Differential localization of ion transporters suggests distinct cellular mechanisms for calcification and photosynthesis between two coral species.

Ion transport is fundamental for multiple physiological processes, including but not limited to pH regulation, calcification, and photosynthesis. Here, we investigated ion-transporting processes in tissues from the corals Acropora yongei and Stylophora pistillata, representatives of the complex and robust clades that diverged over 250 million years ago. Antibodies against complex IV revealed that mitochondria, an essential source of ATP for energetically costly ion transporters, were abundant throughout the tissues of A.

Coral host cells acidify symbiotic algal microenvironment to promote photosynthesis.

Symbiotic dinoflagellate algae residing inside coral tissues supply the host with the majority of their energy requirements through the translocation of photosynthetically fixed carbon. The algae, in turn, rely on the host for the supply of inorganic carbon. Carbon must be concentrated as CO2 in order for photosynthesis to proceed, and here we show that the coral host plays an active role in this process.