Fungal community structure and function shifts with atmospheric nitrogen deposition. (29th November 2020)

• Record Type: Journal Article
• Authors: Moore, Jessica A. M.; Anthony, Mark A.; Pec, Gregory J.; Trocha, Lidia K.; Trzebny, Artur; Geyer, Kevin M.; van Diepen, Linda T. A.; Frey, Serita D.
• Is Part Of: Global change biology. Volume 27:Number 7(2021)
• Page Start: 1349
• Page End: 1364
• Publication Date: 2020-11-29
• Subjects: atmospheric nitrogen deposition -- fungi -- global change -- soil ecology -- target‐probe enrichment -- temperate forest ecosystems; Climatic changes -- Environmental aspects -- Periodicals; Troposphere -- Environmental aspects -- Periodicals; Biodiversity conservation -- Periodicals; Eutrophication -- Periodicals; 551.5
• DOI: 10.1111/gcb.15444
• Languages: English
• ISSNs: 1354-1013

Abstract

Abstract: Fungal decomposition of soil organic matter depends on soil nitrogen (N) availability. This ecosystem process is being jeopardized by changes in N inputs that have resulted from a tripling of atmospheric N deposition in the last century. Soil fungi are impacted by atmospheric N deposition due to higher N availability, as soils are acidified, or as micronutrients become increasingly limiting. Fungal communities that persist with chronic N deposition may be enriched with traits that enable them to tolerate environmental stress, which may trade‐off with traits enabling organic matter decomposition. We hypothesized that fungal communities would respond to N deposition by shifting community composition and functional gene abundances toward those that tolerate stress but are weak decomposers. We sampled soils at seven eastern US hardwood forests where ambient N deposition varied from 3.2 to 12.6 kg N ha −1 year −1, five of which also have experimental plots where atmospheric N deposition was simulated through fertilizer application treatments (25–50 kg N ha −1 year −1 ). Fungal community and functional responses to fertilizer varied across the ambient N deposition gradient. Fungal biomass and richness increased with simulated N deposition at sites with low ambient deposition and decreased at sites with high ambient deposition. Fungal functional genes involved in hydrolysis of organic matter increased with ambient N deposition while genes involved in oxidation of organic matter decreased. One of four genes involved in generalized abiotic stress tolerance increased with ambient N deposition. In summary, we found that the divergent response to simulated N deposition depended on ambient N deposition levels. Fungal biomass, richness, and oxidative enzyme potential were reduced by N deposition where ambient N deposition was high suggesting fungal communities were pushed beyond an environmental stress threshold. Fungal community structure and function responses to N enrichment depended on ambient N deposition at a regional scale. Abstract : Fungal decomposition of soil organic matter depends on soil nitrogen (N) availability. We hypothesized that fungal communities would respond to N deposition by shifting community composition and functional gene abundances toward those that tolerate stress but are weak decomposers. Fungal biomass, richness, and oxidative enzyme potential were reduced by N deposition where ambient N deposition was high suggesting fungal communities were pushed beyond an environmental stress threshold.