Ammonia Volatilization in a Hypertrophic Prairie Lake

Abstract

During 2 periods of high pH and high NH3 concentrations, disappearance rates of NH3 of 20-30 .mu.g N .cntdot. L-1 .cntdot. h-1 were observed in Lake 885, a hypertrophic prairie lake. At these times, rates of NH3 uptake by phytoplankton were 2.6-4.3 .mu.g N .cntdot. L-1 .cntdot. h-1 as measured by a 15N method. The high excess rates of NH3 disappearance are best explained by volatilization of NH3 from the lake surface. The loss of NH3 induced N fixation; much larger quantities of NH3 were lost via NH3 volatilization after algal bloom collapsed than the algae could fix in 1 season.