摘要
Wastewater with relatively high nitrogen concentrations is a major source of nitrous oxide(N_2O) and methane(CH_4) emissions and exerts multiple stresses on the environment.Studies have shown that plant diversity plays an important role in ecosystem functioning.However, the effects of plant species diversity on CH_4 and N_2O emissions under high ammonium(NH_4^+-N) loading rates remain unclear. In this study, a microcosm experiment simulating vertical constructed wetlands supplied with high NH_4^+-N water levels was established. The treatments included four species richness levels(1, 2, 3, 4) and 15 species compositions. There was no significant relationship between species richness and N_2O emissions. However, N_2O emissions were significantly reduced by specific plant species composition. Notably, the communities with the presence of Rumex japonicus L. reduced N_2O emissions by 62% compared to communities without this species. This reduction in N_2O emissions may have been a result of decreased N concentrations and increased plant biomass. CH_4 emissions did not respond to plant species richness or species identity.Overall, plant species identity surpassed species richness in lowering N_2O emissions from constructed wetlands with high NH_4^+-N water. The results also suggest that communities with R. japonicus could achieve higher N removal and lower greenhouse gas emissions than other wetland species.
Wastewater with relatively high nitrogen concentrations is a major source of nitrous oxide(N_2O) and methane(CH_4) emissions and exerts multiple stresses on the environment.Studies have shown that plant diversity plays an important role in ecosystem functioning.However, the effects of plant species diversity on CH_4 and N_2O emissions under high ammonium(NH_4^+-N) loading rates remain unclear. In this study, a microcosm experiment simulating vertical constructed wetlands supplied with high NH_4^+-N water levels was established. The treatments included four species richness levels(1, 2, 3, 4) and 15 species compositions. There was no significant relationship between species richness and N_2O emissions. However, N_2O emissions were significantly reduced by specific plant species composition. Notably, the communities with the presence of Rumex japonicus L. reduced N_2O emissions by 62% compared to communities without this species. This reduction in N_2O emissions may have been a result of decreased N concentrations and increased plant biomass. CH_4 emissions did not respond to plant species richness or species identity.Overall, plant species identity surpassed species richness in lowering N_2O emissions from constructed wetlands with high NH_4^+-N water. The results also suggest that communities with R. japonicus could achieve higher N removal and lower greenhouse gas emissions than other wetland species.
基金
supported by the National Natural Science Foundation of China(Nos.31670329,31470463,31500321,31770434)
