ABSTRACT

Nitrification is the biological oxidation of ammonia into nitrite, followed by the oxidation of nitrite into nitrate by small groups of autotrophic bacteria and Achaea. NH₃ removal is beneficial to the plant system as build up is dangerous. Presence and activities of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) in freshwater fishpond of a circulating aquaponics system was examined in respect to random points in the aquaponics system (the fish tank, the bio-filter, and the line supplying water to the plants). The samples FT4, FT6, BF5, BF6, BF1, LN1, LN2, and LN3 were all rod-like in shape, when viewed with 40 objective light compound microscope.While samples BF7 and FT7 were both circular in shape. samples FT4, FT6, FT7, BF5, BF6, BF1, LN1, LN2 and LN3 retained their primary dye ( blueblack colouration). Sample BF7 retained its secondary colour (pink colouration). , samples FT4, FT5, LN2, LN3, LN1 were all in chains. Samples FT6, BF6, and BF1 were spaced. Samples BF7 FT7 were clustered together. From the statistical analysis, it was deduced that nitrifying bacteria can be isolated from any point in the aquaponics unit. Most nitrifying bacteria were discovered to have good yield of plasmid DNA. The potential nitrification activities and oxidation rates were shown to be linear and activity of ammonia-oxidizing and nitrite oxidizing bacteria was highest in samples from the bio-filter.