999 Marsh foraminiferal and vegetation distributions in Nemuro Bay wetland areas, eastern Hokkaido

Abstract

Although much work has been done on brackish water foraminifera, this is the first report of modern marsh foraminifera from Japan. Two transects were sampled in marshes of eastern Hokkaido for salt marsh foraminifera. Although these marshes were tidal, salinities were very low as evidenced by the freshwater plants that dominated the transects. Foraminifera present were low in diversity but extremely high in abundance-some of the highest ever recorded for a salt marsh. Miliammina fusca dominated lower areas together with Trochammina macrescens f. macrescens which dominated at all levels in both trasects. In the upper elevations of both transects, Haplophragmoides manilaensis became prominent and thecamoebians occupied the upland regions. Vertical zonation was generally poorly developed in both the foraminiferal and vegetation distributions which is typical of very brackish regions with low tidal ranges. Many typical brackish foraminiferal species observed in the Atlantic marshes are either rare or completely absent here.