Effect of irradiance and heterotrophy on the main physiological parameters of C. caespitosa.

(A) Symbiont concentration, (B) chlorophyll concentration per skeletal surface, (C) chlorophyll concentration in symbiont cells, (D) protein content, (E) calcification rate, and (F) C:N ratios for symbionts, coral host, and released POC/PON, for fed and unfed nubbins maintained at low and high irradiances. Data are means ± standard errors of means of n = 12 (A), n = 6 (B to E), n = 23 (F, symbionts and host), or n = 3 (F, POC/PON) measurements. Bars with different letters (a to d) are significantly different.