Description

Abstract: Dissolved oxygen dynamics and vertical water circulation in high density integrated fish culture ponds were monitored monthly at 2-h intervals for 26h from March through September at the Pearl River Delta, China. Stable thermal stratification was found almost daily in May through September. Vertical circulation began daily between 8 and 10 p.m. The average depth for this turnover in summer can be as great as 0.7-1 m. Complete vertical circulation occurs only during major storms. A convection turbulence model was used to examine the vertical mixing process and showed that light wind (<100 cm/s) and surface cooling (<2