Alpine lakes
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What are Alpine lakes in Europe?
Alpine lakes are a group of significant European lakes located on the fringes of the Alps. These lakes are set amid magnificent scenery and are the focus of settlement and tourism.
Most Alpine lakes are in valleys formed during the uplift of the Alps. During the Ice Age, glaciers deepened these valleys, leaving moraines (waste material deposits). As the glaciers shrank, water filled the excavations or was dammed by the moraines.
The Alpine watershed divides the lakes into northern and southern groups. The southern group includes Lake Geneva and the Insubrian lakes (Maggiore, Lugano, Como, and Garda), while the northern lakes include Lakes Neuchâtel, Luzern, Zürich, Constance, Chiemsee, and Attersee. Lake Geneva is the largest Alpine lake in Europe.
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Where are most Alpine lakes located in Europe?
Most Alpine lakes are situated along the great mountainous mass of the Alps. These lakes are divided into a northern and a southern group by the Alpine watershed that runs from west to east.
The southern group, found in an Alpine environment, consists of Lake Geneva and the Insubrian lakes, including Lake Maggiore, Lake Lugano, Lake Como, and Lake Garda. The northern lakes, such as Lakes Neuchâtel, Luzern, Zürich, Constance, Chiemsee, and Attersee, are in the Alpine foothills or slightly beyond.
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How are Alpine lakes usually formed?
Alpine lakes, common in the Alps and other high mountain ranges, primarily form through glacial activity. During the Ice Age, glaciers carved out valleys, deepening and excavating the ground. As these glaciers receded, they left behind moraines, which are deposits of waste material.
The depressions and excavations filled with water, or were dammed by moraines, leading to the creation of long, narrow, and deep lakes set amid magnificent scenery. These lakes are divided by the Alpine watershed, with the southern group including Lake Geneva and the Insubrian lakes, while the northern group lies in the Alpine foothills.
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What are some famous Alpine lakes in Europe?
Europe's Alpine lakes, set amid magnificent scenery, attract considerable settlement and tourist traffic. These lakes originated in valleys formed during the uplift of the Alps, deepened by glaciers during the Ice Age.
Some famous Alpine lakes:
* Lake Geneva The largest Alpine lake in Europe, Lake Geneva, is crescent-shaped and lies between Switzerland and France. Geneva and Lausanne are the largest lakeside cities.
* Lake Constance Lake Constance borders Switzerland, Germany, and Austria. The lake stores and reflects heat, contributing to the mild climate along its shores.
* Lake Como In Lombardy, northern Italy, Lake Como is known for its natural beauty and villas. Noted lakeside resorts include Como, Lecco, Bellagio, Tremezzo, Menaggio, and Varenna.
* Lake Lugano A lake between Switzerland and Italy.
* Lake Maggiore Bordering Switzerland and Italy.6 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
Why do Alpine lakes often have clear or turquoise water?
Alpine lakes often exhibit clear or turquoise waters due to the presence of rock flour, a fine-grained sediment produced by glacial erosion. This sediment, composed of tiny particles, remains suspended in the water for extended periods and is responsible for the green color of Alpine lakes. Additionally, the water composition of Alpine lakes is generally uniform, with bicarbonate being the primary constituent. Color shifts, ranging from blue to green or olive-brown, occur due to varying amounts of humic substances from organic decay.
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How do Alpine lakes influence the local environment and tourism?
Alpine lakes significantly influence their local environments and economies. These lakes, nestled within the Alps, attract considerable tourism due to their magnificent scenery. However, the influx of tourists and settlements has led to water pollution and degradation of the Alpine environment, including slope erosion and waste issues.
These lakes also play a crucial role in regulating the local climate. They store heat, cooling the air in summer and warming it in winter, which results in lake-effect snowbelts and modifies regional weather patterns. Eutrophication, caused by increased nutrient pollution, poses a threat to the water quality, endangering aquatic life and affecting the suitability of the water for recreational use.
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Alpine lakes, the 11 significant European lakes fringing the great mountainous mass of the Alps. Set in magnificent scenery, they are the focus of considerable settlement and a thriving tourist traffic as well as being of great scientific interest.
Most of the Alpine lakes lie in valleys that were formed during the uplift of the mountain chain of the Alps. During the Ice Age of the geologically recent Pleistocene Epoch (i.e., less than 2.6 million years ago), glaciers flowed through these valleys, deepening and excavating the ground, and leaving moraines (deposits of waste material) when they shrank at the end of the glacial period. Water filled up the excavations or was dammed up by the moraines.
The lakes that originated in mountain valleys are long and narrow and are generally very deep. In some cases, the glaciers advanced from the Alps into the adjacent plains, where they began to diverge fanwise. In such cases, the end of the associated lakes broadens or bifurcates.
The lakes are divided into a northern and a southern group by the Alpine watershed running from west to east. The southern group, which lies in an Alpine environment, is made up of Lake Geneva and the Insubrian lakes (Maggiore, Lugano, Como, and Garda). Parts of the northern lakes (Lakes Neuchâtel, Luzern, Zürich, Constance, Chiemsee, Attersee) are situated in the foothill zone of the Alps or even some distance beyond.
Scientific study of Alpine lakes started in Switzerland, with F.A. Forel, who studied the stationary oscillations of the water level (seiches) caused by the wind and also made classic observations on the interrelationship between physical and biological processes in lakes. In his work Le Léman (1892–1904), he created the term limnology to characterize the comprehensive study of lakes.
In the lakes of the Eastern Alps the phenomenon of the thermocline (zone of rapid decrease of lake temperature below the warm surface stratum in summer) was first studied in the Wörther See (1891). In the same lake, in 1931, it was discovered that there was an absence of total water circulation during the winter in lakes with wind-sheltered sites. These lakes were henceforth characterized as being of meromictic type. The currents caused by the Rhine’s flow through Lake Constance were investigated in 1926. The increasing pollution of Lake Zürich brought attention to chemical and biological changes, and, by the late 20th century, a number of institutes were studying the pollution of the Alpine lakes.
The water composition of the Alpine lakes is quite uniform. The chief constituent in solution (up to 96 percent) is bicarbonate associated with calcium or, to a lesser degree, with magnesium. Different amounts of brown humic substances (derived from organic decay) cause colour shifts from blue toward green to olive or brown-green. About 100 years ago almost all the Alpine lakes were poor in plant nutrients, especially in phosphates. During the 20th century, however, many lakes were manured and otherwise polluted by the water wastes from households and hotels. The phosphorus content increased, causing algae known as phytoplankton to multiply, in a process called eutrophication. The extreme growth of phytoplankton under these conditions makes the water turbid and less suitable for bathing. It also intensifies oxygen consumption in the deep layers of the lake as a result of the increased decomposition of dead algae. In extreme cases the spawn of some fish species developing near the bottom can be endangered.
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Two methods are used to correct eutrophication. In Switzerland organic substances are removed by mechanical and biological purification, and phosphate is eliminated through additional treatment. In Germany pipelines around the lake borders collect the waste water from catchment areas.