Temporal and Spatial Variations of Bottom Sediment the Tama River Mouth in Tokyo Bay

This study was aimed at investigating temporal and spatial variations of the bottom sediment characteristics at Tama River mouth in Tokyo Bay. The bottom sediment samples were taken every 3 months from 28 points, including an offshore site(<-24), shoal(-2m ~ -10m) and river line bed around Tama River mouth. The paper shows the drastic change of sediment properties, such as water content and organic content, especially at the offshore site by the attack of the typhoon in the early September of 2007 and it took about 2 year for the sediment properties have recovered to the condition before the event. The paper also discusses the seasonal variation of sediment properties depend on the sampling sites.