The recent news has been dominated by an interesting phenomenon, taking place in the Lonar Lake of Buldhana district, Maharashtra. In a span of few days, the lake water has taken on a reddish hue. This triggered interest within the local administration and led them to ask the National Environmental Engineering Research Institute (NEERI), Nagpur, to investigate the cause.
Key Observations from Lonar Lake
A noticeable shift was identified in the colour of the water in Maharashtra’s Lonar Lake, more commonly known as the Lonar Crater. This change, however, seems to be a normal occurrence when the lake receives rainwater.
Identifying Probable Causes
Several theories have been put forward to explain this change.
Algal Bloom
Algal bloom, a term used to describe the rapid increase or accumulation of algae in freshwater or marine water systems, is often indicated by a change in the water’s colour. The switch to a red colour is primarily considered to be due to the algal bloom in the lake, particularly around monsoon season.
Change in Salinity
Salinity levels in the water have risen due to evaporation. This increase in saltiness is also considered to be another factor influencing the change in colour of the lake water.
Biological Change
Another cause for the colour transformation appears to be a biological one. During the lockdown period, the Lonar crater experienced no disturbances, and this could have contributed to the natural shift in colour.
About Lonar Lake
The Lonar Lake, or Lonar crater, is an officially recognized National Geo-heritage Monument. It is a saline and soda lake located in the Buldhana district of Maharashtra.
Geo-Heritage Significance
Geo-heritage refers to geologically significant features that either have intrinsic or cultural importance. These features allow insight into the earth’s evolution, history of earth science, or can be used for educational purposes. The Geological Survey of India (GSI), the parent body, constantly works towards the identification and protection of such geo-heritage sites.
The Lonar Lake is situated inside the Deccan Plateau, a large plain of volcanic basalt rock formed due to eruptions. It is estimated to have been created over 52,000 years ago due to a meteorite collision. Formed in a basaltic rock, the crater spans 1.85 km in diameter and has a depth of 500 feet.