A 50,000-year-old crater lake in western India has left scientists baffled after it mysteriously changed colour to pink.<br /><br />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. <br /><br />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.<br /><br />According to NASA Earth Observatory, the colour change was probably caused by microscopic life that responded to stressful environmental conditions.<br /><br />A unicellular green algae called Dunaliella salina, which is present in many water bodies, is green when “water conditions are favourable.” <br /><br />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. <br /><br />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.<br /><br />Lonar Lake was formed 50,000-years-ago after a high-velocity meteor struck the Earth's surface.
