A sediment-water mesocosm experiment was set up to identify the effects of different debris biomass P. crispus decomposition on water body physicochemical properties and greenhouse gas emissions in Dongping Lake, a typical shallow macrophytic lake in the north of China. The results indicated that the decomposition of high biomass (BL-2) of P. crispus could significantly affect the physicochemical properties of water bodies, especially within the first 47 days. During the experiment, DO and water pH in BL-2 were significantly lower, while NH3-N, NO2--N, DOC, and DRP in surface water and OM in sediment were significantly higher than those in the low biomass treatment (BL-1) and zero control (CK). Moreover, the DOC in BL-1 were significantly higher than CK. The decomposition of P. crispus significantly affected the emission fluxes of CH4 and CO2, but had no significant impact on N2O emission. CH4 and CO2 fluxes were generally more significantly correlated with the properties of surface water in BL-2 than in BL-1. High debris biomass decomposition significantly promoted the emission of CH4 enhancing the source effect of water body, while the decomposition of both low and high biomass notably promoted the emission of CO2 converting the water bodies from sink to source of CO2. There were significant differences in global warming potential among the three groups in which CH4 contributed most. Considering the negative impact on water environment and elevated carbon emission during the decomposition of P. crispus, it was suggested to strengthen the management of P. crispus in Dongping Lake.
Keywords: Decomposition; Dongping Lake; Emission fluxes; Greenhouse gases (GHGs); Physicochemical properties; Potamogeton crispus.
© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.