Abstract
In situ measurements of oxygen uptake by benthic layer (including sediment surface and over-lying water) in Hiuchi-Nada, the Seto Inland Sea were made with a specially designed system having a bell-jar. Mean values of obserbed oxygen uptake of three periods, Sep.1986 and Jul, and Sep.1987 were 650 and 410 mg·m-2·d-1 in the central part and the western part of the Hiuchi-Nada, respectively. Since oxygen supply by photosysthesis in the benthic layer was found in the eastern part of the basin, oxygen uptake in this area was estimated to be 950 mg·m-2·d-1 by compensating its effect. The high vale of the oxygen uptake in Hiuchi-Nada was found in the eastern part with high organic carbon content in sediment.
