In shallow water, less than 30 meters, the survival of hard corals depends on photosynthetic unicellular algae (zooxanthellae) living in their tissues. But how does the coral adapt at depth when the light disappears? French researchers from the CNRS, EPHE-PSL and their international collaborators, associated with Under the Pole (Expedition III), have studied for the first time the distribution of these so-called mesophotic corals in the French Polynesian archipelago, from the surface to 120 meters deep (with a record descent of 172 meters).
Click here for original story, Record breaking observations at a depth of 172 metres shed light on how hard coral survives without light
Source: Phys.org