20 May, 2021
The image shows a fluorescence microscopy close-up of polyps of the cauliflower coral Stylophora pistillata and their dinoflagellate endosymbionts. The coral host exhibits green fluorescence due to natural GFP expression, and the symbiotic Symbiodinium microadriaticum dinoflagellates are visible because of their red fluorescence from excited chlorophyll.