Today’s Image of the Day from NASA Earth Observatory features three Ethiopian lakes – Shala, Abijata, and Langano – which were once all connected by a large inland sea called Lake Galla. Around 10,000 years ago, Galla began to shrink when tectonic movement diverted key rivers that supplied it with water.
By 2,000 years ago, Lake Galla had declined so much that it became three separate bodies of water, explained NASA. “Despite their shared origin, the lakes have evolved separately and now have different appearances and water chemistries.”
“Lake Shala, the largest and deepest of the three, fills an expansive volcanic caldera that collapsed 3.5 million years ago. With several hot springs and fumaroles near it, the lake’s waters are known for being unusually warm, saline, and rich in phosphate. It is classified as a soda lake because the water is strongly alkaline, meaning it has a high pH.”
“Like many other soda lakes, Shala is biologically productive despite the extreme water conditions. It supports an array of life ranging from an abundance of microorganisms to small crustaceans to vast flocks of flamingos.”
Lake Langano, which appears brown in the photo, is a freshwater lake that is mainly supplied with water from nearby streams. This water carries reddish brown sediment from the mountains.
The most shallow of the three Ethiopian lakes is Lake Abijata, with a maximum depth of 46 feet. According to NASA, the green color of the water is likely due to the presence of phytoplankton.
The image was captured on March 29, 2022 by the Operational Land Imager (OLI) on Landsat 8.
Image Credit: NASA Earth Observatory