Response of Stream Biofilm Function to Pulsed Increases in Velocity and Nutrients: An Artificial Stream Study
Abstract
Pulsed increases in flow within streams alter abiotic conditions such as nutrient concentrations and velocity which can influence the function of stream ecology, including biofilms. A 31-day artificial stream experiment at Thames River Experimental Stream Sciences (TRESS) Centre, London, Ontario, assessed the response of stream biofilm function (decomposition, primary production, community respiration) to individual and combined increases in velocity and phosphorus associated with a 48-hour hydrological pulse event. There was some evidence of an interactive subsidy effect of increased phosphorus and velocity on algal productivity. Decomposition increased as a result of increased phosphorus but there was no synergistic interaction of phosphorus and velocity. Ecosystem respiration did not show a substantive response to velocity or phosphorus increases. This study contributes to furthering ecological knowledge of the effect of hydrological pulses on biofilm function and to progressing understanding of the potential ecological implications of alterations to nutrient loading and stream hydrology.