Рубрики:
SUB-ARCTIC TUNDRA
SOIL-NITROGEN
ALASKAN TUNDRA
ORGANIC-MATTER
Кл.слова (ненормированные):
permafrost -- tundra -- protein depolymerization -- nitrogen mineralization -- nitrogen limitation -- plant productivity
SUB-ARCTIC TUNDRA
SOIL-NITROGEN
ALASKAN TUNDRA
ORGANIC-MATTER
Кл.слова (ненормированные):
permafrost -- tundra -- protein depolymerization -- nitrogen mineralization -- nitrogen limitation -- plant productivity
Аннотация: 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 N-15 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.
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Держатели документа:
Univ Vienna, Dept Microbiol & Ecosyst Sci, Vienna, Austria.
Austrian Polar Res Inst, Vienna, Austria.
Univ Gothenburg, Dept Earth Sci, Gothenburg, Sweden.
Stockholm Univ, Dept Environm Sci & Analyt Chem, Stockholm, Sweden.
Stockholm Univ, Bolin Ctr Climate Res, Stockholm, Sweden.
Univ Vienna, Dept Ecogen & Syst Biol, Vienna, Austria.
Univ South Bohemia, Dept Ecosyst Biol, Ceske Budejovice, Czech Republic.
Leibniz Univ Hannover, Inst Soil Sci, Hannover, Germany.
Russian Acad Sci, VN Sukachev Inst Forest, Siberian Branch, Krasnoyarsk, Russia.
Stockholm Univ, Dept Phys Geog, Stockholm, Sweden.
Stanford Univ, Dept Earth Sci, Stanford, CA 94305 USA.
Russian Acad Sci, Cent Siberian Bot Garden, Siberian Branch, Novosibirsk, Russia.
Martin Luther Univ Halle Wittenberg, Soil Sci & Soil Protect, Halle, Saale, Germany.
Univ New Hampshire, Dept Nat Resources & Environm, Durham, NH 03824 USA.
Univ Lancaster, Lancaster Environm Ctr, Lancaster, England.
Ernst Moritz Arndt Univ Greifswald, Inst Microbiol, Greifswald, Germany.
Доп.точки доступа:
Wild, Birgit; Alves, Ricardo J. Eloy; Barta, Jiri; Capek, Petr; Gentsch, Norman; Guggenberger, Georg; Hugelius, Gustaf; Knoltsch, Anna; Kuhry, Peter; Lashchinskiy, Nikolay; Mikutta, Robert; Palmtag, Juri; Prommer, Judith; Schnecker, Joerg; Shibistova, Olga; Takriti, Mounir; Urich, Tim; Richter, Andreas; Alves, Ricardo; Austrian Science Fund (FWF) [I370-B17]; German Federal Ministry of Education and Research [03F0616A]; Czech Ministry of Education, Youth and Sports [MSM 7E10073-CryoCARB]; Russian Ministry of Education and Science [14.B25.31.0031]; Swedish Research Council [824-2009-77357]; Norwegian Research Fund (NFR) [NFR-200411]; JPI Climate Project (COUP-Austria) [BMWFW-6.020/0008]; Czech Science Foundation [16-18453S]