A continuous-flow system for growing fresh-water sponges in the laboratory

Two fresh-water sponge species, Ephydatia fluviatilis and Spongilla alba , were grown from gemmules in the laboratory. A system incorporating a continuous flow of filtered habitat water and live bacteria from a chemostat culture as a food source were used. Experiments with this system demonstrated a relationship between the concentration of bacteria and sponge growth rate. Because the continuous flow of water eliminates the effects of substances released by sponges and growth rate can be predicted for a given bacterial concentration, this system permits experimental studies which were not feasible in the past.