Scientists rediscover active coral communities in reef system presumed dead for decades

Scientists have discovered thriving coral communities in a reef system off the coast of Benin, West Africa, that was presumed dead for decades. The finding, reported by researchers using underwater drones, reveals that the reefs are teeming with life in the ocean's 'twilight zone'—a dimly lit layer between 60 and 150 meters deep where sunlight barely penetrates. The discovery was made during a survey of the region's marine ecosystems, which had been largely unexplored due to the area's strong currents and murky waters.

The reefs were long believed to have been destroyed by coastal development, pollution, and overfishing, with no signs of active coral growth for about 60 years. However, the underwater drones captured images of healthy coral communities, including branching and plate corals, as well as a variety of fish and other marine life. The findings were published in a study in the journal Frontiers, and the research was conducted by scientists from the University of Ghana and other institutions.

This discovery matters because it challenges assumptions about the resilience of coral reefs in the face of human pressures. The 'twilight zone' reefs may serve as refuges for species that have declined in shallower waters, offering a potential source of larvae to help repopulate damaged areas. The study also highlights the value of using advanced technology like underwater drones to explore deep, inaccessible habitats that may harbor overlooked biodiversity.

According to the source, the research team deployed autonomous underwater vehicles to map and film the reefs off Benin. The drones revealed extensive coral cover and high fish diversity, including species not previously recorded in the region. The scientists noted that the reefs are located in an area with strong upwelling, which brings nutrient-rich cold water to the surface, possibly supporting the unexpected coral growth.

The findings suggest that similar 'hidden' reef ecosystems may exist elsewhere along the West African coast. The researchers plan to conduct further surveys to assess the extent of these communities and to develop conservation strategies. They emphasize the need to protect these deep reefs from threats such as bottom trawling and climate change, which could affect even these relatively sheltered habitats.