N2-fixation by methanotrophs sustains carbon and nitrogen accumulation in pristine peatlands

• DOI: 10.1007/s10533-014-0019-6
• Publication Date: 2014-08-13T15:07:18Z
• Authors: Melanie A. Vile; R. Kelman Wieder; Tatjana Živković; Kimberli D. Scott; Dale H. Vitt; Jeremy A. Hartsock; Christine L. Iosue; James C. Quinn; Meaghan Petix; Hope M. Fillingim; Jacqueline M. A. ...; Katherine A. Dyna...; Todd R. Jackman; Cara M. Albright; Dennis D. Wykoff
• Keywords: Sphagnum; Carbon fixation

Symbiotic relationships between N2-fixing prokaryotes and their autotrophic hosts are essential in nitrogen (N)-limited ecosystems, yet the importance of this association pristine boreal peatlands, which store 25 % world's soil (C), has been overlooked. External inputs N to bogs predominantly atmospheric, given that regions Canada anchor some lowest rates found globally (~1 kg ha−1 year−1), biomass production is thought be limited primarily by N. Despite historically low deposition, we show have accumulated approximately 12–25 times more than can explained atmospheric inputs. Here demonstrate high biological N2-fixation associated with Sphagnum mosses fully account for missing input needed sustain C sequestration. Additionally, amendment experiments field did not increase production, indicating Lastly, examining composition abundance quantifying gene expression 16S rRNA nitrogenase-encoding nifH, driven substantial contribution from methanotrophs, cyanobacteria. We conclude drives sequestration may play an important role moderating fluxes methane, one most greenhouse gases produced peatlands. Understanding mechanistic controls on crucial assessing fate peatland carbon stocks under scenarios climate change enhanced anthropogenic deposition.