Kelimutu lake, the Changing color lake

Indonesia is a vast archipelagic country. Indonesia consists of clusters of islands in which there are various beautiful places without equal. Mountains, hills, beaches, rivers, and seas are widely spread on Indonesian earth.

One of the active volcanoes in Indonesia is on Flores Island, East Nusa Tenggara. This is what is called Kelimutu Mountain in Pemo Village, Kelimutu District, Ende Regency.

This mountain has a beautiful 3-color lake named Lake Kelimutu.

Indonesia is one of the most volcanically active countries in the world because of its tectonic instability. But on the other hand, the soil is also very fertile because of the volcanic activity itself. The islands of Indonesia have hundreds of mountains, most of which are active and inactive volcanoes. One of the most famous is Kelimutu, a popular volcano with three lakes at its peak that can change color from green to blue, black or red.

Kelimutu is a passive degassing volcanic mountain located in the center of the Indonesian island of Flores. It is 1,690 meters (5,544 ft) high at the top

Kelimutu is close to the small town known as Moni and is about 50 kilometers east of Ende. The Kelimutu mountain lake tour is part of the Kelimutu National Park. This tourist park has flora such as pine, casuarinas, redwood and Edelweiss, which are hardly found anywhere else on Flores Island.

There is an interesting part of the Flores mountain, which is covered on one side of the pine forest while the other side is dry with sand and very unstable soil. Mount Kelimutu is considered sacred by the local people and is believed to be able to give fertility to nature.

Kelimutu is famous for its three crater lake peaks that are attractive to both tourists and geologists due to their unique changeable colors even though they are located on the same volcano

The most western of the three lakes is, Tiwu Ata Mbupu (TAM) or "Lake where the souls of parents who have died," which are usually blue. The other two lakes, "Tiwu Nuwa Muri Koo Fai" (TiN), or which means "Lake is where the souls of Young Men and Women are," and Tiwu Ata Polo (TAP), or "the place of the souls of the deceased people who during their lives often do crime, "separated by a towering crater wall with a minimum height of 35 meters (115 feet) above its surface. The water in the lake is usually green or red each.

The color of the lake varies or changes periodically and is a very popular tourist attraction. According to the manager of the Kelimutu National Park and tourist guidebooks, the change in the color of the lake is the result of chemical reactions that occur due to minerals present in water and gas from volcanoes. This explanation, however, is deemed inappropriate according to geologists.

The earliest research on lake Kelimutu was carried out by the French naturalist LeRoux who gave a description in his travel records in 1896. No further significant studies were carried out to understand this phenomenon further until the end of the 20th century

After LeRoux, a Dutch colonial geologist, Kemmerling conducted a more comprehensive geological and topographic survey of Kelimutu in 1920 when he traveled down the island of Flores. He reported volcanic activity seen in the form of steam and gas above the TiN coastline. He also reported that 70 years before his visit, the crater wall separating TAP and TiN was as high as the edge of the surrounding crater but had eroded.

Scientists from Wesleyan University, Connecticut, conducted a geochemical survey of lakes and found that the water in each lake was found to be chemically different so as to produce varying colors

During the survey, temperature, pH, and dissolved oxygen content were taken as well as water samples. TAM is a sulfuric-acid volcanic crater lake that was more active in the 1970s than it is today. TAP is an acid-salt lake and is intermediate in volcanic activity. Color changes that often occur are due to changes in the oxidation state of the water.

TiN tends to be cold or cool, acide-brine, crater lakes with exotic sulfur compounds and there may be a number of copper-rich minerals in the sediment. TiN has the largest volcanic activity which includes fluxes of around 85 tons of sulfur dioxide per day.

Simply put, according to Dr. Gregory B. Pasternack of the University of California, lake color changes are similar to how the color of blood looks through our skin. When there is a lack of oxygen, water looks green like a vein on the wrist. Likewise, when a lake is rich in oxygen, it will appear red or blackish.