Enhanced plant leaf P and unchanged soil P stocks after a quarter century of warming in the arctic tundra

Abstract Phosphorus (P) limits or co‐limits plant and microbial life in multiple ecosystems, including the arctic tundra. Although current global carbon (C) models focus on the coupling between soil nitrogen (N) and C, ecosystem P response to climate warming may also influence the global C cycle. Pe...

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Bibliographic Details
Published in:Ecosphere
Main Authors: McLaren, Jennie R., Buckeridge, Kate M.
Other Authors: Division of Environmental Biology, Division of Polar Programs
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2021
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Online Access:http://dx.doi.org/10.1002/ecs2.3838
https://onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.3838
https://onlinelibrary.wiley.com/doi/full-xml/10.1002/ecs2.3838
https://esajournals.onlinelibrary.wiley.com/doi/pdf/10.1002/ecs2.3838
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Summary:Abstract Phosphorus (P) limits or co‐limits plant and microbial life in multiple ecosystems, including the arctic tundra. Although current global carbon (C) models focus on the coupling between soil nitrogen (N) and C, ecosystem P response to climate warming may also influence the global C cycle. Permafrost soils may see enhanced or reduced P availability under climate warming through multiple mechanisms including changing litter inputs through plant community change, changing plant–microbial dynamics, altered rates of mineralization of soil organic P through increased microbial activity, and newly exposed mineral‐bound P via deeper thaw. We investigated the effect of long‐term warming on plant leaf, multiple soil and microbial C, N, and P pools, and microbial extracellular enzyme activities, in Alaskan tundra plots underlain by permafrost. Here, we show that 25 yr of experimental summer warming increases community‐level plant leaf P through changing community composition to favour relatively P‐rich plant species. However, despite associated increases in P‐rich litter inputs, we found only a few responses in the belowground pools of P available for plant and microbial uptake, including a weak positive response for citric acid–extractable PO 4 in the surface soil, a decrease in microbial biomass P, and no change in soil P (or C or N) stocks. This weak, neutral, or negative belowground P response to warming despite enhanced litter P inputs is consistent with a growing number of studies in the arctic tundra that find no long‐term response of soil C and N stocks to warming.