Effects of plant communities on the emission of soil greenhouse gases in riparian wetlands during spring thaw

Abstract

Spring thawing can affect the soil carbon and nitrogen cycling processes and lead to changes in the emissions of greenhouse gases. The temporal variations and impact factors of soil GHGs fluxes were measured in Phragmites australis and Carex appendiculata with the static chamber from the end of March to the end of May in 2018 in riparian wetlands of Xilin River, which is typical inland river meandering through steppe region in Inner Mongolia, China. The results showed that soil CH4 and N2O emissions of the P. australis were significantly higher than those of the Carex appendiculata, whereas CO2 emissions were no significant difference. The responses of soil GHG fluxes to soil environmental factors in P. australis and Carex appendiculata differed. In the P. australis community, soil CO2 and CH4 emissions were influenced jointly by mainly the soil temperature and microbial biomass nitrogen, whereas soil N2O emission was mainly affected by the soil temperature. The dominant controlling factor for CO2 and N2O was soil temperature in the Carex appendiculata, whereas CH4 was mainly regulated by soil water content. The global warming potential of P. australis was significantly higher than that of Carex appendiculata. Those findings highlight the difference in soil greenhouse gas fluxes in different plant communities and the importance of CH4 and N2O emissions during the spring thaw, which contributes to predicting the riparian wetland soil greenhouse gases and their global warming potential under global climate changes.

N2O emission associated with shifts of bacterial communities in riparian wetland during the spring thawing periods

“…The Xilin River basin is located in a frequent freeze–thaw zone, which is a unique natural laboratory for exploring the relationship between freeze–thaw and riparian biogeochemistry. In our experimental sites, N 2 O fluxes are associated with freeze–thaw and usually occur from the middle of March to the end of April, when temperatures rose above 0°C (Cao et al, 2022). Most previous studies have been conducted indoors to explore N 2 O emission bursts under controlled conditions and the soil physicochemical driving mechanisms of N 2 O emissions, with little exploration of the microbial mechanisms of N 2 O emissions during freeze–thaw.…”

“…The Xilin River basin is located in a frequent freeze-thaw zone, which is a unique natural laboratory for exploring the relationship between freeze-thaw and riparian biogeochemistry. In our experimental sites, N 2 O fluxes are associated with freeze-thaw and usually occur from the middle of March to the end of April, when temperatures rose above 0°C (Cao et al, 2022)…”

“…N 2 O sampling was performed using the static dark chambers and Picarro G 2308. N 2 O sampling methods and flux calculations are detailed in the supplementary(Cao et al, 2022).…”