Source: PIB
Why in News?
A recent study conducted by the Agharkar Research Institute (ARI) and the National Centre for Earth Sciences has shed light on significant climate shifts in the Kaas Plateau during the Early-Mid-Holocene and late Holocene Periods.
The researchers studied the sediments of a seasonal lake to understand and decipher the past climate of the Kaas Plateau.
What is Kaas Plateau?
- The Kaas Plateau, located in Maharashtra's Satara district, is a UNESCO World Natural Heritage Site and a designated biodiversity hotspot.
- Known as Kaas Pathar in Marathi, its name is derived from the Kaasa tree, botanically known as Elaeocarpus glandulosus (rudraksha family).
- The plateau has various seasonal flowers forming a floral carpet over the entire lateritic crust during August and September.
What are the Key Findings of the Study?
Ancient Lake and Environmental Preservation:
The present "Flower Wonder" of the Kaas Plateau is located on an ancient lake that dates back to the Early-Mid-Holocene period, approximately 8000 years ago.
The seasonal lake has been preserved over a long time and provided valuable insights into the past climate of the region.
Climate Shifts during the Early-Mid-Holocene:
- Around 8664 years ago, there was a change in the climate from freshwater to drier conditions with low rainfall.
- Pollen and diatom data indicated a major shift in the Indian summer monsoon activity during this time.
- Despite the drier conditions, there were intermittent humid periods suggested by a significant rise in the number of diatoms.
Late Holocene Climate Changes:
During the late Holocene, approximately 2827 years ago, there was a decrease in rainfall and a weakened Southwest Monsoon.
Recent Environmental Impact:
- Over the last 1000 years, there is evidence of Lake Eutrophication, indicated by the presence of high numbers of planktonic and pollution-tolerant diatom taxa.
- Eutrophication is the process of a water body becoming overly enriched with minerals and nutrients which induces excessive growth of algae or algal bloom, thereby, leading to oxygen depletion of the water body.
- Human activities, including agriculture and cattle/livestock farming in the catchment area, likely contributed to this environmental impact.
Monsoon Intensity and Duration:
The southwest monsoon intensified during the Early Holocene, around 8000 years ago.
The northeast monsoon relatively weakened around 2000 years ago.
It is likely that the 'Flower Wonder' of the Kaas Plateau existed for a longer duration, up to March-April, during the early–mid-Holocene (8000–5000 years), when the monsoon rainfall was more abundant, with more than 100 rainy days.
