Corals may look healthy, but coastal urbanization is destroying their delicate biorhythm (IMAGE)
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Coral reefs in the Gulf of Eilat (also known as the Gulf of Aqaba) have been proven particularly resistant to global warming, rising water temperatures and bleaching events that are crippling their counterparts elsewhere around the world. But the findings of a long-term study, led by Bar-Ilan University researchers along with an international team of marine and data scientists and published in the journal Global Change Biology, confirm a different threat to this coral refuge in southern Israel: massive urban development near the Gulf coastline is taking a devastating toll on the local marine environment. For an entire year a team led by researchers at Bar-Ilan University in Israel examined how and if urbanization is disrupting natural biorhythms, which are responsible for coral metabolism, coral growth and reproduction cycles, and whether urbanization could be an overlooked contributing factor to global coral decline. Two sites in the Gulf of Eilat, at the northern tip of the Red Sea, were sampled -- one in close vicinity to the city of Eilat, and one further away. Despite the corals' relatively healthy appearance, the researchers discovered that natural biorhythms and environmental sensory systems were extensively disturbed in corals living in proximity to urban Eilat. Diel and lunar cycles related to coral metabolism, predation, microbial functional diversity, and circadian clock functions were disturbed by the urban conditions. Altered seasonality patterns were also observed in the microbiomes of the urban coral population, signifying the impact of urbanization on the holobiont (the entire organism), rather than the coral host alone. By contrast, corals in the non-urban site looked healthy and their biorhythms showed normal cycling over the sampling periods. Photo: Coral reef ecosystem in the Red Sea Gulf of Eilat
Credit
Shachaf Ben Ezra
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