Effect of exogenous phosphorus addition on soil respiration in Calamagrostis angustifolia freshwater marshes of Northeast China

► In the short-term, soil respiration declined under P enrichment in Calamagrostis angustifolia-dominated freshwater marshes of Northeast China, and its extent varied with P addition levels. ► Dissolved organic C in soil pore water increased after P addition at both 5 and 15 cm depths. ► Increased P input generally inhibited soil microbial biomass C and enzyme activities, and had no effects on aboveground biomass and soil EOC.