Abstract
Focusing on the possibility that nutrients contained in dredged sediment may function for the growth of eelgrass and Japanese eelgrass, field investigation, soil properties analysis, and chemical analysis were conducted in Oshima tidal flat. Vertical transport fluxes associated with consolidation were obtained from the average concentrations of ammonia nitrogen and phosphate phosphorus in the pore water of dredged soil and the volume of consolidation drainage during the consolidation process. The maximum diffusion transport fluxes were obtained from the ammonium nitrogen and phosphate phosphorus concentration gradients in the pore water. The amount of nutrients required for eelgrass growth from the subterranean stem was significantly insufficient for the amount of nutrients supplied by the dredged soil through pore water due to compaction subsidence and diffusion after convergence. It was suggested that sources other than the dredged material may contribute to maintain enough nutrient concentrations in the surface sediment, or that direct uptake from the overlying water through the leaves was the main source of nutrients.
