2023-09-25 00:27:27
Scientists are concerned about the Red Sea’s famous coral reefs after discovering that a mysterious illness is decimating a population of sea urchins essential to their survival. No explanation has yet been found.
Researcher Lisa-Maria Schmidt and her colleagues from Tel Aviv University began their investigation in January, when they learned that off the coast of Eilat, many sea urchins had died in a very short time.
The scientists, says Ms. Schmidt, went to a site known to be teeming with Diadema setosum and they only found ‘skeletons and piles of thorns’ of these diadem sea urchins, a species characterized by its very long radioles. and a clearly visible orange circle on a black body.
They thought that a one-time chemical spill or an episode of pollution could have played a role in the deaths. But in the two weeks that followed, the Diadema setosum a little further down the coast at the inter-university institute for marine sciences were affected in turn. In less than 48 hours, all these sea urchins installed in tanks fed by water from the Red Sea became extinct.
‘Scary’
Scientists have also realized that another species of sea urchin (Echinothrix calamaris) is also the victim of massive mortality in the same waters, but that apart from these two varieties, other populations continue to flourish among the corals.
Schmidt said Diadema setosum was the most common sea urchin species off the coast of Eilat and its disappearance could have a devastating effect on the environment, as these marine animals feed on rapidly growing algae. By consuming them, they prevent them from covering the corals, which need access to light to grow.
Algae ‘grow more easily than corals, they suffocate them and thus kill entire areas of reefs,’ she explains. The massive mortality of sea urchins is ‘particularly frightening’ for the Red Sea where the corals ‘are known to be robust and I think people have placed a lot of hope in these reefs’, warns Mya Breitbart, biologist at the University of South Florida, USA.
If they only extend under 0.2% of the sea surface, coral reefs would shelter more than 25% of the world’s marine biodiversity.
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