Fig. 1: Schematic hypothetical illustration of phototrophic bacteria and their potential role in the coral holobiont.
From: Phototrophic bacteria as potential probiotics for corals
Phototrophic bacteria have been recovered from coral mucus and skeleton samples, although it also seems to be associated with coral tissue samples. Phototrohphic bacteria contain bacterial chlorophyll and carotenoids. These bacteria fix carbon, to produce organic carbon which can potentially support the host’s diet during and after bleaching-induced starvation periods. However, their contribution to corals’ energy budget and mechanisms of nutrient transfer remains unclear. Additionally, many phototrophic bacteria produce large amounts of carotenoids that could act as antioxidants, scavenging excess reactive oxygen species (ROS) during stressful conditions. These bacteria belong to different taxa and therefore may have varying potential capacities for carbon fixation and antioxidant production.
