Are symbiotic algae nutrient deficient?

Abstract

The evidence for the hypothesis that symbionts in alga−invertebrate associations are nutrient deficient is critically evaluated. It is suggested that the evidence is not consistent with algal symbionts being nutrient deficient, but is consistent with the host regulating its population of symbionts by restricting their supply of nutrients. This distinction is due to the substantial release of photosynthate by symbiotic algae and suggests that there are (at least) two distinct regulatory components involved in the characteristics of nutrient-deficient algal cells.