In an interesting phenomenon, the 56,000-year-old Lonar crater sanctuary lake in Buldhana district has turned dark pink, almost red, and raised quite a few eyebrows within the forest department, scientists, and nature lovers.
The 77.69 hectare lake area is part of the Lonar sanctuary, which is spread across 3.66 sqkm. It is famous as the world’s largest basaltic impact crater. Two similar ones are in Dhala and Ramgarh, in Madhya Pradesh and Rajasthan, respectively. MN Khairnar, deputy conservator of forests (wildlife), Akola, said, “We are observing this for the first time. We will collect samples of the lake water for testing to zero in on what is behind the occurrence. These samples will be sent to National Environmental Engineering Research Institute in Nagpur, and Agarkar Research Institute in Pune.”
Additional principal chief conservator of forest & Melghat Tiger Reserve field director MS Reddy said that a similar phenomenon takes place in Umria lake in Iran, which is well documented. Scientists studying that have concluded that during dry seasons, water level goes down, thus increasing the salinity of water and making it warm too. This becomes the breeding ground for Dunaliella algae.
“This algae, under such circumstance, turns red in colour. The halobacteria also uses a red pigment to absorb sunlight and convert it to energy. This also turns the water red,” he added.
“With monsoon, the water level will increase and water temperatures will go down taking the lake water back to its normal colour,” Reddy said.
However, Harish Malpani, head, department of microbiology, RLT College of Science, Akola, said, “Halobacteria is not harmful to humans but its presence needs to be established. Sudden change in colour of water is strange. It might be because of microbial activities or human interference. Research should be conducted before making any comment.”
“The reason for the unique colour is still not fully understood by scientists, although many suspect it has to do something with the presence of Dunaliella salina microalgae,” said Arun Mapari, an activist fighting to save Lonar.