Effects of warming on N 2 O fluxes in a boreal peatland of Permafrost region, Northeast China.

Climate warming is expected to increasingly influence boreal peatlands and alter their greenhouse gases emissions. However, the effects of warming on N2 O fluxes and the N2 O budgets were ignored in boreal peatlands. Therefore, in a boreal peatland of permafrost zone in Northeast China, a simulated warming experiment was conducted to investigate the effects of warming on N2 O fluxes in Betula. Fruticosa community (B. Fruticosa) and Ledum. palustre community (L. palustre) during the growing seasons from 2013 to 2015. Results showed that warming treatment increased air temperature at 1.5m aboveground and soil temperature at 5cm depth by 0.6°C and 2°C, respectively. The average seasonal N2 O fluxes ranged from 6.62 to 9.34μgm-2 h-1 in the warming plot and ranged from 0.41 to 4.55μgm-2 h-1 in the control plots. Warming treatment increased N2 O fluxes by 147% and transformed the boreal peatlands from a N2 O sink to a source. The primary driving factors for N2 O fluxes were soil temperature and active layer depth, whereas soil moisture showed a weak correlation with N2 O fluxes. The results indicated that warming promoted N2 O fluxes by increasing soil temperature and active layer depth in a boreal peatland of permafrost zone in Northeast China. Moreover, elevated N2 O fluxes persisted in this region will potentially drive a noncarbon feedback to ongoing climate change.