Seasonal Variations of Population Density and Activity of Sulfate-Reducing Bacteria in Offshore and Reed Sediments of a Hypertrophic Freshwater Lake

Abstract

Seasonal variations in population density of sulfate-reducing bacteria (SRB) and sulfate reduction rates were examined for sediments of an offshore and a reed site of Lake Teganuma (freshwater, hypertrophic), Chiba Prefecture, Japan. The numbers of SRB (colony forming units•ml-1) in the surface sediments (0~2 cm) were at a level of 105at the reed site and a level of 104at the offshore one, and they remained ralatively constant throughout the year. The activities at both sites increased from summer to autumn, and the reed sediments showed higher activities (1.08-16.6 times) than the offshore ones in this period; the maximum rates (September) (nmol•ml-1•day-1) in the offshore and reed sediments were 290 in the 0~3 cm layer and 1990 in the 3~6 cm layer, respectively. In situ temperature may have greatly affected sulfate reduction. © 1990, The Japanese Society of Limnology. All rights reserved.