BENEFIT TO SYMBIOTIC ZOOCHLORELLAE FROM FEEDING BY GREEN HYDRA

Abstract

1. The symbiotic zoochlorellae of green hydra grow faster in both light and darkness with increased feeding by the hydra, although growth of algae and of hydra fed at similar frequencies is always less in darkness. 2. The algal cell content of green hydra is similar under all conditions of feeding in both light and darkness. 3. Photosynthesis by green hydra in darkness is negligible when compared to that by hydra in the light. 4. The algae take up 14 C from brine shrimp ingested by the hydra in both light and darkness. 5. It is suggested that food ingested by the hydra serves as a source of inorganic nutrients for the algae, as well as a pool of organic nutrients which the algae utilize for heterotrophic growth in darkness and which the algae may require for growth in the light.