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For New Coral Reefs, Local Rock is Best

DUBAI - Scientists working off Dubai’s coast have found marine breakwaters composed of a locally available rock provide the best potential habitat for establishing new coral reefs.

More coral grew on gabbro, the rock mined in the UAE and used in breakwaters surrounding offshore developments, than on three other materials tested in the year-long study published in this month’s issue of the Journal of Experimental Marine Biology.

But while the gabbro may work better than the sandstone, concrete and granite, manmade reefs play host to a different set of species than
natural ones.

“The species of corals and fish that exist on these mature breakwaters are typically the same species that live on natural reefs in the area, but they differ in relative abundance,” said John Burt, a scientist at Zayed University’s Department of Natural Science and Public Health. “For example, older breakwaters are typically dominated by brain corals, while table corals are much more common on natural reefs.”

In unpublished data, Burt found the mature breakwaters at Jebel Ali Port and Dubai Dry Docks are 40 per cent covered by coral, versus 35 per cent on the natural reefs.

The recent study shows three times the number of sea sponges on the small patches of natural reef sitting in the shadow of the Dubai Waterfront. Burt also said the breakwaters host more large fish – known as pelagic fish – than the natural ones.

Breakwaters off Dubai’s shores are constructed both by Dubai Municipality to protect public beaches and by property companies protecting their offshore developments.

Offshore development has changed the seabed, but Burt said that the breakwaters give coral larvae a place to settle. “There must be something hard for them to settle on. In Dubai the vast majority of the seascape is dominated by sand and by silt,” Burt said.

The researchers attached sandstone, gabbro, granite and concrete tiles to the existing manmade reefs at Jebel Ali Port and Dubai Dry Docks and to

Dr Peter Sale, one of the paper’s authors and assistant director of International Network on Water, Environment and Health at United Nations University said developers can use the information to choose different materials. Nakheel, the property developer responsible for the world and palm developments, works with UNU to study the effects

“Apart from ensuring lack of toxicity, prior choices of materials for building breakwaters have seldom, if ever, considered this effect,” Sale said. The report acknowledged development pressures on coastal areas, noting that the majority of the world lives within 100 kilometres of a coastline, putting pressure on marine resources and increasing the likelihood that more breakwaters will be built.


emily@khaleejtimes.com

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