Blue-green Algal Ammonia Uptake in Hypertrophic Prairie Lakes

Within 24 h of an increase in lake [Formula: see text] concentration, [Formula: see text] uptake by Aphanizomenon flos-aquae and Microcystis aeruginosa increases much beyond the capacity predicted by Michaelis–Menten kinetic studies. In hypertrophic lakes this response enables these blue-green algae to optimize ammonia uptake during large oscillations of [Formula: see text] concentration, to aid them in competing with other algae, and to conserve [Formula: see text] within the ecosystem. Nitrogen limitation in the hypertrophic prairie lakes is a rare event.