The estuary system marks the transition between the Great Altar Desert in northwestern Mexico and the Gulf of California.
The wetlands of Adair Bay (also known as Bahia Adair) mark the transition between the Great Altar Desert in northwestern Mexico and the Gulf of California. A single highway, paralleled by a railroad, cuts across dry salt flats and sand on the northern reaches of the estuary. This photograph, taken by an astronaut on the International Space Station (ISS), also highlights the sediment-rich waterways that allow the mixing of freshwater and saltwater vital to the function of the estuary.
The green areas in the estuary system are salt-tolerant halophytic vegetation, comprised mostly of mangrove trees and shrubs. Salty mudflats, indicated by the blend of gray and white hues, separate the estuary from the adjacent desert sand. Pozos (Spanish for wells), a form of natural freshwater springs, are located throughout the salty mudflats and are common in wetlands along the Gulf of California, though difficult to see from space.
Coastal salt marshes like the wetlands of Adair Bay are sustained by tides. During low tides, water evaporates from exposed soils, creating salt flats; during high tides, nutrients are washed into the estuary, supporting halophytic vegetation growth and the life cycle of aquatic organisms. The wetlands of Adair Bay are a Ramsar site and provide protected nesting grounds for migratory birds, as well as breeding grounds for endangered fish, such as the totoaba.
Astronaut photograph ISS067-E-213849 was acquired on August 1, 2022, with a Nikon D5 digital camera using a focal length of 1150 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 67 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. Caption by Sara Schmidt, GeoControl Systems, JETS Contract at NASA-JSC.