Antarctic Circle

Antarctic circle

axial tilt vs tropical and polar circles

Antarctic Circle Icberg

Antarctic Circle

The Antarctic Circle is one of the five major circles of latitude that mark maps of the Earth. It is the parallel of latitude that runs 66°33′45.9″ south of the Equator. The Antarctic Circle is the most southerly of the Earth's major circles of latitude, lying immediately north of the continent of Antarctica. It marks the boundary between the Southern Temperate Zone and the Antarctic, the region of the Earth surrounding the South Pole.

Geography and Environment

The Antarctic Circle is an imaginary line that encircles the globe, but its position is not fixed. Due to changes in the Earth's axial tilt, the location of the Antarctic Circle slightly migrates over time. The area south of the Antarctic Circle is a cold, icy wilderness covered by the Antarctic ice sheet, the largest single mass of ice on Earth. This region experiences extreme weather conditions and significant variations in daylight hours, ranging from continuous daylight in summer to continuous darkness in winter.

Daylight and Darkness

One of the most remarkable phenomena observed within the Antarctic Circle is the occurrence of continuous daylight or midnight sun during the summer months, and continuous darkness or polar night during the winter months. This is due to the Earth's tilt and its orbit around the Sun. When the South Pole is tilted towards the Sun, regions within the Antarctic Circle experience a period of 24-hour daylight. Conversely, when the South Pole is tilted away from the Sun, the Antarctic Circle undergoes a period of 24-hour night.

Climate

The climate within the Antarctic Circle is predominantly polar, characterized by freezing temperatures, strong winds, and heavy snowfall. The interior of Antarctica is colder than its coastlines, with temperatures reaching as low as −80 °C (−112 °F) in winter. The coastal regions are slightly warmer but still extremely cold, with temperatures just below freezing in summer.

Flora and Fauna

Despite the harsh conditions, life exists within the Antarctic Circle. The region's biodiversity is primarily found in the coastal areas and includes species such as penguins, seals, and various seabirds. The Southern Ocean, which surrounds Antarctica, is rich in marine life, including krill, which is a crucial part of the Antarctic food chain. Terrestrial plant life within the circle is limited to species such as mosses, lichens, and algae due to the extreme climate.

Human Presence

Human activity within the Antarctic Circle is limited due to the extreme environment. It includes scientific research stations from various countries, which are staffed by scientists and support personnel who live there on a temporary basis. The Antarctic Treaty System regulates international relations with respect to Antarctica, banning military activity and protecting the continent's ecozone. Tourism is controlled and minimal, with visitors coming to see the unique landscape and wildlife.

See Also

• Arctic Circle
• Polar regions of Earth
• Geography of Antarctica
• Climate of Antarctica