A seasonal study of phosphorus deficiency in a eutrophic reservoir

SUMMARY Seston elemental composition (C, N, P) and the orthophosphate uptake rate constant, k(upt), were measured in the epilimnion of the eutrophic Římov Reservoir in the period March‐August 1989. Seasonal series of log C/P, log N/P and log [k(upt)] values were highly correlated (r2 in the range 0.84–0.93), but, based on literature‐derived criteria, k(upt) values indicated stronger P deficiency than did the C/P values. The results showed moderate to strong phosphorus deficiency in summer, moderate deficiency at the end of the spring peak of phytoplankton, and no deficiency early in the spring or during the spring clear‐water period.