by University of Erlangen-Nuremberg Nov 2020, in ScienceDaily
Coral reefs are hotspots of biodiversity. As they can withstand heavy storms, they offer many species a safe home, and at the same time, they protect densely populated coastal regions as they level out storm-driven waves. However, how can these reefs that are made up of often very fragile coral be so stable? A team of researchers from Friedrich-Alexander Universität Erlangen-Nürnberg (FAU) and the University of Bayreuth have now discovered that a very specific type of ‘cement’ is responsible for this — by forming a hard calcareous skeleton, coralline red algae stabilise the reefs, and have been doing so for at least 150 million years.
The wide variety of life they support is immediately apparent on images of tropical coral reefs. Their three-dimensional scaffolding provides a habitat for a large number of species. However, the skeletons of the coral are often so fragile that they would not be able to withstand heavy storms by themselves. Even if scientists have long suspected that coralline red algae provide support to reefs with their calcareous skeletons, this is the first time that this link has been proven.
Coralline red algae have been supporting coral reefs for at least 150 million years
The researchers from FAU and the University of Bayreuth were able to prove this supporting function by analysing more than 700 fossilised reefs from 150 million years of the Earth’s history. ‘The coralline red algae form a calcareous skeleton and cement the coral reefs together,’ explains Dr. Sebastian Teichert from the Chair of Palaeoenvironmental Research at FAU. ‘However, several crises over the course of millions of years have limited their capacity to do so.’
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