open access

https://hdl.handle.net/2115/56486

Retention and Release System of Phosphorus in Shinkawa-Kasugagawa River Estuary in the Western Part of Japan

日本語

沿岸環境

2011-02-28

日本海洋学会沿岸海洋研究会

沿岸海洋研究

48(2)

167-178

Seasonal surveys during the flood-ebb tidal cycle were carried out in May, August and November 2006 in order to estimate the phosphorus balance in Shinkawa-Kasugagawa river estuary and to demonstrate the function of the intertidal flat for the coastal environment. Annual abundance of total phosphorus (dissolved inorganic and organic phosphorus + particle phosphorus) discharged from the rivers was similar to that flowing out to the coastal sea, although the main component flowing out to the coastal sea was dissolved inorganic phosphorus. In spring, 50% < of the phosphorus discharged from the rivers was trapped in the intertidal zone, while all of phosphorus discharged from the rivers in summer was retained in the intertidal zone. Two processes of phosphorus retention were estimated. One process involved physical cohesion and sedimentation of particulate phosphorus in the lower saline zone. The other process is the huge filtrating and sedimentation activity of bivalves following the assimilation of dissolved inorganic phosphorus by microalgae. However, abundant phosphorus was released from the intertidal zone in autumn, despite the limited flow rates of the rivers. Our findings show that phosphorus discharge from the rivers does not synchronize with outflow to the coastal sea.

学術雑誌論文

Version of Record

1342-2758

AN10492259