Effects of feeding frequency and symbiosis with zooxanthellae on nitrogen metabolism and respiration of the coral Astrangia danae

Colonies of the temperate coral A. danae occur naturally with and without zooxanthellae. Basal nitrogen excretion rates of nonsymbiotic colonies increased with increasing feeding frequency. There were no significant differences between respiration rates of symbiotic and nonsymbiotic colonies. N excretion and respiration rates of fed colonies increased greatly soon after feeding. N absorption efficiencies decreased with increasing feeding frequency.