Over the past week the waters around Dibba and Fujairah have turned from reddish-brown to mostly blue again and the sea breezes no longer waft in the odd smell from the algal bloom known as red tide. But below the surface things may take a while longer to return to normal.
Though a few patches of the bloom persist, it appears the algae are finally dying off and the clear waters have allowed divers to start exploring the extent of damage done by the red tide to the East Coast's coral reefs, an essential part of the area's ecosystem. "The East Coast is now clear but the tide is still near Umm al Qaiwain, Ajman and Dubai," said Dr Ibrahim al Jamali, director of the Marine Resource Research Centre in Umm al Qaiwain and one of the Ministry of Environment and Water officials involved in monitoring the phenomenon.
Staff from the ministry have begun to make exploratory dives to assess the tide's impact on coral reefs. Signs of coral bleaching, a process indicating the reefs are dying, were reported at the end of last year. Some sites were seriously affected while others were spared severe damage. The ministry is still assessing the full extent of the problem, said Dr al Jamali. Though he said there was no guarantee the red tide, which is the result of complex interplay between natural and man-made factors, would not return, the improved water conditions already brought more customers and much-needed hope to dive centres in the area, which have been affected since the algal bloom was first appeared last August.
"I can see the changes already," said Christophe Chellapermal, owner of Nomad Ocean Adventures, who saw his business drop by half since October. "It has picked up. I was at a point where I was thinking to close doors." "For the past six days, it is very nice," said Jeffrey Catanja, a diving instructor who organises trips from the Sandy Beach Hotel and Resort in Fujairah. "The smell is also gone."
Mario Tapales, a course director with Al Boom Diving, which has a branch at the Le Meridien Al Aqah Beach Resort in Fujairah, did not see any reddish patches of water. "We hope it will stay this way," he said. However, Mr Chellapermal has reported seeing damage to coral reefs at several sites. Branching corals, such as Acropora pharaonis - the most common species in the protected marine area known as Dibba Rock, were particularly badly hit, he said. Most have lost their vibrant reddish colour, turning white and crumbling.
"All reefs of Acropora got severely affected. They are bleaching and falling apart." The damage is believed to be the result of the algal bloom blocking off sunlight and reducing the amount of dissolved oxygen in the water. Mr Chellapermal said that out of 35 sites that he used to visit, six have been so severely affected that he has had to stop taking customers there. One of the most damaged reefs is in a small bay in the Musandam peninsula, some 25 kilometres away from Dibba. Although the area is in Oman's territorial waters, it is representative of the damage witnessed on reefs on the UAE side.
"Before it was bursting with life, now it is like a cemetery, there is nothing," he said. "It will be interesting to see how nature will take over and react to the damage." Corals grow very slowly, sometimes just one centimetre a year. Other factors, such as high salinity, turbidity and temperature of the water, can impair growth. "It will take time, it is not easy," said Dr al Jamali. Besides damaging reefs, the red tide also killed thousands of fish and other sea creatures.
In March, the Ministry of Environment and Water reported that 300 tonnes of dead fish had washed ashore. This is in addition to losses at an aquaculture company, Asmak, which lost 600 tonnes of fish. The Emirates Diving Association (EDA) also surveyed some of the key sites in UAE waters. Two sites, known as Shark Island and Martini Rock, were deemed the healthiest, with the biggest diversity of fish.
"The number of coral families wasn't the highest, but the coral cover area was higher in these two dive sites compared with the poor coral cover from other areas," the association said in a statement. Although less diverse in terms of fish, coral and invertebrates, Dibba Rock boasted the highest number of fish. Earlier this week, the Ministry of Environment and Water released an undisclosed number of fish raised in captivity off the coast of Umm al Qaiwain and Ras al Khaimah. The fish releases are part of an ongoing ministry campaign to address areas affected by the tide, said Dr al Jamali.
The ministry might in future plant live coral in some of the affected locations, he said. Last month, the renowned Woods Hole Oceanographic Institution in the US submitted a proposal to help the UAE create an algal bloom monitoring and management programme. The proposal is currently being discussed by the Government. Although not much can be done to contain a bloom once it has formed, a monitoring programme is expected to help officials to react more quickly and eventually even predict the arrival of blooms.
It will also help scientists identify the links between the various man-made and natural contributing factors. The red tide off the East Coast was partially driven by two species of microscopic algae, believed to have been brought to the area by ships discharging their ballast water at sea. For the first few months, Gymnodinium catenatum, a toxic microorganism which can cause paralytic shellfish poisoning, was the main catalyst. A few months later it was Cochlodinium polykrikoides.
Nutrients such as phosphorus and nitrates encourage algae to grow and end up in the ocean through effluent from sewage treatment plants and through wind, which carries particles into the sea. Rains also contribute by washing off fertilised gardens, car parks and other polluted surfaces. Confined spaces, where breakwaters slow down water circulation, also create favourable conditions for blooms. The coastlines of Dubai, Fujairah and Dibba have all been affected by large development drives, with new ports, marinas and leisure or residential developments.