Litter Decomposition of Six Macrophytes in a Eutrophic Shallow Lake (Baiyangdian Lake, China)

Abstract The decomposition of aquatic macrophytes has important consequences for wetlands because it is closely related to organic matter accumulation and nutrient cycling. A field litter bag experiment was undertaken to investigate the decomposition rates of six dominant macrophytes. And the level of nutrient transfer from plant residues to lake water was also researched in Baiyangdian Lake, a typical macrophyte‐dominated lake in the Northern China Plain. Intact standing plants of Phragmites australis , Typha angustifolia , Nelumbo nucifera , Potamogeton pectinatus , Ceratophyllum demersum , and Chara sp. were collected and different plant tissues incubated near sediment traps. Litter bags were collected at days 6, 26, 60, 104, and 140 to follow biomass loss and nutrient release. Decomposition rates of different macrophytes calculated from an exponential model ranged from 0.0028 to 0.0110 day −1 . For the same external environmental conditions, decomposition rates were significantly affected by initial litter chemistry. The remaining biomass was positively related to the C/N and C/P ratios and negatively related to the N and P concentrations and the N/P ratio. Both stems and roots showed a lower decomposition rate than the leaves of the same species due to the higher C/N ratio. The nutrient release from plant litter to the lake water was substantial. Over the incubation period, the release of N from the litter represented 18.10–88.79% of the initial content, and the release of P from the litter represented 24.26–92.83% of the initial content.