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Nitrogen cycling microbiomes are structured by plant mycorrhizal associations with consequences for nitrogen oxide fluxes in forests
Author(s) -
Mushinski Ryan M.,
Payne Zachary C.,
Raff Jonathan D.,
Craig Matthew E.,
Pusede Sally E.,
Rusch Douglas B.,
White Jeffrey R.,
Phillips Richard P.
Publication year - 2021
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/gcb.15439
Subject(s) - cycling , nitrogen cycle , soil water , abundance (ecology) , nitrogen , environmental science , relative species abundance , microbial population biology , ectomycorrhiza , flux (metallurgy) , soil microbiology , ecology , biology , environmental chemistry , mycorrhiza , chemistry , symbiosis , bacteria , forestry , genetics , geography , organic chemistry
Abstract Volatile nitrogen oxides (N 2 O, NO, NO 2 , HONO, …) can negatively impact climate, air quality, and human health. Using soils collected from temperate forests across the eastern United States, we show microbial communities involved in nitrogen (N) cycling are structured, in large part, by the composition of overstory trees, leading to predictable N‐cycling syndromes, with consequences for emissions of volatile nitrogen oxides to air. Trees associating with arbuscular mycorrhizal (AM) fungi promote soil microbial communities with higher N‐cycle potential and activity, relative to microbial communities in soils dominated by trees associating with ectomycorrhizal (ECM) fungi. Metagenomic analysis and gene expression studies reveal a 5 and 3.5 times greater estimated N‐cycle gene and transcript copy numbers, respectively, in AM relative to ECM soil. Furthermore, we observe a 60% linear decrease in volatile reactive nitrogen gas flux (NO y ≡ NO, NO 2 , HONO) as ECM tree abundance increases. Compared to oxic conditions, gas flux potential of N 2 O and NO increase significantly under anoxic conditions for AM soil (30‐ and 120‐fold increase), but not ECM soil—likely owing to small concentrations of available substrate ( NO 3 ‐ ) in ECM soil. Linear mixed effects modeling shows that ECM tree abundance, microbial process rates, and geographic location are primarily responsible for variation in peak potential NO y flux. Given that nearly all tree species associate with either AM or ECM fungi, our results indicate that the consequences of tree species shifts associated with global change may have predictable consequences for soil N cycling.