The formidable mountain system of the Alps stretches across much of central Europe, with seven countries claiming portions of the mountains within their borders: Germany, France, Switzerland, Italy, Liechtenstein, Austria, and Slovenia. The glacial landscape of the Bernese Alps, located in southwestern Switzerland, is well illustrated by this astronaut photograph. An astronaut took this picture by looking north-northwest while the International Space Station was over the Mediterranean Sea between Corsica and Italy. This oblique viewing angle imparts a sense of perspective to the image. This type of viewing angle complements nadir,or downward-viewing, imagery of the region. Three of the higher peaks of the central Alps are visible: Jungfrau at 4,158 meters (13,642 feet); Moench at 4,089 meters (13,415 feet); and Eiger at 3,970 meters (13,025 feet).
To the east and south of the Jungfrau is the Aletsch Glacier, clearly marked by dark medial moraines extending along the glacier’s length parallel to the valley axis. The medial moraines are formed from rock and soil debris collected along the sides of three mountain glaciers located near the Jungfrau and Moench peaks. As these flowing ice masses merge to form the Aletsch Glacier, the debris accumulates in the middle of the glacier and is carried along the flow direction. Lake Brienz to the northwest results from the actions of both glacial ice and the flowing waters of the Aare and Lütschine rivers, and has a maximum depth of 261 meters (856 feet). The lake has a particularly fragile ecosystem, as demonstrated by the almost total collapse of the whitefish population in 1999. Possible causes for the collapse include increased water turbidity associated with upstream hydropower plant operations, and reduction of phosphorus—a key nutrient for lake algae, and a basic element of the local food web—due to water quality changes.