Relative microbial activity and bacterial concentrations in water and sediment samples taken in the Beaufort Sea

Abstract

A total of 91 water, 8 ice, and 50 sediment samples taken from the southwestern Beaufort Sea were analyzed for relative microbial activity, bacterial cell concentrations, and percentage of respiration (mineralization). These samples were taken during three field-study periods (August to September 1975; April 1976; and August 1976). Both the relative microbial activity and the cell concentrations in water and sediment samples were lower during the April (winter) sampling period than in the August–September (summer) studies. The percentage of respiration of labeled glutamic acid was higher in the winter water samples than in the summer samples. The water samples showed higher percentage of respiration values than did sediment samples. The average maximimum potential rate of glutamic acid uptake was as high or higher than those observed in studies made in more temperate waters. Samples of melted sea ice showed levels of relative microbial activity that were about the same as that found in the associated seawater. When 1:1 mixtures of melted ice and seawater were analyzed for altered microbial activity, little effect could be detected.