Sphagnum-dominated peatlands comprise a globally important pool of soil carbon (C) and are vulnerable to climate change. While peat mosses of the genus Sphagnum are known to harbor diverse microbial communities that mediate C and nitrogen (N) cycling in peatlands, the effects of climate change on Sphagnum microbiome composition and functioning are largely unknown. We investigated the impacts of experimental whole-ecosystem warming on the Sphagnum moss microbiome, focusing on N-2 fixing microorganisms (diazotrophs). To characterize the microbiome response to warming, we performed next-generation sequencing of small subunit (SSU) rRNA and nitrogenase (nifH) gene amplicons and quantified rates of N-2 fixation activity in Sphagnum fallax individuals sampled from experimental enclosures over 2 years in a northern Minnesota, USA bog. The taxonomic diversity of overall microbial communities and diazotroph communities, as well as N-2 fixation rates, decreased with warming (p < 0.05). Following warming, diazotrophs shifted from a mixed community of Nostocales (Cyanobacteria) and Rhizobiales (Alphaproteobacteria) to predominance of Nostocales. Microbiome community composition differed between years, with some diazotroph populations persisting while others declined in relative abundance in warmed plots in the second year. Our results demonstrate that warming substantially alters the community composition, diversity, and N-2 fixation activity of peat moss microbiomes, which may ultimately impact host fitness, ecosystem productivity, and C storage potential in peatlands.
1.Univ Tennessee, Bredesen Ctr Interdisciplinary Res & Grad Educ, Knoxville, TN USA 2.Oak Ridge Natl Lab, Biosci Div, Oak Ridge, TN 37831 USA 3.Georgia Inst Technol, Sch Biol, Atlanta, GA 30332 USA 4.Georgia Inst Technol, Sch Earth & Atmospher Sci, Atlanta, GA 30332 USA 5.Oak Ridge Natl Lab, Div Environm Sci, POB 2008, Oak Ridge, TN 37831 USA 6.Oak Ridge Natl Lab, Climate Change Sci Inst, Oak Ridge, TN 37831 USA 7.CH2M, Atlanta, GA 30328 USA
Recommended Citation:
Carrell, Alyssa A.,Kolton, Max,Glass, Jennifer B.,et al. Experimental warming alters the community composition, diversity, and N-2 fixation activity of peat moss (Sphagnum fallax) microbiomes[J]. GLOBAL CHANGE BIOLOGY,2019-01-01,25(9):2993-3004