Journal of The School of Marine Science and Technology,Vol.4 No.3
Characteristics of dissolved barium and silicate distributions
in the semi-closed estuaries of Japan
Tomomi NAKAMURA, Hiromichi SOEJIMA and Yoshihisa KATO
Abstract
Dissolved barium and silicate in seawaters from the semi-closed area,Ise Bay and the Seto-Inland Sea with
Osaka Bay and Hiroshima Bay, were measured and the distributions of these lithogeneous constituents were
compared with bay to bay.
In Ise Bay, the steep thermohaline front at the mouth of the bay was formed on April in 2003and 2005. In the
inside of the front,the seawaters were in low-salinity and high-barium,and the relation between barium and salinity
showed that the distribution of barium was conservative.In Osaka Bay,observed on April in 2003,barium concentrations
gradually decreased from the Port of Kobe to Tomogashima Channel. Although silicate was depleted in the
central area of the bay,the distribution of barium was conservative from the view of the concentration change versus
salinity.In Hiroshima Bay,observed on Nov.in 2001,the barium concentrations in this bay were rather higher than
that in the estuary of Ohta River.This findings imply that there exist the other riverine barium input in this bay.In
the Seto-Inland Sea,the relationship of the low salinity-high barium in the eastern area and vice versa in the western
area were found out.Although the higher concentration of barium were obtained in the seawaters of Harima-Nada
with longer residence time, the high co-relationship between barium concentration and salinity in the whole area
indicate that the barium distribution is controlled by the mixing between the inland and the open seawaters.