Dynamic change of near bottom dissolved oxygen in summer with wind wave disturbance at the inner Tokyo Bay

Abstract

Field observations of water quality in the summer of 2010 reveal that the wind wave is one of key factors for temporary recovery of near bed dissolved oxygen DO concentration from hypoxic state in the inner Tokyo bay. The observation was a part of monitoring campaign to elucidate the behavior of the hypoxic water in the area. Basic parameters of water quality such as dissolved oxygen, salinity, temperature and turbidity were measured by a mooring system for 3 month from July through September in 2010. Physical parameters were also obtained for current profile by a bottom mounted ADCPs and for wind waves by an ultrasonic wave gauge respectively. DO concentration measured at 50 cm above the bottom intermittently increased especially after relatively higher wave events. The data also shows that the DO concentration near the bed is highly correlated with suspended sediment concentrations.

Tracing fine-grained sediment transport around Tokyo Bay using cesium-134 and cesium-137 originating from Fukushima Daiichi Power Plant

“…The reachable depth in the vertical direction, which is a benchmark of water mass movement due to wave impact, is ca. 10 m in the case of waves with a significant wave period of 4 s observed in Tokyo Bay where deep water waves were taken into account (Nakagawa et al [13]). Therefore, in areas with shallow water depth and tendency for wave development, the influence of wave forces is immediately felt up to ca.…”