Green algae, blue water add to fears over health of Southeast Asia’s Mekong

Successful Farming –

When the normally murky brown Mekong River turned a brilliant blue late last year, villagers in northeastern Thailand were surprised.

Then, this week, unusually large patches of green algae appeared, clogging up nets and making it almost impossible to fish.

Both the Mekong’s strange colour and the algae have heightened worries about the health of the river that more than 60 million people in Southeast Asia depend on for their livelihoods.

“This is unnatural,” fisherman Tongchai Kodrak said of the algae and the blue waters, which both signal a lower level of life-bringing sediment in the water.

He says a bit of algae appears every dry season but this year it is more than anyone can remember.

The year 2020 is shaping up to be crucial for the Mekong River, which is under threat from climate change and faces uncertain changes wrought by two new hydropower dams that have come online in Laos in the last three months.

Many fear the new Lao dams – the first on the Lower Mekong that generates most of the vast system’s sediment – will impede the nutrient flow.

Scientists say the Mekong’s new blue colour – first seen in November in northern Thailand and now evident down the river into Cambodia – is caused by shallow, slower moving waters.

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