Summer bottom oxygen depletion dynamics and the associated physical structure in the Bohai Sea

Summertime oxygen depletion has been more and frequently observed in the bottom water of Bohai Sea last decade. Based on comprehensive hydrography microstructure measurements summer Sea, physical structure dissolved (DO) dynamics were investigated. The study area is characterized by strong tidal currents obvious horizontal temperature DO gradients boundary layer. forcing induces large near-bottom turbulent kinetic energy dissipation rates ( ϵ ~ 5 × 10 -5 W kg -1 ) which can be well parameterized law wall. Tidal advection effects dominate short-term variations hydrography. Although residual current a near-perpendicular direction with gradient (~94°), transport was calculated to 67.4 mg m -2 d 33% magnitude sediment demand. During observation period, we an intense high-turbidity event leading severe drawdown concentration (0.16 L 1.5 hours. consumption rate due this then estimated 33.3 g (1.39 h two orders larger than Rapid induced great increase bioavailable surface seabed when benthic organic matter resuspended. This process should incorporated into coupled physical-biogeochemical model improve accuracy simulating depletion.