Living Inside a Jellyfish: The Symbiosis Case Study of Host-Specialized Dinoflagellates, “Zooxanthellae”, and the Scyphozoan Cotylorhiza tuberculata

The photosymbiosis with host-specific dinoflagellates is a widespread relationship in marine organisms. Despite the evidenced biodiversity of this kind mutualism, most research focuses on study scleractinian corals, and there lack knowledge about other symbiotic cnidarians such as jellyfishes. Mediterranean jellyfish Cotylorhiza tuberculata (Rhizostomae, Scyphozoa) harbors an endosymbiotic dinoflagellate family Symbiodiniaceae. In study, we examine algae distribution within host body well as, pigment content cell density symbiont. Furthermore, size, morphology fluorescence cultured symbionts were studied under light microscopy, Imaging Flow Cytometry (IFC), Scanning Electron Microscopy (SEM). C:N composition optical properties medusa tissue measured to evaluate their role symbiosis. medusae was divided into two different sections investigate hospite : oral arms (OA) umbrella (UM). C. symbiont significantly higher OA section. Mean chlorophyll concentration 1.33 (± 0.83) pg Chl –1 . by HPLC (High Performance Liquid Chromatography), revealed presence 13 pigments, being representative , c 2 peridinin typical pigments Cell diameter freshly isolated from 8.71 ± 0.97 ?m growth rate 0.52 0.09) 10 6 ml d vegetative coccoid cells, doublet motile mastigotes Symbiodiniaceae cultures. A calcifying matrix formed partner bacteria, also observed absorbed at ultraviolet radiation (UVR) region, suggesting that protects photosymbionts negative effect high energetic UVR attenuates intensity reaching inside host. dense population protection elevated environmental irradiance provided tissue, maintain optimal conditions for photosynthesis may be reason added explain success