Primary productivity in Gladfelter pond.

Abstract

Estimations of primary productivity and community respiration in Gladfelter Pond were made on 99 separate days from September 1, 1976, to June 30, 1977. Dissolved oxygen concentration and water temperature, monitored with a Rustrak recorder system, were used to determine productivity by the daily oxygen rate of change method. Community respiration exceeded gross primary productivity producing a heterotrophic system. Gross primary productivity averaged 5.8 g o2 m^-2, da^-1; average community respiration was 12.57 g ox m^-2 da^-1. Daily fluctuations in gross primary productivity were often independent of solar radiation changes, but corresponded to daily variations in nitrate and phosphate levels. The fluctuations showed no pattern and were usually unpredictable; therefore, the need was established for numerous consecutive day measurements when estimating primary productivity in a fresh water system.