David Attenborough can finally focus, with modern techniques aboard a state of the art oceanographic ship and it submersible, on his first and greatest natural love, the Great Barrier Reef, the largest continuous natural structure on earth. Although recent geological study shows it's linked to an abrupt sea bottom sink dating back millions of years, it evolved in recent millenniums. It's built by polyps collecting calcium carbonate from the sea water to build their colonies, in symbiosis with algae who contribute energy by photosynthesis. The territorial coral colonies of many species differ in color etcetera but also rival with long unsuspected intensity. The reefs they build are the home for the richest marine ecosystems, with countless species including fish, their food and predators, many seeking shelter.
—KGF Vissers