A 50,000-year-old crater lake in western India has left scientists baffled after it mysteriously changed colour to pink.
Lonar Lake’s colour shift occurred over the span of a few days and became reddish-pink on June 10.
The new colour lasted for 16 hours and the lake slowly turned back to its usual green.
The two videos show the difference in colour, one showing the lake's strikingly pink colour, the other shows the lake returning to its natural green.
According to NASA Earth Observatory, the colour change was probably caused by microscopic life that responded to stressful environmental conditions.
A unicellular green algae called Dunaliella salina, which is present in many water bodies, is green when “water conditions are favourable.”
Harsh conditions such as surging saline concentration of water or exposure to a lot of light may cause these algae to produce protective carotenoids, such as the orange-red beta carotene, which may turn the water pink.
The water levels at Lonar Lake depleted due to evaporation caused by the dry weather in June.
That may have resulted in more salinity and triggered a change of colour is the theory.
Lonar Lake was formed 50,000-years-ago after a high-velocity meteor struck the Earth's surface.