Blue Lake in Australia

　　Blue Lake is a volcanic lake situated in a low volcanic crater of an extinct volcano at Mount Gambier in South Australia. It is a monomictic lake with an average depth of 72 meters, reaching up to 75 meters in some areas. The lake is remarkable for its dramatic color changes throughout the seasons. From November to February, during Australia’s spring and summer, it displays a vibrant turquoise-blue hue, while from March through October, covering autumn and winter, it shifts to a somber deep greenish-gray blue.

　　The reason behind this phenomenon remains inconclusive, but the most widely accepted theory is that during summer, the surface water temperature of around 20 degrees Celsius causes calcium carbonate to separate from the water, forming tiny microcrystals. These crystals scatter sunlight, resulting in the brilliant blue color. In winter, the lake water becomes thoroughly mixed, producing the darker greenish-gray blue. Additionally, the angle of sunlight and the seasonal activity of plankton in the lake may also contribute to these color variations.

　　Blue Lake Must-visit reason: The most magical color-changing lake Continent: Oceania Country/Region: Australia State/Province: South Australia City: Mount Gambier