Dubinsky Z, Jokiel PL. 1994. Ratio of energy and nutrient fluxes regulates symbiosis between zooxanthellae and corals. Pac Sci 48(3): 313-324.
Full article available.
[Summarizing] the main interactions and feedback mechanisms connecting light intensity, nutrient level, and feeding in zooxanthellate corals:
- Under constant nutrient concentration, light intensity determines the onset of nutrient limitation; as light increases, C : N ratios exceed Redfield ratios.
- The availability of other nutrients, mainly nitrogen, determines the fate of photo-assimilated carbon. Under high C: N ratios, most carbon goes into respiration, calcification, and excreted mucus, whereas low C : N ratios favor increases in zooxanthellae density, reduce translocation, and slow down calcification.
- Feeding on zooplankton by the coral under low light provides carbon for metabolism. Under high light it supplies both algae and animal with nitrogen.
Nutrient balance is one of the most important, but seemingly lease understood aspects of aquarium keeping. This statement from the article summarizes it as well as I’ve seen it summarized. I’ve edited only for clarity.
Also from this article:
Nutrients acquired by predation of the coral on zooplankton are available first to the animal, whereas those absorbed by the zooxanthellae from seawater as inorganic compounds lead first to growth of the algae.