In vivo measurements of the seasonal photosynthetic fluorescence of the Mediterranean coral Cladocora caespitosa (L.)

摘要: In situ photosynthetic fluorescence of the zooxanthellate Mediterranean coral Cladocora caespitosa (L.) was measured seasonally on colonies from 5 to 27 m depth using an INF-300 Integrating Natural Fluorometer (Biospherical Instrument Inc.). This oceanographic instrument, used measure in vivo phytoplankton chlorophyll a (Chl a) fluorescence, adapted record natural C. by SCUBA divers. The resulting curves Chl vs photosynthetically active radiation (PAR 400-700 nm) showed that: (1) limited light availability both deep and shallow all seasons; (2) photosynthesis occurred also winter, when temperature is low seawater turbidity contributes significantly PAR attenuation; (3) efficiency increased summer winter. last finding outlines winter coupling between zooxanthellae activity calcification processes consistent with formation high density band skeleton.