Water Quality Monitoring System for Oxygen Consumption Studies in the Benthic Boundary Layer of the Seto Inland Sea

A monitoring system of water quality in the benthic boundary layer has been designed and built to investigate process of oxygen consumption in bottom layer of the Seto Inland Sea. The system consists of three instruments. The first instrument has been developed to operate on the bottom floor and makes continuous measurement of the vertical distribution of water quality in bottom water layer and various parameters of sediment. It has the specially designed elevetors in which various in situ water quality sensors are attached and the vertical distribution of water quality is obtained by moving the elevetors vertically. The second instrument has been developed to make an in situ measurement of the oxygen consumption rate of sediment on the basis of the bell-jar method. The third instrument measures the vertical distribution of current velocity in the benthic boundary layer and the friction velocity is estimated from the current data.