A Trio of Ethiopian Lakes
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- ethiopianlakes_oli_2022088_lrg.jpg (7581x7741, JPEG)
Metadata
- Sensor(s):
- Landsat 8 - OLI
- Data Date: March 29, 2022
- Visualization Date: October 6, 2022
Tens of thousands of years ago, an inland sea connected the three Ethiopian lakes visible in this image. That large body of water—Lake Galla—began to contract about 10,000 years ago, a victim of changing rainfall patterns and tectonic motion that pushed the landscape upward and diverted key rivers that supplied it with water.
About 2,000 years ago, Lake Galla had declined so much that it became three separate bodies of water: Lake Shala, Lake Abijata, and Lake Langano. On March 29, 2022, the Operational Land Imager (OLI) on Landsat 8 captured this natural-color image of the lakes. 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 flamingoes.
Lake Langano, a freshwater lake fed mostly by streams to the east, stands out for its brown water. The incoming water is often rich with red-brown sediment from nearby mountains. It has become a popular destination for beachgoers, partly because its waters are free of parasitic worms that can cause schistosomiasis, a sometimes-fatal disease spread by freshwater snails.
Lake Abijata is the shallowest and most variable of the three, with a maximum depth of 14 meters (46 feet). The green color of the water is likely due to the presence of phytoplankton. Satellite observations from the Landsat program show the lake has shrunk significantly in recent decades, with some research indicating it has lost more than one-third of its area since the 1970s. Increased water usage by a soda ash factory on the lake, and increased evaporation due to land use and land cover changes around the lake are potential causes for the changes, according to the researchers.
References
- Hailu, B. & Grima, S. (2019) Spatio Temporal Lake Level Change of Lake Abijata, Ethiopia: A Remote Sensing Approach. Environmental Analysis & Ecology Studies, 6 (1).
- Kedirkan, N. (2019) Water Surface Changes of Lakes in the Central Rift Valley of Ethiopia. International Journal of Environment and Geoinformatics 6 (3), 264-267.
- Lanzen, A. et al. (2013) Surprising Prokaryotic and Eukaryotic Diversity, Community Structure and Biogeography of Ethiopian Soda Lakes. PLoS ONE 8 (8), e72577.
- Medium (2016, December 8) The Funky Flamingos of Ethiopia. Accessed October 6, 2022.
- Tekla, M. & Dalle, G. (2020) Impacts of ecosystem degradation on Lake Abijata, vegetation and herbaceous biomass in and surrounding Abijata Shalla National Park. Ethiopian Journal of Biological Science, 19 (1).
- Treehugger (2021, July 16) 12 Amazing Soda Lakes Around the World. Accessed October 6, 2022.
- Wagaw, S. et al. (2019) Review of anthropogenic threats and biodiversity assessment of an Ethiopian soda lake, Lake Abijata. African Journal of Aquatic Science, 2 (44).
NASA Earth Observatory image by Joshua Stevens, using Landsat data from the U.S. Geological Survey. Story by Adam Voiland.
This image record originally appeared on the Earth Observatory. Click here to view the full, original record.