Reports of coral reefs in recent years have mostly been dominated by coral bleaching: the devastating bleaching of corals by overheated water, which can lead to the death of the animals and the destruction of the ecosystem if prolonged duration. All the more beautiful is therefore a report from the South Seas, where a diving expedition has discovered an extensive and above all untouched coral reef off Tahiti at a relatively great depth, as reported by UNESCO. It lies between 35 and 70 meters deep, extends over at least three kilometers in length and is up to 70 meters wide. This makes it one of the largest coral reefs ever discovered at this depth.
As Laetitia Hédouin from the French National Center for Science and her team found out, the reef mainly consists of the two types of Porites Rus, which dominates between 30 and 45 meters, and Pachyseris Speciosa, which determines the community from 50 to 55 meters. Some of the rose -shaped corals reach diameter up to two meters. “It was magical to see huge, beautiful rose coral that expand so far as far as the eye can see. It was like a work of art, «says photographer Alexis Rosenfeld, who is involved in the expedition. The reef lies in the so -called twilight zone, while the typical coral reefs grow up to a depth of 25 meters.
However, this section of the seas has hardly been systematically studied so far, which is why there could be other large reefs in many warmer regions. The deeper water layers may also have protected the corals from bleaching. French Polynesia, for example, only experienced severe coral bleaching in the higher water layers in 2019, but it did not reach the newly found reef. Given the continued warming of the oceans, the twilight zones could become retreats for at least some of the reef inhabitants. However, it is still scientifically unclear what tricks the algae symbionts of the corals have in store in order to be able to carry out sufficient photosynthesis in view of the dim light. This should be one of the research goals of future expeditions.
