Lake Toba

Lake Toba, also known as Toba, is a supervolcano and lake that is located in Indonesia on the island of Sumatra. The volcano reaches an elevation of 2,953 feet and the lake stretches across an area of sixty-two miles and is the largest volcanic lake on earth. Toba holds a caldera complex that is comprised of four volcanic craters that overlap each other, the youngest of which is noted as the largest Quaternary caldera. Visible features within the lake include three craters, four cones, and four stratovolcanoes.

A massive earthquake is thought to have been produced from Lake Toba between 69,000 and 77,000 thousand years ago, known as the Toba eruption or the Toba event. Based on the Toba catastrophe theory, this eruption affected the entire earth, killing most of the human population and creating a population bottleneck in eastern areas of India and Africa. This theory suggests that this is the source of genetic structures today, although the theory is not widely supported due to lack of evidence regarding other species. However, it has been accepted that the eruption caused a volcanic winter, during which time global temperatures would have decreased by 5 to 6 °F. The eruption was thought to have occurred during the summer and it may have caused the die-off of plants in the area and around the world.

Toba has produced many small eruptions since the Toba eruption, including one that created the small cone known as Pusukbukit and several lava domes. The most recent eruption is thought to have occurred at the northwestern edge of the caldera at Tandukbenua, where a lack of vegetation suggests the eruption happened in the last few hundred years. Recent activity includes earthquakes and an uplift of some areas of the caldera.

Lake Toba and its surrounding area hold a variety of plant life including phytoplankton, floating macrophytes, and Sumatran tropical pine forests. The Lake holds many species of bethnic animals like zooplankton, but it does not support many fish species because the water is low in nutrients. Native fish species include the Batak fish, which is threatened by pollution, siltation, and invasive species, and Homaloptera gymnogaster, Channa striata, and Monopterus albus.

Image Caption: Lake Toba. Credit: Pasadena12/Wikipedia (CC BY-SA 3.0)

Lake Toba

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