Coral Species

Using a combination of scuba gear and remotely operated vehicles, marine biologists in California selected more than 1,400 corals from the ocean surface. The samples looked identical, and their internal structures were indistinguishable in scanning electron microscope images. Yet their genomes, their full genetic instruction books revealed the corals had diverged millions of years ago. That made sense for one of the species in the Red Sea's Gulf of Aqaba, which was geographically separated from the others. But the other three newly identified species lived together on the same reefs in the waters off South Asia. If the corals were living together, why didn't one overtake the other two, the team wondered? Examining habitat data from their dives, the researchers found the three distinct coral species favored different water depths, with one abundant in the top 10 meters and the other two flourishing deeper down. The three coral species also had different concentrations of photosynthetic algae and pigments, suggesting they had distinct strategies for hosting their algae partners that provide food.