Enhancement of inorganic nutrient regeneration in a eutrophic sediment-bottom water complex system by adding effective indigenous bacteria

Abstract

To enhance heterotrophic activities for decomposing organic matter in a eutrophic bottom environment, two promising bacterial strains isolated from the study site, named Enterobacter sp. 9410-O and Pseudomonas sp. W-4 were introduced by absorbance onto porous substrates in the sediment-bottom water complex system. Strain 9410-O grew well at >20°C, considered as mesophilic, while the other strain W-4 grew at a wide rage of temperatures from 5°C to 30°C and was psychrotolerant. Addition of 9410-O stimulated net regeneration of inorganic nitrogen (DIN) and inorganic phosphorus (DIP) from the sediment by approximately four-fivefold at a high temperature of 26°C, but some stimulation was noticed at the lower temperature of 13°C. However, strain W-4 stimulated DIN and DIP net regeneration both at low (13°C; approx. threefold) and high temperatures (26°C; approx. four-fivefold). These results suggest that the application of such effective bacteria as described here would be promising for the stimulation of self-purification in the field of eutrophic bottom environments.