This photograph, taken by an astronaut from the International Space Station (ISS), captures the estuarine ecosystem of the Loza Bay wetlands in northwest Madagascar. Estuaries are coastal habitats where fresh water from rivers—in this case, the Ankofia and Maevarano—mixes with salt water from the ocean in partially enclosed basins.
Rivers carry oxidized sediment loads down from Madagascar’s high central plateau toward the Mozambique Channel (not pictured). This reddish-brown sediment-laden freshwater mixes with the clearer, blue saltwater that sloshes in and out of the estuary from the sea with the movement of the tides.
Mangrove forests are common around Madagascar’s major estuaries as the brackish waters create the environmental conditions in which the trees thrive. Mangrove forests play a vital role in sustaining coastal communities—not only as resources for agriculture and aquaculture, but as sources for fuelwood, charcoal production, and timber. However, the unsustainable harvesting of these mangroves and other local vegetation and wildlife threatens the biodiversity of coastal Madagascar.
Astronaut photograph ISS064-E-14839 was acquired on December 19, 2020, with a Nikon D5 digital camera using a focal length of 400 millimeters. It is provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit, Johnson Space Center. The image was taken by a member of the Expedition 64 crew. The image has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by Amber Turner, Jacobs, JETS Contract at NASA-JSC.