Blue Mekong

Remember the blue Mekong last year? It’s back!

This bright color, very different from the usual brown appearance of the river, is the result of very low water levels. Shallow conditions may be allowing more sunlight to the riverbed, enabling the growth of blue-green algae. The shallow conditions and slower-moving current may also be allowing fine sediment to settle to the bottom, making the water clearer.

Thanks to Thee Weerakham for sharing his photos with us from Nakhon Phanom, Thailand. These were taken on 22 November 2020, around the same time that we began seeing this new blue color last year.

You can read more of the scientific explanation for the color change on the US Government's NASA site here.