ISS013-E-77377 Click the photo number to access all resolutions available and the database record.
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.
