2019 Volume 42 Issue 5 Pages 231-237
Water quality deterioration, such as the occurrence of frequent red tides in summer, due to eutrophication is a problem in the marine area around Tokyo. The reconstruction of tidal flats that had formed the past shoreline of Tokyo and that have water-purifying capacity is expected to be an effective solution to this problem. In this study, we quantitatively evaluated the water-purifying capacity of benthos living in the tidal flats of the Tama River estuary; up to now, had not yet been investigated. A large number of brackish water clams, Corbicula japonica, were observed in the tidal flat around Daishi Bridge between the Tokyo Haneda area and the Kawasaki Daishi area, and they were the dominant species among benthos in the estuary of the Tama River. The rate of particulate organic nitrogen (PON) removal by the benthos consisting mainly of Corbicula japonica in the Tama River estuary was estimated to be 58.6 kg day-1 during the period from August to November 2015. This equals 0.5% of the nitrogen load from the Tama River during the same period.
