Earth Observations taken by the Expedition 17 Crew

ISS017-E-013769 (19 Aug. 2008) --- Tunis, Tunisia is featured in this image photographed by an Expedition 17 crewmember on the International Space Station. The city of Tunis, capital of Tunisia, is a rapidly modernizing city located along the Mediterranean coast of northern Africa. Sharing much of its history with famous Carthage to the north, Tunis was also destroyed by Rome in approximately 146 BC. Tunis, however, was rebuilt by the Romans and became an important agricultural center. Modern Tunis serves as the administrative center for the whole of Tunisia, and as a commercial hub for trade in the northern part of the country. The urban area of Tunis is located on a flat coastal plain, and is distinguished in this view from the surrounding desert by the pattern of grey to tan buildings and darker street grid. The city is bordered by an evaporating saline lake to the northeast known as Sebkhet Arina (upper left) -- evaporite minerals such as halite (table salt) and gypsum produce the white deposits surrounding the darker lake center where there is more moisture. To the southeast of the city is Lake Tunis, a lagoon that has been significantly altered by human activities -- such as closing off water exchange with the Mediterranean Sea - dating back to Roman times. The general lack of water circulation and input of nutrients from sewage has lead to the establishment of marine worm reefs, and occasional fish kills. The western urban-rural fringe is defined by a range of low hills (lower left); dark green agricultural fields are visible on the western side of these hills.