EPIPHYTIC DIATOMS AS INDICATORS OF WATER QUALITY IN FARM AND EXPERIMENTAL PONDS IN OKLAHOMA

In 1976 we compared the relative abundance of epiphytic diatoms in two farm ponds and two experimental ponds in Bryan County, OK (1). The purpose of this note is to present the chemical data from that study and relate it to the diatom diversity. Five macrophyte samples for diatom analysis and five water samples for chemical and physical analysis were taken twice from each of the four ponds. Farm ponds were sampled on 5/19/76 and on 8/3/76; experimental ponds were sampled on 5/20/76 and on 8/4/76. Samples at separate locations were taken near pond bottoms about 1.0 to 2.5 m deep. Dissolved oxygen, pH, and temperature of water were measured on site with standard methods. Two-liter water samples were returned to the laboratory for turbidity, Ca, K, Mg, P, N, and Si determinations (2, 3, 4). Diatom species diversity was measured (5, 6). Turbidity, pH, and temperature (Table 1) did not fluctuate appreciably among locations at the ponds, whereas D.O. varied considerably. These parameters did not appear to differ between farm ponds and experimental ponds. Although Si and K were slightly higher in farm ponds than experimental ponds, nutrient concentrations of K, Si, and N did not differ appreciably. Mg was considerably higher in the experimental ponds than the farm ponds. Concentration of P and Ca fluctuated among ponds and between sampling dates. Diatom diversity was different among ponds (Table 1). Indices of species diversity were higher in the farm ponds than experimental ponds. Correlation coefficients (1%* * and 5%*) were determined among 11 of the parameters (Table 2). Species diversity was correlated with turbidity, K, Si, and NO3, but it was inversely correlated with 8