Nitrogen addition turns a temperate peatland from a near-zero source into a strong sink of nitrous oxide

Abstract

Peatlands, as important global nitrogen (N) pools, are potential sources of nitrous oxide (N<sub>2</sub>O) emissions. We measured N<sub>2</sub>O flux dynamics in Hani peatland in a growing season with simulating warming and N addition for 12 years in the Changbai Mountains, Northeastern China, by using static chamber-gas chromatography. We hypothesised that warming and N addition would accelerate N<sub>2</sub>O emissions from the peatland. In a growing season, the peatland under natural conditions showed near-zero N<sub>2</sub>O fluxes and warming increased N<sub>2</sub>O emissions but N addition greatly increased N<sub>2</sub>O absorption compared with control. There was no interaction between warming and N addition on N<sub>2</sub>O fluxes. Pearson correlation analysis showed that water table depth was one of the main environmental factors affecting N<sub>2</sub>O fluxes and a positive relationship between them was observed. Our study suggests that the N<sub>2</sub>O source function in natural temperate peatlands maybe not be so significant as we expected before; warming can increase N<sub>2</sub>O emissions, but a high dose of N input may turn temperate peatlands to be strong sinks of N<sub>2</sub>O, and global change including warming and nitrogen deposition can alter N<sub>2</sub>O fluxes via its indirect effect on hydrology and vegetation in peatlands.

Plant controls over tropical wetland nitrous oxide dynamics: a review

“…In the Pantanal, Brazil, floating mats of E. crassipes have been proposed to release 300 -1,000 kg N ha −1 yr −1 , approximately 10 times as much as carbon (Koschorreck, 2005;Sun et al, 2011). Phosphorus is often limiting in wetland soils (Cheesman et al 2012), and low availability can limit the activity of nitrifying and denitrifying microbial communities (Yi et al 2024). Combined, plant aboveground inputs therefore represent a major seasonal driver of N2O emissions, equivalent to fertiliser applications in agroecosystems.…”

The Effect of Warming-Amplified Phosphorus Addition on a Peatland’s N2O Emissions

“…The warming was passively achieved by the open top chamber (OTC, 0.8 m × 0.8 m at the top and 1.2 m × 1.2 m at the bottom), which increased the air temperature by about 0.6 • C during the growing season (Figure S1). For more information, see Bu, et al [37]; Yi, et al [30]; and Lu, et al [6].…”

“…The N 2 O fluxes were measured eight times (twice in May, July, and September and once in June and August) by the static chamber-gas chromatography method. Gas samples (60 mL) were collected by a syringe from the static chamber at 10-min intervals over a 30-min period (0, 10, 20 and 30 min) and then measured by utilizing the electron capture detector (ECD) of gas chromatography (GC system, Agilent 7980B, Santa Clara, CA, USA) to calculate the concentration of N 2 O; we also determined the N 2 O flux by establishing a regression equation for gas concentration and sampling time (more details in Yi, Lu and Bu [30]).…”

“…The plant covers, including Sphagnum, vascular plants, and then total plant cover, were estimated by visual inspection at the end of July 2019 [38]. More details can be seen in Yi, Lu and Bu [30].…”

“…With the current global warming, the sink function for the greenhouse gases CO 2 and N 2 O in peatlands will be severely weakened due to changes in vegetation composition and the acceleration of peat decomposition [29]. Warming will also stimulate soil enzyme and microbial activities, and directly or indirectly promote N 2 O emissions from peatlands [10,30,31]. Phosphate monoesters and orthophosphates were the dominant forms of P in wetlands [32].…”