This photograph, taken by an astronaut onboard the International Space Station (ISS), shows the only atoll in the South Atlantic Ocean. Rocas Atoll is part of the Fernando de Noronha archipelago, located approximately 260 kilometers (160 miles) off the northeastern coast of Brazil. This image clearly captures the defining boundary between the outer algal ridge, the open ocean, and the sandy bottom closer to the atoll’s center.
An atoll is usually a circular or oval-shaped reef structure with a lagoon in the center. These structures typically form around a volcanic island that has subsided while the coral continues to grow upward. These reef structures are self-contained environments that create ideal conditions for a diverse habitat. Coral reefs are considered among the most diverse ecosystems in the world.
In 1978, Rocas Atoll was named a national biological reserve due to the large populations of migratory and resident seabirds. As the first marine reserve to be established in Brazil, it is the strictest type of protected area, specifically focused on the conservation of biodiversity such that no recreational activity or resource exploitation is permitted.
Astronaut photograph ISS061-E-52673 was acquired on November 21, 2019, with a Nikon D5 digital camera using a 500 millimeter lens and 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 61 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 Laura Phoebus, Jacobs Technology, JETS Contract at NASA-JSC.