect. Our findings thus challenge the perception of ubiquitous N limitation at high latitudes, but suggest a transition from N to C limitation of microorganisms with soil depth, even in high-latitude systems such as tundra and boreal forest. KEY POINTS: 1. We compared soil N dynamics of seven ecosystems along a latitudinal transect. 2. Shifts in N dynamics suggest a decrease in microbial N limitation with depth. 3. We found no decrease in microbial N limitation from arctic to temperate zones; John Wiley & Sons, Ltd 2015-05 2015-05-12 /pmc/articles/PMC4676305/ /pubmed/26693204 http://dx.doi.org/10.1002/2015GB005084 Text en ©2015. The Authors. http://creativecommons.org/licenses/by/4.0/ This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Articles
Wild, Birgit
Schnecker, Jörg
Knoltsch, Anna
Takriti, Mounir
Mooshammer, Maria
Gentsch, Norman
Mikutta, Robert
Alves, Ricardo J Eloy
Gittel, Antje
Lashchinskiy, Nikolay
Richter, Andreas
Microbial nitrogen dynamics in organic and mineral soil horizons along a latitudinal transect in western Siberia
title Microbial nitrogen dynamics in organic and mineral soil horizons along a latitudinal transect in western Siberia
title_full Microbial nitrogen dynamics in organic and mineral soil horizons along a latitudinal transect in western Siberia
title_fullStr Microbial nitrogen dynamics in organic and mineral soil horizons along a latitudinal transect in western Siberia
title_full_unstemmed Microbial nitrogen dynamics in organic and mineral soil horizons along a latitudinal transect in western Siberia
title_short Microbial nitrogen dynamics in organic and mineral soil horizons along a latitudinal transect in western Siberia
title_sort microbial nitrogen dynamics in organic and mineral soil horizons along a latitudinal transect in western siberia
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4676305/
https://www.ncbi.nlm.nih.gov/pubmed/26693204
http://dx.doi.org/10.1002/2015GB005084
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