The Effects of Nitric and Sulfuric Acids on the DiatomNitzschia palea(Kutz.) W. Smith

Abstract The population growth rate of the diatom Nitzschia palea was reduced from the controls by low concentrations (0.0001 M) of either nitric or sulfuric acid during 672 hours of continuous laboratory culture. The measured pH of the treatment systems was not significantly different from the control. The pH for all treatments was (mean ± SD): 7.51 ± 0.15 = control, 7.54 ± 0.18 = nitric, and 7.44 ± 0.12 = sulfuric. The acid treatments reduced the cell count (at 600 hr) to 66% for nitric acid and to 33% for sulfuric acid. The growth rate calculated from the regression, between 500 and 600 hours (in cells per ml per hr), was 1413 for the control, 904 for the nitric acid, and 360 for the sulfuric acid. The slope for the natural log of the cell count was 0.00812 = control, 0.00764 = nitric, and 0.00550 = sulfuric. The natural log cell count intercept was 7.57 = control, 7.45 = nitric, and 8.05 = sulfuric. The calculated cell yield in cells per milliliter at 600 hours was 254,300 = control, 169,300 = nitric, and 85,100 = sulfuric.