Abu Dhabi: A deep underwater sinkhole that acts as a hotspot for marine biodiversity – a blue hole – has recently been discovered in the waters of Al Dhafra region.
The emirate’s environment sector regulator, the Environment Agency Abu Dhabi (EAD), said the rare marine phenomenon had been discovered recently during one of its surveys. Measuring 300 metres long and 200 metres wide, the Al Dhafra blue hole encompasses a total area of 45,000 square metres.
“Preliminary analysis of the seabed area forming the centre of the Al Dhafra Blue Hole, indicates a depressed, semi-circular area roughly around 5,000 square metres. The semi-circular area topography is flat with a maximum depth of 12 metres, and has a bottom composition combination of silt and sand,” the EAD added.
This unique marine habitat holds at least 10 types of coral species, which form a reef at the edges of the hole. It is also home to many fish communities, and provides shelter for a variety of fish, including the grouper (hammour), sweetlips (farsh), emperor fish (shaari) and jackfish.
“This rare blue hole is significantly important, as it provides a glimpse of how historic reefs used to look like in Abu Dhabi,” the EAD said.
In order to enhance the understanding of the localised marine ecosystem and its geological composition, an environmental assessment survey will therefore be conducted.
“Assessment of its environmental parameters – including geological mapping of the area, seawater chemical parameter analysis, and physical composition of the seabed - will facilitate an informed characterisation of the blue hole. In addition, to better determine health of the existing coral reef community and assess localised ecosystem health, EAD will continue to conduct scientific and topographic surveys to further understand this unique natural phenomenon,” it added.
Blue holes are naturally occurring massive underwater sinkholes – an area of deep marine depression compared to the shallow areas that surround it. The deepest blue hole, The Yongle, lies in the South China sea, and reaches300 meters. Other internationally famous blue holes include the Great Blue Hole in Belize, Gozo’s Blue Hole in Malta, the Blue Hole at Dabahb in Egypt and Dean’s Blue Hole in the Bahamas.
While these unique structures fascinate marine researchers, they also attract divers from all over the world. Home to fringing reefs and diverse fish species, they host diverse microbial communities at their depths.