Mid term pollution status changes reflected in the benthic foraminiferal assemblage of Masan bay (south Korea)

Abstract

Masan Bay suffers from severe pollution symptoms such as harmful algal bloom, heavy metal pollution and hypoxia. Large-scale dredging efforts performed from 1988 to 1994 seemed to reduce pollution effects. A mid term pollution status change in Masan Bay was monitored by examining the benthic foraminiferal assemblage.Surface sediments from 20 stations were used for geochemical and benthic foraminiferal analyses. Agglutinated foraminifera had more than 95% appearance in most stations. Opportunistic species such as Trochammina pacifica, Eggerella advena were dominant species. The species number and abundance of the benthic foraminifera decreased in 2010 compared to 1996 and 2002 while the proportions of agglutinated foraminifera were increased. Temporal improvement of the pollution after the large dredging efforts seems to diminish recently. The current results show that the change of foraminiferal assemblage could represent the pollution status of highly polluted estuaries for medium and long term period very well.