Evoking intense curiosity among scientists as well as common men, the waters of the famed Lonar lake changed again. The lake that remains greenish has turned to pink this time prompting scientists to begin an investigation into the mysterious cause.
Lonar lake is believed to have been formed when a meteorite crashed into Earth around 50,000 years ago, is a popular tourist destination, and also attracts scientists from across the globe. The lake is reported to be highly alkaline in nature with a pH of 10.5, but is also unique for its high levels of salinity. According to Gajanan Kharat, a member of the Lonar Lake conservation and development committee, the proliferation of special algae in the lake may be responsible for the change in colour.
Lonar lake is what is known as a soda lake similar to that of Lake Urmia in Iran which Kharat also called attention to. The strange geochemistry of such lakes enables the growth of specific types of microorganisms, some of which are not found anywhere else.
As such, some experts have noted that Lonar Lake’s highly alkaline and saline chemistry supports the growth of a family of bacteria known as Halobacteriacaeae. These organisms thrive in highly saline conditions, producing a red pigment that absorbs sunlight and converts it into energy. When they proliferate in large amounts, the water body that they are in may take on a reddish hue.
Scientists have hypothesised that the change in colour may be due to a particular microalgae known as Dunaliella salina that usually appears green. However, in an environment of high salinity and increased light intensity, it can turn red through the production of protective cartenoids – the same pigment found in carrots.
Lonar Lake is designated as a national geo-hertiage monument, and regarded as the world’s largest basaltic impact crater. According to some reports, the asteroid that formed the crater may have been travelling at a speed close to 90,000 km per hour when it struck the Earth’s surface. The diameter of the lake is reported to be 1.2km, with the crater in which it sits having a diameter of 1.8km.
Although scientists have noted that this isn’t the first time the lake has changed colour, they did express surprise at the intensity of the phenomenon this time around.