Alarming study

Coral reefs in the Red Sea are growing less and less

Coral reefs in the Red Sea are growing more and more slowly, according to a study. In a reef area off the coast of Sudan, growth has decreased by around 80 percent over the past four decades, said marine biologist Sarah Abdelhamid from the University of Rostock, lead author of the study.

Since 1980, researchers at the German Oceanographic Museum have been monitoring the development of four large test areas in the Sanganeb Marine National Park off the coast of Sudan. The coral reefs there were still among the most untouched in the Red Sea, according to the study. The areas were last digitally mapped in 2019.

 "Surprisingly significant" decline, according to the researcher.
"While the net reef growth from 1980 to 1991 averaged between 2.27 and 2.72 centimetres per year, it was only 0.28 to 0.42 centimetres in the period from 1991 to 2019," said Abdelhamid. The decline is therefore "surprisingly significant".

According to the researchers, ecological conditions in the area have generally remained stable for over 40 years, for example in terms of currents and chemical processes. However, shifts in the species composition indicate a change in the coral communities, which can be attributed to coral bleaching as a result of warm water events, among other things.

 More resistant species on the advance
The offspring of sensitive staghorn corals (Acropora) are being displaced by more robust cat's paw corals (Pocillopora), according to the Marine Museum and the university. "As a result of climate change, warm water events that lead to coral bleaching are becoming more frequent," explained Götz-Bodo Reinicke from the German Oceanographic Museum, head of the study. "Reef communities therefore have less and less time to regenerate." More resistant species then establish themselves more successfully