caa a22 4500 605517525 CHVBK 20210128100720.0 cr unu---uuuuu 210128e20151101xx s 000 0 eng 10.1007/s10533-015-0160-x doi (NATIONALLICENCE)springer-10.1007/s10533-015-0160-x Microbial-mediated redistribution of ecosystem nitrogen cycling can delay progressive nitrogen limitation [Elektronische Daten] [Colin Averill, Johannes Rousk, Christine Hawkes] Soil nitrogen (N) availability constrains future predictions of ecosystem primary productivity and carbon storage. The progressive N limitation (PNL) hypothesis predicts that forest net primary productivity (NPP) will decline with age, and that the response of NPP to elevated CO2 will attenuate through time due to negative feedbacks of NPP on the soil N cycle. A central assumption of the PNL hypothesis is that, without changes in exogenous exchange of N in an ecosystem, increases in plant N uptake require increased soil N cycling rates. However, at ecosystem scale, microbial N uptake exceeds plant uptake. Hence, a change in the partitioning of N between plants and soil microorganisms may represent an alternative mechanism to sustain plant N uptake in the face of PNL. To estimate N partitioning of total N cycling between plants and microbes, we measured and modeled growth and N uptake of trees, bacteria, saprotrophic fungi, and ectomycorrhizal fungi across a forest succession and N limitation gradient. The combined plant and ectomycorrhizal N uptake increased from early to late succession, and nearly matched saprotrophic N uptake in late successional sites, while total N cycling remained stable or even declined. Changes in microbial community structure can thus mediate a redistribution of ecosystem nitrogen cycling, allowing an increase in plant N uptake without concomitant increases in soil N cycling. We further suggest that microbe-mediated changes in N partitioning can delay PNL and may thereby act as a mechanism to extend the duration of the land carbon sink in response to rising atmospheric CO2. Springer International Publishing Switzerland, 2015 Nitrogen nationallicence Microbes nationallicence Mycorrhizal fungi nationallicence Progressive nitrogen limitation nationallicence Ecosystems nationallicence Averill Colin Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA aut Rousk Johannes Section of Microbial Ecology, Department of Biology, Lund University, 22362, Lund, Sweden aut Hawkes Christine Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA aut Biogeochemistry Springer International Publishing 126/1-2(2015-11-01), 11-23 0168-2563 126:1-2<11 2015 126 10533 https://doi.org/10.1007/s10533-015-0160-x text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 review-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s10533-015-0160-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Averill Colin Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA aut NATIONALLICENCE 700 1- Rousk Johannes Section of Microbial Ecology, Department of Biology, Lund University, 22362, Lund, Sweden aut NATIONALLICENCE 700 1- Hawkes Christine Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA aut NATIONALLICENCE 773 0- Biogeochemistry Springer International Publishing 126/1-2(2015-11-01), 11-23 0168-2563 126:1-2<11 2015 126 10533