A change in water levels, flow and increasing amounts of algae are among the reasons parts of the Mekong river recently changed from brown to blue-green, according to the Mekong River Commission.
In a press release, it said the phenomenon is apparent in parts of the river in Thailand and Laos and it could create problems for people who depend on the river.
“Fine sediments normally found in fast-flowing and deep waters that give the water brownish colour have dropped out, creating clearer water conditions,” the MRC said. “Clearer water allows microscopic plants or algae to grow on…the river’s bottom causing margins of the river to turn green.”
It said MRC experts warned people to avoid dispensing fertiliser into the river because it will allow the algae to continue to grow and make conditions worse.
“Some of the potential impacts include changes in productivity of the river with less food available for insects and small fish,” the MRC said. “It will reduce the productivity of biodiversity, including fish, due to high water clarity.”
“This will affect fish catches and the livelihoods of local communities living along the Mekong river,” it added.
The MRC noted the change of colour will continue until the next rainy season in May unless dams located upriver discharge stored water.
So Nam, chief environment management officer with the MRC secretariat, said the change in colour will likely spread to other parts of the river with low flows of water.
“It is unlikely such conditions will occur in the main river…but people should be careful when giving a drink of water to their animals when the water is very green,” Mr Nam said.
Chan Youttha, spokesman for the Water Resources Ministry, said low water levels will affect fish spawn and their sources of food.
Mr Youttha said the Mekong river in Cambodia is not yet at risk, but the authorities will continue to monitor the situation.
“We are continuously monitoring the situation and working with the MRC,” he said.
- Tags: Mekong River