Abstract
We developed an automatic ascending/descending water quality profiler to continuously observe vertical profile of water quality in a semi-enclosed coastal region. This profiler can collect vertical profile of water quality according to preset configuration by ascending/descending into seawater utilizing piston cylinder to change its buoyancy. From the end of July to the beginning of September in 2000, we deployed this profiler in the Kaita Bay, that is the most inner branch bay of the Hiroshima Bay of Japan, in order to collect profiles of water temperature, salinity, dissolved oxygen, chlorophyll-a, turbidity and depth at every twenty minutes. As a result, this profiler could catch over-saturated dissolved oxygen in the surface layer due to red tide, and vertical variation of stratification and chlorophyll-a caused by sea-land breeze.
In addition, during the field experiment, a problem occurred with ascending/descending action due to sag of the mooring system, which should be improved in future.
