Floating-leaved macrophyte (Trapa quadrispinosa Roxb) beds have significant effects on sediment resuspension in Lake Taihu, China

Trapa quadrispinosa Roxb is a common floating-leaved macrophyte in China. In this study, the effects of Trapa on sediment resuspension in Lake Taihu, a large, shallow, eutrophic lake in eastern China, were investigated using sediment traps. The study was conducted at stations with and without Trapa beds from 7 September to 18 October, 2003. Results showed that sediment resuspension rates at the station without Trapa were significantly higher than those at the station with Trapa. During the study period (41 days), 10,970 g dw m−2 of surface sediment was resuspended within the Trapa beds and 29,903 g dw m−2 in the pelagic zone. These equate to phosphorus fluxes of 7.4 g m−2 to the water column at the station with Trapa and 16.1 g m−2 at the station without Trapa. Floating-leaved macrophytes, such as Trapa, may be important in sediment resuspension and internal phosphorus loading in shallow lakes.