SEDIMENTARY OXYGEN DEMAND FOR LAMINAR AND TURBULENT BOUNDARY LAYER

摘要

Sedimentary oxygen demand (SOD) is the dissolved oxygen (DO) flux from a water column to a sediment surface, and can control oxygen balance in a water body in lakes, reservoirs, and estuaries. SOD depends on the velocity of water flowing above the sediment surface and on oxygen uptake due to microbial activity inside the sediment. In order to estimate SOD appreciably for the sediment bed of finite (short) length for natural and experimental systems, Higashino and Stefan (2005) investigated how the DO concentration profile and microbial oxygen uptake rate inside the sediment changes as the diffusive boundary layer develops, and proposed models for laminar and turbulent flow. These models incorporate the effect of hydrodynamic condition above the sediment/water interface on DO concentration profile and on microbial activity inside the sediment, and describe the oxygen uptake rate inside the sediment as a function of the microbial growth rate. In this study, the reliability of models is examined with comparison of measured DO profiles near the sediment/water interface (Hondzo et al., 2005) with simulated results. The DO concentration profiles are simulated at experimental velocity conditions, and compared with measured DO concentration profiles by the microprobe. The match is good, and the proposed models are valid for the prediction of the DO concentration profile near the sediment/water interface and of SOD estimation.