Coastline development, including construction in the sea, is one major cause of loss of natural reefs
Bonnie James Gulf Times 31 Dec 10;
High sea temperatures are causing the death of stony corals in Qatar, a noted Qatari environmental and marine researcher has said.
Though the optimum growth temperature for corals is between 20C and 23C, in June this year a sea temperature of 37.8C was recorded, Dr Mohsen Abdulla al-Ansi, the director of Qatar University’s Environmental Studies Centre, said.
The high temperature caused coral bleaching in reefs at Halul Island, Ras Rakan, Khereis, Um Alushran and Sherahou as well as the death of some fish.
Dr al-Ansi, who heads one of the oldest research centres in the Gulf region, presented a study about the status of corals at the Qatar Foundation Annual Research Forum held earlier this month.
Stony corals are composed of limestone structures formed by the deposits of living organisms. These are tiny animals (polyps) that live in a symbiotic relation with algae.
The algae produce the food energy needed by the polyps by photosynthesis. The coral is as such a colony. Numerous colonies on shallow waters, where sunrays can reach them, form a coral reef.
“Coral reefs can be extensive, such as the Great Barrier Reef, or can form localised reefs as in Qatar,” the researcher said.
Coral reefs support a third of the Gulf’s fish populations and local economies. Qatar has less than 20 species of stony coral and these are localised in only a few areas.
Coral reefs harbour numerous organisms including sponges, crabs, sea urchins, brittle stars and fish, and exist where environmental conditions are optimal for their flourishing, such as Southeast Asia, with Malaysia considered one of the best areas with 350 coral species known to occur.
Given that sea urchins and some fish are ferocious feeders on coral, they may cause the death and bleaching of stony corals through extensive feeding.
Climate change, in particular high sea temperature, can destroy coral reefs, and excessive rains with fresh water seeping to intertidal coral reefs will also cause coral bleaching.
“Coastline development, including construction in the sea, is one major cause of loss of natural reefs,” Dr al-Ansi said.
Aggressive fishing whether by harpoons or metal traps that are later left behind, destroy the reef.
“Bleaching of corals did also happen in Qatar and the rest of the Gulf in 1989 and 2002 when sea temperature rose,” he said.
The oil spills from the second Gulf War was another cause of coral bleaching in the regional waters.
Desalination plants, necessary for supplying fresh water to the countries along the Gulf coast, are also a threat to corals.
These plants spew hot brine and chemicals into the sea, warming their surrounding waters and increasing salinity.
A recent forum on marine conservation held in Abu Dhabi had come to the conclusion that the coral reefs of the Arabian Gulf have in large part been ruined and part of the damage is irreversible.
An international scientific study has revealed that 20% of the world’s reefs are damaged beyond repair.
It was pointed out at the Abu Dhabi forum that the main causes of the deterioration of coral reefs include the sharp drive for development, especially the construction of artificial islands and large ports, as well as the building of desalination plants and sewer dumped into the water.
The most heavily damaged areas are those along the coasts of Qatar, Bahrain and the United Arab Emirates, especially off Abu Dhabi and Dubai, the Abu Dhabi forum warned.
The coral reefs that are the most intact are instead those in front of the Musandam peninsula in Oman, just off the Strait of Hormuz.
Over the past decade, according to a study by the University of Warwick, fish density has gone from 4,000kg per hectare to less than 1,000kg.
Shrimps, crabs, lobsters and other seafood which account for a large part of the fishing industry live in the coral reefs.
The decline of some are inevitably leading to that of the others and, down the chain, marine fauna.
