HOST FEEDING REGIME AND ZOOXANTHELLAL PHOTOSYNTHESIS IN THE ANEMONE, AIPTASIA PALLIDA (VERRILL)

¹ Department of Biological Sciences, State University of New York at Buffalo, Buffalo, New York, 14260

Oxygen production was measured in the anemone Aiptasia pallida (Verrill) maintained at varying feeding regimes in the laboratory. Host feeding regime had no significant effect on: (1) zooxanthellal gross photosynthesis (GPP_max) expressed as µg O₂ · µg chl a^-1 · h^-1 or µg O₂ · 10⁶ zooxanthellae^-1 · h^-1; (2) the light intensity at which GPP_max occurs (K_m); or (3) the chlorophyll a content of the zooxanthellae. Starvation significantly reduced GPP_max expressed as µg O₂ · mg host protein^-1 · h^-1 and zooxanthellal density within the host. Zooxanthellal translocation efficiency was measured by short term incubations of anemones in NaH¹⁴CO₃. Host feeding regime had no effect on the percentage of ¹⁴C translocated to the host.

These results suggest that, under these conditions, starvation did not alter the photosynthetic capability of the zooxanthellae but decreased total photosynthate translocated to the host by decreasing zooxanthellal density within the host.