Phytoplankton production dynamics in nutrient pulsed systems.

Phytoplankton production is determined by light and inorganic nutrients which govern the biomass of primary producers. These variables are a function of watershed rainfall periodicity and water quality from the run-off in pulsed systems or reservoirs. Reservoirs receive water and nutrient inputs from a tributary. I measured reservoir primary production and those environmental variables known to govern production as a function of pulses along three zones (riverine, transition, lacustrine) in Waco Lake to determine how production dynamics are controlled by water pulses. In this system the Riverine Zone was affected by pulses. Riverine Zone -2 had a phytoplankton production maximum of 787 mgCm at 40 cfsec of discharge (approximates base flow). The Transition Zone was the most productive zone during pulses. This zone had a maximum -2 production of 2175 mgCm~ with pulse of 760 cfsec . The Lacustrine Zone production was affected by the nutrient concentration.