39 Aiming high

Just like a gigantic fan, a one and a half metres high stony coral of the genus Acropora dominates the reef at Raja Ampat (Indonesia). Thousands of polyps built this marvellous structure. Some Acropora species grow about 25 centimetres per year and literally overshadow their neighbours with ease. Since tropical corals can only survive as long as symbiotic algae in their branches catch enough light for their photosynthesis, Acropora’s rapid progress might reduce the reef biodiversity.

However, it was revealed that the dominant genus is sensitive to rising water temperatures and sedimentation. Elevated carbon dioxide concentrations might impair reproduction, development of larvae and growth at early life stages of certain Acropora species.

Photo: Solvin Zankl