The Effect of humic substances on the number of nitrogen transformation bacteria

The effect of humic substance (HS) on growth of different groups of nitrogen cycle bacteria (ammonifying, denitrifying, phase I and phase II nitrifying, and proteolytic bacteria) isolated from Piaseczno Ma e dystrophic lake was investigated. The water samples were supplemented with a humic compounds preparation and the rate of proliferation of bacteria was examined after seven days of incubation with the humic preparation. Humic substances either stimulated or inhibited the growth of nitrogen cycle bacteria, depending on a particular group of microorganisms, the concentration of humic substances, the physical and chemical parameters of the lake water.